Exploring the World of Reptiles and Amphibians

Exploring the world of REPTILEs AND AMPHIBIANS Copyright © 2009 The Brown Reference Group plc All rights reserved. No...

Author: Jen Green | Richard Spillsbury | Patricia Taylor

500 downloads 2737 Views 133MB Size Report

This content was uploaded by our users and we assume good faith they have the permission to share this book. If you own the copyright to this book and it is wrongfully on our website, we offer a simple DMCA procedure to remove your content from our site. Start by pressing the button below!
Report copyright / DMCA form

DOWNLOAD PDF

Exploring the world of REPTILEs AND AMPHIBIANS

Copyright © 2009 The Brown Reference Group plc All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For information contact: Chelsea House An imprint of Infobase Publishing 132 West 31st Street New York, NY 10001 Library of Congress Cataloging-in-Publication Data Green, Jen. â•‡ Exploring the world of reptiles and amphibians / authors, Jen Green, Richard Spilsbury, Barbara Taylor. â•‡â•‡â•‡â•‡â•‡â•‡ p. cm. â•‡ Includes index. â•‡ ISBN 978-1-60413-256-4 (hardover) â•‡ ISBN 978-1-4381-2543-5 (e-book) 1. â•‡ Reptiles—Encyclopedias, Juvenile. 2. â•‡ Amphibians— Encyclopedias, Juvenile. â•‡ I. Green, Jen. II. Spilsbury, Richard, 1963- III. Taylor, Barbara, 1954- IV. Title. â•‡ QL644.2.G737 2009 â•‡ 597.9—dc22

Chelsea House books are available at special discounts when purchased in bulk quantities for businesses, associations, institutions, or sales promotions. Please call our Special Sales Department in New York at (212) 967-8800 or (800) 322-8755.

You can find Chelsea House on the World Wide Web at http://www.chelseahouse.com

Printed and bound in China For The Brown Reference Group plc

Project Editor: Sarah Eason Designer: Paul Myerscough Picture Researcher: Maria Joannou Indexer: Angela Anstey-Holroyd Cartographer: Darren Awuah Design Manager: David Poole Managing Editor: Miranda Smith Editorial Director: Lindsey Lowe Consultant Editor John P. Friel, Ph.D. Curator of Fishes, Amphibians and Reptiles Cornell University Museum of Vertebrates Ithaca, New York Authors Jen Green; Richard Spilsbury; Barbara Taylor

Contents Introducing reptiles and amphibians Reptile and amphibian family tree

8 10

Adder African sand snakes Alligator snapping turtle Alligators American alligator American bullfrog Anaconda Armadillo lizard Asian horned frog Australian toadlets Australian water-holding frog Axolotl Blind snakes Blue-tongued skink Boas Bush squeaker Bushveld rain frog Caecilians Caiman lizard Caimans Cane toad Cape skink Chameleons

12 16 18 22 24 28 30 34 36 38 42 44 46 48 5â†œ2 56 58 60 64 66 68 72 74 80 82 86

Clawed toads Cobras Common frog

Common toad Congo eels Copperhead Coral snakes Crocodiles Darwin’s frog Dragon lizards Eastern box turtle Eastern newt Edible frog Eyed lizard File snakes Fire salamander Fire-bellied toads Flying frogs Flying lizards Frogs and toads Galápagos giant tortoise Garden lizard Garter snakes Geckos Gharial Ghost frogs Giant galliwasps Giant plated lizard Giant salamanders Glass frogs Glass lizards Golden-tailed gecko ˘

88 90 92 94 98 102 104 108 1â†œ1â†œ0 1â†œ1â†œ2 1â†œ1â†œ4 1â†œ1â†œ6 1â†œ1â†œ8 122 124 126 128 134 138 140 144 148 150 1â†œ5â†œ2 1â†œ5â†œ4

156 162 164 166

Grass snake Great South American river turtle Green iguana Green toad Green tree python Green turtle Harlequin toads Hellbender Horned lizards House snakes Iguanas Indian cobra Jungle racer Komodo dragon Kuhl’s flying gecko Leaf frogs Leatherback turtle Leopard gecko Leopard tortoise Lizards Loggerhead turtle Malaysian tree toad Mambas Mantellas Marine iguana Matamata Mexican burrowing frog Midwife toads Milksnake

168 1â†œ72 1â†œ74 1â†œ76 1â†œ78 1â†œ82 1â†œ84 186 1â†œ88 1â†œ92

1â†œ94 1â†œ98 200 202 206 208 2â†œ1â†œ2 2â†œ1â†œ4 2â†œ1â†œ6 2â†œ1â†œ8 2â†œ24 2â†œ26 2â†œ28 2â†œ30 2â†œ32 2â†œ36 238 240 242 ˘

Monitor lizards Monkey-tailed skink Mudpuppy Namaqua chameleon Natterjack toad Newts Night lizards Olm Painted turtle Panther chameleon Pipe snakes Plumed basilisk Poison dart frogs

˘

Puff adder Pythons Rain frog Ratsnakes Rattlesnakes Red salamander Reticulated python Rough-skinned newt Salamanders Saltwater crocodile Sand lizards Sandfish Sea snakes and sea kraits Sharp-ribbed newt Sidewinder Sirens

246 250 254 256 258 260 264 266 268 270 272 276 278 284 286 290 294 296 302 304 306 308 3â†œ1â†œ4 3â†œ1â†œ6 3â†œ1â†œ8 320 326 328 330

Skinks Slimy salamander Slow worm Smooth newt Snakes Spadefoot toad Spotted turtle Surinam toad Tegu Terciopelo Thorny devil Tiger salamander Tokay gecko Tomato frog Tortoises Treefrogs Tuatara Turtles Vipers Viviparous lizard Wall lizards Water frogs Whiptails Worm lizards Xenosaurs

332 336 338 340 344 350 352 354 356 358 362 364 366 368 370 374 378 380 384 388 390 394 398 402 406

Glossary Further resources Picture Credits

4â†œ1â†œ0 4â†œ1â†œ3 4â†œ1â†œ4 ˘

INTRODUCINGâ•‹REPTILES AND AMPHIBIANS R

eptiles are some of the most feared animals on this planet. But only a few species are so deadly that they could kill someone. Most would rather run or slither away. What unites them all is that they are all cold-blooded creatures with scaly skin, which they shed to grow and replace worn-out skin. Reptiles cannot regulate their own body temperature, so they bask in the sunlight to warm up. Most reptiles lay eggs on the land, but a few species keep the eggs inside their bodies and then give birth to live young. With the exception of the crocodilians, most reptiles do not care for their young. Like the reptiles, amphibians are cold-blooded animals. They are the link between animals that live in water and those that live on land. The majority

of amphibians start their lives as eggs in the water. The eggs hatch as tiny larvae, which breathe in the water using gills. Through an amazing transformation called metamorphosis, these aquatic larvae become land-dwelling adults that breathe air through their lungs. Most amphibians also have the ability to breathe through their smooth, moist skin. When you read books or surf the Internet to find information about reptiles and amphibians you might come across the word herpetology. Scientists often use this word to describe the study of reptiles and amphibians. Herpetology comes from the Greek word herpeton, meaning “creeping animal.”

Exploring the World of Reptiles and Amphibians

F

rom adders to xenosaurs, these six volumes of Exploring Reptiles and Amphibians contain more than one hundred articles that look at the amazing world of reptiles and amphibians. Some of the articles focus on a single species, such as the Indian cobra or Komodo dragon. Others talk about larger groups of reptiles or amphibians, such as lizards, snakes, or turtles. These overview articles are highlighted in bold typeface within the table of contents for each volume. Each volume has a number of useful features, such as a family tree, which shows how reptiles and amphibians fit into the animal kingdom, how they are related to one another, and provides cross references to articles in this set; a glossary of terms used throughout the set; a further resources page, which includes information about good books to

˘

read or Web sites to visit; and a volume-specific index. Volume 6 contains a complete set index. Within each article you will find a Fact File box, which summarizes the main features of the reptile or amphibian. It provides information about the breeding habits, coloration, diet, size, and status of a reptile or amphibian. Other items include Did You Know? boxes, which highlight some amazing facts about specific reptiles and amphibians, and box features that take a closer look at one interesting aspect of the creature in question. Throughout the book, large, colorful photographs and illustrations increase the reader’s enjoyment and understanding of the world of reptiles and amphibians.

Family ties

A

bove each Fact File in every article there is a color bar that highlights in which particular group the reptile or amphibian belongs. There are four main groups of reptiles: crocodilians; snakes and lizards; turtles, terrapins, and tortoises; and tuataras. So there are four color codes for the reptiles. Amphibians are divided into three main groups: frogs and toads; newts and salamanders; and the wormlike caecilians. So there are three color codes for the amphibians. Just look at the color code to figure out in which group the animal belongs.

CROCODILIANS

FROGS AND TOADS

SNAKES AND LIZARDS

NEWTS AND SALAMANDERS

turtles, terrapins, tortoises

CAECILIANS

TUATARAS

World Conservation Union (IUCN) The World Conservation Union (IUCN) is the largest and most important conservation organization in the world. It aims to protect the natural world by promoting the conservation of animals and plants that are threatened with extinction. A living creature may be placed in one of the following categories in the IUCN Red List of Threatened Species: Extinct—there is no reasonable doubt that the last member of the species has died Extinct in the wild—the species survives only in captivity, in cultivation, or as a population well outside its past range Critically endangered—facing an extremely high risk of extinction in the wild Endangered—facing a very high risk of extinction in the wild Vulnerable—facing a high risk of extinction in the wild Near threatened—likely to qualify for a threatened category in the near future Least concern—is not threatened Data deficient—there is not enough information available to make an assessment

The IUCN status for the reptiles and amphibians in this book is highlighted at the foot of the Fact File panel in every entry.

Classifying reptiles and amphibians Scientists like to group reptiles and amphibians into categories in which all the animals share certain body features. This is called classification. Animals that share body features are likely to be closely related because they have similar genes, which are the instructions found inside cells that tell the animal what to do. The family tree overleaf shows the relationships between all the different reptiles and amphibians. All the reptiles belong to the class Reptilia, while all the different amphibians belong to the class Amphibia. Scientists divided each class into several large groups, called orders, which contain more closely related reptiles or amphibians. In turn, each order comprises smaller groups called families. Families contain genus groups, which are collections of species—the smallest family unit. Reptiles or amphibians belonging to the same species can breed to produce offspring.

˘

REPTILE AND AMPHIBIAN FAMILY TREE Animals with a backbone (PHYLUM Chordata, SUBPHYLUM Vertebrata)

ANIMAL KINGDOM (Animalia)

The numbers below refer to volume and page numbers where a particular animal or group of animals is discussed in an article.

CROCODILIA

(Alligators 1:18; Crocodiles 2:26)

CLASS: BIRDS (Aves) REPTILES (Sauropsida) AMPHIBIANS (Amphibia) FISH (Osteichthyes—bony fish, Chondrichthyes— cartilaginous fish) MAMMALS (Mammalia)

ALLIGATORS (American alligator 1:20; Caimans 1:62)

REPTILES

CROCODILES (Gharial 3:8; Saltwater crocodile 5:38)

TUATARAS (6:34) (Lizards 4:10)

SAURIA SQUAMATA

(Snakes 5:68)

SERPENTES WORM LIZARDS (6:58)

CHELYDRIDAE (Alligator snapping turtle 1:14) CHELIDAE (Matamata 4:28)

TESTUDINES

(Turtles 6:36, terrapins, tortoises 6:26)

CHELONIIDAE (Green turtle 3:42; Loggerhead turtle 4:16) DERMOCHELYIDAE (Leatherback turtle 3:72)

AMPHIBIANS

EMYDIDAE (Eastern box turtle 2:36; Painted turtle 4:60) PELOMEDUSIDAE (Great South American river turtle 3:32; Spotted turtle 6:8) TESTUDINIDAE (Galápagos giant tortoise 2:62; Leopard tortoise 4:8)

CAECILIANS (1:56) ANURA

(Frogs and toads 2:56) Ambystomidae (Axolotl 1:40; Tiger salamander 6:20) Congo eels 2:18 Giant salamanders 3:16 (Hellbender 3:46)

CAUDATA

(Newts 4:52 and salamanders 5:32)

Newts 4:52 Salamandridae (Eastern newt 2:38; Fire salamander 2:46; Rough-skinned newt 5:30; Sharp-ribbed newt 5:50; Smooth newt 5:64) Plethodontidae (Red salamander 5:26; Slimy salamander 5:60) Proteidae (Mudpuppy 4:46; Olm 4:58)

10 6

AGAMIDAE (Dragon lizards 2:32; Garden lizard 2:66; Flying lizards 2:54; Thorny devil 6:18) ANGUIDAE (Giant galliwasps 3:12; Glass lizards 3:24; Slow worm 5:62) CHAMELEONS 1:70 (Namaqua chameleon 4:48; Panther chamelon 4:62) CORDYLIDAE (Armadillo lizard 1:30) GECKOS 2:72 (Golden-tailed gecko 3:26; Kuhl’s flying gecko 3:66; Leopard gecko 3:74; Tokay gecko 6:22) GERRHOSAURIDAE (Giant plated lizard 3:14) IGUANAS 3:54 (Green iguana 3:34; Horned lizards 3:48; Marine iguana 4:24; Plumed basilisk 4:68) LACERTIDAE (Eyed lizard 2:42; Sand lizards 5:40; Viviparous lizard 6:44; Wall lizards 6:46) NIGHT LIZARDS 4:56 SIRENS 5:54 SKINKS 5:56 (Blue-tongued skink 1:44; Cape skink 1:68; Monkey-tailed skink 4:42; Sandfish 5:42) TEIIDAE (Caiman lizard 1:60; Jungle racer 3:60; Tegu 6:12; Whiptails 6:54) VARANIDAE (Komodo dragon 3:62; Monitor lizards 4:38) XENOSAURS 6:62

BLIND SNAKES 1:42 BOAS 1:48 (Anaconda 1:26) COLUBRIDAE (African sand snakes 1:12; Garter snakes 2:68; Grass snake 3:28; House snakes 3:52; Milksnake 4:34; Ratsnakes 5:18) ELAPIDAE (Cobras 2:10; Indian cobra 3:58; Coral snakes 2:22; Mambas 4:20; Sea snakes and sea kraits 5:44) FILE SNAKES 2:44 Arthroleptidae (Bush squeaker 1:52) Bombinatoridae (Fire-bellied toads 2:50) Bufonidae (Cane toad 1:64; Common toad 2:16; Green toad 3:36; Harlequin toads 3:44; Malaysian tree toad 4:18; Natterjack toad 4:50) Ghost frogs 3:10

PIPE SNAKES 4:64 PYTHONS 5:10 (Green tree python 3:38; Reticulated python 5:28) VIPERS 6:40 (Adder 1:8; Copperhead 2:20; Puff adder 5:8; Rattlesnakes 5:20; Sidewinder 5:52; Terciopelo 6:14)

Glass frogs 3:22 Mantellas 4:22 MEGOPHRYIDAE (Asian horned frog 1:32) Microhylidae (Bushveld rain frog 1:54; Tomato frog 6:24) Midwife toads 4:32 Myobatrachidae (Australian toadlets 1:34) Pipidae (Clawed toads 2:8; Surinam toad 6:10) Poison dart frogs 4:70 Rain frog 5:14 Rhacophoridae (Flying frogs 2:52) Rhinodermatidae (Darwin’s frog 2:30) RHINOPHRYNIDAE (Mexican burrowing frog 4:30) Spadefoot toad 5:74 Tree frogs 6:30 (Australian water-holding frog 1:38; Leaf frogs 3:68) Water frogs 6:50 (American bullfrog 1:24; Common frog 2:14; Edible frog 2:40)

11 7

ADDER The adder is the only venomous snake in Britain and northern Europe. This shy northern viper is one of the world’s most successful snakes, found living throughout Europe and Central Asia. It can even survive in the extreme cold of the Arctic.

12

Snakes and Lizards

A

dders can be found living in many habitats, including moors and heaths, mountains, woodland clearings, and even grassy banks beside railway lines. The number of adders in a habitat depends on how much prey is available, but may be as high as 100 adders per acre. An adder habitat is a dry meadow with lots of bushes and open areas for basking (warming up in the sun). Adders usually bask in a coiled position. At first, they are loosely coiled, with their bodies flattened to absorb as much heat as possible through their undersides. The adders coil more tightly as they warm up.

Colors and Stripes The adder is easy to recognize from the dark, zigzag markings along its back. These marks break up the outline of its body, making it hard to see in the shadow of bushes. One rare form of the adder has a continuous black line along its back instead of the usual zigzag, or sometimes the line may be broken up into separate blotches. There is also an all-black form of the adder. Black adders are more common in colder, northern parts of the adder’s range, particularly on some of the small islands in the Baltic Sea.

Fact File ADDER Vipera berus Family: Viperinae (subfamily Viperinae) Order: Squamata Where do they live?: Europe and Central Asia Habitat: From mountains and moorlands to grasslands and forests Size: Head–body length 24–30 in. (61–76 cm); weight 3.3–4 lb. (1.5– 1.8 kg); females are larger than males Coloration: Dark zigzag stripe on lighter gray or brown background Diet: Reptiles, birds, frogs, small mammals, and invertebrates Breeding: 3–18 young, born after gestation period (pregnancy) of 112 days Life span: About 10 years; possibly up to 20 years Status: Abundant in places

Food and Feeding Adders usually feed on small vertebrates (animals with backbones), such as young birds, lizards, or mice. The adder has a large head and a rounded snout, with a distinct “X” or “V” marking on the top of the head. Adders have vertically slit pupils in each eye.

13

ADDER

DID YOU KNOW? The name adder comes from the Anglo-Saxon word naedre, which means “creeping thing.” Hundreds of adders may hibernate together. A baby adder is about the size and shape of an earthworm when it is born, but it can still give a poisonous bite. An adder’s bite does not usually kill people since its venom is weaker than that of other vipers.

They may ambush or attack prey, keeping very still and then suddenly stretching their head forward to deliver a poisonous bite through hollow fangs. Once they are warm, however, adders often go in search of food, poking their heads into birds’ nests, burrows, and crevices. Sometimes, adders climb into low bushes in search of birds’ nests. With large prey, such as mice, shrews, and voles, the adder bites and then releases the animal, which soon dies from the effects of the poison. The

adder has to follow the scent trail of the dying animal before it can start to feed.

Winter Sleep Adders usually hibernate (go into a deep sleep) through the five coldest months of the year. This sleep can last for up to eight months in the northernmost parts of the adder’s range. Males usually emerge from hibernation earlier than females. Both males andâ•‚females shed their dull winter skin after hibernation. The males follow the scent trails left by the females to find a mate.

When an adder strikes its prey, it delivers a dose of venom through its hollow fangs. It waits for the venom to take effect before swallowing its prey. This avoids injuries caused by struggling with the prey. 14

Snakes and Lizards

Life Cycle The courtship display of the adder consists of the maleâ•‚crawling along the female’s back, rubbing her with his chin. Sometimes, the male has to fight off a rival male before he can mate with the female. Females may also mate with more than one male. Pregnant females spend a lot of time basking, since the warmth of the sun helps the young snakes to develop inside the mother’s body. The duller color of the female helps to protect her from predators, such as birds of prey, while she basks. The female gives birth in late summer. Newborn adders do not feed in the first year of their birth. They can survive on the goodness of the yolk sac stored inside their stomachs. The young adders take about three to four years to mature into adults but onlyâ•‚about 10 percent of them will survive long enough to raise young of theirâ•‚own.

Out in the cold The adder lives farther north in the world than any other species of snake. Adders can survive in cold places partly because of their small size and dark color, which allow them to warm up more quickly in the sun than larger, lightercolored snakes. Female adders also keep their eggs inside their bodies until they hatch. This makes it easier for the females to keep their eggs warm while they develop. They give birth to live snakes, which are more likely to survive in cold places than a clutch of eggs.

Adder Wrestling Match Male adders fight each other to stand a better chance of mating with a female. During this show of strength, the two males twist the front part of their bodies around each other and rear up in the air.

Each male tries to force his rival down to the ground, rather like a wrestling match. The winner is usually the largest adder, which then chases away his rival.

The dark body of the adder helps it absorb as much heat from the sun as possible. 15

AFRICAN SAND SNAKES African sand snakes are alert, fast-moving snakes that hunt during the heat ofâ•‚the day. They can often be seen speeding across roads and tracks in front of vehicles. These common snakes have a strong venom, but they rarely bite people.

16

Snakes and Lizards

W

ith their narrow heads, long tails, and long, slim bodies, African sand snakes move swiftly through their grassland and dry scrubland habitat in search of their prey. These snakes can change direction rapidly and maintain high speeds over long distances. Larger sand snakes can sustain speeds of 6 miles per hour. African sand snakes often raise their heads off the ground to get a better view of their surroundings and can move along in this position as well. African sand snakes hunt mainly lizards. They use their large eyes to track their prey by sight, then chase it down, grip the lizard firmly in their jaws, and kill it with a lethal dose of venom. Some African sand snakes are good climbers and scale bushes to take young birds from their nests. Larger species can overcome prey as large as mice and shrews.

Tails and Scales African sand snakes are one of the few kinds of snakes that can break off their tail to escape from predators such as birds, small mammals and African file snakes, which eat other snakes. Unlike lizards, however, African sand snakes cannot grow a new tail to replace the one they have lost. Another unusual behavior is the way the African sand snakes “polish” their scales by covering them with an oily substance from their nostrils. This may help to seal their scales and protect the snakes from drying out in the scorching heat.

Fact File AFRICAN SAND SNAKES Family: Colubridae; subfamily Psammophinae (23 species) Order: Squamata Where do they live?: Africa, Middle East, and Pakistan Habitat: Tropical grassland, mountain grassland, and dry scrub Size: Head–body length 31 in. to 5.9 ft. (80 cm to 1.8 m) Coloration: Gray, brown, or olive, often with light or dark stripes; some species have intricate markings on head and neck Diet: Lizards, birds, frogs, and small mammals Breeding: Female lays up to 30 eggs, which hatch after 45–70 days Life span: Not known Status: Varies, most species locally common

Sand snakes use their slender bodies to move with great speed. They use their large eyes to track lizards and other prey across the African scrub.

17

ALLIGATOR SNAPPING TURTLE The alligator snapping turtle is the heaviest freshwater turtle. It is named for its powerful snapping jaws and the bumpy ridges on its shell, which look like the big, tough scales on the back of an alligator back.

18

Turtles, Terrapins, Tortoises

T

he muddy-brown color of the alligator snapping turtle camouflages (disguises) it against the bottom of deep, dark, slow-moving rivers. This turtle often feeds during the day and eats almost anything, from fruit and nuts to birds, fish, mammals. Alligator snapping turtles can even overcome and eat smaller turtles, such as the common musk turtle and their smaller relatives, the common snapping turtles. The alligator snapping turtle is a poor swimmer, and it is too big and bulky to chase after its prey. Instead, it is an ambush predator, sitting still and waiting for its prey to pass within reach of its powerful, hooked jaws. This turtle also has a clever way of luring prey into its mouth. By pumping blood into its tongue, it creates a thin red strip, which it moves to make it look like a wriggling worm. When prey animals come to eat the “worm,” the turtle snaps shut its massive jaws. The alligator snapping turtle has a keen sense of smell, which helps it to find the decaying remains of dead animals in the river. It also eats a lot of plant matter, such as acorns and persimmons. It gathers the fruits and nuts as they fall into rivers from trees and bushes overhanging the water.

Fact File ALLIGATOR SNAPPING TURTLE Macroclemys temminckii Family: Cehlydridae Order: Testudines Where do they live?: Central and southeastern North America

Tropic of Cancer

Habitat: Slow-moving rivers Size: Shell length 26 in. (66 cm); weight 219 lb. (99.5 kg) Coloration: Dark brown Diet: Fruit, nuts, shellfish, fish, birds, other turtles, and small mammals Breeding: Up to 50 eggs in a clutch; eggs hatch after 100 days

Eggs and Nests

Life span: 60–100 years

Alligator snapping turtles mate in the spring, between February and April. Mating lasts between five and twenty-five minutes and takes place under the water.

Status: Vulnerable to rare in many places, protected locally

The alligator snapping turtle is one of the largest freshwater turtles in the world. It lives in the rivers and streams of the southeastern United States.

19

ALLIGATOR SNAPPING TURTLE

DID YOU KNOW? Alligator snapping turtles are strong enough to catch prey such as raccoons and wood ducks, dragging them underwater to drown them. One of these turtles was trained to find dead people in the waterways of Indiana. The nest chamber of the alligator snapping turtle may extend more than 12 inches under the ground.

When they mate, the male uses his sharp claws to hold onto the female’s shell and releases a steady stream of bubbles from his nose. If several males gather near one female, they often behave aggressively toward their rivals to drive them away. When the female is ready to lay her eggs, she drags her heavy body out of the water and digs a nesting chamber with her back feet. She starts by digging a large pit and then lowers her body down into the hole. She then digs a smaller hole at the bottom of the large one and lays the eggs there. The female produces one clutch of eggs each year. The number of eggs depends on the size of the female. Larger females lay larger clutches of up to fifty eggs, while smaller ones lay only about ten eggs.

The eggs are hard and round, with smooth shells. Alligator snapping turtles do not look after their nests, which can sometimes be raided by predators such as raccoons.

Baby Turtles It takes about 100 days for the eggs to hatch, and most of the young turtles emerge from their eggs in September or October. Higher nest temperatures cause more females to hatch out of the eggs than males. The hatchlings make their way to the water, where they are often caught and eaten by predators such as alligators, adult alligator snapping turtles, or gar fish.

Mossbacks Many large alligator snapping turtles look like they have green shells and are nicknamed “mossbacks.” The green color is due to a dense covering of algae (not moss). The algae grow when the turtles spend a lot of time in shallow water. Sunlight falls on their backs, warming them up and triggering the growth of the algae. To attract prey, such as fish, the turtle pumps blood into its tongue. This makes the tongue look like a worm, which draws in the fish.

20


fearsome flippers Once they have grown into adults, alligator snapping turtles are very dangerous for people to handle. As well as their strong jaws, these large turtles also have extremely powerful flippers, which end in sharp claws. They can even bite chunks out of boats when people try to lift them on board. Despite the dangers,

alligator snapping turtles were once heavily hunted to make turtle soup. In some areas, hunting continues to be a problem for these formidable reptiles. Water pollution has forced them to change their diet, and the turtle population has also been reduced as people continue to drain rivers and swamps.

21

ALLIGATORS The armor-plated alligators are survivors from a prehistoric age. These fearsome reptiles are members of the crocodile family, along with caimans, crocodiles, and gharials. There are two true alligators alive today—the American alligator and the Chinese alligator.

22

H

ow can you tell an alligator and a crocodile apart? It is not always easy, but when an alligator closes its mouth, all its bottom teeth are hidden. One large bottom tooth can still be seen in the closed mouth of a crocodile. Alligators also usually have wider, shorter, and more rounded snouts than crocodiles. This allows alligators to tackle a wider range of prey, including birds and mammals. Crocodiles have narrow, pointed snouts, which are more suited to eating fish.

Fact File In addition to the physical differences, the two crocodilians have some behavioral differences. Alligators can survive in cooler places than crocodiles. During the winter, alligators become sluggish and rest at the bottom of a waterway or burrow into a riverbank. They only emerge when the weather is warm. Alligators can even survive in the water under a layer of ice, as long as they keep a breathing hole open. Theyâ•‚do lose their appetite in the winter, however, and may stop eating if the temperature is too low for them to digest theirâ•‚food.

Chinese Alligator Smaller than the American alligator, the Chinese alligator lives only in the Yangtze River valley of China. It is critically endangered, with a total population of 150 individuals. Chinese alligators are being bred in captivity in China and overseas, with the hope of returning some captive-born alligators to the wild.

Alligators Family: Alligatoridae Order: Crocodilia Where to they live?: American alligator in the southeastern United States; Chinese alligator in the Yangtze River Valley in China Habitat: Rivers, marshland, and swamps Size: American alligator—Head–body length 13 ft. (4 m); weight 550 lb. (249 kg). Chinese alligator—7 ft. (2.1 m); weight 88 lb. (40 kg) Coloration: Dark green-black; Chinese alligator has lighter patterns Diet: Snails, mussels, clams, fish, turtles, birds, small mammals Breeding: American alligator—30–70 eggs; Chinese alligator—10–50 eggs. Hatchlings emerge after 2 months Life span: 50–80 years Status: American alligator—least concern; Chinese alligator—critically endangered

Alligators and Caimans Alligators are represented by the caimans in both Central and South America. Caimans have the same rounded snouts as true alligators, and their lower teeth are hidden when their mouths are closed. However, caimans are usually much smaller (apart from the black caiman) and have sharper, longer teeth. Most American alligators are pale brown to green. The body of the alligator appears much greener if it lives in water full of algae. 23

AMERICAN ALLIGATOR Once on the brink of extinction, American alligators have made a comeback. They are now a key species in their swampy environment. American alligators use their powerful tails to move swiftly through the water, and they can run faster than a person on the land.

24

crocodilians

A

merican alligators help plants and other animals to thrive by digging “gator holes” using their tail and snout. These deep pits fill with water and provide temporary reservoirs for a variety of wildlife in the dry season. Plants always grow well around “gator holes” because of the rich mud that the alligators dig up and deposit around the edges of the holes. Regular paths worn by alligators also create channels through which water can run into marshlands when it rains heavily.

Lazy Lifestyle American alligators can move quickly over short distances when they have to. Most of the time they float on the surface of the water, looking more like logs than living reptiles. In this lazy position, the alligators can spot and ambush prey. They can also warm up in the sun without leaving the water. They absorb heat into their blood through bony swellings on their back called osteoderms. The dark color of the American alligator also helps it to absorb heat easily, which is especially useful during the colder winter months.

Fact File american alligator Alligator mississippiensis Family: Alligatoridae Order: Crocodilia Where do they live?: Southeastern United States Habitat: Rivers, marshland, and swamps Size: Head–body length 13 ft. (4 m); weight 550 lb. (249 kg) Coloration: Dark green-black Diet: Snails, mussels, clams, fish, turtles, birds, small mammals Breeding: Female lays 30–70 eggs, which hatch after 2 months Life span: 50–80 years Status: No longer endangered— least concern

Teeth and Feeding The mouth of an American alligator contains approximately eighty teeth. As the old teeth wear out or break, new ones growing in the jaw underneath push up to replace them. Teeth last for around two years and are replaced throughout the life of the alligator. The gaping mouth of the American alligator reveals rows of sharp teeth. Alligators open their mouth in this way to cool down in the heat.

25

AMERICAN ALLIGATOR

DID YOU KNOW? The American alligator can run at speeds of up to thirty miles per hour over very short distances. The roar of an American alligator can be heard over one mile away. The American alligator’s eggs will not survive if they are left underwater for more than twelveâ•‚hours.

They grow more slowly in older alligators. Without a mouthful of sharp teeth, older alligators may have difficulty holding on to their prey and may even face starvation. American alligators can kill people. Alligators are not usually a major threat, but now that their numbers have increased, they do come into conflict. Attacks usually happen when alligators are caught unawares or threatened. Older alligators are more likely to attack people as they are an easy target. Feeding alligators is dangerous, since they come to associate people with food.

Courting Gators Male and female American alligators live on their own for most of the year but come together to mate

26

in the spring. Males fight each other to win their own special area, called a territory, and they bellow loudly to attract females. Males also give off a strong, sweet smell, which is very attractive to female alligators. Females visit the territories of several males between March and May. After she has laid her eggs, the female stays close to the nest for about two months, guarding it from raccoons and other predators. When she hears “yipping” calls inside the eggs, she digs them out and carries them to water in her mouth. The hatchlings are about 9 inches long and are more brightly colored than the adults. They stay in a group, called a pod, near to their mother until they are about two years old.

crocodilians

During this time, their mother tries to protect them from predators, such as large male alligators, birds, and fish.

Back from the Brink In the first half of the twentieth century, up to ten million American alligators were killed for their valuable skins. However, the trade in alligator skins, teeth, and meat is now controlled and alligator numbers have increased due to conservation measures. These include taking some eggs from the nests of wild alligators, hatching them on alligator farms, and then returning some of the young alligators back to the wild. There are now more than 150 farms in various states, including Florida, Louisiana, and Texas. Rearing alligators in captivity has helped to increase understanding of their biology. In turn, this has helped to develop better ways of managing wild alligator populations. Better habitat management has made larger areas available to alligators and the wildlife living alongside them. There are still some concerns, however. One problem is water pollution from factories, which has included poisonous metals, such as

mercury. Alligators are at the top of the food chain, so the poisons build up in their bodies as they eat more and more contaminated prey. Since alligators live for such a long time (at least fifty years), the long-term effects are unknown.

Adult American alligators can grow up to 13 feet, but their babies are only 9 inches long when they hatch out.

Dry nest sites In June or July, a female American alligator chooses a dry nesting site near the water. She piles up plant material to a height of about 6 inches. In the middle of this mound of plants, the female digs a hole and lines it with mud. She lays her eggs in the hole and then seals them up inside the mound. As the plants rot, they give off heat, which warms the eggs and helps them to develop. Higher temperatures encourage more male alligators to develop.

Alligators spend most of their time basking in the heat of the sun. 27

AMERICAN BULLFROG American bullfrogs are the largest of all the frogs in North America, with a huge appetite to match their size. Males are famous for their loud, bellowing calls, which they use to attract females to their territory in spring.

28

Frogs and Toads

T

he American bullfrog spends almost all of its life in or near water, floating just below the surface or basking at the water’s edge. These frogs control their body temperature by warming up in the sunlight or cooling down in the shade or in the water. At night, bullfrogs come onto land to forage for food. Bullfrogs are sensitive to danger, however, and will quickly jump into the water if they are disturbed on land. With their heavily webbed back feet, and long, powerful back legs, bullfrogs can swim several feet with just one or two kicks. They can also make huge leaps of 3 to 6 feet to hide among plants on land. In the spring and early summer, male bullfrogs come ashore to call for a mate. The males call the females from the water and mating takes place. The female lays thousands of eggs, which hatch as tadpoles. The tadpoles then gradually change into adults in a process called metamorphosis, which can take up to two years.

Food Feast Bullfrogs eat a variety of prey, including insects, lizards, snakes, and small mammals. They even eat frogs, including other bullfrogs. They are attracted to the distress calls of frogs, probably in the hope of finding an easy meal. Usually, bullfrogs sit and wait for their prey to come within striking range of their long, sticky tongue. They lunge towards their prey and may use their short legs to push food into their mouth.

Fact File AMERICAN BULLFROG Rana catesbeiana Family: Ranidae Order: Anura Where do they live?: North America; introduced into parts of Europe, Central America, and Asia Habitat: Ponds and lakes Size: Snout–toe length 3.5–8 in. (9–20 cm); 36 in. (90 cm) stretched out; weight up to 7.25 lb. (3.3 kg) Coloration: Mottled olive, brown, or green above; legs, chin, and throat have dark markings Diet: Large invertebrates (animals without backbones) and small vertebrates, including other frogs Breeding: Female lays around 11,000 eggs (80,000 in a lifetime), which hatch after 4 days Life span: 5–9 years in the wild; up to 16 years in captivity Status: Least concern

The American bullfrog is a large aquatic frog. Most are green or brown with darker blotches on the back, with a yellow or white underside.

29

ANACONDA Female anacondas are the world’s heaviest snakes— male anacondas are only half the size. These massive snakes live in the lakes, rivers, and swamps of South America. Some are big enough to kill and eat caimans, large turtles, and even small deer.

30

Snakes and Lizards

L

arge adult anacondas are so big that they rely on the water to support their weight. An anaconda’s body may measure as much as 39 inches around its thick coils. Despite their great weight, anacondas are probably not the world’s longest snakes. This record belongs to the reticulated python from Asia, which can measure up to 29.5 feet long.

Dangerous Predator Anacondas are formidable killers. They are ambush predators, lying in wait, ready to strike should any prey stray within range. Once they capture a prey animal, anacondas swiftly wrap their muscular coils around the victim’s body. Then they stop the animal from breathing by squeezing it or pulling it underwater until it drowns. An anaconda usually eats mammals, such as white-tailed deer and large rodents, including the capybara, which is the largest rodent of all. They will also attack much larger animals, even jaguars, if they get the chance. There is a chance that large anacondas will attack people, especially if they live around villages and plantations where they often come into contact with people. After a large meal, an anaconda may go for several months before feeding again.

Fact File ANACONDA Eunectes murinus Family: Boidae Order: Squamata Where do they live?: South America, mostly in the Amazon River and Orinoco River basins Habitat: Rivers, lakes, swamps, and flooded grasslands Size: 16.5–19.75 ft. (5–6 m); weight over 400 lb. (200 kg) Coloration: Greenish with dark oval spots along the back; black line runs from each eye to the jaw Diet: Birds, other reptiles, and mammals Breeding: 10–20 babies born after a gestation period (pregnancy)â•‹of 182–280 days Life span: 10–30 years Status: Common

Mating Games Anacondas mate in water during the dry season, and several males may be attracted to the same female. The jaws of the giant anaconda can open wide to swallow prey much wider than itself. Strong acids in the stomach then slowly digest the meal.

31

ANACONDA

Life cycle When they are born, anacondas are 24–39 inches long. They can eat large prey animals from the start, but they have a more varied diet than their parents. They will eat fish and frogs, as well as

When fully grown, an anaconda’s diet even includes animals as large as turtles.

32

birds and mammals. They grow rapidly, with males being large enough to breed when they are two or three years old. Females grow much larger and take a year or two more to reach this stage.

OW? DID YOU KN Anacondas can go without food for up to three years. Female anacondas can give birth to up to eighty babies at a time! Early Spanish travelers called the anaconda “matatoro,” which means “bull killer.”

Males do not fight for the right to mate as other snakes do, but instead form a mating “ball”. After mating, the female anaconda may eat the smaller males. When one animal eats another animal of the

Snakes and Lizards

same species, it is called cannibalism. It is rare in nature and very unusual among snakes. Cannibalism among anacondas may happen because the pregnant females need food to help them survive without eating for six months until their babies are born. Another idea is that females that are not ready to mate are attracted to the mating balls and take advantage of an easy meal of male anacondas. Big snakes need to eat a lot and it is not always easy for them to find food. After mating, the female stops feeding. Females do not lay eggs. Instead, the young develop inside her body and hatch as live anacondas.

The female basks in the sunlight because the warmth helps the baby anacondas to develop inside her.

Anacondas are constrictors. They can coil their muscular

Other Anacondas

bodies around

The most common anaconda is the green anaconda, described here, but there are two other anaconda species. The yellow anaconda (Eunectes notaeus) is smaller than the green anaconda, reaching lengths of up to 15 feet. It lives in the southwestern parts of the Amazon River Basin. The yellow anaconda is more aggressive than the green anaconda, and it is endangered. De Schauensee’s anaconda (Eunectes deschauenseei) lives in the Guianas and on Ilha Marajó, an island at the mouth of the Amazon River. De Schauensee’s anaconda is extremely rare.

their prey and squeeze it tightly until the animal dies as the internal organs are crushed or it stops breathing. Anacondas sometimes drown their prey by dragging it under the water. When their prey is dead, the snake swallows its meal in one gulp.

33

ARMADILLO LIZARD Like a suit of armor, the back of the armadillo lizard is covered in thick, spiny scales. Just like a real armadillo, this small lizard rolls into a ball to protect its soft belly and holds its tail tightly in its mouth. Predators soon decide to leave this spiny ball alone.

34

Snakes and Lizards

T

he armadillo lizard lives in a dry, semidesert region called Namaqualand in southern Africa. The landscape consists of low, rocky hills surrounded by flat plains of gravel. The armadillo lizard lives in colonies in the rocky hills, hiding away in crevices in the rocks. They move slowly and rarely stray far from their rocky homes. They sit and wait for insect food to pass by, retreating back into cracks in the rocks to escape danger. These lizards roll into an armadillo-like ball if they are caught out in the open.

Lizard Families Armadillo lizards live in family groups. These usually contain about two to six lizards, although groups of up to forty can sometimes be found living together. Larger groups live in big, hard-to-reach cracks in the rocks, while smaller groups live in the narrower cracks formed by piles of smaller rocks. Armadillo lizards living on their own are usually males. In late summer, females usually gives birth to one or two live young. The offspring are born large—about half the length of the adult. The mother looks after her young for the first few months of its life. She may even catch small invertebrates such as insects and spiders and feed them to her young from her mouth. This level of parental care is unusual for a lizard. When the young lizard grows up, it may leave their family group to set up home elsewhere.

Fact File ARMADILLO LIZARD Cordylus cataphractus Family: Cordylidae Order: Squamata Where do they live?: Southwestern area of South Africa Habitat: Rocky places Size: Head–tail length 7 in. (18 cm); weight 8–17 lb. (3.6–7.7 kg) Coloration: Back pale brown, underside yellowish Diet: Insects Breeding: 1 or 2 young Life span: 8–12 years Status: Facing a high risk of extinction in the wild—vulnerable

The armadillo lizard is covered with thick square scales on its back. Short, jagged spikes around the tail make it difficult for predators to tackle.

35

ASIAN HORNED frog The Asian horned frog looks exactly like a dead leaf, so much so that it is almost impossible to see among dead leaves on the rain forest floor. It has a large head, wide mouth, and pointed “eyebrows,” or horns.

36

frogs and toads

A

sian horned frogs are nocturnal amphibians. They hide under logs and rocks during the day and emerge at night to forage for food or look for mates. These frogs have short back legs, and they move by crawling slowly over the forest floor rather than jumping or hopping. If it senses danger, the Asian horned frog crouches down with its legs tucked under its body. In this position, the leaf-shaped back blends in with the leaf litter. This camouflage is extremely effective. The back of the Asian horned frog has ridges that look like leaf veins and black patches that look like the holes in a leaf. It even has small bony lumps that look like the galls made by insects on leaves. When the Asian horned frog spots prey, it leans forward quickly to seize the animal in its huge mouth. It eats cockroaches, snails, and small frogs, as well as young lizards and snakes.

Breeding Pools Asian horned frogs breed in slow-moving forest streams at the start of the rainy season. At night, the males call loudly for females with a loud, metallic honk that can be heard for miles. They call once and then wait for ten minutes or more before calling again. The female lays her eggs in clusters on rocks or roots at the edge of the water. The tadpoles hang from the surface of the water, using their funnel-shaped mouth to feed on small particles of food floating on the water.

Fact File ASIAN HORNED TOAD Megophrys montana Family: Megophryidae Order: Anura Where do they live?: Sumatra, Borneo, and Malaysia Habitat: Tropical rain forests Size: 2.5–5 in. (6.3–12.5 cm), females are almost twice as big as the males Coloration: Brown and black Diet: Large invertebrates (animals without backbones) and small vertebrates, including other small frogs Breeding: Female lays clusters of eggs, which hatch into tadpoles Life span: Not known Status: Common but rarely seen— least concern

The Asian horned frog is named for the large pointed horns, or ridges, over its eyes. This large frog often has a fleshy lump on the end of its snout.

37

AUSTRALIAN TOADLETS Australian toadlets, or southern frogs, are a family of chubby frogs, with large, bulging eyes. The family includes species that swallow their eggs, one that keeps its eggs in hip pouches, and one that raises its young in underground chambers.

38

frogs and toads

A

ustralian toadlets live in a range of habitats in Australia and New Guinea. Species from Queensland and New South Wales in Australia lead secretive lives among the leaf litter and logs on the floor of rain forests. There they find plenty of insects to eat. Many other species, such as the streamlined torrent frogs, live in fast-moving forest streams or behind waterfalls, sheltering in cracks in the rocks. The tadpoles of the torrent frogs have large, suckerlike mouths, which help them to cling to rocks and avoid being swept away by the strong water currents. River floodplains are one of the most typical habitats for Australian toadlets. Many of them burrow under the ground in hot, dry weather and emerge to feed and breed only when it rains. In dry, sandy deserts or sand dunes, Australian toadlets spend most of their lives in underground chambers to prevent their bodies from drying out. They only emerge above ground during cool winter nights to look for food.

Digging Feet Several Australian toadlets are good burrowers and look like the American and European spadefoot toads. Australian burrowing frogs such as the green-striped burrowing frog spend much of the year buried under the surface to escape the heat. When the rains come, the frogs emerge to breed quickly in puddles and flooded claypans (clay layer in the soil). The red-crowned toadlet is named for the bright red T-shaped marking on the top of its head. This toadlet

Fact File AUSTRALIAN TOADLETS Family: Myobatrachidae (122 species) Order: Anura Where do they live?: Australia and New Guinea

Tropic of Capricorn

Habitat: From alpine meadows, rain forests, and woodlands to marshes, streams, and sand dunes Size: Snout–rump length typically ranges between 0.6 and 3.1 in. (1.6 and 7.9 cm) Coloration: Usually gray or brown, often with bright colors in armpits, thighs, or both these areas Diet: Invertebrates Breeding: Eggs laid in water, damp soil or moss and hatch into tadpoles; some tadpoles develop inside their eggs, others in the hip pouches or stomachs of adult Life span: Not known Status: Several species are endangered, vulnerable or threatened; gastric (stomach) brooding frogs may be extinct

lives in a small area around Sydney, Australia.

39

AUSTRALIAN TOADLETS

The most

Musical Males

brightly

At the start of the breeding season, male Australian toadlets call loudly to attract mates. This usually happens at night, and often at the start of the rainy season, although breeding is also related to temperature. Males also call to tell other males to keep out of their special area called a territory. They may even fight each other to win a breeding territory. The names of Australian toadlets sometimes give a clue to the mating calls that they make. For example, the banjo frog makes a “plink” sound like a banjo being played, while the woodworker frog makes a sound like a hammer being tapped on wood. The shoemaker frog has a similar call. Other names that describe the

colored of all Australian toadlets is the corroboree toad.

40

calls of Australian toadlets include the moaning frog, the humming frog, and the trilling frog. After mating, female marsh frogs make “nests” of foam on the water’s surface to protect the eggs from predators until they are ready to hatch. Males often rest underneath the “nests” to guard the eggs from predators. Heleioporus species also make foam nests but not on the surface of the water. Instead, they lay their eggs in burrows or dips in the ground, and the foam probably helps prevent the eggs from drying out. Pseudophryne species also lay their eggs in dips in the ground,

OW? DID YOU KN Male tusked frogs may fight using “false” teeth on their bottom jaws. Males are bigger than females. The turtle frog is one of the few frogs that burrow headfirst, using its front legs to dig. Crinia bilingua is named for its two different types of call— bilingua means “two tongues.” If Australian spadefoot toads are threatened by a predator, they produce a smelly, poisonous chemical that becomes sticky after a few minutes.

frogs and toads

and Bibron’s toadlet often uses horses’ hoofprints. The eggs develop slowly and development may stop in dry weather. As soon as it rains heavily, the tadpoles hatch suddenly and are washed into the nearest pond.

Unusual Tadpoles The Baw Baw frog lays its eggs under the ground in soggy soil or moss, and its tadpoles develop without needing to feed. Other species, including the sandhill frog, have tadpoles that stay inside their eggs until they are fully developed. In three species of Australian toadlets, the parents carry the eggs or tadpoles around with them until they have developed into smaller versions of the adults. Male marsupial frogs have a pair of small pouches on their hips. Female marsupial frogs lay a clump of about ten eggs on land. When the eggs are ready to hatch, the male pushes his way into the middle of the clump of eggs. The tadpoles wriggle their way into his small hip pouches and stay there until they are fully developed. Even more unusual are the two species of gastric-brooding frogs. Females swallow the eggs after the males have fertilized them.

Warning colors Some Australian toadlets are brightly colored to warn predators that they are poisonous. Several Australian toadlets, such as the red-crowned toadlet (pictured above), have bright patches of skin on their undersides. One species called P. corroboree has yellow and black markings like a fire salamander. It gets its name from the “corroborees”—traditional aboriginal ceremonies in which people paint their black skins with stripes of yellow. The sunset frog is covered in orange, red, and blue markings.

The tadpoles develop in the safety of the female’s stomach, and she spits them out when they are fully formed. 41

AUSTRALIAN WATER-HOLDING FROG This frog survives in the harsh desert by burrowing into the soil and forming a cocoon of dead skin that prevents water from escaping from its body. In the outback, Australian Aboriginals dig up the buried frogs and squeeze them to extract the precious water.

42

frogs and toads

T

he Australian water-holding frog belongs to the family of tree frogs, but rather confusingly it lives on the ground not in the trees. This frog has a heavy, muscular body, whereas the typical tree frog has a slim, lightweight body suited for climbing on thin branches. In dry weather, Australian water-holding frogs dig burrows in the soil using the bony spadelike plates on their back feet. The burrows can be up to several feet long. Inside the burrow, the frog keeps the thick layer of dead skin that it sheds each week, building up layer upon layer to form a cocoon around its body. (Most frogs pull off their old skin and throw it away or eat it.) As the layers of skin harden, the frog looks like it is covered in shrink-wrap. The frog loses much less water from its body than it would without its cocoon.

Rain Babies At the start of the rainy season, Australian waterholding frogs dig their way back up to the surface of the soil. The males and females mate, and the female then lays thousands of eggs in shallow pools of water that collect on the flooded ground. The eggs hatch into tadpoles, which mature into young frogs quickly so that they can leave the water before it dries up. The young frogs eat as much as they can before the dry season begins. This helps them to survive up to ten months in their underground burrows while they wait for the start of the next rainy season.

Fact File AUSTRALIAN WATERHOLDING FROG Cyclorana platycephala Family: Hylidae Order: Anura Where do they live?: Northern Australia Habitat: Dry semideserts, woodlands, and grasslands Size: Snout–rump length 2.75–4 in. (7–10 cm) Coloration: Brown and green; dark “mask” from snout to jaw, through eyes, and down side of body Diet: Other frogs and large insects, such as beetles and grasshoppers Breeding: Female lays 100–1000 eggs; sometimes up to 7,000 eggs depending on the conditions Life span: Not known Status: Common—least concern

The Australian water-holding frog has a broad, flat head and muscular body. The skin color varies from dull gray to dark brown or green.

43

AXOLOTL The word axolotl means “water monster,” but there is little to be scared of by these giant tadpoles. Wild axolotls are rare, living only in the mountain lakes of Central Mexico. However, captive axolotls are bred in large numbers for teaching and research.

44

Newts and Salamanders

T

he axolotl is unusual because it is a Mexican mole salamander that has not grown up and changed completely into an adult. As a result, the axolotl retains many of its tadpole features, such as gills outside its body and fins around its tail and along its back. The skin of the axolotl does not look like the skin of an adult salamander and, like a tadpole, it lives in the water. Yet it develops some adult features, such as small lungs inside its body and a reproductive system. If axolotls are injected with body chemicals containing iodine, they will change into adult salamanders. Wild axolotls live in Lake Xochimilco south of Mexico City, which exists as a network of canals and lagoons. As the building up of Mexico City continues, the fate of the axolotl is uncertain.

Fact File AXOLOTL Ambystoma mexicanum Family: Ambystomidae Order: Caudata (Urodela) Where do they live?: Central Mexico Habitat: Mountain lakes Size: Head–tail length 8–12 in. (20–30 cm); weight 11 oz. (312 g) Coloration: Gray with black spots in wild; typically white in captivity Diet: Fish, tadpoles, insect larvae, and worms Breeding: Female lays up to 1,000 eggs at a time, which hatch after 2 weeks

Breeding and Feeding

Life span: 10–15 years

Axolotls breed at any time of year. Females attach their eggs to underwater plants, twigs, or rocks and may lay up to 1,000 eggs. Small larvae hatch out of the eggs. At first, they feed on small water creatures, such as water fleas, but their appetite grows as they grow larger. The diet then changes to include larger water creatures, such as fish and worms. Axolotls snap at the prey as they swim by, sucking it into the stomach. They may even snap at the legs from other axolotls, although axolotls can grow new legs to replace the missing ones.

Status: Critically endangered in the wild; common in captivity

In captivity, axolotls come in different colors. This white axolotl with black eyes is called a leucistic axolotl and differs from the wild type, which is brown or dark gray with dark spots.

45

BLIND SNAKES There are over 300 different kinds of blind snakes, and they include some of the smallest snakes in the world. Many species would fit into the palm of an adult’s hand. These snakes burrow underground and have smooth, glossy, overlapping scales to help them slide easily through the soil.

46

Snakes and Lizards

B

lind snakes probably developed from burrowing lizards without legs, and they were the first snakes to appear on the Earth. Blind snakes use the short, pointed scale at the tip of the tail to push against the ground when they are crawling or burrowing. Some have shovel-shaped heads to force their way through the soil. Since they spend most of their lives underground, scientists know very little about them. New species are being discovered all the time. The eyes of blind snakes are covered with large scales and some have no eyes at all, which gives these snakes their common name. Sight is not an important sense for them, however, since they live in darkness under the ground. They probably sense their surroundings and communicate by means of chemical signals.

Fact File BLIND SNAKES Superfamily: Scolecophidia Families: Typhlopidae (more than 215 species of blind snakes); Leptotyphlopidae (more than 90 thread snakes); Anomalepidae (15 dawn blind snakes) Order: Squamata Where do they live?: Africa, Central and South America, Asia, Australia, the Caribbean, southeastern Europe, and the Middle East

Small Meals, Small Young Blind snakes are small and have narrow, rigid skulls. Many blind snakes specialize in eating ants or termites, which are very small, so they have to eat vast numbers of them. Many species even live inside termite mounds where there is lots of food available all the time. They protect themselves from attack by smearing a chemical secretion all over their bodies. The eggs of blind snakes can be as small as rice grains, and the young blind snakes that hatch from them are tiny. Their threadlike bodies are often less than 2 inches long.

Habitat: Usually underground in sand or soil Size: Head–tail 4 to 39 in. (10 cm to 1 m) Coloration: Pink, purple, or brown; some species are darker with lightcolored heads and tails; a few have stripes or blotches Diet: Small invertebrates, such as ants, termites, and worms Breeding: Females lay 1–60 eggs, which hatch after 5–40 days

The wormlike body of the blind snake is the same

Life span: Not known

thickness from head to tail. Its eyes are the dark

Status: Varies according to species

spots, which are covered with scales.

47

BLUE-TONGUED SKINK The slow-moving blue-tongued skink cannot rely on speed to escape from predators. Instead, it puffs up its body, hisses loudly, and sticks out its bright blue tongue to scare them away. This lizard is not poisonous but can give a sharp bite to defend itself.

48

Snakes and Lizards

T

he blue-tongued skink is a large lizard that lives in a range of habitats in Australia, New Guinea, and various Indonesian islands. Some live in the desert or dry scrub, but many prefer the tropical forests. The legs and claws of the blue-tongued skink are not strong enough for it to dig its own burrows, so it shelters in the burrows of other animals, as well as in hollow logs, the spaces between rocks, and in leaf litter. When it moves through thick undergrowth, the blue-tongued skink folds its back legs out of the way and wriggles along like a snake. Blue-tongued skinks are active during the day, but they may retreat into their burrows during the hottest periods. During the dry season, when food and water are hard to find, large lizards save energy and moisture by staying in their burrows. They let their own body metabolism (normal body processes) slow down.

Fact File BLUE-TONGUED SKINK Tiliqua scincoides Family: Scincidae Order: Squamata Where do they live?: Eastern and northern Australia, and Irian Jaya in Indonesia Habitat: Forests, grasslands, and gardens Size: Head–tail length up to 24 in. (60 cm), males are longer and slimmer than females Coloration: Gray, tan, or silver with dark bands; bright blue tongue Diet: Berries, flowers, fruit, insects, and dead animals Breeding: Up to 25 young born after a gestation period (pregnancy) of 110 days

Breeding Behavior

Life Span: Up to 20 years

For most of the year, blue-tongued skinks live on their own. They come together to mate. Males usually start to look for a mate when it warms up in spring. The males fight for the right to mate, and many become seriously injured at this time. When a male finds a female who is ready to mate, he grips her neck or shoulder in his powerful jaws, and scratches her back with one of his back legs. After mating, males may sometimes guard females for up to twenty-five days.

Status: Common

Skinks are large, slender lizards, with short limbs and narrow heads. The blue-tongued species are named for their distinctive blue tongues.

49

BLUE-TONGUED SKINK

DID YOU KNOW? Just like a dog, a blue-tongued skink pants to cool down. The long tail makes up about half the length of the whole body. In the breeding season, males fight fiercely over the females.

Teeth and Feeding Blue-tongued skinks are omnivores. This means that they feed on a wide range of animals and plants. They prey on animals that move more slowly than they do. Favorite foods include insects, fruit, flowers, leaves, fungi, snails, eggs, small vertebrates, and the remains of dead animals (carrion). The teeth at the front of the mouth are smaller than those farther back and are used to pick up insects and bite off pieces of plants. Snails and insects are crushed in the hard jaws before being swallowed. The strong jaws of the blue-tongued skink are also useful in defense, biting

This skink sticks out its blue tongue and hisses to deter predators.

50

predators such as brown falcons, kookaburras, dingoes, monitor lizards, and snakes. Blue-tongued skinks were once thought to be poisonous. In the past, many were killed by people.

Mother and Babies Four different species of bluetongued skinks give birth to live young instead of laying eggs. The number of young produced tends to increase with the size and age of the female. While young skinks develop inside their mother’s body, they are nourished by a body part similar to the placenta through which a human baby receives food from its mother.

Snakes and Lizards

Live Young There are many advantages to producing live young instead of laying eggs. The female is less likely to be attacked and eaten by predators than the eggs would be. This gives the young a greater chance of survival. Blue-tongued skinks do not rely on speed to escape from predators or to catch food, so the pregnant females are not affected too much by the weight of the developing young inside them. The pregnant females bask in the sun because the warmth speeds up the development of their young. They tend to rest with their back legs and tail raised off the ground because of the size and number of young inside them. There are also disadvantages to giving birth to live young. If a pregnant blue-tongued skink is killed, all the young die with her. Basking increases the danger of attack by predators, as the bluetongued skink is out in the open, away from the safety of her burrow. Also it is not possible for a female to give birth to several lots of young lizards each year in the same way that many egg-laying lizards lay several clutches a year. In many parts of their range, female blue-tongued skinks

may not breed every year, especially if there is a shortage of food.

Parental Care After the baby skinks are born, they have to fend for themselves. The parents play no part in looking after their young. Young skinks take three years to develop into adults.

Suburban skinks Many eastern blue-tongued skinks have made their homes in city gardens with plenty of shelter and food, such as caterpillars, plant material, snails, and slugs. They live in rockeries, pipes, and the spaces under houses. Lawns and paths are ideal places to bask. However, there are some disadvantages to the suburban lifestyle. Dangers include the chemicals used to kill garden pests and diseases. Many blue-tongued skinks are also killed by cats and dogs.

51

BOAS The boa family includes two of the world’s largest snakes—the giant anaconda and the common boa or boa constrictor. Boas are not poisonous snakes. Instead, they kill by constriction, which means they wrap their body coils around their prey and squeeze the unfortunate victims until they die of suffocation. Most boas give birth to live young instead of laying eggs.

52

B

oas are unusual snakes because they have tiny hip bones and the remains of back legs in the form of spurs at the back of their body. Most other snakes do not have these features. Boas also have a working left lung. In other snakes the long right lung does all the work. The boa’s head may be covered in small, grainy scales, or large plate-like scales that are typical of other snakes. They have the flexible skull that is a feature of advanced snakes.

Killing Coils Boas grab and hold their prey with their small, hooked teeth as they coil their muscular bodies

Fact File around what they have caught. Powerful muscles steadily squeeze tighter and tighter each time their victim breathes out. Eventually, the prey stops breathing. Then the boa releases the dead prey and swallows it headfirst. It may take anything from a couple of minutes to an hour for a boa to swallow its prey. Larger prey causes a bulge in the stomach, making it hard for the snake to move quickly. If the snake is attacked by a predator after a large meal, it may be forced to cough up its prey to escape.

BOAS Families: Family Boidae—Subfamily Boinae (27‑species of typical boas) and Subfamily Erycinae (14 species of burrowing boas); Family Bolyeriidae (2 species of Round Island boas); Family Tropidophiidae (25 species of dwarf boas or wood snakes) Order: Squamata Where do they live?: Africa, North, South and Central America, southeastern Europe, India, Middle East, New Guinea, Sri Lanka

Island Dangers Many boas that live on islands are threatened because their habitat has been cleared for farmland, or they have been destroyed by goats introduced by people. Other introduced predators, such as cats and mongooses, are also a danger to island boas, such as the Haitian vine boa. Mona Island boas are one of the most threatened species because they live only on the small island of Mona off Puerto Rico. There, predatory domestic cats have escaped from homes and now run wild in vast numbers.

Burrowing Boas Boas in the family Erycinae live in a wide range of habitats. These burrowers are short, stout snakes, with blunt snouts and short tails.

Equator

Habitat: Forests, mountains, grasslands, deserts, islands Size: Length 12 in. to 19.75 ft. (30 cm to 6 m); weight up to 400 lb. (200 kg) Coloration: Brown, red, yellow, green, and black; often with camouflage markings Diet: Birds, lizards, and mammals Breeding: Females bear 3–100 live young after a gestation period (pregnancy) of 6–8 months Life span: 20–30 years Status: Some rare or endangered

The Madagascar ground boa is the largest snake on the island of Madagascar. Brown and orange markings on the snake’s back camouflage it in the leaf litter of the forest floor. 53

BOAS

The tails of some boa species may be waved around as a “false head” to distract a predator’s attention from the real head, which it hides in its coils. Many members of the Boinae family have heat-sensitive pits around their mouths, but burrowing boas do not. These pits would quickly become clogged with sand or soil as the snakes burrowed underground.

Sand Boas There are eleven species of sand boa (family Erycinae). These snakes live in habitats from southeastern Europe and North and East Africa, through the Middle East, to India. The upper jaw of the sand boas overhangs the lower

jaw so that these snakes can force their way through the ground without getting any sand or soil in their mouths. Sand boas that live in loose, sandy habitats “swim” underground, while species that live in harder soil form tunnels, often coming to the surface under a stone. As in other burrowing snakes, the eyes of the sand boas are found on top of the head so that they can ambush prey while they are partially buried in the ground.

Boa Relatives Two families are given the common name “boa” even if this is not strictly correct. They are the two Mascarene boas from Round Island in the

2 1 Common boa 2. Emerald tree boa 3. Rainbow boa 4. Dumeril’s boa

1

5. Pacific ground boa

3

5 4 54

BOAS

True boas The family Boinae includes the boa constrictor, the anacondas, and the tree boas. Tree boas have slimmer, flatter, and lighter-weight bodies than their large ground-dwelling relatives. This body shape helps them to slide easily through the trees. Tree boas also have long, gripping tails that hold tightly to tree branches while they climb or rest. Along their lips, tree boas have pits that can sense the heat given off by birds, which are their main prey. Their long, curved teeth help them to catch and hold onto their prey. The smaller Mona Island boas specialize in eating Anolis lizards, which sleep on the tips of branches at night. These agile boas catch the lizards by hanging down from branches or plucking them from their night-time roosts.

Indian Ocean (family Bolyeriidae) and the dwarf boa from Central and South America (family Tropidophiidae). One of the Round Island boas is probably now extinct. The surviving species is the Round Island keel-scaled boa (Casarea dussumieri). Dwarf boas are usually found under stones, logs, and in leaf litter. They come out at night. Two dwarf boas species are also known as “banana boas” because they can be carried around the world on ships taking bananas from Central America to other parts of theâ•‚world.

OW? DID YOU KN The largest boa constrictor was 18 feet long but theâ•‚smaller boas grow fewer than 39 inches long. Young emerald tree boas are born bright yellow or pink, but they turn green as they mature. Rubber boas coil into a tight ball when they are threatened. The Calabar ground boa is an unusual boa that lays eggs, rather than giving birth to live young. 55

BUSH SQUEAKER Squeakers are small African frogs named for their short, high-pitched call, which sounds like the noise made by a cricket. Females lay large eggs that hatch into tiny frogs with small tails. These frogs do not have a tadpole stage in their life cycle.

56

frogs and toads

T

here are about seventy-nine species of squeaker frog, most of which live in Central and West Africa. The unusual hairy frog is from West Africa. During the breeding season, the male develops hairlike flaps of skin, which help him to take care of the eggs. The bush squeaker (Arthroleptis wahlberg) is one of just two species from southern Africa. Squeakers prefer to live in damp places, which helps them to absorb oxygen through their skin as well as through their lungs. During short periods of dry weather, the squeakers retreat into burrows in the soil, crevices in logs, or hollow tree trunks.

Direct Development Squeakers breed at the start of the rainy season, with males calling to attract females. Females lay large eggs with plenty of yolk, often in a small cavity in the ground. The eggs develop into adult frogs without going through a tadpole stage. This is called direct development. It helps squeakers to survive in places where there are no pools necessary for the tadpole stage of development. Squeakers show some level of parental care, staying near the spawn while the eggs are developing to protect them from predators. The tiny frogs that hatch out of the eggs are only as big as a bluebottle fly. The frog hatchlings grow quickly, however, and some species are ready to breed after only about three to four months.

Fact File BUSH SQUEAKER Arthroleptis wahlbergi Family: Arthroleptidae Order: Anura Where do they live?: Tropical parts of the east coast of South Africa Habitat: Leaf litter under bushes, hedges, and garden shrubs; can be seen in large cities Size: HeadÂ�–tail length 1 in. (2.5 cm) Coloration: Brown with dark brown mask through the eyes Diet: Small invertebrates (animals without backbones), including ants and termites Breeding: Female lays 11–30 eggs, which hatch after four weeks Life span: Under 1 year Status: Common, although much of their natural habitat has been destroyed by people—least concern

This squeaker frog is very well camouflaged against leaf litter in the damp tropical rain forests of Cameroon in Africa.

57

BUSHVELD RAIN FROG The secretive bushveld rain frog spends most of its time hidden in its underground borrows, emerging to feed when it rains. These frogs can burrow as deep as 20 inches underground, using the “spades” on their back feet to dig through the soil.

58

frogs and toads

B

ushveld rain frogs are most likely to be seen and heard during the rainy season, when it is time for breeding. Every evening, the males call from their burrows or from underneath thick bushes to attract the females. When a female turns up, the male produces a sticky substance from his underside and glues himself to the female’s back. The female then uses her spadelike hind feet to dig backward down into the soil with the male still on her back. Once the burrow is deep enough, the female lays her eggs in a small chamber, often next to a buried rock or log. The eggs are quite big, measuring about half an inch including the jelly surrounding them. The female may also lay a number of empty jelly capsules, possibly to prevent the eggs from drying out. The eggs develop and hatch into tadpoles inside the egg mass and do not feed. Soon after the tadpoles turn into tiny frogs, they emerge from the burrow. The young are about 0.25 inch in length. The whole process takes between four and six weeks.

Rain Coat In the dry season, bushveld rain frogs puff up their bodies and produce a slimy waterproof coating that stops water from escaping from their skin. The frogs then bury themselves in a burrow about 20 inches below the surface, surviving several months of dry weather with their slimy coat around their body. Resting through a dry season is called estivation.

Fact File BUSHVELD RAIN FROG Breviceps adspersus Family: Microhylidae Order: Anura Where do they live?: Southern Africa

Equator

Habitat: Dry grassland and sand dunes in deserts Size: Up to 2 in. (4.7 cm) Coloration: Pale gray with dark brown markings Diet: Small invertebrates (animals without backbones), especially termites Breeding: Female lays small clumps of large eggs Life span: Not known Status: Common—least concern

The bushveld rain frog is a compact frog with a short snout and short legs. Spade shapes on the hind feet help these frogs dig their underground nests.

59

CAECILIANS Caecilians are worm-like amphibians that live in hot places and survive by burrowing in the damp soil. There are about 160 different caecilians, but their underground lifestyle means they are difficult to observe and poorly understood.

60

caecilians

C

aecilians are unusual amphibians. They have no bones in the legs, hips or shoulders, and their bodies are made up of a series of rings called annuli. Some species have a short tail, but most have no tail. The skin is tough on the outside but the inner layers have special cells, such as slime glands and poison glands. Caecilians taste nasty to many predators and may even be poisonous to eat. In South America, however, coral snakes often prey on them. The bright colors of some caecilians may act as a warning signal to deter predators.

Fact File CAECILIANS Families: Caeciliidae (89 species); Ichthyophiidae (36 species); Rhinatrematidae (9 species); Scolecomorphidae (6 species); Typhlonectidae (13 species of South American caecilians that live in water); Uraeotyphlidae (6 species) Order: Gymnophiona Where do they live?: Central Africa, Central and South America, India, the Seychelles, Southeast Asia, and Sri Lanka

Bending and Burrowing When caecilians are burrowing through the soil, they move in a straight line using their wedge-shaped heads like a trowel as they push themselves along. Caecilians have a solid, bony skull, with a tough cap of skin that fits tightly over it. As the caecilian creeps along its burrows, it expands and contracts the muscles in its body, making the body wider or narrower in different places. Wider sections grip the sides of the burrow, allowing other parts of the body to stretch forward. In turn, these parts expand and result in a sequence of “push-and-pull” cycles that ripple along the body. Sometimes caecilians find themselves on the surface, perhaps after they are washed out of their burrows by heavy rain. There they can move by bending their bodies from side to side like a snake.

Habitat: Moist, loose soil and leaf litter in tropical forests; some burrow in mud at bottom of water Size: 2.75–27.5 in. (7–70 cm) Coloration: Most blue–gray or black; some yellow or orange Diet: Insects, lizards, small rodents, worms, and dead fish Breeding: Some species lay eggs; others give birth to live young after a gestation period of 7–11 months Life span: Not known

With its segmented body and lack of any limbs, this small caecilian from Costa Rica looks almost

Status: Varies according to species. Most are data deficient

exactly like a dark-colored earthworm.

61

CAECILIANS

DID YOU KNOW? Caecilians have lungs—all except one species. Some caecilians have scaly patches on their skin, which are like fish scales rather than reptile scales. The young of some caecilians develop inside their mother for up to eleven months—longer than babies do inside a human mother.

Some caecilians spend almost all of their lives in the water. The rubber eels are a group of aquatic caecilians that live in South America. Some of the species in this group may grow up to 2 feet or more.

62

Feeding Habits Caecilians are long, thin amphibians, so they have to eat long, thin prey. They also have to eat prey that lives under the ground. Earthworms are therefore an important part of their diet. Caecilians approach the worms slowly, grabbing them suddenly in their jaws. The jaws open in an unusual way. The bottom jaw stays more or less still, while the top jaw opens upward, rather like the jaws of a crocodile. This adaptation probably makes it easier for caecilians to feed in the restricted space of a burrow. The teeth of a caecilian are well developed on both jaws. They curve backward, so that the caecilians can

hold on to slippery prey, and they also have sharp cutting edges. As a caecilian chews, the backward curve of the teeth allows the food to move down its throat.

Eggs and Young Female caecilians lay their eggs in burrows near the edges of streams. They coil around the eggs to keep them warm. They hatch into larvae that wriggle down into the water. The larvae have gills so they can breathe in the water. Eventually, they change into small adults and slither back onto the land. Some species skip the larval stage. The eggs hatch out into miniature versions of the adults.

caecilians

Some caecilians give birth to live young. The female keeps the eggs inside her body until they are ready to hatch. The young absorb the egg yolk at first and then feed on the “milk” produced in the walls of the mother’s egg tubes. The developing caecilians have tiny teeth to scrape this milk off the walls. They also have gills to take in oxygen, and perhaps nutrients, from their mother’s own bloodstream. The young caecilians shed their gills just before they are born, or a few hours after birth. The mother may eat the discarded gills.

Seychelles Caecilians Seven species of caecilians live in the Seychelles Islands in the Indian Ocean. They live only in damp areas and are becoming rare. Tourism is a vital industry to the people of the Seychelles, and they are draining marshes to make way for new hotels. People have also introduced many predators, such as chickens and pigs. Large numbers of a caecilian called Hypogeophis rostratus have also been killed by the endangered Seychelles magpie robins. These birds have increased in numbers since Birdlife International started a conservation program for them in 1989.

Senses Most caecilians have small eyes, which are covered with skin or bone. The eyes are simple and detect only light and dark. The ears have no openings but can pick up vibrations in the soil. Caecilians have a small tentacle on each side of the head, between the eye and the nostril. The tentacles can detect chemicals, so the caecilians probably use them to search for food. Burrowing caecilians close their nostrils to stop them from getting clogged up with soil. Instead, they use their tentacles to “smell” when they are under the ground. Above ground, caecilians draw the tentacles back inside their bodies and seal off the opening. Below ground, they can extend their tentacles using pressure from fluids produced by the orbital gland—a gland that keeps eyes moist in other vertebrates.

63

CAIMAN LIZARD The caiman lizard looks more like a small member of the crocodile family than a lizard thanks to its large, heavy scales. Very little is known about the behavior of this Brazilian lizard in the wild.

64

Snakes and Lizards

C

aiman lizards live in the flooded forests, swamps, and streams within the Amazon River Basin in South America. These large, powerful lizards spend most of their time swimming, moving near the surface with their head out of the water. Their flattened tail helps to propel them through the water. Caiman lizards often bask on roots or branches overhanging the water. If they are disturbed or threatened, they will drop into the water and quickly swim away. The muscular, whip-like tail is also used by the lizard for defense and can deal a powerful blow to a predator. Young caiman lizards are often eaten by birds and larger mammals. People are the greatest threat to these lizards, since they are hunted for the reptile leather trade.

Fact File CAIMAN LIZARD Dracaena guianensis Family: Teiidae Order: Squamata Where do they live?: Amazon River Basin of South America Habitat: Swamps, riverbanks, and flooded areas Size: Length 36–42 in. (91–107 cm); weight 3–6 lb. (1.4–kg) Coloration: Bright green, olive, or brown body with orange head; young more colorful than adults Diet: Mostly water snails Breeding: Female lays 2 eggs

Snail Meals


When they are foraging for food, caiman lizards dive into deep water and walk across the bottom, flicking their forked tongue in and out to sense food. One of their favorite food items is apple snails. When a lizard finds a snail, it picks it up in its mouth, tilts its head up and rolls it toward the back of its jaws. The lizard then uses its powerful jaws and flat, grinding teeth to crush the shell. It swallows the soft body of the snail and carefully pushes the shell fragments out of its mouth with its tongue. During the dry season, when snails are not available, caiman lizards often climb into trees in search of insects and possibly even birds’ eggs.

Status: Rarely seen

The caiman lizard has a red-orange head and green body, which is covered with large, heavy scales. The long, flat tail helps to propel the lizard as it swims.

65

CAIMANS Caimans are small, agile members of the crocodile family, which also includes the alligators and crocodiles. Strong, bony plates on the body of these strong swimmers protect them from predators.

66

crocodilians

C

aimans are closely related to the alligators in the family Alligatoridae. Like the true alligators, caimans have rounded snouts and their lower teeth generally do not show when their mouths are closed. However, most caimans are smaller than alligators, and they have longer, sharper teeth. The black caiman is an exception since it is the only species that can grow bigger than an alligator. In fact, the black caiman is one of the largest reptiles in the world—second only to the saltwater crocodiles of Southeast Asia and Australia.

Cunning Hunter The black caiman has sharp eyesight and a keen sense of smell, and it uses both of these senses to good effect when hunting prey. The black caiman uses its powerful tail to stun and catch fish. First, the caiman moves quietly toward the fish. Then it lashes out with its tail, using it like a hand to scoop up fish into its mouth. Black caimans hunt at night, and it is possible to find them in the dark by listening for the smacking sound made by their tails on the surface of the water. Large caimans can hunt large mammals such as deer and tapirs when they come to the water to drink. People have killed large numbers of black caimans for the reptile leather trade and to protect their cattle from attack. The number of black caimans in South America is now believed to be just 1 percent of the numbers that existed there a century ago.

Fact File CAIMANS Family: Alligatoridae (6 species: common caiman, Yacaré caiman, broad-snouted caiman, dwarf caiman, smooth-fronted caiman, and black caiman) Order: Crocodilia Where do they live?: Central and South America Habitat: Swamps, lakes, and rivers Size: Head–tail length usually around 7.75 ft. (2.4 m); black caiman may be up to 20 ft. (6.1 m) and weigh up to 500 lb. (227 kg) Coloration: Black with lighter markings, especially in young Diet: Young eat invertebrates (animals without backbones) and small fish; larger caimans eat bigger prey, including some mammals, such as capybaras, dogs, and pigs Breeding: Female lays 20–60 eggs, which hatch after 6–10 weeks Life span: 30–50 years Status: Least concern

The dwarf caiman is the smallest member of the alligator family. Young dwarf caimans eat invertebrates; the adults also eat fish.

67

CANE TOAD Cane toads are large toads with big appetites and will eat anything that fits in their mouths. They are very adaptable amphibians, changing their lifestyle, diet, and breeding habits to suit a variety of habitats. They can even survive in the middle of bustling cities.

68

frogs and toads

T

he cane toad eats a wide range of food, from insects, smaller frogs and toads, and lizards, to small snakes, birds, and mammals. Unlike most other frogs and toads, which only hunt moving prey, cane toads can smell animals. Cane toads use their keen sense of smell to locate food, and they will often gather in places where people have left out food for their pets. Cane toads also wait at the entrance to beehives to snap up bees, and they visit garbage dumps where they eat vegetable scraps. In the middle of cities, cane toads hide under buildings by day, emerging at night to sit around the base of street lamps and snap up insects attracted by the light. When cane toads live side by side with other toad species, the cane toad is usually much better at finding food. This makes it difficult for the other toads to survive. Indeed, scientists have observed that American toads nearly always die when they are kept in cages with cane toads. This is not because they are attacked, but because they give up trying to compete with the cane toads for food.

Deadly Skin Cane toads are immune to attack from almost any predator. Their skin contains many poison glands, with two very large glands located just behind the head. These glands exude strong poisons as a sticky, milky sap. This usually oozes out of the glands, but cane toads can also squirt the sap up to 3 feet.

Fact File CANE TOAD Bufo marinus Family: Bufonidae Order: Anura Where do they live?: Central and South America and southern Texas in the United States; introduced to many countries, especially Australia Habitat: Varies depending on location; includes towns and villages Size: Snout–rump length 4–9.5 in. (10–24 cm); weight up to 3 lb. (1.4 kg) in wild, up to 5.6 lb. (2.5 kg) in captivity Coloration: Brown, sometimes with darker blotches Diet: Varied, including insects and smaller vertebrates Breeding: Females lay up to 35,000 eggs, which hatch within 2 days Life span: 5 years in the wild; 15 years in captivity Status: Common, reaching plague numbers in places—least concern

Cane toads show a remarkable variety of colors and markings on the back, ranging from gray to brown or olive. They have much paler undersides.

69

CANE TOAD

DID YOU KNOW? The biggest recorded cane toad measured 15 inches. Cane toads make strong poisons that can easily kill a dog or a cat. The cane toad was introduced to Australia to save sugarcane crops from pests. That is how the toad got its name.

The cane toad is a large, round amphibian with dry, warty skin. These toads have a bony head, with distinct ridges above each eye that run down to meet at the snout.

70

If the poison gets into the mouth, eyes, or an open wound, it causes severe pain, and a predator will drop the toad immediately. Cats, dogs, crows, monitor lizards, and snakes have died as a result of eating cane toads. Even highly venomous snakes, such as Australian death adders, will die if they eat a cane toad. As well as their deadly skin poisons, cane toads defend themselves by making their bodies look even bigger than they already are. To do this, the cane toad flattens its body, stands straight on two legs on one side of the body, and tilts the body toward the predator to look as menacing as possible.

Eggs and Tadpoles Cane toads breed at any time of year in most types of water, including ditches, ponds, and streams. In places where it rains throughout the year, cane toads breed at different times. Spacing out the breeding helps to avoid competition between the tadpoles. The male cane toad calls to attract a mate using a loud, tuneless croak that sounds rather like an outboard motor on a small boat. Females lay thin threads of eggs that can reach up to 20 yards in length and contain up to 35,000 small, black eggs. The eggs usually hatch into tadpoles within two days.

frogs and toads

Like the adults, the tadpoles do not taste very nice at first, but they lose some of their poisons when they turn into tiny toads. This happens between twelve and sixty days after they hatch from their eggs. The hatchlings are small at first and swarm together like a mass of black flies. This is the time when they are most in danger from predators and many are killed before they are able to develop into adult toads.

Problem Toads Cane toads have often caused problems when they have been introduced to other countries. They compete with native frogs and toads for food and breeding places. They also eat some of the local wildlife, which is a particular problem in Australia where the wildlife is not found anywhere else in the world. Cane toads were introduced to Australia in the 1930s in order to control the beetles that were eating sugarcane. The toads thrived in their new home, partly because they had no predators and few competitors. They spread rapidly, eating helpful insects as well as the harmful ones, and cane toads are still spreading across Australia today.

What’s in a name? Cane toads are also known as marine toads. The second part of their scientific name, marinus, suggests that they are linked to the sea. This is not the case, however, although tadpoles have been found close to the shore. These tadpoles die in water containing more than 15 percent salt water. So the tadpoles must have been living in fresh water draining down to the sea.

Cane toads have been introduced into many other regions or countries to help control populations of pest insects, including Florida, Puerto Rico, the Philippines, and many Pacific and Caribbean islands. In most cases, they have upset the balance of nature in their new homes and numbers are reaching pest levels. 71

CAPE SKINK The stocky Cape skink is probably the most familiar lizard in southern Africa, except in the Namib Desert and northern regions. It has spiny scales on its feet that help it to grip the sandy soil.

72

Snakes and Lizards

T

he stout body of the Cape skink is covered with circular scales, and it also has a large scale under each eye that extends to its top lip. The ear openings are covered with small scales to prevent sand from entering when the skink is digging. The Cape skink has five long toes on each foot. The well-developed legs allow it to escape predators, including birds such as the fiscal shrike, by running quickly to its burrow. Cape skinks are only active on sunny days. They emerge in the sunlight and bask in open areas for long periods until their body temperature is high enough for them to move around with ease.

Eggs or Young Some Cape skinks lay eggs and some give birth to live young. The reproductive strategy depends on the climate and the habitat in which they live. In areas with high rainfall and steady temperatures over much of the year, females lay between six and twelve eggs in November and December. The young hatch out after about two months. In other areas, there are very hot summers and cold winters. During the winter, the skinks go into a deep sleep called hibernation. The temperature is too low for eggs buried in the soil to develop. Instead, the female skinks keep their eggs inside their bodies for four months, which helps to keep them warm. In March, the female gives birth to between five and eighteen young.

Fact File CAPE SKINK Mabuya capensis Family: Scincidae Order: Squamata Where do they live?: Large parts of southern Africa Habitat: Varied, including coastal bush, gardens, and grassland Size: Head–tail length 8–10 in. (20– 25 cm), females generally larger than males Coloration: Light brown, dark green, or gray, with three pale stripes and brown or black spots between the stripes Diet: Insects, spiders, and worms Breeding: In some areas, 5–18 young born after a gestation period (pregnancy) of 4 months; in other areas, females lay 6–12 eggs, which hatch after 2 months Life span: Not known Status: Common

The Cape skink has three pale stripes running down the length of its back. Dark bars run across the back and extend onto the lizard’s sides.

73

CHAMELEONS Most chameleons live in the tropical forests of Africa and the island of Madagascar. They are unusual, slow-Â�moving lizards, with a long, gripping tail, eyes on turrets, and a very long tongue for catching insects. They are famous for their amazing camouflage, changing color to match their surroundings.

1

2 3

C

hameleons are strange reptiles. Their bodies are flattened from side to side to help them move through the trees. The males of some species, such as Jackson’s chameleon, have horns on the head. Males use them to fight off rivals. Most species have a spiny crest along their back and underside. The large crest of the sail-fin chameleon is like a fan. Male and female Pfeffer’s chameleons have a throat crest made of long, soft “spines.”

4

Feeding and Diet Most chameleons feed on insects, but some larger species eat frogs, other lizards, and small birds and mammals. When they are hungry, chameleons may stalk their prey. Usually, they sit patiently on a branch and wait for insects and other small invertebrates (animals without 74

5 1 African dwarf chameleon

5. Veiled chameleon 6. Jackson’s chameleon

2. Stump-tailed chameleon 7. Panther chameleon 3. Parson’s chameleon 4. Namaqua chameleon

8. Western pygmy chameleon

Fact File CHAMELEONS Family: Chamaeleonidae (131 species divided into 6 genera): Bradypodion (21 species of dwarf chameleons); Brookesia (23 species of stump-tailed chameleons); Calumna (18 species of Madagascan chameleons from humid areas); Chamaeleo (42 species from Africa, India, southern Europe, the Middle East, and Sri Lanka); Furcifer (19 species of Madagascan chameleons from arid areas); Rhampholeon (8 species of leaf chameleons)

6

Order: Squamata Where do they live?: Most in Africa and Madagascar, others in southern Asia, southern Europe, and the Middle East

7

Equator

8

Habitat: Bushes and trees in mountains, rain forests, and scrubland Size: Head–body length 0.75–11.2 in. (1.8–28.5 cm)

backbones) to come within reach of their long tongues. The tongue shoots out and back into the mouth in a fraction of a second. Rather than being sticky, the tongue works like a rubber sucker, but it needs to be moist to stick to the prey. Muscles in the tongue squeeze together to propel the tongue from the mouth. After the tongue hits the target, muscles contract to bring the prey back into the chameleon’s mouth.

Coloration: Brown, green, and yellow; some species can change color Diet: Mainly insects; some eat vertebrates such as frogs, lizards, birds, and small mammals Breeding: Females of most species lay 4–70 eggs at a time; some give birth to live young after a gestation period of 4–7 months Life span: 5–10 years Status: Varies according to species. Vulnerable in some areas

75

CHAMELEONS

chameleon senses Chameleons move their eyes independently from each other, which gives these lizards amazing wide-angle vision. The eye sockets stick out from the side of the head, but most of the eye is covered by skin so the eyes look very small. Small eyes probably make it more difficult for predators to spot the chameleons. When a chameleon spots its own prey, it swivels both eyes forward so it is able to judge the distance between itself and the prey accurately. It then shoots out its long tongue, and the prey “sticks” to the bulb-shaped tip. When the chameleon laps water, it flattens its tongue.

76

Chameleons seem to have little or no sense of smell. They press their tongues against branches from time to time, but scientists do not known why they do this. It may be a way of detecting the scent left by other chameleons. Chameleons have no distinct call, but they do sometimes make a faint hissing sound. Unlike other lizards, they do not have an external ear opening. However, they can detect air vibrations through a membrane on each side of the skull. This membrane is connected to the inner ear inside the chameleon’s head, where the vibrations may be interpreted as sound.

CHAMELEONS

When the tongue is not being used, it is folded like an accordion inside the mouth. Sometimes, a chameleon may seize prey in itsâ•‚jaws if the prey is too large to stick to the tongue or if the prey is near enough to be grabbed easily.

Slow Movers Chameleons move slowly and deliberately most of the time, but they can move quickly when they have to. The long legs bend at the knee and elbow so that the feet tuck under the body. To grip a branch tightly, a chameleon places two toes around one side of the branch and three toes around the other side. The opposing toes provide a strong grip. Chameleons also have a gripping (prehensile) tail, which can be curled around branches like an anchor or extended out behind their body for balance.

Defense and Camouflage A chameleon’s best form of defense is to stay still and rely on its camouflage colors for protection. Stump-tailed and leaf chameleons are camouflaged by their shape as well as their color. They “freeze” until the danger has passed. The tiny Brookesia peyrierasi looks like a thin piece of wood when it keeps very still. Moss even grows on the skin of Rhampholeon spectrum, making it look just like a dying leaf. To escape a predator, a chameleon may jump from one branch to another or fall to the ground. Sometimes a chameleon will hiss, puff up its throat, or sway with its mouth wide open.

Most chameleons spend much of their time keeping very still, using their sharp sense of vision to search for prey or possible danger.

OW? DID YOU KN Most chameleons have no voice, but the veiled chameleon makes a loud, hoarse hissing sound. An ailing chameleon usually turns a sickly shade of yellow. Some chameleons have tongues that are almost twice the length of their bodies. 77

CHAMELEONS

This is an attempt to make itself look larger and fiercer than it really is. This tactic may fool a predator into leaving the chameleon alone. Some chameleons play dead by lying sideways on a branch or hanging under a branch with their tongues lolling out of their mouths. Most predators prefer to eat fresh prey, so they will leave the “dead” chameleon alone.

Courtship and Young Male chameleons often have some form of head decoration, such as horns, a crest, or spurs, to attract mates during courtship. Females of some species sometimes have these features, but they are always smaller than those of the males. In

The gaping mouth of a chameleon usually shows that it is too hot. Females of some species also gape when approached by courting males. 78

some Madagascan chameleons, the males and females are different colors. Furcifer labordi males are green with white stripes, while the females have a red throat and blue sides. Male chameleons start their courtship display by swaying their head slowly and changing to a brighter color. Females that are ready to mate do not change color. Mating can take from a couple of minutes to an hour or more. After mating, females change color to show that they are not “available” to other males. Some chameleons lay eggs in a hole in the ground. The eggs have leathery shells that absorb moisture while the baby chameleons develop inside them. When they are ready to hatch, the young make slits in the eggs so that they can push their heads through the shell. The rest of their bodies stay inside the shell until all the yolk has been absorbed. This may take as little as an hour or as long as two days. The young chameleons often hatch during a wet period because the ground is softer and it is easier to dig their way to the surface. Some females keep the eggs inside their body until the young hatch as live chameleons. The gestation (pregnancy, or time carrying live young) varies from four to seven months, depending on the species and the temperature of the surroundings. The young are born as tiny versions of the adults and are able to look after themselves. Most young chameleons are brown to camouflage themselves against the branches and twigs on which they live.

CHAMELEONS

Colorful Chameleons

Most chameleons are well camouflaged in

Chameleons use color to attract or ward off potential mates, or to threaten rivals or predators. Males live in their own special areas called territories. They use colorful battle displays to warn intruders to keep out of their territory. Females full of eggs or young often have very bright colors and patterns. This warns males to keep away but does not help to hide them from predators. However, keeping still is good protection from predators. Even a colorful chameleon can be very hard to spot. Color changes are also related to the outside temperature. A cold chameleon is usually dark, almost black, which helps the

shades of green and brown, which helps to hide them among leafy tree branches.

OW? DID YOU KN About half of all chameleon species lives on the island of Madagascar, off the coast of East Africa. The largest chameleon of all is 27 inches long from head to tail. Many male chameleons have horns on their heads.

chameleon to absorb heat. When they are hot, they often turn a lighter color to reflect the heat away from their body. Chameleons then look for shade among the tree leaves. 79

Clawed toads Named for the claws on their huge webbed back feet, clawed toads have flat bodies and spend all of their time in the water. They do not have a tongue and most have a sensory organ, called a lateral line, which they use to detect movement in the water.

80

FROGS and toads

T

hree main groups of clawed toads live in Africa. The dwarf clawed toads (Hymenochirus and Pseudhymenochirus species) are small toads with grainy skin and webbed front feet. Clawed toads from the group Xenopus have three black, horny claws on their large back feet (Xenopus means “strange feet”). Clawed toads from the group Silurana have four bony claws instead of three. This group is named for the tadpoles’ “whiskers,” which make them look like Silurus catfish. Seven species of clawed toad live in South America. They belong to a group called Pipa. They use their webbed back feet for courtship and egg-laying as well as for swimming. Their front feet end in four-pointed star-shaped structures that are sensitive to touch.

Feeding and Breeding Clawed toads use their lateral line to detect prey such as small fish and water invertebrates. They suck in the prey with a mouthful of water. They can also use their clawed feet like forks to stuff prey into their mouths. Unlike most frogs and toads, clawed toads do not have vocal cords. Males attract females by moving two bony rods in their throats. This makes a clicking or buzzing sound. Females from Xenopus and Silurana attach their eggs to underwater plants. Females from Hymenochirus lay their eggs on the surface of the water. Eggs laid by Pipa females are collected by the males and placed on the female’s back, where they stick fast.

Fact File Clawed toads Family: Pipidae (30 species in five genera) Order: Anura Where do they live?: Africa and South America

Equator

Habitat: Lakes, ponds, reservoirs, rivers, small pools, and swamps Size: Snout–rump length 1.5– 7.75 in. (4–20 cm); weighs up to 5.6 oz. (160 g) Coloration: Dull gray or brown Diet: Carrion, invertebrates, fish, and amphibians—even its own larvae Breeding: Females lay 40 to several hundred eggs; females from the genus Pipa carry the eggs on their backs Life span: About 10 years Status: Varies according to species; most lower risk—least concern

The African clawed toad lives in the ponds and rivers of South Africa. These amphibians swim very quickly, hunting for small fish such as minnows and guppies.

81

Cobras Cobras are secretive snakes with angular heads and lithe bodies. When a cobra feels threatened, it lifts the front part of its body off the ground, spreads the hood on its neck, and hisses loudly to scare away enemies. If this warning display does not work, the cobra can give a deadly bite.

82

C

obras are highly venomous snakes. They are related to other dangerous snakes, including coral snakes, death adders, and mambas. All these snakes have short, fixed fangs at the front of their mouths. The fangs fit into slots on the floor of the mouth when the snake’s mouth is closed. Most people can recognize a cobra by its hood. When threatened, these snakes stretch their ribs outward, which makes their hoods expand.

Fact File Cobras kill their prey by injecting venom through thin pipes that run down the middle of their fangs. These snakes never run out of venom. As the venom is used up, the cobra makes more. Cobra venom works by stopping its prey’s heart from beating. It also causes respiratory failure. Cobras rarely attack people unless they are provoked. When they do bite, cobra venom acts quickly and can be fatal. In the most severe cases, people can die within ten minutes of being bitten by a cobra. Some African cobras can also spray venom through openings in the front of the fangs. The venom of these “spitting” cobras can travel more than 6.5 feet. It can make someone blind if it gets into the person’s eyes. One type of spitting cobra, called the rinkhal from southern Africa, is the smallest of all the cobras. This snake measures about 4 feet in length. The rinkhal is unusual because its scales are keeled (bumpy) instead of smooth, and females give birth to live young instead of laying eggs. The rinkhal preys on toads. When it is threatened, it defends itself by pretending to be dead. Predators prefer to eat living prey, so they leave it alone.

Cobras Family: Elapidae (270 species, of which around 25 species are cobras) Order: Squamata Where do they live?: Africa and southern and southeast Asia Habitat: Deserts, grasslands, forests, scrubland, swamps, and water Size: Head–tail length up to 18.5 ft. (5.7 m); most range from 3–7 ft. (0.9–2.1 m); weighs up to 20 lb. (9 kg) Coloration: Color varies from gray, brown, or black to yellowish white; some species have collars or crossbands Diet: Birds, fish, frogs, lizards, toads, other snakes, and small mammals such as rats Breeding: Females lay between 12 and 60 eggs that hatch after 45–80 days; rinkhals give birth to 20–30 live young Life span: Up to 30 years Status: Varies according to species

Wearing a Hood A cobra’s hood is skin that has been stretched across a series of long ribs. The cobra normally keeps these ribs folded flat. The skin then rests against the body, and the cobra looks the same as any other snake. When the cobra feels threatened, it moves the ribs out to the side, stretching the neck skin to form a wide hood. 83

Cobras

This makes the cobra look bigger and sends out a message: “I am dangerous and will bite you if you come any closer!” It also makes the cobra look too big for a predator to swallow. Some cobras have bands, eye markings, or other patterns on the back of their hoods. These may help to distract predators or frighten them away. King cobras have long, narrow hoods. Unlike other species, the hoods do not have markings. A black-necked spitting cobra gets ready to attack a predator in the Kalahari Desert.

84

Egg Warmer The female king cobra is the only snake known to make a nest for her eggs. The female uses her head and body to scrape together leaves and other debris into a mound. She then lays her eggs and covers them with the nesting material. The female sits on top of the eggs to incubate them (keep them warm). She guards the eggs from predators until they hatch. The male king cobra stays with the female and her eggs. The male and female take turns guarding the nest and hunting for food.

Cobras

OW? DID YOU KN The venom from one bite of a king cobra is enough to kill a fully grown adult elephant or up to fifteen adult humans. The king cobra is the world’s longest poisonous snake. It can rear up and look a person in the eye. King cobras eat other snakes, even highly poisonous species such as Indian cobras, kraits, and smaller king cobras. The venom of a young cobra is as strong as that of the adult. A king cobra’s hiss sounds similar to a dog growling.

The Hunt is On... Cobras are active hunters. They chase after their prey, quickly moving with their head raised off the ground. They are also good swimmers and may cross wide rivers. Cobras hunt mainly at dusk, flicking their forked tongue in and out to “taste” the smells in the air and get as close as possible to their prey. The final attack is a quick strike that injects a massive dose of venom. The cobra’s fangs are 0.5 inch long and penetrate the skin deeply. They inject venom directly into the bloodstream of the prey. This keeps the prey still so the snake can swallow it. Cobras hang on to their prey until they are sure enough venom has entered the wound. Cobras have flexible jaws, so they can open their jaws wide to swallow large prey. A large meal takes days or weeks to digest. They can survive for months without eating anything, because their metabolism works so slowly.

charming snakes The Indian, or spectacled, cobra has a unique pattern on the back of its hood. There are two circles linked by a curved line, making the cobra look as if it is wearing spectacles. The Indian cobra is a popular species among snake charmers, who remove the fangs for safety. It looks as though the snake is swaying from side to side in time with the snake charmer’s music, but the snake is really following the movement of the flute. Snakes cannot hear music like people do, but they can sense vibrations in the ground and are probably sensing the vibrations from the tapping foot of the snake charmer.

85

Common Frog In spring, these amphibians breed in water, but they will spend the rest of the year on land, living in damp fields, woodlands, as well as gardens in Europe and Central Asia. Common frogs catch insects and other invertebrates using their long, sticky tongues.

86

FROGS and toads

C

ommon frogs are hardy amphibians. They can survive in cold places in Scandinavia and Russia and even high up on mountains such as the Alps and the Pyrenees in Europe. During the cold winter, these frogs go into a deep sleep known as hibernation. They hibernate in burrows, under piles of rotting leaves, or in the soft mud at the bottom of ponds. When the ponds freeze over, the frogs survive by taking in oxygen from the water through their skin. They can even survive being frozen, thawing out when it warms up again.

Frog Life Cycle Large numbers of common frogs migrate to breeding ponds in the spring to look for a mate. Some travel for 6 miles or more. Male frogs croak to attract females. If successful, a male climbs onto the female’s back and fertilizes her eggs as she releases them into the water. The eggs are protected by a jellylike layer and float to the surface of the water where they can develop in the warmth of the sunlight. After about seven to forty days, the eggs hatch into tadpoles. The tadpoles have tails and breathe underwater using gills. After nine weeks, the tadpoles develop lungs, which they use to breathe air from the surface of the water. They grow hind legs at six to nine weeks, and front legs at twelve weeks. After seventeen weeks, the tadpoles complete this process of change, called metamorphosis. The adults have no tail at all and are about as long as an adult’s fingernail.

Fact File Common frog Rana temporaria Family: Ranidae Order: Anura Where do they live?: Central and northern Europe eastward to Siberia Habitat: Varies from bogs, ditches, fields, and hedges, to meadows, ponds, streams, woods, and sluggish rivers Size: Head–body length 2–4 in. (5– 10 cm); weighs 0.75 oz. (22.7 g) Coloration: Varies from brown, green, and yellow to pink or tan; dark “mask” behind eyes; dark bars on back legs Diet: Invertebrates such as insects, slugs, and snails Breeding: Females produce between 700 and 4,500 eggs that hatch after 7–40 days depending on the temperature Life span: Up to 8 years Status: Lower risk—least concern

The common frog has large brown eyes with inner eyelids to protect them when they are underwater. A darker “mask” covers the eyes and eardrums.

87

Common toad The common toad’s warty skin and short back legs help to distinguish it from the common frog. These toads can survive in drier places than frogs due to their thick skin, which helps to seal in moisture. Common toads may even burrow into the soil in dry weather.

88

FROGS and toads

T

he common toad is a secretive amphibian. It comes out at night to hunt small invertebrates. These amphibians are useful to gardeners because they eat pests such as slugs. Common toads are rarely seen in the garden, however, because they hide away in crevices, under logs, or in greenhouses during the day. They hide to avoid predators such as birds of prey, cats, dogs, and hedgehogs. When they are spotted, common toads use their potent skin poisons in defense. Grass snakes are immune to these poisons. Instead, the toad puffs up its body and stands high off the ground on stiff legs to look as big as possible.

Eggs and Tadpoles Common toads breed in water and migrate to ponds, lakes, or slow-moving rivers in the spring. Many toads are killed by road traffic if the migration route takes them across busy highways. As a result, local people sometimes set up “toad crossings” to help the toads cross the road in safety. Males compete to mate with females. They swarm around one female and form a large ball shape around her body. After mating, the female lays eggs in double strings, measuring up to 16 feet long. When the eggs hatch, the tadpoles form shoals in the water. In a process called metamorphosis, the tadpoles change into tiny toadlets. They measure just 0.5 inch long. They will not breed themselves until they are between three and seven years old.

Fact File Common toad Bufo bufo Family: Bufonidae Order: Anura Where do they live?: Most of Europe, parts of northwestern Africa, and across Central Asia Habitat: Gardens, heaths, meadows, and woodlands Size: Head–body length: 3–8 in. (8– 20 cm); weighs 9 oz. (250 g) Coloration: Brown, gray, or reddish, with no markings Diet: Invertebrates such as earthworms, insects, and slugs Breeding: Females lay between 3,000–8,000 eggs, which hatch after 2–3 weeks Life span: Up to 40 years Status: Lower risk—least concern

The eyes of the common toad are orange with black horizontal pupils. Two glands behind the eyes produce a foul-tasting chemical to deter predators.

89

Congo eels Congo eels may look like eels or snakes, but in fact they are amphibians and closely related to salamanders. Congo eels were named because scientists used to think they lived in the African Congo, but they are found only in southeastern North America.

90

newts and salamanders

C

ongo eels live in slow streams and swampy rivers. They hide in underwater burrows during the day and emerge at night to feed. Adult Congo eels have tiny legs and a few toes. There are three species: the one-toed, two-toed, and three-toed amphiuma (Congo eels). In the larval stage, these amphibians have much larger legs that can be used to walk. Adults wriggle along like eels, however, both in the water and on land. In very dry places, Congo eels burrow into the mud and rest in a slimy cocoon until rains fall once again. They can survive in this state for up to three years. Congo eels eat more crayfish than anything else, but they also eat earthworms, fish, insects, snails, and even clams, snakes, and turtles. If they are attacked, Congo eels can give a painful bite. They also have a slimy layer that covers their bodies, which makes it difficult for predators to hold onto them.

Eggs and Young In the winter, female Congo eels lay their eggs in burrows or small crevices. They coil around their eggs until they hatch several months later in summer. By this time, the nest cavities may be above the water. The larvae breathe underwater using external gills. This stage does not last long, and the larvae lose their gills after about three weeks. Adults breathe using lungs, but they keep a pair of gill slits—the openings through which the gills emerge at the larval stage.

Fact File Congo eels Amphiuma spp. Family: Amphiumidae Order: Caudata (Urodela) Where do they live?: Southeastern North America Habitat: Slow-moving streams, water-filled ditches, ponds, and swamps Size: Head–tail length up to 39 in. (100 cm); weighs 5.5 lb. (2.5 kg) Coloration: Black or dark brown with small, light spots Diet: Aquatic creatures such as crayfish, fish, frogs, snails, and water snakes Breeding: Females lay 50–150 eggs; eggs hatch after 20 weeks Life span: Captive Congo eels live for up to 27 years Status: One-toed amphiuma—near threatened; two-toed and three-toed species—least concern

The two-toed amphiuma is a large, thick-bodied salamander from the swamps of Florida, Virginia, and Louisiana in the southeastern United States. 91

Copperhead The copperhead lives in the forested hills of the American southeast. Copperheads are common snakes, but they are often overlooked because of their excellent camouflage. These snakes are poisonous but will bite only if disturbed or provoked.

92

snakes and lizards

C

opperheads prefer to live in forests, with clearings in which to bask and warm up in the sunlight, and rocky outcrops in which to hide and hibernate (sleep through the winter). In very cold places, these snakes may hibernate for up to six months of the year. They may share their hibernation sites with timber rattlesnakes and black ratsnakes. When people settle in copperhead habitats, the snakes remain if there are enough natural areas left. These may be nature reserves and neglected farmland where there are woodpiles and empty buildings in which the snakes can find shelter.

Feeding and Breeding Copperheads are pit vipers. They have heat pits to detect warm-blooded prey such as birds and rodents. Unlike other pit vipers, however, they also eat coldblooded prey, such as frogs, lizards, salamanders, small snakes, and insects, including cicadas. During the breeding season, males may wrestle for the right to mate. After mating, the females give birth to live young, which are about 8 inches long. The mother stays with her young for about a week, until they have shed their skin for the first time. The young snakes have a yellowish tip to their tail, which they wave to and fro to lure frogs and lizards to within striking range. As the snakes grow and change their typical diet to mice, the tail loses its bright color because it is no longer needed as a lure.

Fact File Copperhead Agkistrodon contortrix Family: Viperidae Order: Squamata Where do they live?: Southeastern United States and northeastern Mexico Habitat: Rocky areas and woody hillsides near ponds and streams Size: HeadÂ�–tail length 24 in. to 4 ft. (61 cm to 1.2 m); weighs 10.5 oz. (300 g) Coloration: Beige to tan background color, with rich brown or coppery markings, each shaped like an hourglass Diet: Amphibians, invertebrates, lizards, and small mammals Breeding: 4–14 live young are born after gestation period (pregnancy) of 83–150 days Life span: Up to 29 years Status: Lower risk—least concern

The copperhead is the most abundant venomous snake found in the eastern United States, where it is also known by the name highland moccasin.

93

Coral snakes Coral snakes live in the Americas. These secretive snakes are burrowing reptiles from the cobra family. Their brightly colored rings of red, black, and yellow warn other animals to leave them alone. Coral snakes have a potent venom and are very dangerous.

94

snakes and lizards

M

ost coral snakes live in the rain forests. They search through the leaf litter for prey such as smaller snakes. Other species live in deserts, scrubland, or dry thorn forests. These snakes can be active during the day or night, but mostly hunt at night to avoid the intense daylight heat. Many species from Central and South America eat burrowing reptiles, especially worm lizards, which they follow through their tunnels. One large coral snake, Micrurus surinamensis, spends a lot of time in the water and preys on eels. Coral snakes usually bite their prey and inject it with a powerful venom that affects the nervous system. This venom is known as a neurotoxin. The coral snake bites and then hangs onto its prey with its teeth. Gradually, the venom begins to paralyze the victim, until it stops moving completely. The snake then swallows the prey headfirst. The snake uses the direction of the prey’s scales to find the head.

Fact File CORAL SNAKES Family: Elapidae Order: Squamata Where do they live?: Americas Habitat: Varies from deserts to rain forests Size: HeadÂ�–tail length 10.5 in. to 5 ft. (27 cm to 1.5 m); weighs 2–5 lb. (0.9Â�–2.2 kg) Coloration: Brightly colored rings of red, black, and yellow Diet: Burrowing lizards, worm lizards, and snakes Breeding: Lays 3–8 eggs, but the exact details of breeding behavior are unknown Life span: On average 10–15 years Status: Common

Mystery Lives Very little is known about the breeding behavior of coral snakes. One species that has been relatively well studied is the eastern coral snake (Micrurus fulvius) from the coastal plains of North Carolina to Louisiana in the southeastern United States. Like all coral snakes, the females lay eggs—between three and eight at a time. The hatchlings are the same bright colors as the adults when they emerge from their eggs. Clark’s coral snake is native to southeastern Costa Rica and western Colombia. Like all coral snakes, this species has a potent venom that can be fatal.

95

Coral snakes

DID YOU KNOW? The largest coral snakes grow up to 5 ft. (1.5 m) in length. The venom from a coral snake is strong enough to kill people, but attacks on people are very rare. Some coral snakes have bands of only two colors, such as red and yellow or black and white. The name of one genus, Micrurus, means “flickering tail” and is named for the snake’s defensive display.

Hard-working Colors The bright colors of coral snakes probably help them to survive in several different ways. Surprisingly, the conspicuous colors provide good camouflage in the dappled sunlight of the rain forest. This makes it hard for a predator to spot a coral snake in its natural habitat. Next there is the element of surprise. Any predator searching for food in the leaf litter The red milksnake mimics the bright warning coloration of the coral snakes. Other animals think the milksnake is dangerous when in fact it is

will be startled when it uncovers a brightly colored coral snake. It may draw back and hesitate before it attacks. This gives the snake vital seconds to make good its escape. When a coral snake moves quickly through dead leaves or green, leafy plants, its bands of color flicker in the light. Predators often find it hard to make out the shape of the snake and figure out the direction in which it is moving. By the time it does this, the coral snake has disappeared. If a predator persists with its attack, a coral snake starts a warning display to frighten the predator and show that it is dangerous. It raises its tail, coiling and uncoiling it over and over again to divert attention away from its head, which it often hides under its body. Then it wriggles around, thrashing its head from side to side and snapping at anything it touches. The bright colors make this warning display even scarier.

Color Copies

96

Predators seem to avoid animals with bright colors instinctively. Very often these animals are deadly or do not taste good. Harmless snakes may mimic, or copy, the bright colors of venomous snakes to give themselves a much better chance of surviving. This

snakes and lizards

survival strategy is known as Batesian mimicry. It was named for the English scientist Henry Walter Bates, who first put forward this theory in the middle of the nineteenth century. Many coral snake mimics, such as the milksnake, Lampropeltis triangulum, also thrash around if they are disturbed, making them look even more like the real coral snakes. The sequence of colored rings on some false coral snakes does not always match those of the real species, but predators cannot tell the difference. When the predator finds its meal, it has to make a quick decision. In most cases, a predator will not risk attacking a snake with bright colors.

Fake Snakes Some of the false coral snakes, such as the California mountain king snake, Lampropeltis zonata, live in places where there are no real coral snakes. Even so, it is possible that the false coral snakes may have lived side by side with real coral snakes in the past. Their predators also include birds that move freely from place to place—and may have seen coral snakes in a different location. So their bright colors will still help to protect them from predators.

Around the world The coral snakes from the Americas are the true coral snakes, but there are many similar species in Asia and Africa. Confusingly, these snakes are also called coral snakes and include species from the Malaysian genera Maticora and Calliophis, Aspidelaps lubricus from South Africa, and the Australian Simoselaps australis. The Malaysian blue coral snake (Maticora bivirgata; shown above) is one of a few snakes that has bright blue skin. When these snakes feel threatened, they display their bright red undersides to warn other animals that they are venomous and dangerous. Malaysian blue coral snakes have powerful venom. The venom glands of these snakes extend back from the head to about one-third of the length of the body. Malaysian blue coral snakes burrow underground in search of snakes to eat. Large, wide venom glands on the head would make this hunting tactic very difficult.

97

Crocodiles M Crocodiles have been around for more than 265 million years. In fact, the ancestors of these reptiles lived at the same time as the dinosaurs. Crocodiles are the largest of all reptiles, with tremendous power in their huge jaws. These fearsome predators show a remarkable level of care for their eggs, nests, and young.

98

ost crocodiles live in or near fresh water. They hunt and feed in the water and then move onto land to bask in the warmth of the sunlight. Females also lay their eggs on the land. Many crocodiles once roamed the world’s oceans. They were fearsome predators of the sea. Today, only two species A saltwater crocodile opens its enormous jaws.â•‹These fearsome predators will attack

animals as big as water buffalo. Attacks on people are rare, but those that do occur are usually fatal.

Fact File regularly swim in saltwater environments. They are the saltwater crocodile from the Indo-Pacific region, and the American crocodile from the Caribbean. The Nile crocodile may venture into the sea on rare occasions. All crocodiles have salt glands at the back of their mouths. This suggests that all the ancestors of crocodiles may once have lived in the sea. The salt glands allow crocodiles to get rid of excess salt without losing too much water from their bodies and becoming dehydrated.

CROCODILES Family: Crocodylidae—13 species: African dwarf crocodile (Osteolaemus tetraspis), African slender-snouted crocodile (Crocodylus cataphractus), American crocodile (C. acutus), Central American crocodile (C. moreletii), Columbian crocodile (C. intermedius), Cuban crocodile (C. rhombifer), Johnston’s crocodile (C. johnstoni), mugger (C. palustris), New Guinea crocodile (C. novaeguineae), Nile crocodile (C. niloticus), Philippine crocodile (C. mindorensis), saltwater crocodile (C. porosus), Siamese crocodile (C. siamensis) Order: Crocodylia Crocodylian

Super Senses Crocodiles have much sharper senses than other reptiles. Since they tend to hunt at night, their eyes have vertical, slit-shaped pupils, which can be opened wider to allow more light into the eyes. The eyes also have a reflective layer on the retina, which makes the eyes glow in the dark if a light shines on them. This layer works like a mirror, reflecting back the available light and helping to provide a clearer image. Crocodiles have excellent vision in daylight, and they can see in color. A see-through shield covers and protects their eyes while underwater and still allows the crocodiles to see well. If the water is muddy, crocodiles use their keen sense of smell to detect their prey. They also have acute hearing, which they use both for hunting and communicating with other crocodiles. Adult crocodiles keep in touch with each other by bellowing and slapping their head down on the surface of the water. These noises carry some distance, so they can be heard by other crocodiles in the area.

Where do they live?: Africa, southern Asia, Australia, and Central and South America

Equator

Equator

Habitat: Lakes, rain forests, rivers, swamps, and islands in tropical regions Size: HeadÂ�–tail length 6.5–23 ft. (2–7 m); weighs up to 2,200 lb. (1,000 kg) Coloration: Brown, black, green, and sandy yellow Diet: Antelope, birds, cattle, fish, frogs, horses, insects, snakes, turtles, zebras Breeding: Females lay 10–90 eggs that hatch after 55–110 days Life span: Usually between 20 and 50 years, but some live up to 100 years Status: The Orinoco, Philippines, and Siamese crocodile are critically endangered; the Cuban crocodile is endangered; the African dwarf crocodile and the mugger are vulnerable; the American crocodile is threatened with extinction

99

Crocodiles

have to swallow their food whole or rip it into chunks. Crocodiles sometimes work together to tear apart the body of their prey. One crocodile holds on to the body, while the other spins around underwater, ripping off chunks of meat. Teeth fall out and are replaced throughout their lives. They usually last up to two years before falling out.

Nests and Eggs Saltwater crocodiles are giants of the reptile world. Adult males can grow to 20 ft. (6 m) or more and weigh more than 2,200 lb. (1,000 kg). Females are usually half the size of the males.

Female crocodiles can also hear the sound of the young calling from the nest as they are hatching. Adults are highly sensitive to the distress calls of hatchlings and young crocodiles and quickly come to help them.

Jaws and Teeth The shape of a crocodile’s snout provides a clue about what it eats. Crocodiles with long, narrow jaws and small, sharp teeth are fish-eaters. An example is Johnston’s crocodile. Species with wider jaws, such as the saltwater crocodile, feed mainly on mammals. In some cases, they can eat mammals almost as big as themselves. The fearsome, spiky teeth in a crocodile’s jaws are used to grip and pierce the flesh of prey, but they cannot be used to chew food. Crocodiles 100

Crocodiles reproduce by laying eggs on land. The eggs have hard shells, like those of birds. Females start to reproduce when they are about nine years old. They lay their eggs and bury them under a large mound of plants and soil. As the plant material rots, the heat keeps the eggs warm and helps the embryos develop. The American crocodile is unusual because the females often just dig a hole in the sand and lay their eggs at the bottom of it.

OW? DID YOU KN An ancient crocodile called Deinosuchus grew to more than 50 ft. (15.2 m) long and probably hunted duck-billed dinosaurs. Nile and saltwater crocodiles are big enough to kill people and large animals. But most crocodiles are secretive reptiles that rarely threaten people. Saltwater crocodiles can stay underwater for more than an hour. The muscles that open a crocodile’s jaws are weak. A thick rubber band will easily keep the jaws of a young crocodile shut.

crocodilEs

Awesome ambush Many large crocodiles lie in wait for their prey, suddenly lunging toward the animal in a surprise attack. The crocodile’s body is well suited to this ambush attack. This large, powerful reptile lurks just beneath the surface of the water with only the tops of its ears and eyes visible. In this position, the crocodile looks more like a floating log than a hidden predator. For the final attack, the crocodile moves incredibly quickly, seizing the prey in its wide jaws and dragging it under the water. It is important for a crocodile to overcome its prey quickly as it cannot chase it over land. Crocodiles also tire easily and take a long time to recover from exercise of any kind. They usually kill their prey by drowning them. They then eat every part of the animal, including the bones.

The temperature of the nest controls whether the hatchlings turn out to be male or female. Higher temperatures produce more males, while temperatures below 88 °F (31 °C) produce more females. The nest temperature also affects the skin coloration and patterning of the young. Females often stay near to the nest and guard the eggs from predators. The males often help the females to protect the nest. When the eggs are ready to hatch, the young crocodiles make yelping noises from inside their eggs. The

female hears these calls and digs the eggs from the nest. Females may also help their eggs to hatch. They roll their eggs to and fro in their mouths, pressing them gently to crack the shell open so the hatchlings can emerge. Once the young crocodiles have hatched, the female often carries them in her mouth down to the water. The hatchlings are vulnerable to predators at this early stage, so the female stays nearby to guard them until they have grown and can take better care of themselves. 101

Darwin’s frog These tiny frogs are named for the English naturalist, Charles Darwin, who may have seen them in Chile in 1835. Darwin’s frogs are famous for the way in which males carry their tadpoles in their mouths to protect them while they develop.

102

FROGS and toads

D

arwin’s frogs live along the shallow, cold streams in the beech forests of Chile and Argentina in South America. When they feel threatened, these amphibians leap into the water and often land upside down. This sudden movement shows off their distinctive black and white undersides. The frogs then keep very still and just drift in the water, acting as if they are dead. Most predators prefer to eat living prey, so they tend to leave the frogs alone.

Caring Fathers The male Darwin’s frog calls for a female with a highpitched whistle, which is similar to birdsong. After mating, the female lays her eggs on damp ground and then has nothing more to do with them. The male fertilizes the eggs and stands guard until they hatch about 20 days later. As soon as the tadpoles begin to wriggle around, the male picks them up in his mouth and moves them to a stretchy throat pouch called the vocal sac. He carries the tadpoles around for 50 days as they develop into froglets. During this time, they may absorb a nourishing liquid called “male’s milk,” which is produced in the vocal sac. When the froglets have developed, they crawl out of their father’s mouth. The other member of this family is a small frog known by its Latin name Rhinoderma rufum. Males carry the tadpoles to water rather than holding them in their mouths while the tadpoles develop.

Fact File Darwin’s frog Rhinoderma darwinii Family: Rhinodermatidae Order: Anura Where do they live?: Southern Chile and neighboring parts of southern Argentina Habitat: Streams in beech forests Size: HeadÂ�–body length 1–1.25 in. (2.5–3 cm) Coloration: Bright green, brown, or reddish brown, with a black and white underside and gray throat Diet: Small invertebrates Breeding: Females lay 30–40 eggs; males hold developing tadpoles in their throat pouch Life span: Not known Status: Vulnerable

The English naturalist Charles Darwin is thought to have discovered the frog during his expedition on HMS Beagle in the nineteenth century.

103

Dragon lizards Dragon lizards are also called chisel-toothed lizards because of the shape of their teeth. These lizards often have spines, crests, or flaps on their heads and backs. There are hundreds of different species.

104

snakes and lizards

D

ragon lizards have several features in common. They all have four legs and long, rounded tails. Seen from above, the heads of these lizards often seem to be a triangular shape. Many species have plump, pear-shaped bodies, but a few are more slender. Most of these lizards have large eyes, good eyesight, and colorful skin. Some species have large, pointed or spiny scales, while others have smaller scales and a silky texture to their skin. Males are usually brighter than the females and young of the same species. Males may have elaborate crests and neck frills. Females of some species have less obvious decoration.

Chisel Teeth The teeth of most lizards are loosely joined to the sloping inside edges of their jawbones. In dragon lizards, the teeth are firmly joined to the top edges of the jawbones. The teeth at the front of their heads are often joined to form wider, chisel-shaped teeth. These are more like the incisors (cutting teeth) of mammals than the typical pointed teeth of most lizards. Dragon lizards are similar to iguanas in many ways, but the shape of their teeth is the main feature that sets the two different groups apart. Dragon lizards live in Africa, Asia, Australia, and the Middle East. Many dragon lizards have similar lifestyles to the iguanas of the Americas and Madagascar. American horned lizards are similar to the Australian thorny devil.

Fact File Dragon lizards Family: Agamidae—430 species divided into 49 genera, including Agama (31 species of agamas); Draco (28 species of flying lizards); Phrynocephalus (43 species of toad-headed agamas) Order: Squamata Where do they live?: Africa, Asia, Australia, and the Middle East; one species from southeastern Europe

Equator

Habitat: Varies from dense tropical forests to deserts Size: Head–tail length 1.6–14 in. (4–35 cm) Coloration: Brown, gray, or black; some forest species are green Diet: Varies from plants and invertebrates to other lizards and small mammals Breeding: Most species lay eggs, that hatch after about 6–8 weeks; toad-headed agamas may give birth to live young Life span: Up to 15 years

Chinese water dragons live in the humid forests


of central and southeast Asia, where they hunt insects and other small prey from the treetops.

105

Dragon lizards

lay eggs, but some of the toad-headed agamas from Central Asia may give birth to live young.

Australian water dragons have a row of long spikes at the base of their

Australian Dragons

heads, forming

Scientists think that the first dragon lizards appeared in Australia around 20 million years ago. The Australian water dragon of the northeastern forests is a descendant of these ancient reptiles. Other modern groups include Diporiphora species, which live across Australia. They have slender bodies and are marked with light stripes. Species from the group Ctenophorus often have camouflage colors. During the breeding season, the males may have brightly colored heads and necks. Some of the larger Australian bearded dragons can puff up their necks, making their pointed scales stand out like “beards.” Species from the group Tympanocryptis are called earless dragons because they have no ear openings on their heads.

what is known as a nuchal crest.

DID YOU KNOW? Pogona species have a “beard” on the throat, which is made of pointed scales. The thorny devil is covered with spines that protect it from predators. Draco species from southeast Asia can glide from tree to tree on “wings” of skin supported by their ribs. Butterfly lizards also use their ribs to expand small, colored flaps of skin, although these are not used to fly.

106

The Central American basilisks look similar to the water dragons and sail-fin lizards that are found from southeast Asia and Australia.

Lizard Lifestyle Dragon lizards usually live on the ground or in the treetops, but many hide in burrows at night or during very hot or cold weather. A few live along rivers and jump into the water to escape predators. Flying lizards take to the air for the same reason. Almost all dragon lizards eat meat. Many will also eat plant material from time to time. The thorny devil of Australia specializes in eating ants, lapping them up with its tongue. Male dragon lizards may threaten or fight other males of the same species to win females for mating. Sometimes they use their large front teeth in the battles. Most female dragon lizards

Spines, Sails, and Tails Many Asian water dragons live in humid rain forests. Many have bright green colors, with low crests of large, pointed scales. Some have prickly spines on the back of their necks and over their eyes. The three sail-

snakes and lizards

fin lizards have high crests on their heads and backs. They live on islands in Indonesia and the Philippines and are some of the largest dragon lizards. Toad-headed agamas live in the deserts and grasslands of Central Asia, the Middle East, and the Arabian peninsula. They have flat bodies, wide heads, and thin, spindly legs. One common species is Phrynocephalus mystaceus. When threatened, it hisses, opens its bright red mouth, swings its tail around rapidly, and jumps at its attacker.

Butterfly Lizards Seven species of butterfly lizards live in the humid forests of China and southeast Asia. Several species have red and black markings along their flanks. These reptiles can expand their ribs a little, which flattens their body and shows off their brightly colored sides. These look like the wings of a butterfly, which is where these lizards get their common name. Scientists once thought that butterfly lizards could glide short distances. As they live on the ground, not in the treetops, but this seems unlikely.

Sri Lankan Specials Several unusual agamids live only on the island of Sri Lanka in the Indian Ocean. These lizards survive in the few patches of rain forest there, especially in the Knuckles Range in the center of the island. They include the hump-nosed lizard (Lyriocephalus scutatus; see right), which has a large, rounded bump on its snout, as well as the rare pygmy agama (Cophotis ceylanica). There are also five species of horned agamas from the genus Ceratophora, but two of these lizards do not have any horns. The rarest horned agama, called Ceratophora tennentii, lives only in one small part of Sri Lanka, much of which is now converted into farmland. This species is in danger of becoming extinct.

107

Eastern box turtle Eastern box turtles take their name for the way in which they close up their shells like a box when threatened. Some eastern box turtles live for more than 130 years. They have even appeared on an American postage stamp.

108


T

he domed upper shell, called a carapace, reveals a lot about the lifestyle of the eastern box turtle. It indicates that these reptiles spend much of their lives on land. Turtles that live in the water usually have more streamlined shells. The domed shell of these turtles can sometimes cause problems for males when they mate with the females. If the males fall upside down, they find it very hard to turn the right way up again. In most cases, the males use their powerful necks to flip themselves over. The bottom shell, or plastron, of a box turtle has two hinges. This allows the turtle to shut its shell completely, which protects it from predators and also allows it to conserve moisture.

Deep Sleep In the northernmost part of its range, the eastern box turtle enters into a deep sleep, called hibernation, during the winter months. Hibernation usually starts in late October or November. These turtles usually hibernate in the same sites each year, choosing to burrow down into the soil or bury themselves under vegetable debris or the muddy bottom of a pond or stream. Several eastern box turtles may share the same hibernation sites. The hibernating turtles burrow deeper as the soil temperature drops. Sometimes they bury themselves 24 inches beneath the surface. Those that survive the winter usually emerge from hibernation in April. Mating takes place soon after.

Fact File Eastern box turtle Terrapene carolina Family: Emydidae Order: Testudines Where do they live?: Eastern United States to northern Mexico Habitat: Open areas of woodland; sometimes also in marshy areas Size: Shell length up to 8 in. (20 cm); weighs 2.1 lb. (1 kg) Coloration: Brown with orange and yellow markings on the chin and front legs Diet: Vegetable matter and fruit, invertebrates, smaller vertebrates, and carrion (dead animals) Breeding: Females lay 3–8 eggs that hatch after 9–18 weeks Life span: More than 130 years Status: Lower risk—near threatened

The color of the shell varies between turtles. In most cases, it is brown or black and covered with yellow or orange blotches, lines, or spots.

109

Eastern newt Adult eastern newts are also called red spotted newts because of their distinctive coloration as they mature. Adults usually live in water, while the young orange newts, called efts, live on the land.

110


E

astern newts have three main stages in their life cycle. These amphibians begin life as larvae in the water. Over time, the larvae change into efts, which live on the land. The efts then gradually develop into adults and return to the water to breed. The most familiar form in this cycle is the eft stage. Efts are small, orange amphibians that live among the leaf litter. They are usually active during the day. The bright color of the eft warns other animals that its skin is poisonous. Indeed, the efts are much more poisonous than the adult eastern newts. Predators such as American toads, garter snakes, red-tailed hawks, and raccoons will avoid the efts at all costs. Their colorful defense does not work so well in the dark, however, and bullfrogs and some turtles will eat them.

Newt Courtship Eastern newts usually have a very simple courtship. A male displays in front of a female, she nudges his tail, he drops a sperm packet, and she picks it up. More complex courtship displays involve the male grasping the female with his back legs and rubbing her snout with the sides of his head and front legs. He also curls his tail around and wafts scent past her nostrils. After an hour or so, the male releases the female and drops his sperm packet. If all goes well, the female picks up the packet. However, she may swim away or another male may replace the sperm packet with his own.

Fact File Eastern newt Notophthalmus viridescens Family: Salamandridae Order: Caudata (Urodela) Where do they live?: Eastern part of North America Habitat: Lakes, ponds, reservoirs, swamps, and water-filled ditches in forests or open farmland Size: Head–tail length 2.5–4.5 in. (6.3–11 cm) Coloration: Young are orange; adults are olive green above and yellow below, with row of red and black spots Diet: Small invertebrates Breeding: Females lay 25–350 eggs that hatch after 20–35 days Life span: From 12 to 15 years Status: Lower risk—least concern

The red eft is the intermediate stage between the larval and adult forms of the eastern newt. The eft spends all of its time on the land.

111

Edible frog When a pool frog breeds with a marsh frog, they produce a hybrid called the edible frog. This cross between two different amphibian species has large back legs, that are eaten as a delicacy in some parts of the world, especially in France.

112

frogs and toads

E

dible frogs are active during the day, even in bright, warm weather. They sit near water, often under a clump of grass or other plants that provide cover from predators. The color of the skin of these amphibians blends in well with their surroundings, providing good camouflage. If they are disturbed, edible frogs jump into the water and swim to the bottom, using their strong back legs and webbed feet. They soon resurface, looking around for danger with eyes that bulge out from the top of their heads. Males have a pair of white or pale-colored vocal sacs on the sides of their heads. They puff these out to make their calls louder. Males produce loud calls to attract females during the breeding season, which is usually in May. Female edible frogs are larger than the males. Edible frog tadpoles are usually dark brown or greenish and are 1–3.5 inches in length.

Fact File Edible frog Pelophylax esculenta Family: Ranidae Order: Anura Where do they live?: Central and eastern Europe Habitat: Canals, lake edges, ponds, pools, and water-filled ditches; also lives in brackish (slightly salty) water Size: Head–body length 4.75 in. (12 cm); weighs 20–75 lb. (9–34 kg) Coloration: Green with a lighter stripe in center of back; back of the thighs are often yellow Diet: Invertebrates Breeding: Female lays up to 4,000 eggs in 3 clutches Life span: 5–6 years Status: Lower risk—least concern

Mixed-up Frogs Edible frogs are unusual because they are not a true species. These amphibians are the result of a cross between a pool frog (Pelophylax lessonae) and a marsh frog (Pelophylax ridibunda). When these two frogs breed they produce a hybrid edible frog. Most hybrids cannot breed and produce young of their own. Edible frogs are unusual because they can breed and produce their own young. They can also breed with other marsh frogs and pool frogs if there are no edible frogs around. Edible frogs are green with black spots and stripes over the back and legs. These amphibians live in ponds, lakes, and streams across Europe. 113

Eyed lizard The eyed lizard is a large, powerful European lizard that will eat almost anything. The male’s blue spots look like simple eyes, or ocelli, which is why this lizard is also called the ocellated lizard.

114

snakes and lizards

D

espite its size, the eyed lizard is a shy, secretive reptile. When disturbed, it runs away at great speed, crashing noisily through the undergrowth. It does not live up to its scientific name lapida, which means “graceful.” Eyed lizards usually hide from danger in burrows, under large rocks, or in holes in walls or piles of rocks. If a predator such as fox, weasel, or large bird of prey corners one of these lizards before it can hide, it will open its mouth wide and make a loud hissing noise. As a last resort, the eyed lizard will jump forward and bite hard.

Males and Females Male eyed lizards guard their own feeding and breeding area. This is known as their territory. The male will sit on top of a large rock or log and watch for rival males, as well as predators. Males of a similar size and strength may fight for their territory. They circle each other with their throats puffed out. Suddenly, one male will dart forward to try and bite its rival while he is not looking. A male will mate with any females that live within his territory. About ten weeks after mating, females lay their eggs in the soil or leaf litter or under a rock or a log. The hatchlings are about 4.5–5 inches long and look different from the adults. They are brown or olive, with white spots on their back and flanks. It takes about three years for them to develop into mature adults.

Fact File Eyed lizard Lacerta lepida Family: Lacertidae Order: Squamata Where do they live?: Spain, Portugal, southern France, and northwestern Italy Habitat: Dry hillsides, olive groves, roadsides, scrubland, and vineyards Size: Head–tail length 24–30 in. (60–76 cm); weighs up to 17.6 oz. (500 g) Coloration: Green or brownish green, with black stippling and blue spots on the sides; females may not have blue spots Diet: Fruits and other plant matter, insects, frogs, lizards, snakes, young nestlings, and small mammals Breeding: Females lay 4–6 eggs that hatch after 8–14 weeks Life span: Not known Status: Common

The eyed lizards are the largest in their family in Europe. The biggest males may grow to 2 feet or more. Despite their size, these reptiles are timid creatures.

115

File snakes The three species of file snakes take their name for their rough skin, which is similar to the surface of a file. These reptiles are also called wart snakes because their bodies are covered in small, wart-like scales. File snakes live in freshwater or saltwater and are helpless on land.

116

snakes and lizards

F

ile snakes are well suited to a life in the water. Their bodies are flattened from side to side and have a keel, or ridge, of scales underneath. The keel helps these snake to swim more efficiently. Their skin is loose and baggy, allowing them to change their body shape when swimming and push through the water quickly. A prehensile (gripping) tail allows these snakes to hang on to underwater logs and plants, stopping them from being swept away by strong water currents. File snakes can stay submerged for forty minutes or more, sealing their nose and mouth to keep the water out. Their lungs are large and have a greater surface area than those of other snakes. File snakes also have nearly twice as much blood as snakes of the same size (apart from sea snakes), so their blood can carry twice as much oxygen. When they do come to the surface, file snakes take several breaths for fifteen to twenty seconds, then they dive underwater again.

Seeking Prey File snakes rarely swim in open water. They prefer to crawl over the ocean floor, using their long tongues to explore their surroundings and find food. File snakes feed on fish such as eels. They hunt at night when the eels are asleep in their burrows. They grasp their prey in their jaws and use their rough scales to hold the victim in place as they squeeze it to death. The scales are rough because each one ends in a small bristle.

Fact File File snakes Acrochordus arafurae, A. javanicus, and A. granulatus Family: Acrochordidae Order: Squamata Where do they live?: From India and Sri Lanka across southeast Asia to northern Australia and southern New Guinea Wart snake (acrochordidae)

Equator

Equator

Habitat: Fresh or brackish (slightly salty) water and seawater Size: Head–tail length 39 in. to 10 ft. (1–3 m); males are smaller than the females Coloration: Drab brown or gray; A. granulates is dark gray with bars of off-white on the sides Diet: Mainly fish, including eels Breeding: Females give birth to 11– 27 live young every few years Life span: Not known Status: Not endangered or threatened

The Javan file snake is well-suited to a life underwater. A flap in the upper jaw closes off the nostrils when these snakes are submerged.

117

Fire salamander The bright colors of the fire salamander warn other animals that it is poisonous. This large, secretive amphibian spends most of the day hiding under a log, in moss, or under leaf litter. It emerges at night to feed.

118


T

he fire salamander takes its name from the belief that these amphibians could survive in a fire. This myth probably originated when people saw the salamanders crawling out of logs that had been thrown onto fires. This would have been seen as a sign that the salamanders had supernatural powers. In fact, they were probably just hiding in the logs when they were collected for firewood and were forced to emerge to avoid being burnt by the flames.

Fact File Fire salamander Salamandra salamandra Family: Salamandridae

European salamander & newt (salamandridae) Order: Caudata (Urodela) Where do they live?: Europe; closely related species live in north Africa and western Asia

Poison Packs Fire salamanders are highly toxic. These amphibians have large poison glands, called parotid glands, behind each eye and two rows of poison glands along their backs. The colored areas of the skin usually coincide with the location of these glands. The salamander’s poison is so potent that it can cause convulsions (muscle spasms). If they are attacked by a predator, fire salamanders can squirt poison from their glands at distances of up to 6 feet. They do this by squeezing the muscles around the glands. They even tilt their body so that streams of milky, sticky poison are aimed at the predator. This is unusual because most other salamanders can only release poison when a predator bites or squeezes them. As well as repelling predators, the fire salamander’s poisons may also work like antibiotics, protecting its sensitive skin against attack by microorganisms such as bacteria and fungi.

Size: Head–tail length 7–11 in. (18–28 cm); weighs 0.6 oz. (19.1 g) Coloration: Jet black with bright yellow, red, or orange markings Diet: Insects and worms Breeding: Females usually give birth to aquatic larvae; some forms give birth to live young Life span: More than 14 years Status: Lower risk—least concern

Most fire salamanders are black with yellow spots and stripes. Others come in shades of red or orange, although these are much rarer.

119

Fire salamander

DID YOU KNOW?

Lifestyle and Feeding

Fire salamanders usually emerge at The word night to feed. The eyes of the adults salamander are adapted to see best in dim light. comes from During the night, adult salamanders an Arabic word, which means may wander up to 30 yards from “lives in fire.” their daytime hiding places, but Salamander they always find their way back to larvae may eat each other the same spot. The larvae also avoid if larvae of bright light and hide under stones different sizes and dead leaves during the day. live together. When the weather is dull and rainy, The venom from a fire salamander however, adult fire salamanders may will easily kill a come out during the day. dog and possibly even a person. Fire salamanders use their senses Fire salamanders of sight and smell when hunting for sometimes have prey. The sense of smell is probably bright yellow skin with no markings. not as important as their sense of

sight. Fire salamanders eat a wide variety of prey, depending on where they live. Larvae and young adults usually eat whatever suitable prey is available in their habitat. The Pyrenean fire salamander feeds on earthworms, and many will eat nothing else. On the other hand, the central Spanish fire salamander lives around high mountain lakes where there are no earthworms. It feeds mainly on beetles and flies.

Courtship and Young Fire salamanders are ready to breed when they are three or four years old. The breeding season usually starts in the fall. Males claim areas, called territories, and defend them from rival males. The older male usually wins these fights. During courtship, the male nudges the female’s head and flanks before moving under her body and looping his front legs over hers from below. He drops his sperm packet on the ground and then swivels sideways to allow the female to pick up his sperm. Females can store sperm for up to two and a half years. When Fire salamanders are often found on mossy tree trunks near water.

120


Meet the family There are four recognized species of fire salamander. They are Salamandra salamandra from Europe, S. algira from North Africa, S. corsica from Corsica, and S. infraimmaculata from the Middle East. Alpine salamanders are closely related to fire salamanders and have now been split into two species. The alpine salamander

they mate in the fall, the eggs are usually fertilized by the sperm the following spring. The developing young are held inside the female’s egg tube for up to a year in some cases. The female usually gives birth to larvae. She reverses into shallow water so the larvae can swim away from her body to continue their development in the water. Sometimes

(S. atra) is found across the Alps. Lanza’s alpine salamander (S. lanzai) is a close relative but is larger and has a flattened head. It lives in the southern foothills of the Alps in Italy and in parts of France. Another relation is Luschan’s salamander (S. luschani), which lives in southwestern Turkey and islands off the Turkish coast.

she keeps the larvae inside her body until they have changed into adults. In this case, she gives birth to fully formed young. Fire salamanders from colder places, such as mountains, are more likely to give birth to fully formed young. The developing young are better protected inside their mother’s body than they would be outside in a harsher environment.

During mating, the male fire salamander slides under the female’s body and drops his packet of sperm for the female to pick up. 121

Fire-bellied toads The fire-bellied toads are named for their bright red, orange, or yellow patches on their undersides. An unusual feature is that the pupils in their eyes are triangular or heart-shaped.

122

frogs and toads

F

ire-bellied toads live in small groups, called colonies, around a small area of water, such as a pond or flooded field. These toads usually float on the surface of the water with their legs outstretched. In this position, their green and black backs provide good camouflage. When threatened, fire-bellied toads dive rapidly and bury themselves in the mud, or they swim to the edges of the water to hide among the vegetation. The webbed hind feet means these frogs are good swimmers. When confronted by a predator, they may show off their brightly colored bellies as a warning that they are poisonous and not good to eat. Species from the rare group Barbourula are in the same family as fire-bellied toads, but they do not have brightly colored undersides. They spend even more time in the water and have flattened heads, webbed front feet, and large, webbed back feet for swimming.

Tiny Tongues Many frogs and toads have long tongues that they shoot out of their mouths to pick up prey from a distance. Fire-bellied toads have short, rounded tongues, so they cannot catch their prey in the same way. Instead, these frogs are ambush predators. They sit and wait until prey moves close by and then lunge forward to grab it. They will eat almost anything that fits in their mouth, which is mostly insects and other small invertebrates that share their habitat.

Fact File Fire-bellied toads Family: Bombinatoridae (7–10 species divided into 2 genera): Bombina and Barbourula Order: Anura Where do they live?: China, Europe, Korea, southern Japan, northern Vietnam, Philippines, and Borneo

Fire-bellied toad (bombinatoridae)

Tropic of Cancer Tropic of Cancer

Habitat: Forest clearings, peat bogs, pools, shallow lakes, streams, and flooded fields in wetlands, scrubland, or forest clearings Size: HeadÂ�Â�–body length 1.5–2 in. (3.8–5.5 cm); weighs 1–2 oz. (28–56 g) Coloration: Green with black spots on back; bright red with black spots on underside Diet: Adults eat invertebrates; tadpoles eat algae, fungi, and plants Breeding: Females lay between 40–110 eggs that hatch after 5–8 days Life span: Up to 20 years

The striking color on the belly of the fire-bellied toad


warns other animals that they are not good to eat. The dull colors on its back provide good camouflage.

123

Flying frogs Flying frogs glide among the trees of the rain forest by spreading out their huge webbed feet and using them like parachutes to break their fall. Flying frogs stick their eggs to leaves or tree trunks overhanging water. The tadpoles then drop down into the water when they hatch.

124

frogs and toads

R

einwardt’s flying frog and several of its close relatives, such as Wallace’s flying frog and the harlequin treefrog, spend most of their lives in the rain forests, high in the treetops. These amphibians rarely venture to the forest floor, except during the breeding season. The only other time they might move to the forest floor is if they are chased by predators. In this situation, the frog jumps from a branch, holds its legs out to the side, and spreads out its large webbed feet. As the frog glides through the air, it steers by changing the position of its legs. The frog then lands on a branch or large leaves lower down the tree. The toes of these frogs end in large sticky pads, similar to suckers, which help them to grip tightly when they land.

Tadpole Homes Reinwardt’s flying frog breeds in shallow forest ponds, often using the pools made by rhinoceroses or wild pigs when they wallow in the mud to cool down or remove pests from their skin. Other species from the group Rhacophorus lay their eggs over flowing streams, and their tadpoles live in the spaces between rocks and stones, or in quiet streamside pools full of dead leaves and other debris. The brown treefrog sticks its eggs to tree trunks above holes full of water, or the pools formed between the large, flat buttress roots of the giant forest trees. When the eggs hatch, the tadpoles of the flying frogs have rounded bodies and high fins.

Fact File Reinwardts’s flying frog Rhacophorus reinwardtii Family: Rhacophoridae Order: Anura Where do they live?: Southeast Asia (Borneo, Java, Malaysia, and Sumatra) Habitat: Rain forests Size: Head–body length 1.75–2.6 in. (4.6–6.6 cm); females are usually bigger than the males Coloration: Bright or dark green, sometimes yellow on sides; webbing between the toes is yellow and blue or black and blue Diet: Insects Breeding: Eggs laid in a foam nest; later hatch into tadpoles Life span: Not known Status: Lower risk—least concern

Flying frogs such as Wallace’s flying frog cannot fly. They glide like parachutes, using the webbing between the toes and skin flaps on the arms and legs.

125

Flying lizards Flying lizards live on the trunks of large trees in the rain forests of southeast Asia. Using their collapsible “wings,” these reptiles glide from tree to tree. Other gliding reptiles include flying geckos and snakes.

126

snakes and lizards

T

he wings of the flying lizards are not true wings, like those of a bird. Instead, they are formed from flaps of skin on each side of the body and supported by extra-long ribs. When a flying lizard wants to glide, it drops down at a steep angle with its wings folded and its tail raised. The lizard then opens its wings and lowers its tail to slow down the descent. Flying lizards glide almost horizontally, using their tails as rudders to steer, and their wings and tails as brakes. After landing on a tree with their heads up, these lizards fold their wings up like a fan. The flying lizard then runs up the tree to make up the height that it lost during the glide. Flying lizards can glide for up to 50 feet or more but they normally glide for much shorter distances—often only a few yards from one tree to the next.

Female Flyers Female flying lizards have larger wings than the males. The extra surface area may help the females to glide when they have the additional weight of their eggs inside their bodies. Females descend to the forest floor to lay their eggs. They are vulnerable to predators at this time because they cannot move very well in the leaf litter. The females lay small clutches of long, spindle-shaped eggs. The eggs have hard caps at each end. This egg type is unique to flying lizards. No one knows the reason for the shape. The behavior of the flying lizard hatchlings in the wild is also a mystery.

Fact File COMMON FLYING dragon Draco volans Family: Agamidae Order: Squamata Where do they live?: Southeast Asia (Borneo, Indonesia, Malaysia, and the Philippines) Habitat: Rain forests Size: Head–tail length 6–8 in. (15– 20 cm); females are slightly larger than the males Coloration: Wings are mottled orange and black; males have a yellow dewlap (throat flap) and females have a blue dewlap Diet: Mainly ants and termites Breeding: Females lay 3–6 eggs and bury them in the ground; eggs hatch after 32 days Life span: Not known Status: Common

The common flying dragon glides through the air. Flaps of skin along the sides of its body act like a parachute to slow the lizard’s descent.

127

Frogs and toads T Frogs and toads were the first animals on the Earth to have a true voice. These amphibians are often heard calling, especially in the breeding season. There are about 4,800 different species of frogs and toads, making up 88 percent of all amphibians.

128

o zoologists, there is not a great difference between frogs and toads. Frogs and toads come from the large group Anura, and they are often called “anurans.” The main distinction between frogs and toads is their skin. Toads are usually dry, warty species that run or walk. The red-eyed treefrog is a striking species that lives in the rain forests of Central America.

Fact File Frogs have smooth, damp skins, live near the water, and move by leaping. Another way of distinguishing frogs and toads is to think of all amphibians without tails as frogs and use the word “toad” for members of certain families, such as the Bufonidae. The toad family Bufonidae is one of the most successful of all the frog and toad families. It has more than 450 species that live in every part of the world apart from Antarctica. Hylidae is a successful frog. It contains around 835 species of treefrogs, marsupial frogs, and leaf frogs living in most parts of the world, except Africa. Although there are more than 1,100 species of rain frogs, most of them live in Central and South America. Tropical forests are home to the greatest numbers of anurans. A few acres of tropical forest in South America may contain as many as 80 different species, which is the same as the total number of species found in the United States. The island of Madagascar off the southeastern coast of Africa is also home to a huge variety of species, nearly all of which are unique to the island. Tropical forests are ideal places for frogs because they are warm and moist, there are plenty of places in which to hide from predators, and there are many insects and other invertebrates for them to eat.

Body Forms The body shapes of frogs and toads suit the environments in which they live. For example, the spadefoot toads have powerful legs that end with horny “spades” that are used for digging. Other species have pointed snouts, which are

Frogs and toads Families: There are 28 families divided into about 346 genera, including Leptodactylidae (about 1,110 species of rain frogs); Bufonidae (about 454 species of true toads and harlequin toads); Hylidae (835 species of treefrogs, marsupial frogs, and leaf frogs); Ranidae (729 species of water frogs); Microhylidae (358 species of narrow-mouthed frogs). Order: Anura Where do they live?: Every continent apart FrogsAntarctica and toads from

Equator

Equator

Habitat: Most habitats except polar regions and very dry deserts Size: Head–body length 0.2–34.5 in. (1–88 cm); most 0.8–4.75 in. (2–12 cm); largest species weigh up to 8 lb. (3.6 kg) Coloration: Green, brown, gray, black, red, orange, yellow, or even blue Diet: Adults eat plants, invertebrates, small vertebrates, and carrion (dead animals); tadpoles eat plants and small invertebrates Breeding: Females lay eggs in water or on moist ground; eggs develop in or on one of the parents; most species hatch into tadpoles but some develop inside the egg and hatch as small froglets Life span: 1–10 years in captivity, although some may live more than 35 years Status: Varies according to species

129

Frogs and toads

Treefrogs and other climbing species have suckerlike pads on the tips of their toes that help them to cling on to slippery branches.

used to burrow headfirst through the soil. Swimmers also have pointed snouts, as well as webbed feet and streamlined bodies to glide effortlessly through the water. The African ghost frogs have huge pads on their toes to help them cling to slippery rocks behind waterfalls. In dry climates, frogs with short, stout bodies survive well because they have a relatively small surface area. This reduces the amount of water they lose through their skin.

Skin Secrets Frogs and toads breathe through their skin as well as through their lungs. The skin must be kept moist to allow oxygen to enter the body and waste carbon dioxide to leave. Glands keep

Waxy coat The waxy frog (right) from the dry Chaco region of South America has a clever way of surviving the dry season. It covers itself with a waxy substance produced from glands in its skin. It wipes the wax all over its body using its long, back legs. This creates a waterproof layer that holds in moisture and prevents the frog from drying out. Most frogs live in the tropics because the air is so humid. They do not need to be near water to keep their skin moist. It is much easier for a frog to survive in a damp place than a dry place.

130

Frogs and toads

their skin moist, but in very dry conditions, frogs and toads lose too much water and dehydrate. Species that live in the desert and other dry places have fewer moisture-producing glands in their skin, so they do not dry up as quickly. However, this also means they cannot breathe through their skin as efficiently, so they need larger lungs.

Extreme Survival Frogs and toads living in arid places often spend the dry season underground to avoid drying out. Some species form cocoons of mud that bake hard around their bodies and seal in the moisture. They only come to the surface when heavy rain breaks up the mud and allows them to escape. Species from cold places, high in the mountains, often have dark skin. This helps their bodies to absorb as much heat as possible on sunny days and also protects them from the Sun’s harmful radiation, which is much stronger at higher altitudes. Most parts of the world have at least one “urban frog” species that lives in drains, garden ponds, and greenhouses. Some species travel with greenhouse plants and crops when they are sent to markets or shops, and end up hundreds of miles away from their homes.

Food and Feeding All adult frogs and toads are carnivores (meateaters). They prefer to eat living, moving prey. The choice of prey depends largely on its size

The cane toad eats prey that has been killed by other animals, which is known as carrion.

OW? DID YOU KN The biggest froglike amphibian is the Goliath frog, which is 34.5 in. (88 cm) long. The smallest is probably the Cuban leaf litter frog, at only 0.33 in. (1 cm) long. The skin of the yellow poison dart frog exudes enough poison to kill up to 1,000 people. Some frogs have bright colors to warn other animals to leave them alone because they are poisonous.

131

Frogs and toads

and availability, but frogs and toads are not very fussy eaters. Anurans do not chew their food. Instead, they swallow it whole. Frogs and toads will try and eat more or less anything they can fit in their mouths. Different species find and catch prey in different ways. Larger species tend to sit and wait for their prey to pass by them. They often have camouflage colors or hide under leaves or moss. Smaller species are usually more active and spend hours searching in crevices and under leaves in the hope of finding small insects and other invertebrates. Many species have long tongues that are folded on the base of the mouth, with the tip pointing back toward the throat. The frog flicks out the tongue quickly to pick up passing prey. Some burrowing species even live in the nests of their prey. The larvae (tadpoles) of most frogs and toads use several rows of rasping teeth to scrape algae and bacteria from leaves, rocks, and underwater

OW? DID YOU KN The common toad lives at altitudes of more than 26,000 ft. (8,000 m) in the Himalayas of Central Asia. When food is scarce, tadpoles may eat other tadpoles, sometimes even their own brothers and sisters! The tadpoles of poison dart frogs eat special eggs that their mother lays for them. Newly hatched Gardiner’s frogs are about the size of a grain of rice.

132

debris. Some filter food from the water instead. As they grow, the mouthparts of the larvae become more powerful, and they may switch to plant leaves and stems. Eventually, they may snap up invertebrates that live in the water or are unfortunate enough to fall into the water. A few tadpoles even eat the eggs of other frogs. When food is particularly scarce, some tadpoles may eat other tadpoles.

Life Cycles The life cycles of frogs and toads vary between different species. The typical life cycle of a European common frog starts in the spring. Males start to call from breeding ponds to attract the females. Nearly all anurans that mate in the water pair up with the male clinging to the back of the female. This position is called amplexus, and it is the best position for the male to fertilize the eggs as they are being laid. The eggs then begin to hatch into free-swimming tadpoles that grow legs, lose their tails, and emerge onto land as adults. Variations on this typical life cycle include that of the midwife toad, in which the male carries a string of eggs wrapped around his back legs. In the marsupial frogs, the female carries the eggs around with her. Frogs and toads that live in places where there are no suitable ponds or streams may lay eggs that hatch into miniature versions of the adults. The tadpole stage occurs inside the egg before it hatches. Other species carry their developing

Frogs and toads

young inside their bodies, for example, in their mouths, stomachs, or inside the female’s egg tubes. The adults do not let their young out of

their bodies until they have developed into fully formed frogs or toads.

Frog life cycle When it hatches, a common frog looks very different from its parents. It is a tadpole. It has no legs—just a large head, a tail for swimming, and gills to take in oxygen from the water. Over 16 weeks,

the tadpole goes through a dramatic change called metamorphosis. It grows four legs, loses its tail, and starts to breathe using newly developed lungs inside its body. Year 4:â•‹The adult frogs mature and are ready to produce young of their own.

Day 1: Tadpole breathes through its skin. It feeds on yolk in its stomach.

Days 2–3: Tadpole starts to swim and feeds on plants. It breathes through feathery gills outside its body.

ONâ•‹LAND

IN WATER

Week 16: Tadpole is now a tiny frog without a tail. The young frog leaves the water but remains nearby for some time.

Week 3: Tadpole has grown bigger and breathes through gills inside its body.

Weeks 8–10: Tadpole has back legs and breathes air from the surface using lungs inside the body. It starts to eat meat instead of plants.

Week 12: Tadpole has front and back legs, a shorter tail, bigger eyes, and a wider mouth.

133

Galápagos giant tortoise The largest tortoises in the world live on the Galápagos Islands in the Pacific Ocean. These reptiles probably drifted across the ocean from Central America, perhaps on floating tree trunks. The biggest Galápagos tortoises weigh as much as three men and may live for 200 years.

134


T

he Galápagos Islands were formed when volcanoes erupted through the seafloor about 600 miles off the coast of Ecuador in northern South America. The first giant tortoises washed up on the beaches of the island of Española. Later, more giant tortoises landed on the islands of southern Isabela, Volcan Darwin, and Volcan Alcedo. A third batch of tortoises landed on other islands in the group. It may seem unlikely that tortoises could just drift across the ocean for hundreds of miles and end up on some remote islands. Yet tortoises are often carried far from land during floods and they can survive very well at sea. They stay afloat with little effort, bobbing along on the ocean waves. They can survive for long periods without eating. They use the stores of body fat to supply them with energy. One female is all that is needed to start a new population of tortoises if she already carries a male’s sperm inside her body. Female tortoises can lay eggs for up to four years without a male being present. The young giant tortoises on the Galápagos Islands would have hatched in a safe environment, with plenty to eat and few predators, allowing their numbers to build up very quickly.

Fact File Galápagos giant tortoise Geochelone nigra Family: Testudinidae Order: Testudines Where do they live?: Galápagos Islands in the South Atlantic Habitat: Upland areas Size: Shell length from 29 in. (74 cm) to more than 4 ft. (1.2 m); weighs 500 lb. (227 kg) Coloration: Dull brown; males often have a yellow area on the lower jaw and throat Diet: Wide range of vegetation— even cactus shoots Breeding: Females lay 2–10 eggs that hatch after 3–4 months Life span: Up to 200 years Status: Vulnerable

Three Types of Tortoise Scientists put the different groups of Galápagos giant tortoises into three separate groups based on the way in which they have adapted to their environment. Galápagos tortoises with saddleback shells have longer necks and legs. They need to stretch to reach tall vegetation on the dry islands on which they live.

135

Galápagos giant tortoise

A male calls loudly to attract a female to mate.

The first group is the saddlebacks. They are named for the way the front of their shells rise up above their necks, similar to a horse’s saddle. These tortoises live on dry islands where they need to stretch up to feed on taller plants. The smaller plants on these islands die back during dry periods. Saddlebacks have long legs and long necks, so they can stretch as high as possible. The second group is the tortoises with dome-shaped shells and short necks. This group lives on upland areas of the islands,

where there are plenty of lush plants at ground level. The third group includes tortoises with characteristics partway between the saddlebacks and the dome-shelled tortoises.

Island Races Several groups of the Galápagos giant tortoise live isolated from each other on the twenty different islands in the Galápagos group. Each group has adapted to the different conditions on the islands. The shape of their shells, their maximum size, and the lengths of their necks and limbs vary according to where they live. These differences helped the British naturalist Charles Darwin to figure out his ideas on evolution when he visited the islands as the zoologist on board the HMS Beagle in 1835.

Tortoise Troubles In the nineteenth century, many Galapágos giant tortoises were taken from the islands and used to feed the crews of European whaling ships. So many tortoises were taken that three groups became extinct—on Charles Island, Barrington Island, and Narborough Island. Hunting is now banned, and the tortoises are fully protected by laws passed by the 136


mating games The courtship rituals of the Galápagos giant tortoises are extremely aggressive. The larger male tortoises bash the shells of the females and pin them down by clambering on top of them. The males often make a roaring sound when they mate with the females. The females lay between two and ten hard, spherical eggs from July to December. The young tortoises hatch during the rainy season when there is fresh grass and plenty of other vegetation to eat.

DID YOU KNOW? Galápagos giant tortoises move at speeds of about 590 yards (550 m) every hour. A giant tortoise can live without food for up to 14 months. The shell of a newly hatched giant tortoise measures only 2.5 in. (6 cm) in length.

government in Ecuador. However, the Galápagos giant tortoises still face many problems. Goats left on the islands by sailors long ago now compete with the tortoises for food and can destroy their nests as well. Other introduced species include pigs and rats, and these eat the tortoises’ eggs.

Saving the Tortoises Many conservation programs have been set up to help the Galápagos giant tortoises. The introduction of foreign species is being controlled to prevent competition for food or danger to the eggs and young

Male tortoises stretch their long necks and rise up on their legs in a display of dominance. The taller, larger male usually earns the right to mate with the female.

tortoises. These tortoises are also being bred in captivity. Over the last forty years, the Darwin Foundation on the Galápagos Islands have hatched more than 2,500 young tortoises, adding to a total population of about 10,000 individuals. The tortoises are kept safely in pens and protected from predators, such as birds of prey, until they are three years old. Then they are released into the wild. 137

Garden lizard Garden lizards are found throughout the warmer parts of southern and southeast Asia. They are also called changeable lizards as they can change color. Males take on a bright red body color during the breeding season, giving rise to their other name “bloodsuckers.”

138

snakes and lizards

T

he garden lizard lives in a wide range of habitats across Asia and adapts well to living near people. It is active during the day and is often seen resting on tree trunks and bushes, even near busy roads. Unlike other lizards, the tail of a garden lizard does not break off if it is attacked by a predator. The tail can be long, stiff, and pointed. Both males and females have a crest along the top of the body.

Courtship and Eggs During the breeding season, males are very aggressive. They develop a bright red head, throat, and shoulders. These colors become brighter if a male is winning a fight with a rival, while the defeated males lose their bright colors. Males attract females to their territory by extending a pouch in their throat called the gular pouch, while doing “push-ups” and opening and shutting their mouth rapidly. Females store energy as fat in the bodies to help them produce their eggs. They can also store sperm and keep developing eggs in their egg tubes. As a result, they can lay their eggs when the young lizards are most likely to survive. The female slows the development of eggs inside her body so that they do not become too big to be laid. She does this by lowering the temperature of her body to 73ºF. Both males and females only produce eggs and sperm if they are with members of the opposite sex and therefore able to mate.

Fact File oriental garden lizard Calotes versicolor Family: Agamidae Order: Squamata Where do they live?: Middle East, India, Sri Lanka, Indochina, South China, and Sumatra; also Andaman Islands, Mauritius, and the Maldives Habitat: Open forests, gardens, parks, and the edges of fields Size: Head–tail length up to 20 in. (51 cm) Coloration: Light brown to buff, sometimes faint dark bands; males develop red chests and throats during breeding season Diet: Small invertebrates Breeding: Females lay 10–20 eggs that hatch after 6–7 weeks Life span: 2–4 years Status: Widespread

The Oriental garden lizard is a common sight in many parts of Asia. The throat of the male turns bright red in the breeding season to attract females.

139

Garter snakes The common garter snake is active during the day. The body stripes of these snakes blend in well with the surroundings, making it surprisingly difficult to see them in the wild. These reptiles are named for the patterns on old-fashioned garters, used to hold up stockings.

140

snakes and lizards

G

arter snakes live over a wide area of North America, and they come in many different colors. The endangered San Francisco garter snake has a red head and bright red stripes edged in black on either side of a white central stripe. (Most garter snakes have this white central stripe.) The California redsided garter snake and the Oregon red-spotted garter snake also have large areas of red on their bodies. The northern red-sided garter snake has red spaces between its black scales. The red only shows when the skin is stretched, for example, when it flattens its body if it is threatened by a predator. All-black garter snakes usually live in coastal areas and islands, including the islands of the Great Lakes.

Varied Diet Garter snakes eat a wide range of animals, including earthworms, leeches, fish, and frogs. Some hunt small fish in tidal pools on the beach. Others eat California newts, which are poisonous. Scientists think that the adult garter snakes somehow pass on immunity to the newts’ poison to their young. Garter snakes hunt mainly by sight, but they need to be stimulated by smell before they will strike their prey. These snakes eat prey, such as worms, that cannot fight back, so they usually just grab and swallow their meals. Garter snakes are not poisonous and constrict (squeeze) their prey to death.

Fact File Common garter snake Thamnophis sirtalis Family: Colubridae Order: Squamata Where do they live?: North America Habitat: Ponds, streams, and water-filled ditches in dry regions; damp meadows, marshes, parks, and gardens Size: Head–tail length 18 in. (45 cm) to 4.25 ft. (1.3 m) Coloration: Several long stripes from neck to tail; width and color of stripes vary with location Diet: Invertebrates such as worms, amphibians, and fish; larger snakes eat young birds and small mammals Breeding: Females give birth to 10–30 live young that are born after gestation period (pregnancy) of 60–90 days Life span: Captive garter snakes live for up to 10 years Status: Lower risk—least concern

Common garter snakes do not lay eggs like most other reptiles. Instead, the females give birth to live young around three months after mating.

141

Garter snakes

A garter snake eats a northern leopard frog. Snakes usually swallow their prey headfirst.

DID YOU KNOW? Between 35 and 50 percent of garter snakes do not survive the winter. Some hibernation dens may contain up to 10,000 garter snakes. Some females give birth to eighty young snakes at a time.

142

Hibernation In warmer parts of their range, garter snakes are active all year. In very cold areas, these snakes enter a period of deep sleep, called hibernation, for several months during the winter. During hibernation, the snakes can survive temperatures close to freezing because they shut down essential body processes. The blood thickens as it starts to freeze, and the body temperature falls. Garter snakes have small amounts of “antifreeze” chemicals, mainly in their liver and heart, that stop their cells from freezing solid. Even so, many garter snakes die during hibernation. Garter snakes usually gather in large groups to hibernate. They migrate to limestone caves where the frost cannot reach them. Abandoned

ant mounds are also good places in which to gather. The number of garter snakes at these hibernation sites range from a few hundred to several thousand individuals. The snakes stay together because there is a shortage of good hibernation sites. Hibernating in numbers also means the snakes can share their body warmth, and it stops their bodies from drying out.

Developing Young Males feed throughout the summer to build up fat reserves that will last them through the next winter’s hibernation. Females stop feeding when their developing young begin to take up space inside their bodies. The young take in nourishment from

snakes and lizards

their mother’s blood, which also takes waste products away from the developing snakes. In colder climates, young snakes have a better chance of survival if they stay inside the body of their mother rather than develop inside eggs. The female can bask in the sunlight to help the young snakes develop. The babies are also protected inside their mother’s body from predators. However, the extra weight of the babies makes the female sluggish and slow-moving. About eight to twelve weeks after mating, the female will usually give birth to ten to thirty young. The newborn snakes can survive on their own as soon as they are born. Almost immediately, the young snakes start to hunt for food to fatten up as much as possible in preparation for the winter hibernation. Females that have carried their young throughout the spring and early summer have had little time to build up their fat reserves. For this reason, it seems likely that garter snakes living in the colder northern regions breed only every second year. In the warmer southern areas, garter snakes have a longer summer season in which to feed and can breed every year.

Breeding patterns Common garter snakes from different places have different breeding pattern. In the far north, garter snakes breed for a few weeks directly after they emerge from hibernation. Females give off a scent containing a pheromone that attracts the males. There is huge competition between males. They form “mating balls” around each female. Each male rubs his chin along the female’s back and tries to mate with her. One male succeeds, leaving a waxy plug in the female to stop other males from mating with her. He can then move on and mate with other females. Females move to their summer feeding sites as soon as they have mated. Feeding sites can be up to 11 miles away from the hibernation sites. The males do not leave until all the females have gone.

143

Geckos Geckos are small lizards. They are named for the distinctive “gekok” noise made by some species when they call. Geckos usually emerge at night to forage for insects, spiders, and other small invertebrates. Some species are spectacular climbers.

O

f the three main gecko families, the one with the most species is the Gekkonidae. Nearly all the species from this family have small, granular scales. A few species, such as the frog-eyed geckos and the fish-tail geckos, have larger overlapping scales. Most of these geckos emerge at night to hunt for food, so their eyes are large to let in as much light as possible.

They often use their long tongues to wipe their eyes clean. In bright light, the pupils of nightactive geckos close down to vertical slits to stop the light from damaging their eyes. The colored part of the eye, called the iris, can have delicate and attractive markings. Some of the species in the Gekkonidae family are active during the day. They have smaller eyes and round pupils.

Feet and Toes Gekkonid species have a variety of different feet and toes that are suited to the ways in which they move. Many “house” geckos are brilliant climbers. They can run up any vertical surface, Dark spots cover the head and body of the leopard gecko. The pattern varies among different lizards, however, and some have no spots at all.

144

Fact File rough or smooth, and even rest upside down on ceilings. These lizards have toe pads with special structures called lamellae arranged in rows along each toe. Each lamella consists of thousands of hairlike cells, called setae. In turn, each seta is further divided into even smaller branches. Each of these branches ends in a slightly swollen tip. There may be up to one billion of these tips on each toe. They interact with the surface on which the gecko is moving, allowing the lizard to “stick” to it. When the gecko wants to move its foot, it has to curl up the ends of its toes to “unstick” them. Other gekkonids have claws instead of sticky pads to help them climb among the branches of trees and bushes. These include members of the group Cyrtodactylus (“curved toe”) and the group Gymnodactylus (“naked toe”). Ground geckos do not climb at all. These lizards include species from the groups Chondrodactylus (“grain toe”), and Pachdactylus (“thick toe”). They are common in desert regions, where there is often nothing for them to climb. Ground geckos prefer to live in burrows or the spaces between rocks. Some of them have large heads with powerful jaws for crushing insects with hard bodies, such as beetles. In Africa, barking geckos have fringes of hairlike scales around the edges of their feet to prevent them from sinking into the desert sands. All the ground geckos are active at night.

Southern Geckos Members of the Diplodactylidae family are called “southern” geckos because they live only in the Southern Hemisphere. These lizards are

Geckos Families: 3 families divided into 95 genera: Gekkonidae (about 910 species of typical geckos and American dwarf geckos); Eublepharidae (22 species of eyelid geckos); Diplodactylidae (about 115 species of “southern” geckos) Order: Squamata Where do they live?: Gekkonidae: worldwide, except the polar regions; Equator Eublepharidae: North America, Central America, Africa, Middle East, Japan, eastern China, Malaysia; Diplodactylidae: Australia, New Zealand, and New Caledonia Habitat: Varies from forests to urban habitats Size: Head–body length 2–13 in. (5–33 cm); weight 0.02–10.5 oz. (1–300 g) Coloration: Nocturnal (night active) geckos usually gray or brown with mottled markings; diurnal (day active) geckos vary from bright green with red markings to bluish green, yellow, or black-and-white; males may be more brightly colored than females Diet: Typically small invertebrates; larger species eat other lizards, small snakes, birds, and small mammals; diurnal geckos also eat fruit, pollen, and the nectar from flowers Breeding: Most females lay 1–2 eggs that hatch after 5–8 weeks; some “southern” geckos may give birth to live young after a gestation period of up to 14 months Life span: 5–25 years Status: At least two species are critically endangered, four are endangered, and nine are vulnerable

145

Geckos

common in Australia, New Zealand, and New Caledonia (an island in the Pacific Ocean to the east of Australia). They include several unusual species, such as the New Zealand Hoplodactylus and Naultinus geckos, which all give birth to live young instead of laying eggs. Southern geckos live in a wide range of habitats, from deserts to dense forests. Southern geckos called velvet geckos prefer specific habitats. Some live under the bark of fallen trees, while others prefer standing trees. Still others make their home under flakes of broken rocks. The aptly named fringe-toed velvet gecko has a fringe of scales around its toes and a gripping, or prehensile, tail to help it climb. The jeweled gecko from Australia and the day geckos from New Zealand also have prehensile tails. The fringe-toed gecko, the New Caledonian geckos, and the pad-tailed gecko even have sticky pads on the tips of their tails as well as on their toes.

OW? DID YOU KN Typical geckos have no eyelids, but members of the family Eublepharidae have movable eyelids. Web-footed geckos have webbed feet to help them run across loose sand without sinking. Wonder geckos and the viper gecko make a sound by rubbing the scales on their tails together. 146

The common barking gecko lives in the Kalahari and Namib deserts of southern Africa. It hides in burrows to escape the hottest parts of the day.

Eyelid Geckos All the members of the Eublepharidae family have movable eyelids. None of them have sticky toe pads. They usually lay their eggs in pairs. Like the southern geckos, the eggs of these geckos have rubbery shells that absorb water during their development. All eyelid geckos live on the ground, except for the cat gecko from Malaysia. This strange gecko has a prehensile tail that it holds in a coiled position as it moves slowly along twigs. Species from North America, Africa, and the Middle East live in dry habitats. Species from Central America and Asia live in rain forests. Species from China and Japan prefer to live in cool, moist habitats, especially in caves. Even though there are only twenty species of eyelid geckos alive today, they live in many different parts of the world. Scientists think that these species are all that remains of a much larger family that was once more widespread.

GECKOS

Threats to Survival There are more than 1,000 species of geckos. Many species are thriving, but some are on the brink of extinction thanks to human activities such as deforestation. These activities destroy

the gecko’s prime habitats. The Paraguanan ground gecko and a species known by the Latin name Phelsuma antanosy are both listed as Critically Endangered by the International Union for the Conservation of Nature (IUCN).

Terrific tails When a predator grabs them, many geckos can break off their tails to make their escape. The gecko then grows a new tail as a replacement. The tail of a gecko may help it to survive in other ways. Some species, such as the leopard gecko, have black-and-white tails that attract attention. The distinctive tails of these geckos help to keep predators away from more vulnerable parts of the body, such as the head. Other geckos, especially

those from very dry places, have thick, carrot-shaped tails that are used to store food. This helps the geckos to survive when food is scarce. The flat tails of the Madagascan and Australian leaf-tailed geckos can be pressed against tree trunks when they rest to cut out shadows. This provides excellent camouflage. Asian flying geckos even have fringes around the edges of their tails that help them to glide through the air.

The fat-tailed gecko from Africa uses its thick, stumpy tail to store fat. The fat store will see it through the times when food is scarce.

147

GHArIAl with its unmistakable narrow snout, the gharial is one of the largest members of the crocodile family. this giant is a danger only to fish in the rivers of india and neighboring countries in which it lives.

148

CrOCODilians

G

harials are large reptiles with distinctive narrow snouts and longer legs than their relatives—the alligators and crocodiles. The male is bigger than the female and has a swollen end to his snout. The shape of the snout looks like rounded cooking pots, called gharas, which are used in parts of northern India. This is where the gharial gets its common name. Adult gharials hunt in fast-moving rivers. They swim using their webbed back feet and their wide, long tails. Gharials lie on the riverbed with their mouths wide open. When a fish swims by, it quickly moves its head through the water and snaps its jaws around its prey. The gharial comes to the surface and raises its head out of the water before swallowing its food. Otherwise it would swallow too much water with its meal.

Breeding season Gharials live alone, but males and females meet to breed between November and January. The male blows bubbles through his swollen snout to attract and mate with the female. The female then digs her nest on land near the river in which she lives. She buries her eggs in the nest and only digs them up when she can hear the hatchlings calling her. each one is about 14 inches long at birth. She carries them to the river, and they swim off to fend for themselves. young gharials hunt insects, frogs, and small fish. They move onto larger prey, such as catfish, when their mouths are big enough.

fact file GHarIal Gavialus gangeticus family: Crocodylidae Order: Crocodylia Where do they live?: Northern India and Nepal and other parts of the Indian subcontinent Habitat: Rivers size: Head–tail length 10–21 ft. (3–6.4 m); weight: up to 2,200 lb. (977 kg) appearance: Olive-green or tan with dark bands and blotches across the body Diet: Mostly fish; some individuals eat water birds or are scavengers of dead animals Breeding: Female lays 28–43 eggs that hatch after 2 to 3 months life span: 40–60 years status: Critically endangered

A gharial has 102 razor-sharp teeth that curve outward and forward to grip even the most slippery, fast-moving fish.

149

GHOST FrOGS Ghost frogs are a rare group of amphibians that live in rushing water high in the mountains of southern africa. they have different ways of gripping onto rocks so they do not get washed away.

150

FrOGs anD tOaDs

G

host frogs are medium-sized frogs that live in and around the streams and waterfalls that flow through the permanently cool, moist mountain forests. Adults are nocturnal (active at night) and clamber over rocks in search of food. During the day, these frogs hide away from predators such as hawks. They squeeze their flat bodies into the cracks between rocks. The color of their skin camouflages them against the mossy rocks.

fact file GHOst frOGs Heleophryne species family: Heleophrynidae Order: Anura Where do they live?: Southern Africa

Breeding Ghost frogs breed after the rainy season between spring and midsummer. The males hide away beside waterfalls and call to the females at night. The females are attracted by the calls, and the frogs then mate in pools. The females lay large, yellow eggs, which hatch into tadpoles after about a week. The gradual change from tadpole to adult is called metamorphosis. In this process the larvae develop limbs to move on land.

Holding On Ghost frogs are well adapted for a life in rushing water. Adults have flat bodies that allow water to flow easily over them. Triangular, sticky pads at the end of their long toes help them cling to rocks. Tadpoles feed on water plants called algae that grow on the rocks of the pools in which they live. A tadpole’s mouth is shaped like a disk. The tadpole holds onto a rock by sucking on the surface, grating off algae at the same time.

Equator

Habitat: Fast mountain streams and waterfalls size: Head–body length 1.2–2.5 in. (3–6.5 cm) appearance: Tan, dark brown, or green with stripes and blotches of brown or yellow Diet: Adults eat insects, snails, and other small invertebrates (animals without backbones); tadpoles eat algae from rocks Breeding: Females lay between 50 and 200 eggs under damp rocks or in gravel on the banks of rivers and streams; tadpoles take 2 years to become adult frogs life span: Not known

The Natal ghost frog lives in the mountain forests of southern Africa. This species is in decline due to

status: Two species critically endangered, most least concern

human activities such as deforestation for farming.

151

GIANT GAllIWASPS six different lizards go by the common name giant galliwasp. Four species live in the Caribbean—one in Jamaica, one in Haiti, and two in the Dominican republic. the other two species live in Central america.

152

snakes anD lizarDs

G

iant galliwasps are medium-sized lizards with thick bodies, short legs, and pointed snouts. Their shiny, overlapping body scales have round edges. Their heads are covered in large scales. These protect their heads as they move through the damp mud of swamps or the leaf litter on the rain forest floor.

lizard in Decline Giant galliwasps are rare, and some are endangered. One species that lives in Jamaica may be extinct. The main problem for these lizards is deforestation. People have cleared large areas of rain forest in the Caribbean and Central America to plant crops to sell and provide pasture where their livestock can graze. Another major problem for the giant galliwasps is their coloration. They have bright stripes rather like some venomous snakes, and some local people also kill these lizards because they think they are dangerous. yet another problem is caused by introduced animals. In the past, people came to the Caribbean to make a new home. They brought cats to kill the rats and mice that might damage food stores. They also brought mongooses to kill venomous snakes. Harmless animals, including the giant galliwasps, were also killed. Different zoos around the world are trying to help giant galliwasps. At Nashville Zoo in Tennessee, nine pairs of Haiti giant galliwasps have produced more than 300 young. The young will be released into the wild to increase populations of these rare lizards.

fact file GIaNt GallIWasPs Celestus and Diploglossus species family: Anguidae suborder: Sauria Order: Squamata Where do they live?: Caribbean and Central America Habitat: Swamps and leaf litter on the rain forest floor size: Head–tail length up to 18 in. (46 cm) appearance: Brown with yellow or orange stripes Diet: Plants and fish Breeding: The eggs of most species hatch inside the female’s body, so they appear to give birth to live young life span: Up to 25 years status: Rare; some possibly extinct

A giant galliwasp uses its short legs to push itself through the leaves that collect on the rain forest floor.

153

GIANT PlATeD lIZArD Giant plated lizards are big, heavily armored lizards that live among the rocky outcrops of southern africa. when these large lizards sense danger, they wedge themselves into gaps between the rocks.

154

snakes anD lizarDs

G

iant plated lizards have short legs and long claws. They use them to scrape the soil beneath bushes and around rocks to find food. These lizards clamber over rough ground but may slide down gentle grass slopes on their bellies. Giant plated lizards spend much of their lives near their burrows. These can be gaps among rocks or even a broken termite mound. They use their large eyes to keep a lookout for predators such as eagles.When disturbed, the lizards disappear into their burrows, puffing up their bodies to wedge themselves inside. long folds of skin along the sides of the lizard allow the body to increase in size easily.

fact file GIaNt PlateD lIZarD Gerrhosaurus validus family: Gerrhosauridae suborder: Sauria Order: Squamata Where do they live?: Southern Africa, including Namibia, Zambia, and Zimbabwe

Equator

living and Breeding Giant plated lizards spend most of their time feeding and resting. They warm up, or bask, in the morning sunlight. This gives them energy to digest food and to move around. These lizards are found in the same area but live alone. The exception is during the breeding season, from November to December, when males and females meet to mate. The throats of the males change color to purple or blue to attract the females. After mating, the female lays her white, leathery eggs in the soil between rocks. The hatchlings emerge around a month later. They are just over 6 inches in total length. The mother does not look after her young. Instead, they must search for their own food, which includes small insects, and find their own burrows.

Habitat: Grassy hillsides with bare, rocky outcrops size: Head–tail length 14 in. (36 cm) appearance: Brown with whitish throat and cream stripes along the back Diet: Insects, small lizards, baby tortoises, berries and flowers Breeding: Females lay between 2 and 5 eggs life span: Not known status: Common

The flat bodies of giant plated lizards are covered in thick rectangular scales. Underneath this armor they also have bony plates, which protect the body inside. 155

GIANT SAlAMANDerS Giant salamanders are the largest amphibians in the world. these monsters are found only in freshwater rivers in Japan and China and in damp forests along the pacific coast of north america.

156

newts anD salaManDers

t

he largest giant salamanders live in Japan and China. As adults, these massive amphibians can measure more than 39 inches from head to tail, and they can weigh more than 12 pounds. The Chinese giant salamander and the Japanese giant salamander both have flattened heads and bodies, and short, paddle-shaped legs. The tiny eyes of these two species are sunken into their wrinkly skin. Giant salamanders also live in North America. There is the California giant salamander, Cope’s giant salamander, the Idaho giant salamander, and the Pacific giant salamander. All of them measure less than half the length of the two species from Asia. larger than the other American species, the hellbender is the North American equivalent of the Asian salamanders.

Different Habitats Chinese and Japanese giant salamanders almost always live in the rivers that flow down mountain slopes. The rivers are usually about 50 feet wide and shallow, with a stony riverbed.The larvae of these salamanders are always found at the riverbed among the loose stones. However, adults live in rock crevices or burrows at the edge of the river. They may travel away from the river bank when the ground is wet after rain. Outside China and Japan, giant salamanders live in the damp forests along the Pacific coast of North America. The West Coast has a high level of rainfall.

fact file GIaNt salamaNDers family: Cryptobranchidae Andrias species (Chinese and Japanese giant salamanders; two species) family: Dicamptodontidae Dicamptodon species (Pacific giant salamanders; four species) Order: Caudata (Urodela) Where do they live?: China and Japan and the Pacific coast of North America Habitat: Mountain rivers, streams, lakes, and moist ancient forests size: Head–tail length up to 13 in. (36 cm) for Pacific species and up to 52 in. (1.4 m) for others appearance: Reddish brown to gray with mottled patches Diet: Crabs, crayfish, fish, and frogs in the water; lizards, mice, slugs, and snails on the land Breeding: Females lay between 80 and 600 eggs in water life span: Up to 90 years status: Chinese giant salamander critically endangered; otherwise varies according to species

The Japanese giant salamander is the largest amphibian in the world, and it can live for fifty years or more in the wild.

157

Giant salamanders

Wet air blows in from the Pacific Ocean and then falls as rain. The trees have moist bark dripping with mosses and other plants, and thousands of streams drain water from the forests. The salamander larvae live in these cool streams, but the adults hide under bark and thick moss, and in burrows in the soft soil in hotter weather. They move about during the damp nights.

Den Masters

The California giant salamander is reddish brown in color, with dark brown to black markings on its

The Asian giant salamanders breed early in the fall, usually in September. Males and females travel to breeding sites along the rivers in which they live. Sometimes they travel 2,000 feet or more from their usual living area to the breeding sites. The adults then search for suitable places in the riverbank, where they can dig their

underwater burrows. These burrows can be more than 39 inches deep. The males fight for the right to breed with the females. The largest and strongest males, called den masters, win and then breed with many females. After mating, each female lays about 500 eggs in two long strings inside her nest. For the next two months, the den master patrols his territory, which may include the nests of several females and contain thousands of eggs. The den master guards the nests in his territory from other males that might wander in and eat the eggs. When the eggs finally hatch, the larvae measure about 1 inch in length. In a process called metamorphosis, the larvae transform into the adult salamanders. This takes about five years, at the end of which, the salamanders measure about 12 inches. They continue to grow throughout their lives.

back and head.

Feeding Habits

158

As larvae, the giant salamanders from North America start by eating aquatic insects and other small prey. As the larvae develop and grow bigger, they eat bigger items, such as frogspawn. The adults have huge appetites.


Hunting at night, they will eat just about anything from slugs and snails to mice and worms. Adult giant salamanders have sharp, curved teeth, which help them to grab anything that their mouths can fit around. Indeed, these salamanders often fight and eat each other. In a fight, the adults arch their backs and hold their bodies off the ground by stretching out their legs. This makes their bodies look as big as possible to intimidate their rivals.

The salamanders growl at each other and may lash out at their opponent’s head with their long tails. They do this because the skin on the tail creates a poisonous liquid that stings their opponent’s eyes.

A California giant salamander feeds on a banana slug in the moist forests of northern California in the

Threats to Survival

United States.

The biggest threats to the survival of all giant salamanders are the destruction of their habitats and the increasing levels of pollution found across the range of these amphibians. 159

Giant salamanders

DID YOU KNOW? Pacific giant salamanders may climb as high as 7 feet up trees in the forests in which they live. These giant salamanders group together near springs and stream sources to breed. Females lay eggs one at a time and stick them individually to rocks or pieces of sunken wood.

Deeply folded and warty skin provides a greater surface area through which the Japanese giant salamander can absorb oxygen from the water.

Pollution happens when the air or water in a region becomes dirty and affects the health of animals and plants that live there. The rivers in which the giant salamanders live are polluted by waste from agriculture, mining, and many other human activities. The water can become cloudy when soil washes off the land. This happens when people cut down forests to sell the timber or to clear the land for farms or houses. Dirt in the water can make it difficult for amphibians to breathe through their skin and can clog up their gills. When the land is cleared of trees and fallen logs, there is less 160

shade for the giant salamanders on the forest floor. There are also fewer places for the salamanders to live and hide. Streams may dry up and there are fewer places where the larvae are able to survive.

Eternal Youth Cope’s giant salamander spends all of its life in the clear, cold mountain streams of Washington and Oregon in the United States. This salamander usually never changes into the landliving adult form by the gradual process of metamorphosis. Instead, it remains as a larva. However, Cope’s salamander is unusual because it can


breed. This process is called neoteny. It means that the adults retain some of the characteristics of their young. The California giant salamander also displays neoteny but to a lesser degree. These salamanders transform into mature adults, but some of them retain the external gills of the larvae.

Barking Salamander Unlike most salamanders,which do not make any noise, Pacific giant salamanders can make quite a loud call when startled. When they come across a predator, such as an otter, water shrew, or weasel, they often make a short croaking sound, which sounds rather like a barking dog. If the predator launches an attack, these salamanders resort to their chemical defense—a terrible-tasting milky liquid that oozes from glands on the tops of their tails.

OW? DID YOU KN The Chinese giant salamander and its eggs are considered a delicacy in southwestern China. Sometimes they are reared on special salamander farms.

Skin breathers Oxygen is vital for almost every living thing on the Earth. People breathe in oxygen from the air using their lungs, while fish absorb oxygen dissolved in water using their gills. Amphibian larvae generally hatch from eggs in water. They breathe using feathery gills that stick out of the sides of their necks or tucked inside folds of skin. Oxygen moves from the water into their blood at the gill surface. The gills are feathery to provide a large surface area for blood to pick up oxygen. During metamorphosis, the gills change gradually into lungs inside the young body of the amphibian. Adult amphibians breathe partly through their lungs. However, they also breathe partly through their skin. Adults need to live in damp places to keep their skin moist. Damp skin allows more oxygen in the air to dissolve and move into their blood.

The Japanese giant salamander has been declared a national treasure in Japan. People protect the salamanders and their 161

Glass frogs Glass frogs are small, delicate-looking frogs with large eyes set upon their relatively small, flat heads. These amphibians get their name from their almost transparent (see-through) skin, which is especially noticeable on their undersides.

162

FROGS and toads

S

ome glass frogs are unusual because they have green bones as well as green skin. Others are unusual because the males have spines or hooks on their forelimbs.The males use them to attack each other when they fight over territory. The males sit on their patch of leaves and call loudly to warn other males away. A fight starts if the calling does not work.

Fact File Glass frogs Centrolene, Cochranella, Hyalinobatrachium, and Nymphargus species Family: Centrolenidae Order: Anura Where do they live?: Central and South America

Breeding Female glass frogs lay their eggs on the leaves of branches overhanging small streams. The leaves form part of the male’s territory. Most females lay eggs on leaves a few inches above the water, but some lay eggs on leaves several yards above. When the tadpoles hatch, they drop into the water and swim away. Until then, the male guards the eggs to stop predatory wasps from eating them. The wasps carry the eggs to their nests one by one until there are none left. The males stand guard over the eggs and chase the wasps away.

T-shaped Toes Some glass frogs have special T-shaped toes. The toes may help them to climb because they are often found 5 or 6 feet up in the trees. These glass frogs lay their eggs in water, not on leaves. They only grow to about an inch long. Their bodies are grayish green, gray, or bronze with darker markings. They also have small warts on their heads and backs.

Equator

Habitat: Rain forests Size: Largest species is 3.3 in. (8.5 cm) long Appearance: Green with dark or light mottled markings Diet: Insects Breeding: Females lay eggs on the leaves of branches overhanging small rivers and streams Life span: Not known Status: Varies according to species

With its pale-green, see-through skin, the emerald glass frog is a typical tree-dwelling species. It lives in the rain forests of Central America.

163

GlASS lIZArDS Glass lizards look more like snakes than lizards because they do not have any legs. they get their name from their tails, which break into pieces like shattering glass when they are shed in defense against predators.

164

snakes anD lizarDs

G

lass lizards may look like snakes, but they are different in many ways. like snakes, glass lizards have no legs, but there may be short, pointed flaps of skin where the legs should be. Glass lizards also have eyelids, while snakes do not. Most glass lizards are diurnal, which means they are active during the day. They move quickly by twisting their body from side to side like a snake. At night they sleep in the burrows of other animals, such as owls and prairie dogs. During cold winters, glass lizards may stay inside their burrows for months in a special sleep called hibernation.

Breaking away Glass lizards are sometimes spotted by predators such as foxes, hawks, or raccoons. When threatened, glass lizards hiss and bite as the first line of defense. If they are caught, however, the glass lizard has a special way of escaping. It twists its body and jumps about until part of the tail breaks off. Sometimes the tail breaks into several pieces. even though they are broken, the pieces continue to wiggle around. The movements distract the predator, and this gives the lizard a chance to escape. The tail will eventually regrow, although it will be shorter and darker in color than the original. The breaking and regrowing can only happen once in a lizard’s life, but it might make the difference between life and death.

fact file Glass lIZarDs Ophisaurus sp. family: Anguidae Order: Squamata Where do they live?: Europe, North America, North Africa, India, and eastern Asia Habitat: Prairies and open woodland size: Head–tail up to 4.5 ft. (1.4 m) appearance: Brown fading to yellow with lighter underside; darker stripes run down length of the body Diet: Invertebrates (animals without backbones) such as beetles, snails, grasshoppers, and spiders; also the eggs of birds and reptiles Breeding: Females lay up to 12 eggs in a burrow once every 2 years life span: Usually up to 9 years; some may reach over 20 years status: Varies according to species, mostly least concern

Glass snakes slither through grassland and across woodland floors in search of small invertebrates such as beetles, slugs, and snails.

165

Golden-tailed gecko The tail of the tiny golden-tailed gecko is not purely decorative. It forms part of this beautiful lizard’s defense system. The tail shoots out a smelly and nasty-tasting fluid to get rid of predators.

166

snakes anD lizarDs

t

he tail of the golden-tailed gecko contains tiny glands that produce a sticky substance. When threatened, these lizards will try to scare predators by opening their mouths and swinging their tails. If the predator persists, the golden-tailed gecko squeezes muscles around the glands and swings its tail to shoot out the sticky liquid up to 18 inches or more. Scientists think that the bright tail and body markings act as warning signals to predators that might attack.

nocturnal life

fact file GOlDeN-taIleD GecKO Strophurus taenicauda family: Diplodactylidae suborder: Sauria Order: Squamata Where do they live?: Australia (eastern Queensland) Habitat: Dry forests and woodlands dominated by eucalyptus trees size: Head–tail length 4.75 in. (12 cm)

The golden-tailed gecko lives in Queensland, Australia, where it is hot and very dry. To avoid the daytime heat, these lizards shelter under bark from trees or in hollow trunks or branches. They emerge at night to feed on insects among pine, wattle, and eucalyptus trees. In the winter, the nighttime temperatures often drop below freezing. In these cold conditions, the geckos may stop feeding and hide away for days or weeks on end.

appearance: Gray with black spots and a bright orange stripe running along the top of the tail

Breeding

status: Common

Diet: Invertebrates (animals without backbones) such as flies Breeding: Females lay 2 eggs, which take more than 2 months to hatch life span: Up to 5 years; rarely up to 15 years

Golden-tailed geckos breed in spring. Females lay eggs in a damp place on the ground. The eggs’ shells are papery and need moisture to stop them from drying out. Females produce pairs of eggs every twenty days or so for four or five months. The hatchlings cannot squirt liquid from their tail. They rely on camouflage (special body markings) to hide from their predators. Like most other geckos, the golden-tailed gecko will drop its tail to confuse predators when threatened. The tail grows back again very quickly.

167

GrASS SNAke the european grass snake lives near water but catches most of its food on land. Grass snakes prey on frogs and toads, which they swallow live and headfirst. Grass snakes sometimes eat other prey such as fish, mice, shrews, and slugs.

168

snakes anD lizarDs

G

rass snakes are typically dark green or dull brown in color, and they have characteristic yellow collars behind their heads. These markings give these snakes their alternative common names— the ringed snake or collared snake. The color and markings may vary according to the place in which they live. In Britain, the grass snake is typically graygreen with black spots and a yellow or cream collar. The grass snake is the largest British reptile, reaching more than 4 feet in length.

keeping warm like all reptiles, grass snakes are cold-blooded animals. Since they cannot generate their own body heat, they rely on the heat from the sun to keep their bodies warm. The main problem for the european grass snake is that in many parts of northern europe the winters can be long and very cold, while the summers are very short. The grass snake still manages to survive by being active during the day and basking in the sunlight whenever it can in order to warm its body. Grass snakes that live in the northernmost part of their range sleep out the cold months between October and March. They rest in hollow logs, on tree trunks, or under rocks. This long sleep is known as hibernation. In some cases, many snakes curl up together to hibernate in old rabbit burrows, wall crevices, and under piles of manure and roots of trees.

fact file Grass sNaKe Natrix natrix family: Colubridae suborder: Serpentes Order: Squamata Where do they live?: Found throughout Europe and parts of North Africa and the Middle East, and a large part of Central Asia Habitat: Live near fresh water, including canals, lakes, ponds, and slow-moving rivers size: Head–tail length 4 ft. (1.2 m) up to 6.5 ft. (2 m) appearance: Olive brown or olive green. In some parts of their range, grass snakes can be black, black and gray, or black with white specks Diet: Fish, frogs, newts, and toads Breeding: Females lay clutches of between 8 and 40 eggs, which hatch after 42–70 days life span: Up to 25 years status: Lower risk—least concern

Grass snakes sometimes hiss and strike out at attackers. They usually strike out with their mouth closed and they hardly ever bite.

169

Grass snake

to build up a fat supply so she can survive hibernation during the cold winter months. The eggs hatch out after between forty-two and forty-five days. The young hatchlings measure between 5 and 8 inches.

Methods of Defense

Female grass

Breeding

snakes are

The eggs of all snakes develop best when they are kept at a constant, steady temperature. Female grass snakes lay their eggs in hollow tree trunks or under rocks. In the cooler temperate regions, grass snakes lay their eggs in piles of decaying leaves or seaweed. As the leaves or seaweed rot, they produce heat that keeps the grass snake’s eggs warm. Females sometimes lay eggs in compost and manure heaps for the same reason. Female grass snakes lay their eggs between June and July. A typical clutch contains between ten and thirty leathery eggs. After laying the eggs, the female spends the rest of the year hunting for food. She needs

bigger than the males and have longer, thicker

170

When a grass snake is attacked by a predator, it squirts out a foul-smelling substance from a gland near its anus (bottom). As it does so, the grass snake twists and turns to smear as much of the stinky liquid over its attacker as it can. If this does not scare off the attacker, the grass snake opens its mouth and hangs out its tongue so that it looks dead. The snake moves again only when it thinks it is safe.

Conservation Grass snakes usually live around ponds and lakes and in other damp and boggy places. Many of these habitats are being taken over for farmland. Sometimes these areas are drained and the land used for building new houses. When the habitat of the grass snake disappears, these reptiles have to move on. Some move into gardens, but the food

snakes and lizards

OW? DID YOU KN When they travel between areas, grass snakes usually travel along hedges or through woodlands. A grass snake can travel between thirty and one hundred yards a day. Over a year a grass snake may travel a total distance of 2.5 miles! Female grass snakes share good egg-laying sites. The record number is 3,500 to 4,000 eggs, which were laid together in the cellar of a saw mill in Germany.

supply there is usually limited. In many parts of their range, grass snakes are facing extinction in the wild. These snakes are protected by law in many countries, but numbers are still in decline. One of the main problems for the survival of these snakes is that there are not enough sites for the females to lay their eggs. In many places, such as gardens, farms, and public parks, the land is being cleaned up. So piles of leaves, compost heaps, and other vegetation are much rarer than they were in the past. German zoologists are building manure heaps so these snakes can lay their eggs in them. People can also help the snakes by building compost heaps in gardens and leaving piles of leaves in parks and woods.

Swimming skills Sometimes grass snakes hunt for toads and frogs in water. Grass snakes swim in still or slowmoving water around the edges of lakes and ponds. The snakes swim with their body just below the surface of the water and their head held above the water. If they are surprised, by a predator for example, they can dive under water and stay there for up to thirty minutes!

171

Great South American river turtle The largest turtles in South America live in murky, muddy rivers. These wide, flat reptiles rarely leave the water except when it is time for the females to nest and lay their eggs.

172


T

he shell of the giant South American river turtle is wider at the back than at the front. Its gray head has a square jaw, and the chin has two dangling barbels that look like short worms. The barbels are sensitive to touch. The turtle uses them to sense food and other animals swimming in the river water when it is too cloudy to see clearly. Both sexes look very similar, but the females are usually bigger. Some turtles can weigh up to 100 pounds.

Nesting Season Giant South American river turtles nest during the dry season, which falls between September and November in Brazil and between March and April in Venezuela. During this time, the rivers in which the turtles live have the lowest water levels. During the breeding season, adult turtles mate in the water. Females crawl onto the sandy beaches at the edges of the rivers. There the females bask in the sunlight for one to two weeks to keep warm, which helps their eggs to develop. Then each female digs a nest 3 feet wide and about 24 inches deep. She lays approximately eighty round, soft eggs in the sand. She covers them and returns to the river. About forty-five days later, the young turtles hatch and dig their way out to the surface. The hatchlings are 2 inches long and have yellow spots on their shells for camouflage. These markings make the babies harder for predators to spot.

Fact File Great South American river turtle (arrau) Podocnemis expansa Family: Pelomedusidae Order: Pleurodira Where do they live?: Brazil and Venezuela in northern South America; also on the Caribbean islands of Trinidad and Tobago

Equator

Habitat: Rain forests near fresh water Size: Head–tail length 16–31 in. (40–80 cm) Appearance: Brown, olive green, or black on top of shell, and yellow or gray underneath; head usually has red, orange, or yellow markings Diet: Adults eat fruits, river plants, and seeds; young eat insects and other river animals Breeding: Females lay clutches of between 50 and 150 eggs, which hatch after about 45 days Life span: Up to 20 years

The giant South American river turtle spends most of its active life in the water. Even mating takes place in

Status: Lower risk—conservation dependent

the water, although the young turtles hatch on land.

173

GreeN IGUANA the green iguana is one of the most easily recognizable lizards. this massive reptile lives in forest trees and looks rather like a dinosaur, with tooth-shaped scales forming a crest along its back and part of its tail.

174

snakes anD lizarDs

G

reen iguanas have long toes tipped with sharp, curved claws. They use them like grappling irons to haul their long bodies through the trees. Green iguanas can fight with their claws. However, they often just drop from trees into forest rivers.

sociable Young lizards Adult iguanas tend to live alone most of the time except during the breeding season, but the young are much more sociable. young iguanas hatch from eggs that are buried underground in nesting chambers. Immediately after hatching, the young lizards eat some soil. Bacteria in the soil help the young iguanas to digest their food. The hatchlings then emerge from the nest together. This provides safety in numbers against predators such as eagles and snakes, which become confused by all the young moving at the same time. The young iguanas have a better chance of escaping as a group than if they emerge one at a time. The hatchlings move off into low shrubs together. They maintain contact by nipping, rubbing, and licking each other. They may move off alone through the branches feeding on leaves, but they then group together again at night to sleep. As they get older, the young green iguanas move higher up into the trees and form groups with the adults. The group usually contains one large male and several females with which he breeds, along with several youngsters.

fact file GreeN IGUaNa Iguana iguana family: Iguanidae suborder: Sauria Order: Squamata Where do they live?: Central and South America and some islands of the Caribbean Habitat: Rain forest and dry forests size: Head–tail length up to 6.5 ft. (2 m); weighs up to 20 lb. (10 kg) appearance: Young iguanas are bright green but become brown, gray, or red with age; often have dark stripes on the back and tail Diet: Mostly leaves Breeding: Females lay between 9 and 71 eggs, which hatch after about 3 months life span: Up to 35 years status: Generally common

Adult green iguanas are coated with green tough scales. Tooth-shaped scales form a crest along the back and part of the tail of the green iguana.

175

Green toad Green toads are fairly common across Europe, Asia, and North Africa. They often live in dry habitats, usually nearby villages or towns. Like almost all amphibians, green toads return to water-filled ditches, ponds, and swamps to breed.

176

FrOGs anD tOaDs

G

reen toads are plump animals with distinctive markings, but they are not always easy to spot. They spend their days hiding in cool places such as gaps under stones and logs, and they also scrape out rough burrows with their tough hind feet. These toads are most active at night when the temperature is cooler.

Feeding time Green toads hunt for food such as ants, which they gather with their short sticky tongues. Glands behind the eyes of the green toad release poisons, which make the animal taste bad for most predators, including cats, owls, and waterbirds. Grass snakes still eat green toads and seem immune to the poisonous skin.

returning to the water like nearly all amphibians, green toads live near water. They climb into it to cool down on hot days. They can remain in ponds for weeks during the breeding season in spring. The adult males repeat a high-pitched trilling noise that lasts about ten seconds each time. Females mate with males who make the clearest or loudest call. each female lays thousands of eggs in rows of strings. In each string, the eggs are arranged in two or four rows measuring up to 13 feet. The eggs hatch within a week, and it takes up to three months for the larvae to develop into young toads. They usually leave the water on rainy nights when the ground is wet.

fact file GreeN tOaD Bufo viridis family: Bufonidae Order: Anura Where do they live?: Throughout Europe, including Russia; central Asia; and North Africa Habitat: Fields and woodlands with sandy soil; ponds, reservoirs, and water-filled ditches at breeding time size: Head–tail length 3.5–4.75 in. (9–12 cm) appearance: Buff or light gray with large, irregularly shaped green blotches and pinkish warts Diet: Small invertebrates (animals without backbones) such as ants and worms Breeding: Females lay between 2,000 and 3,000 eggs in the water, which hatch after 3 to 6 days life span: Up to 10 years status: Lower risk—least concern

Variations in the colors and patterns of green toads occur across their range, but most have green to dark brown bodies with white or pale yellow undersides.

177

Green tree python The green tree python is one of the few snakes in the world that spends all of its life in trees. This large snake feeds, breeds, and even lays eggs in the trees, coiling and draping its body over the branches with ease.

178

snakes anD lizarDs

t

he green tree python’s body is slightly flattened, but it has a central ridge that is caused by the snake’s backbone. The body is lighter and more slender than many other pythons. This is an adaptation for life in the trees. If the python was too heavy, the branches might not be able to support its weight. Adult green tree pythons move slowly through the branches. Their typical speed is only around one mile per hour. Their tails can grip the branches tightly while they arch the rest of their bodies onto the next branch.

eggs in the trees Adult green tree pythons spend all their lives in the trees. They even mate and lay eggs there. The female often finds a hollow in, or a thick patch of ferns growing on, a tree. There she lays her white, leathery eggs and then coils up on top of them. Female green tree pythons usually produce between twelve and twenty-five eggs per clutch. Females kept in captivity have been observed supporting their eggs among their coils. The female guards her eggs for about two months until the young hatch. This ensures that no egg-eating predators, such as eagles or monkeys, take the eggs. The female shivers if the air gets too cold. In this way, she produces enough heat to keep the young warm as they develop inside their eggs. When they hatch, young snakes are usually a lemon yellow color, with broken stripes and spots of purple and brown.

fact file GreeN tree PYtHON Morelia viridis family: Pythonidae suborder: Serpentes Order: Squamata Where do they live?: New Guinea, Indonesia, and northern Australia Habitat: Rain forests, and garden trees and hedges in towns size: Head–tail length on average about 5.5 ft. (1.7 m) but can reach 7.2 ft. (2.2 m) appearance: Adults are bright green with blue or white markings running along the back; young are yellow, orange, or red Diet: Adults eat mammals; young eat lizards and also frogs Breeding: Females lay between 6 and 30 eggs, but usually 10; eggs hatch after 40–60 days life span: Up to 20 years status: Common in suitable habitat

Green tree pythons have roughly heart-shaped heads that are coated with small scales. All the scales around the mouth have heat pits, for sensing prey.

179

Green tree python

Green tree pythons often drape over a branch when they are resting and look a little like a green saddle!

In some cases, a golden or orange snake may appear in the clutch. These bright colors fade to green as the snakes grow older.

Hiding in the Trees Green tree pythons often just rest and wait for their prey to pass by. Their green skin color is similar to the leaves and branches in which they live. These tree snakes have blotches of white or even blue on their backs that look a little like the dappled light shining through the trees. The pythons remain so still that other animals often cannot see them. Pythons can see and smell well, but they also have another way to detect prey in the dark forest. They have deep pits in the skin around their mouth. The pits can detect the slight 180

variations in air temperature caused by approaching mammals such as mice. Mammals produce heat as they carry out everyday life processes such as digesting food.

Twitching a Meal The tip of the tail of a young green tree python is black and white. When the snake is hungry or has seen prey moving nearby, it may lower its tail and make it twitch. Frogs, lizards, and other prey become attracted by this movement. The python then strikes when its prey is close enough. It sinks long fangs into the skin of its prey to get

snakes and lizards

a good grip. It then kills its victim by squeezing the animal’s body until it can no longer breathe. Once the prey is dead, the python searches for the animal’s head. It swallows the prey headfirst, gradually releasing the rest of the body from the coils. A large meal can sustain the python for many weeks or even months.

OW? DID YOU KN Sometimes adult green tree pythons are found that are bright blue! These are highly prized by snake collectors. Pythons have four rows of teeth in their upper jaw. They also have sharp fangs, but they cannot produce poison like many other types of snakes.

Color change Green tree pythons hatchlings are not green. They are usually bright yellow, orange, or even brick red. These colors stand out from the green vegetation, but look like fruits and flowers. The lizards that these pythons eat may be attracted to the bright colors, making an easy meal for the young snakes. The young have dark lines on their skin from their nose, across the eye to the back of the head. This makes it hard for other animals to tell that it is a snake’s head. Young snakes get their green color when they are nine to fifteen months old. The change may be sudden and happen over just a few days.

181

Green turtle The green turtle is a large, heavy marine turtle. In the water, it paddles gracefully along in shallow seas. Green turtles move rather clumsily on the land, where they lay eggs or, rarely, bask in the warm sunlight.

182

turtles, terrapins, tOrtOises

G

reen turtles are typical marine turtles. Unlike most land-dwelling turtles, green turtles cannot pull their small heads inside their shells. The turtle’s paddle-shaped legs propel it through the water, and the shell is streamlined so the turtle can glide easily. Marine turtles are massive because a bulky body loses heat to the cool ocean waters more slowly than a small body. Nevertheless green turtles often swim at the surface to warm themselves in the sunlight. Green turtles from Hawaii even crawl onto beaches during the day to bathe in the sunlight. Scientists think they might do this when there are lots of tiger sharks in the water that might attack the turtles and eat them.

under threat Green turtles are an endangered species. In the past, green turtles were heavily hunted for their meat and attractive shells. Changes to turtle habitats also affected these reptiles. For example, hotel developments spoiled some beaches, and coastal fishing damaged the turtles’ feeding grounds.Today, they are much better protected. The beaches on which these reptiles breed are out of bounds to people at certain times of the year. Green turtles are raised on ranches in some places. People harvest eggs from beaches and raise the young in pens. These turtles are often killed for meat and souvenirs made of shells. This may seem cruel, but it should mean that fewer wild turtles are harmed.

fact file GreeN tUrtle Chelonia mydas family: Cheloniidae Order: Testudines Where do they live?: Throughout Atlantic, Indian, and Pacific oceans Habitat: Coastal regions where marine plants grow size: Upper shell length up to 5 ft. (1.5 m); weighs up to 700 lb. (317 kg) appearance: Shell is greenish brown with light stripes or blotches; skin also green in color Diet: Adults eat sea grass and seaweed; young eat small crabs, jellyfish, and other marine animals Breeding: Females lay between 100 and 200 eggs up to 5 times every year; eggs hatch after about 65 days life span: More than 80 years status: Endangered

The green turtle roams the tropical and subtropical oceans throughout the world. Its paddlelike limbs are well adapted for swimming in the ocean currents.

183

HArleQUIN TOADS Harlequin toads are brightly colored for a reason. the colors warn any predators that their skin is poisonous. twenty years ago, these amphibians were common but many species are now extinct in the wild.

184

FrOGs anD tOaDs

H

arlequin toads are diurnal, which means they are active during the day. Their long, spindly legs are good for walking over mossy rocks by streams and across grasslands in the Andes Mountains. They also swim in the water using their webbed feet. At night, these toads sleep on leaves out of the water. Harlequin toads face extinction in the wild. People are generally to blame. In the past, people took too many from the wild and sold them as pets. This is because they are attractive and are a symbol of good luck to some local people. Harlequin toads are also losing habitat because people are cutting down rain forests. Scientists believe that the toads are also disappearing due to infections caused by a fungus (a plantlike mold) in stream water and because trout introduced into South American rivers eat the tadpoles.

sending Messages One member of this group, called the golden frog, communicates using gestures. This is easier than using sounds when living by noisy, rushing streams. Males guard territories by streams in which the toads breed. When another male moves into his territory, the male makes his gesture. He slowly waves a forelimb to show he is ready to fight. Most males will be put off by the gesture and move away. However, others may wave back and attack. The loser of a fight stops waving and lies still. Females mate with the toads that win.

fact file HarleQUIN tOaDs Atelopus species family: Bufonidae Order: Anura Where do they live?: Central and South America Habitat: Alongside streams on high grasslands and in rain forests size: Head–body length 1–2 in. (2.5–5 cm) appearance: Skin comes in a range of colors, from bright golden yellow and red to darker brown or black; the skin may be plain or covered in stripes or blotches of bright color Diet: Small insects such as ants Breeding: Females lay eggs in long strings, which hatch after 24 hours life span: Up to 10 years status: Varies according to species but many critically endangered

The harlequin toad atelopus varius from the rain forests of Costa Rica displays a range of bright colors to warn predators that it is poisonous.

185

HellBeNDer these flat, wrinkly inhabitants of mountain streams have many curious names that suggest they should be avoided. in fact this rather unattractive salamander is harmless to people.

186

newts anD salaManDers

H

ellbenders hide during the day and emerge at night to hunt crayfish and other aquatic invertebrates (animals without backbones). They have small, beady gray eyes to detect light. They also have light-sensitive dots all over their body. These help them to make sure they are hidden—even their tails. The adults breed in the fall, when males and females gather in certain areas of the river. each male scoops out gravel from under large rocks. He sits in the nest and drives passing females inside. The male keeps the female in the nest until she lays her eggs, which he then fertilizes (adding his sperm to the eggs). The male drives the female away, guarding the eggs until they hatch into larvae with gills. The larvae live in the gravel for up to eight years until they become adults.

Falling numbers The streams running from the Appalachian Mountains contain around ten hellbenders for every 120 square yards. However, the population is in decline. Many streams are now unsuitable for hellbenders, because much of the land surrounding the streams has been cleared for agriculture and mining. These activities produce runoff of soil or chemicals, which ends up in the water. The water gets clogged up with the runoff, and there are fewer gaps for hellbenders to hide in. The slower-moving water contains less oxygen for hellbenders to absorb through their wrinkly skin.

fact file HellBeNDer (mUD DevIl, DevIl DOG, Or alleGHeNY allIGatOr) Cryptobranchus alleganiensis family: Cryptobranchidae Order: Caudata Where do they live?: Around the Appalachian Mountains of the United States

Tropic of Cancer

Habitat: Clear, fast-flowing mountain rivers and streams size: Head–tail length 12–29 in. (30–74 cm) appearance: Yellowish-brown to olive-green with dark black spots or blotches Diet: Mostly crayfish, but also other amphibians, snails, and small fish Breeding: Females lay between 150 and 400 eggs in strings, which hatch after 45–84 days life span: About 25–30 years status: Near threatened

Hellbenders are flat and wide with a wrinkled fold of skin down their sides. This shape helps to stop them from being washed away by fast-flowing water.

187

HOrNeD lIZArDS studded with a collar of spiny horns around their heads, horned lizards are unmistakable reptiles. they live in hot, sandy parts of north and Central america and feed almost exclusively on ants.

188

snakes anD lizarDs

H

orned lizards are unmistakable reptiles. They have lots of spines that form a fringe around their flat oval bodies. There are also lines of spines on the back and short tail. Some species have a crown or coronet of larger spines pointing out from behind their head. young horned lizards have smoother skin, but they still have the spines.

fact file HOrNeD lIZarDs (alsO KNOWN as HOrNeD tOaDs) Phrynosoma species family: Iguanidae suborder: Sauria Order: Squamata Where do they live?: United States and Mexico

warming up and Cooling down At night horned lizards dig into the soil which is still warm from the previous day’s sunlight. They dig by moving the spines on their bodies backward and forward. The temperature is very cold early in the morning, so the lizards need to bask in the sunlight to warm up. like all reptiles, horned lizards are coldblooded creatures. They get their energy from the sun and do not create it from their food. The lizards keep just their heads in the sunlight so blood under the skin can move heat around their bodies. As they warm up further, they expose their backs to the sunlight. They flatten and tilt their bodies toward the sun to take in as much heat as possible. Only when they are warm enough do these lizards become active. Sometimes horned lizards get too hot. When this happens, the lizards may stretch their legs so their bodies are not resting on the warm soil. They also make their bodies less flat so they do not warm up too quickly. They may even seek the shade under a bush. Unlike its common name suggests, the Texas horned

Equator

Habitat: Dry woodlands and dry, sandy scrub with scattered bushes size: Head–tail length 2.5–4 in. (6–10 cm) appearance: Yellow, brown, or pale pink with darker bands across the body and a paler stripe along the center of the body Diet: Mostly ants Breeding: Females lay 25 eggs, which hatch after about 60 days life span: Between 5 and 8 years status: Varies according to species but many least concern

lizard is not confined to one state but ranges across the United States, from Colorado to northern Mexico.

189

horned lizards

DID YOU KNOW? Native Americans called the Anasazi thought that the horned lizard could cure illnesses if they were treated well. Horned lizards are becoming rare in some areas because the ants they like to eat are being driven out by fire ants spreading northward from South America.

Some horned lizards have a special way of getting water. They stand up in the early morning as fog forms over high ground. Water vapor in the fog condenses on their horns and trickles down onto their flattened backs and toward their mouths.

Ant Specialists Some species of horned lizards will occasionally eat beetles, caterpillars, and spiders, but most feed solely on harvester ants. The bones of the lizard’s skull are adapted to their diet. Their jaws can gape open rapidly to snap up their tiny prey. Horned lizards move between

The spines on the back and sides of the horned lizard are modified scales, but those on the head are true horns.

190

anthills and settle on a trail used by ants. They then sit and wait for ants to walk by, flicking out their short, sticky tongues to capture them. Horned lizards often eat more than 200 ants per day. They have a large stomach to accommodate their prey, and this gives these lizards a rounded appearance. For this reason, they are sometimes called horned toads.

Defending Themselves The usual defense tactic adopted by the horned lizard is to keep still. Their coloration and jagged shape makes it very difficult for predators to spot them against the stony, sandy soil. Different species of horned lizards have colors that match the habitat in which they live. When the camouflage does not work, horned lizards suck in air to inflate their bodies. This makes them look much bigger than they are and makes their spines stick out. It becomes hard for predators, such as birds of prey, coyotes, ground squirrels, roadrunners, and snakes, as well as cats and dogs, to pick up the lizards. If they do manage to do so, the lizards may become stuck in their throats.

snakes and lizards

last line of defense When all else fails, the horned lizard has a drastic last line of defense. If a predator such as a fox or coyote manages to get hold of the lizard, it squirts blood from its eyes. Horned lizards do this by bursting tiny blood vessels around their eyes. The blood

can squirt several inches, and the lizard can lose up to one third of its blood. The blood tastes very nasty because it contains tiny amounts of poison from the ants they eat. The poison builds up and is strong enough to deter predators from eating these lizards.

191

HOUSe SNAkeS House snakes are some of the most widespread and familiar of all the african snakes. they live around farms, villages, and other settlements because this is where their favorite food—rats—are plentiful.

192

snakes anD lizarDs

t

here are up to fifteen different species of house snakes. They all have slender bodies covered with shiny, diamond-shaped scales. Their heads are only slightly wider than their necks. Different species can be told apart by their coloration and by where they live. Olive house snakes are green, while aurora house snakes have an orange stripe on their bright green bodies. The Seychelles house snake lives only in the Seychelles (islands off mainland Africa), while the brown house snake is found across the continent. Adult house snakes look alike, but females are much bigger than the males. This is an advantage because they can store more eggs. Females may lay a clutch of eggs every four to eight weeks through the summer breeding season. In a year, they can produce more than thirty eggs. The hatchlings are like small versions of the adults. They are about 6 inches long. They start to feed after they have shed their skin for the first time.

Big appetites House snakes have big appetites. They eat mostly rodents up to the size of rats, but they also prey on bats and lizards. House snakes hunt at night. They attack their prey by striking with their long, sharp fangs. The snake then coils its body around the prey and squeezes tight until the prey can no longer breathe. like other snakes, house snakes can dislocate their jaws and swallow their prey whole.

fact file HOUse sNaKes Lamprophis species family: Colubridae suborder: Serpentes Order: Squamata Where do they live?: Africa south of the Sahara Desert but also parts of Morocco Habitat: Open fields and grassland, scrub with scattered bushes, and in buildings size: Head–tail length 3 ft. to 4.75 ft. (90–150 cm) appearance: Pale orange-brown, brown, olive-green, or black; may also have different colored stripes along body or on the head Diet: Mostly mice and rats Breeding: Females lay between 5 and 16 eggs, which hatch after 60–90 days life span: Up to 15 years status: Varies according to species

House snakes are welcomed in some farming communities because they eat the rodents that damage stores of human food such as grain.

193

Iguanas The iguanas are one of the major families of lizards. All iguanas have four legs with five toes and long tails, but they vary greatly from species to species in size, shape, and color.

194

T

here is no typical member of the iguana family (Iguanidae). The family includes the true iguanas, such as the green iguana, which have stocky bodies, with crests along their backs, and long, whiplike tails. The heavyweight among the true iguanas is the powerful rhinoceros iguana, which has tough

Fact File skin and horns on its massive head. These large reptiles are probably the most familiar, but other members of the iguana family are much more common. These include the slim, agile anoles, which live mostly in bushes on the Caribbean islands; the short, spiky horned lizards of the United States and Mexico (see pages 48–51); and the basilisks. Basilisks have especially long legs, and they are fast runners. Some can run even faster on their hind legs alone, so they lift their forelimbs off the ground when running.

Passing on Messages Most members of the iguana family use colors and body postures to communicate with other members of their own kind. Generally, anoles have bright green bodies, but these lizards also have a patch of bright red skin called a dewlap. This flat flap of skin covers a bone that sticks out from the lizard’s throat. The dewlap acts as a signal to other anoles. For example, male anoles flick their dewlaps down to warn off other males that intrude on their territories. As they grow older, large male iguanas often grow large permanent dewlaps. These are a sign to all the neighboring males that they are strong enough to fight them. The intruders keep away from the dominant male’s territory and do not breed with the females that live there. Spiny tailed iguanas are large reptiles with distinctive enlarged spiny scales on their tails. Unlike their close relatives, the green iguanas,

Iguanas Family: Iguanidae Suborder: Sauria Order: Squamata Where do they live?: Americas, islands of the Caribbean, and Madagascar

Equator

Habitat: Ranges from deserts and rain forests to the oceans Size: Head–tail length ranges from 4 to 72 in. (10 cm to 2 m) Appearance: Varies Diet: Small invertebrates such as insects and spiders; smaller lizards; some eat flowers, fruit, and leaves; one species eats just seaweed Breeding: Females lay up to 60 eggs 4 times a year; eggs hatch after 30–60 days Life span: Up to 60 years Status: Varies according to species

OW? DID YOU KN The thorntail iguana lives in holes high up in the treetops. These reptiles have very fat, spiky tails. They often push their tails out of these holes to block out any predators trying to get in. In parts of Central America, the plumed basilisk is known as the “Jesus Christ lizard.” This is because it can walk, or more accurately, run up to 62 feet across water on its wide, webbed toes.

these lizards are not very easy to tame. 195

Iguanas

Other iguanas use color and body posture to pass on messages to predators. The fringe-toed lizard has a white tail with bold black stripes on its underside. When they spot a predator, these lizards raise their tails and wave them from side to side. The idea is to ensure that the predator sees the signal. The message tells the predator that the iguana is so confident it can run fast, that it does not need to hide, and therefore that there is no point in chasing it. It stops the lizard wasting energy by running in the desert heat.

Different habitats Most iguanas live in temperate or tropical rain forests, where they crawl among the branches of tall trees. Some live on barren oceanic islands, while others are found in hot deserts. Many iguanas have special adaptations for life in these different habitats. Side-blotched lizards live beside seabird colonies on islands, where they eat fish dropped by seabirds or flies attracted to the bird guano. Fringe-toed lizards live in desert sand dunes. They have long, pointed scales around their toes. These give their feet a wide surface so they do not sink into the shifting sand. They also have flaps to prevent sand from getting into their ears. To chase insects in the sand, they listen and then dive headfirst into the sand to catch them.

196

Ocean Lizard The marine iguana is unique among lizards because it is the only species in the world to spend time in the ocean. Marine iguanas live only in the Galápagos Islands in the Pacific Ocean. They are strong swimmers. They can hold their breath and swim under the waves to graze on seaweed growing on rocks. There are special salt glands by their nostrils. The glands collect the excess salt from the food and seawater that they take into their bodies,

Iguanas

1

2

1 Cuban brown anole 2. Rhinoceros iguana 3. Fringe-toed lizard

3

which could make them sick. The iguanas keep a grip on the slippery rocks above the sea using their long claws. They bask on the rocks in large groups to warm up after swimming in the cold ocean. The black color of the skin helps them warm up much faster.

Feeding Time Iguanas are usually herbivores, which means they eat only plant material such as leaves, flower buds, fruits, and succulent shoots. Some iguana species also eat insects such as crickets and other invertebrates, such as worms. In turn, the iguanas themselves often become food for many meat-eaters, including people. In Central and South America, iguanas are bred and reared on farms for their meat.

Breeding Time After mating, females of most iguana species dig a burrow in which to lay their eggs. The female usually chooses a sunny area, so the heat from the sun provides a constant temperature needed for the eggs to keep warm. After a short incubation, the eggs usually hatch together. The young iguanas then dig their way to the surface with no help from their parents. The young are then left to fend for themselves. Young iguanas face many dangers. There is the habitat loss through human activities such as deforestation, as well as the threat from introduced species, such as cats and dogs, that prey on wild iguanas. Some species, such as the Jamaican iguana, face extinction in the wild unless measures are taken to protect them. 197

INDIAN COBrA the indian cobra rears up and spreads its hood wide to look as big and as scary as possible. people have every reason to fear the cobra’s deadly bite since these snakes are some of the most poisonous on the planet.

198

snakes anD lizarDs

t

he Indian cobra is the most familiar member of the cobra family. Cobras are long snakes with smooth scales and large shield scales on their heads. They are all venomous. Their front fangs are fixed in their skulls. Grooves run along the outside of the fangs. venom moves from the venom glands (special cells) along the grooves to the end of the fang. Cobras use venom to kill prey such as toads, which they eat whole, or as defense against dogs, people, or mongooses. Indian cobras lay their eggs in animal burrows, piles of leaves, or termite mounds. The female forms a rough nest in which she lays up to thirty-six eggs. The hatchlings are 7–11 inches long and more aggressive than adults. They have just as much venom as the adults and their bite can easily kill an adult person.

Hooded snake The hood of the Indian cobra is made of extra long ribs. Skin stretches out over the ribs on either side of the cobra’s neck. This makes the cobra look like it has a massive head. Cobras spread their hood when they feel threatened by another animal. The cobra also raises the front part of its body off the ground to rear up to the same level or above the animal. It may turn its head away to show off the spectacle marking on its neck or sway slowly backward and forward. If these displays do not scare the other animal, the cobra strikes fast with its venomous fangs.

fact file INDIaN cOBra Naja naja family: Elapidae suborder: Serpentes Order: Squamata Where do they live?: India, Nepal, Pakistan, and Sri Lanka Habitat: Forest, grassland, fields, and gardens size: Head–tail length 4–5 ft. (1.2– 1.7 m) appearance: Brown or black with white or cream “spectacle” marking on the back of its neck Diet: Frogs, mice, rats, toads, and other snakes Breeding: Females lay 12–22 eggs, which hatch after 8 to 12 weeks life span: Up to 30 years status: Rare and endangered locally

The hood of the Indian cobra folds back down when the threat of a potential predator has past, so it does not get in the way as the snake slithers around.

199

Jungle racer The jungle racer is one of the few lizards that is increasing in numbers as forests are cut down and disturbed by people. This shy reptile loves sunny, open spaces near enough to the forest so that it can run for cover when it feels threatened.

200

snakes anD lizarDs

t

he jungle racer is a shy, small to medium-sized lizard with a long, pointed nose. It is covered with very small scales that look like tiny pinheads. It has strong legs and long claws to get a grip as it runs and climbs in the trees. So long as the racer stays still, its coloration provides good camouflage. Jungle racers are common lizards. They breed for about six months of the year. Females lay about five eggs in holes in the damp soil or sandbanks by rivers. The hatchlings start to hunt and can run fast as soon as they dig their way out of the nest.

fact file JUNGle racer (alsO KNOWN as JUNGle rUNNer aND tHe DWarf teGU) Ameiva ameiva family: Teiidae suborder: Sauria Order: Squamata Where do they live?: South America, from Panama to Argentina Equator

Heading for the Clearings The development of the rain forest near the Amazon river and other parts of South America has increased the number of jungle racers. Habitat destruction and deforestation usually reduces the population of most species because they have less space in which to move around and find food. But the jungle racer can find more food and basking sites by forest clearings, paths, and roads than in untouched rain forest. Jungle racers like warm tropical temperatures. When it reaches 79°F or more, the racer emerges from its hiding place under a rock or log to bask in the open or hunt insects that are attracted to sunny clearings. Clearings are also safer for the racer, because many predators, such as birds of prey and snakes, do not like to hunt out in the open.

Habitat: Clearings, paths, and roadsides through forested areas size: Head–tail length 16–24 in. (41–60 cm) appearance: Mostly brown with bright green patches on its back; banded pattern of light and dark spots on the sides of the body Diet: Insects such as crickets and cockroaches; small lizards Breeding: Females lay between 2 and 9 eggs, which hatch after 60–90 days life span: Not known

The jungle racer gets its common name from its habit

status: Common

of scuttling quickly into the cover of the surrounding vegetation at the first sign of danger.

201

kOMODO DrAGON adult komodo dragons are the largest lizards in the world. they live on several indonesian islands in southeast asia, including the island of komodo, which gives these giant lizards their common name.

202

snakes anD lizarDs

t

he komodo dragon is a massive reptile with a small head and rounded snout. Its tough, folded skin is covered with small, even scales, which gives it the appearance of chainmail armor. komodo dragons have muscular tails and strong legs. The toes end with sharp claws, which can measure up to 2 inches. Despite their huge size, komodo dragons can run at speeds of 12 or 13 miles per hour, which is about the same as a fast marathon runner. komodo dragons are also good climbers and swimmers.

ambush Hunters komodo dragons hunt by stealth. They usually hide in long grass and remain perfectly still as they lie in wait for prey such as deer, goats, pigs, wild boar, and even mammals as big as buffalo and horses. When the prey comes into range, usually within 4 feet, the komodo dragon rushes out and delivers a bite with its short, sharp teeth. If this is enough to stop the prey from escaping, the komodo dragon then uses its claws to rip open its unfortunate victim. If the animal escapes, it usually dies anyway. This happens because komodo dragons have lots of harmful bacteria in their saliva, which can easily infect the bite wound. Zoologists think that the saliva is also slightly poisonous. komodo dragons also feed by scavenging, which means they eat carrion or the remains of dead animals, including animals that they have infected by biting.

fact file KOmODO DraGON Varanus komodoensis family: Varanidae suborder: Sauria Order: Squamata Where do they live?: Islands of Indonesia in Southeast Asia Habitat: Dry forest and grassland, dry riverbeds size: Head–tail length up to 10.4 ft. (3.1 m); weighs up to 330 lb. (150 kg) appearance: Adults are brown to grayish red; young are green with yellow and black stripes Diet: Adults may consume prey as large as deer or horses; younger Komodo dragons feed on insects, lizards, and smaller mammals Breeding: Females lay up to 30 eggs, which hatch after 8 months life span: Up to 50 years status: Vulnerable

Komodo dragons have poor senses of sight and hearing. These huge reptiles use their long, yellow tongues to smell and taste their prey.

203

Komodo dragon

The lizards flick out their long tongues to sense smells given off by carrion (dead animals). They can smell carrion from up to five miles away. Often many Komodo dragons smell the same carrion and arrive to form a feeding group. There is a pecking order

The Dragon’s den In the wild, Komodo dragons live on six islands that are part of Indonesia, which is a group of islands north of Australia. These islands include western Flores, Komodo, and Padar. Komodo dragons live in an area that totals around 390 square miles.The islands have steep slopes as they were formed by volcanic eruptions that occurred a long time ago. The normal daytime temperature is 80°F. Rainfall mostly falls in one wet season called the monsoon. Adults usually live in dry, open forests and dry grassland at the foot of the volcanic slopes. Young Komodo dragons live in dense forests around rivers. Komodo dragons spend most of the day patrolling a territory. This is an area in which they can find food and shelter. They dig large burrows where they can keep cool during the hottest part of the day, and to which they can retire at night to keep warm.

204

of who eats first. Dominant males eat the most meat before smaller males and females move in to feed. Young Komodos will feed only once all the adults have moved away. They have to be careful because adults will attack and eat young of their own kind.

snakes and lizards

Breeding

The Komodo dragon is a fearsome-

Komodos usually breed in July and August, which are dry months. Females produce smelly feces (waste) that attracts the males. After the lizards mate, females sometimes lay their eggs in their own burrows. They may also bury them in the nest mounds of wild turkeys. The nest mounds of leaves and other decaying plant waste get hot inside. This keeps the temperature warm for both young turkeys and Komodo dragons to develop properly inside their eggs. The young Komodo dragon hatchlings measure 15 inches. They emerge from the eggs in April, just after the monsoon, which is when there are lots of grasshoppers and other plant-eating insects around for the young to eat.

looking reptile, with a small head,

Komodo dragons are threatened for a variety of reasons. Sometimes individuals are captured and illegally smuggled abroad to animal collectors. The biggest threats, however, are local people cutting down forests and killing Komodos to eat. In addition, forest fires and volcanic eruptions on the islands can destroy habitat naturally.

Dragons in Danger

Captive Komodos

Komodo dragons face extinction in the wild. There are between 3,000 and 5,000 wild Komodo dragons. They are considered a national treasure in Indonesia and laws have been passed to protect them. This is partly because many tourists visit the islands to see wild Komodos. This protection is not enough, though.

The massive size and fearsome reputation of the Komodo dragon makes it a popular zoo exhibit. Zoologists have learned a lot about their behavior by studying them in zoos. Komodo dragons become tame in captivity very quickly, but they are unpredictable and must be treated with care at all times.

long body, and a long, muscular tail.

DID YOU KNOW? Komodo dragons may cover more than 6 miles every day in search of food. Young Komodo dragons are prey to the eagles, snakes, and wild dogs living on the islands.

205

kUHl’S FlyING GeCkO this lizard is one of the few reptiles that can glide through the air, moving easily through the dense rain forests of southeast asia. Geckos prey on insects and spiders on the trunks of the tall trees that grow there.

206

snakes anD lizarDs

k

uhl’s flying gecko is a medium-sized lizard that lives in warm, humid rain forests of Southeast Asia. These geckos grip onto the tree trunks using the sticky pads on the ends of their toes. The pads are so effective that the geckos can also hold onto smooth surfaces, such as walls and even glass in houses. Female geckos lay pairs of eggs every three to four weeks. She tucks them in gaps behind bark on the tree trunks. young geckos look exactly like their parents and are at home in the trees.

equipped for Gliding kuhl’s flying gecko has several adaptations that help it to glide well. It has large folds of skin down each side of its body, a fringe of skin around its tail, and webbed toes. These adaptations make its body surface greater when it glides. When the gecko launches off a tree, the skin flaps spread out and slow the fall. The gecko uses its tail like a rudder to change direction. When the gecko lands it sits completely still. even if a predator, such as a hawk, sees the gecko gliding, it will still find it difficult to spot the gecko on the tree trunk. The color of the skin camouflages the gecko against the bark, and the skin flaps act like a cloak to stop the gecko’s body from forming shadows—predators use shadows to help spot prey. Once the gecko is certain it is not being chased, it scuttles up the tree feeding on insects and spiders until it is ready to glide again.

fact file KUHl’s flYING GecKO Ptychozoon kuhli family: Gekkonidae suborder: Sauria Order: Squamata Where do they live?: Southeast Asia, from Thailand to Indonesia Habitat: Tropical rain forest; occasionally houses size: Head–tail length 8 in. (20 cm) appearance: Brown, gray, or olive with darker zigzag stripes and patches on the body Diet: Insects and spiders Breeding: Females lays 2 eggs, which hatch after 13 weeks life span: Not known status: Common

The flaps of skin along the sides of the flying gecko’s body not only help these lizards to glide. At rest, the flaps help the lizard to blend in with the tree bark.

207

Leaf frogs The leaf frogs are the same color as the leaves of rain forest trees on which they live. They also use leaves to make nests for their eggs. When they hatch, the tadpoles drop into ponds below.

208

FrOGs anD tOaDs

l

eaf frogs are a varied group of small amphibians that live in the trees of tropical rain forests. Most species have wide heads and very narrow waists. Their legs are long and thin and the toes close toward each other. Opposable toes such as these are a common feature of animals such as monkeys that need to grip the branches through which they move.

leaf Jelly The scientific name for leaf frogs is Phyllomedusa, which means “leaf jellyfish.” The group got its name for the way in which the females lay their eggs on the leaves. When she is ready to lay her eggs, the female finds a bush or tree overhanging a forest pond or slow-moving stream. There she lays between 300 and 600 tiny, jelly-covered eggs. At first sight, the wobbling mass of eggs resembles a jellyfish. The jelly protects and nourishes the young as they develop. The female rolls the edges of leaves around the mass of eggs using her back feet. The jelly sticks to the leaf, forming a roll. There are two reasons to treat the eggs like this. It hides them from egg-eating predators, such as wasps, and it prevents the eggs from drying out. The tadpoles hatch from the eggs less than a week after the female lays them. They have long tails, large eyes, and wide mouths. The tadpoles drop from the leaf and roll into the water, where they feed on tiny insects and other floating objects that land on the water’s

fact file leaf frOGs (alsO KNOWN as mONKeY frOGs) Phyllomedusa sp. family: Hylidae Order: Anura Where do they live?: Central and South America Habitat: Usually tropical rain forest but some are found in dry forests size: Head–tail length up to 3 in. (7.5 m) appearance: Bright green back; other bright colors such as orange on the sides of the body and the insides of the legs Diet: Large insects, such as crickets and cockroaches, and spiders Breeding: Females lay between 300 and 600 eggs, which hatch after about 6 days life span: Not known status: Varies according to species

The barred monkey frog has black and orange bands on the flanks and the inside of the legs. This gives the frog its alternative name—the tiger-striped leaf frog.

209

leaf frog

DID YOU KNOW? Leaf frogs do not leap like many other frogs unless they feel threatened by a predator. The giant leaf frog faces extinction in the wild because people kill them for the wax on their skin. They believe the wax can be used to make medicines to cure illnesses such as cancer.

surface. The tadpoles of some types of leaf frogs group together in the water. This confuses fish and other predators in the pool that would easily catch individual tadpoles.

prey to come close enough to eat. This frog lifts its front feet and slowly moves the fingers. White marks on the fingers look like wriggling worms. The prey moves closer because it thinks there are worms to eat.

Sit and Wait Adult leaf frogs are sit-and-wait predators. They tuck their legs in and sit on branches waiting for insects or spiders to come close. When the prey gets in range, the frog unrolls its long, sticky tongue and shoots it out of its mouth. The tip sticks to the prey, and the tongue rolls back up to pull the unfortunate victim into the frog’s mouth. Burmeister’s leaf frog has a special way of encouraging

Flashes of Color Leaf frogs sit still and rely on the color of their skin to keep them safe from predators such as lizards and snakes. Leaf frogs tuck in their legs and often close their eyes. The bright green color of the leaf frog’s back closely matches the rain forest leaves on which it rests. When the frog is moving, it flashes bright colors. The barred monkey frog or tiger striped leaf frog has orange and black stripes down its flanks and back legs. The colors may allow other frogs to recognize the species. They may also startle some predators.

The waxy monkey leaf frog lives among the treetops of the dry pampas of South America. 210

FROGS and toads

frog wax Most amphibians need to keep their skin moist so it can absorb oxygen, making it easier for the amphibian to breathe. This is the reason why most amphibians live in moist habitats. But leaf frogs such as the waxy monkey leaf frog live in dry forests in South America rather than moist rain forests. They have two ways of stopping their skin from drying out. First, they produce a waxy paste from skin glands.

They smear the wax all over their bodies using their flexible back legs. The wax reduces water loss through their skin by about one tenth. Frogs protected with wax often sit on branches, basking in direct sunlight. Second, leaf frogs also lose far less water than other frogs when they urinate (pee). Their urine is like a thick paste, similar to bird droppings, rather than a watery liquid.

211

leATHerBACk TUrTle the leatherback turtle is the largest marine turtle in the world. it roams across the world’s oceans feeding on jellyfish. the leatherback is unusual among turtles because it has a leathery, rather than hard, shell.

212

turtles, terrapins, tOrtOises

l

eatherback turtles have long, leathery shells with seven ridges down their lengths. Most turtles have hard shells, but the skin on the shell of the leatherback turtle is smooth and rubbery. It is also streamlined so the turtle can glide easily through the water. every two years, males and females meet at breeding sites in warm, tropical waters. After mating, the females leave the water and lay their eggs on sandy beaches. Females prefer sites where they do not have to haul their bodies over sharp reefs or rocks. A female digs a hole in the beach with her flippers and deposits the eggs inside. Two months later, the baby turtles dig their way to the surface. They move quickly into the water to avoid being eaten by predators such as seabirds.

fact file leatHerBacK tUrtle Dermochelys coriacea family: Dermochelyidae Order: Testudines Where do they live?: All the oceans except Arctic and Antarctic waters

Equator

Habitat: Open ocean

Dangers for leatherbacks People used to hunt leatherbacks for the oil in their skin, which was used for cosmetics and medicines. leatherbacks are now protected, but they still face many dangers. These turtles eat jellyfish, but they cannot always tell the difference between jellyfish and the plastic waste floating in the oceans. The plastic gets caught in the stomach and kills the turtles. Some also drown or injure their flippers when they are caught in fishing nets. leatherbacks also face natural dangers. Adults may be eaten by ocean predators such as great white sharks and killer whales. Their eggs may be washed away from nesting beaches in stormy weather.

size: Head–tail length up to 8 ft. (2.4 m); weighs up to 1,650 lb. (750 kg) appearance: Light to dark gray shell with white blotches Diet: Jellyfish Breeding: Females lay about 80 eggs up to 9 times every breeding season; eggs hatch after 65 days life span: Not known status: Critically endangered

Leatherbacks travel thousands of miles through the oceans. They have very long front flippers, which provide the swimming power to travel such distances.

213

leOPArD GeCkO the attractive leopard gecko lives in the rocky deserts of Central asia. unlike climbing geckos, which have suckers on their toes, leopard geckos have clawed toes. they use them to dig burrows and clamber over the rocks.

214

snakes anD lizarDs

t

he leopard gecko is an unusual gecko. It has the broad head and cylindrical body of other geckos. Unlike other geckos, however, this species has eyelids. This is an adaptation that protects the leopard gecko’s eyes from windblown dust in its desert habitat.

life in the Desert The leopard gecko is well suited to life in the desert. It avoids the intense daytime heat by burrowing in the sand. Usually, these lizards emerge between dusk and midnight, before it becomes too cold. During this time, they listen and look for movements of small animals such as beetles and scorpions. The geckos move fast to catch their prey. They also listen for nocturnal (night active) predators such as owls and snakes. In the warmer months leopard geckos feed a lot and develop a broad carrot-shaped tail. Geckos stay in their burrows for the whole winter. They do not hunt but live off the fat stored in their tails. By the end of the winter, the tail is thin and withered. Several geckos may live together in colonies around a stony hillside. Several females and young geckos live inside the territory of a male—the area in which the male hunts for food. During the breeding season, females hide their eggs in moist, sandy soil. The young geckos that hatch have bigger, bolder markings than the adults. The markings are shaped rather like saddles but fade into spots with age.

fact file leOParD GecKO Eublepharis macularius family: Eublepharidae suborder: Sauria Order: Squamata Where do they live?: Afghanistan, India, Iran, Iraq, and Pakistan Habitat: Desert and dry scrub in mountain areas size: Head–tail length 8–10 in. (20–25 cm) appearance: Yellow or tan with small dark-brown spots; tail often striped black and white Diet: Mostly insects, spiders, and scorpions Breeding: Females lay 2 eggs every 3 weeks during the breeding season; eggs hatch after 40–60 days life span: Up to 20 years status: Common

In the wild, leopard geckos are a creamy yellow color with black spots and stripes. Captive individuals show a wide range of color variations.

215

Leopard Tortoise The leopard tortoise is a common sight in the African savannah. Leopard tortoises are active during the day. They wander through their grassland habitat in search of food, such as thistles.

216


T

he leopard tortoise gets its name for the spots on the shell, which look like the spots of a leopard. This reptile has a tall, dome-shaped shell, which is very attractive. Some local people not only eat tortoise meat, but also use the shell to make musical instruments.

Protective Shell The shell of the leopard tortoise protects it in different ways. The yellowish dappled pattern blends in with the dry grasses of the savannah and provides camouflage against predators. When a predator approaches, these reptiles are too slow to run away. Tortoises up to the age of about three years may be eaten by mammals including hyenas and birds such as hornbills. These predators can crush the weak shells of young tortoises. Adult tortoises have tougher shells, which offer greater protection. The shell can even shield the tortoise from fires that burn in the savannah during hot times of year.

Fact File Leopard tortoise Geochelone pardalis Family: Testudinidae Order: Testudines Where do they live?: Eastern and southern Africa Habitat: Open areas such as dry grassland or savannah Size: Shell length up to 24 in. (60 cm); weighs up to 70 lb. (32 kg) Coloration: Shell color is yellowbrown with darker blotches Diet: Plants such as grasses and thistle Breeding: Female lays between five and 30 eggs up to 6 times a year; eggs hatch after 8–18 months Life span: 50–150 years Status: Common

Going Underground Adult tortoises breed all year round. The female digs a hole about 12 inches deep. She lays her eggs inside, covers them with soil, and leaves the burrow. The young hatch around a year later. They measure about 2 inches long and have a special tooth on their snout to break open the egg. They also use the tooth to dig up to the surface from their burrow. The young tortoises have to find food and look after themselves. A leopard tortoise forages in the grass. These reptiles tuck their heads and legs into their shells to protect themselves from predators, such as hyenas.

217

Lizards There are more lizards on Earth than any other reptile. Lizards come in many different shapes and sizes. They live in a wide variety of habitats. Some hide in burrows, while others make their homes in the treetops.

218

T

here are about 4,700 known species of lizard. One family of geckos, called Gekkonidae, contains more than 900 species. Geckos are fast-moving climbing lizards that typically scurry across walls and ceilings. The collared lizard takes its name for the black bands around its neck and shoulders.

Fact File These lizards spend much of their time searching for insects to eat. One of the largest lizard families is the Iguanidae (the iguanas). Species include the marine iguanas, which live along rocky seashores of the Galápagos Islands off the coast of Ecuador; iguanas called horned lizards that lap up ants in the scorching deserts of the United States; and the colorful anoles that flash their throat flaps (called dewlaps) at each other to both attract a mate or frighten off another lizard or predator. The smallest family contains just one species—the Borneo earless monitor. This burrowing, brown lizard lives only in damp caves on the island of Borneo.

Skin Deep Like all reptiles, a lizard’s skin is covered with scales. These help to protect reptiles and also to conserve water. This is important because most reptiles live in hot, dry places where water is scarce. The scales may be knobby and heavy, as in the Australian stump-tailed skink. Scales can also be tough like armor-plating, as in the alligator lizard, or they may be shaped like the overlapping scales on a pine cone, as in the Texas spiny lizard. Tough scales can help lizards to avoid predators, because the jagged edge breaks up the outline of the reptile so it is trickier to spot.

Lizards Species: More than 4,700 Families: 20 Suborder: Sauria Order: Squamata Where do they live?: Worldwide except for the Arctic and Antarctic

Equator

Habitat: Wide range from rain forest and desert to river and ocean Size: Head–tail ranges from 0.75 in. to 15.6 ft. (1.6 cm to 4.75 m) Coloration: Varies widely Diet: Mostly insects, spiders, and small reptiles; some eat the flowers, fruits, and leaves of plants; a few large species eat mammals; marine iguanas even eat seaweed Breeding: Females may lay many tough, leathery eggs, usually in burrows or holes; the eggs hatch after 30–60 days Life span: Up to 60 years Status: Varies according to species

Moving Around Most lizards have four limbs that point toward the ground.They crawl by moving one front leg and the opposite back leg at the same time. 219

Lizards

Then the other front leg and is opposite hind leg move forward, so the lizard wriggles as it walks. In many families, such as Lacertidae (wall lizards), the back legs are longer than the front legs so the lizard can move faster. Some lizards, such as basilisks, can run on their hind legs. The Scincidae (skink family) have small legs that fold against their sides. They are good at burrowing through soil or sand or moving through dense plants, in which larger legs might obstruct their movements. Other lizards, including blind lizards and slowworms, look like snakes because they have no legs at all! Many lizards have adaptations that help them to climb. Chameleons have two pairs of toes on each leg that close toward each other. These act like pincers, helping the lizard to grip. They even have a curly, gripping tail, called a prehensile tail, to help them stay in the trees. Most geckos have tiny folds of skin under their toes that help them stick onto surfaces that are as smooth as glass. Some geckos have flaps of skin between their toes and along the sides of their bodies. They stretch the skin flaps wide so they can glide through the air between trees. The spiny-tailed skink lives in cracks in the rocks or under large boulders. They stay close to home, hunting and basking near the safety of their crevices. 220

Sight Hunters Many lizards rely on their sense of sight to find prey, avoid predators, and communicate with their own kind. Some lizards come out at night to forage for food. They have large eyes to take in as much light as possible in the darkness. Burrowing lizards, such as blind lizards, lack eyes because they would get damaged as they moved through soil. The skin color of a lizard usually provides camouflage in its habitat. For example, desert lizards often have a sandy color. Anole lizards are green to hide among the leaves of tropical trees. These lizards flash a red flap of skin, called a dewlap, on their throats. Males do this to scare away other males and to attract females to mate. The leaf-tailed gecko looks just like the mottled gray tree bark on which it lives, but opens its mouth to show off a bright red tongue to startle predators. Lizards such as chameleons can

Lizards

change the color of their skin. This happens because tiny dots of different pigments under the skin expand or contract. Chameleons change color depending on the temperature of the surroundings and also to indicate their mood. For example, frightened chameleons often turn red to startle predators. Cold chameleons may turn black so their skin can absorb more heat.

Members of the chameleon family have eyes that can look in different directions, long tongues that fly out to catch insects, and the ability to change skin color according to their mood.

Not Quite a Lizard The tuatara is a rare reptile from New Zealand that looks just like a lizard. In fact, this unusual creature is related to both lizards and snakes. 221

Lizards

Scientists know this because it has some unusual body features. The spine is made of hourglass-shaped bones, which are more like those of a fish than a reptile. Unlike any other reptile, the tuatara has two rows of teeth in its upper jaw and one in the lower jaw. It also has a third eye on top of its head, hidden inside the skull. The eye is not as developed as the two proper eyes, but can sense light and dark. The green-brown color of the tuatara matches its surroundings, providing camouflage when it hunts prey such as insects, frogs, and small lizards.

222

OW? DID YOU KN The Namibian palm-footed gecko has webbed toes that are rather like snowshoes. The webs increase the surface area of the gecko’s feet so the lizard does not sink in the sand as it runs over the surface. Some species of lizard can shed their tails when attacked. The fallen tail wiggles, distracting the attacker as the lizard escapes. The lizard’s tail grows back a few weeks later. The world’s smallest lizard could fit on a dime! It is called the jaragua sphaero, and was discovered in 2001 on the Caribbean island of the Dominican Republic.

Lizards

Poisonous lizards Many lizards can bite people, but only two species can kill with their poisonous bite. The Gila monster (below) and the Mexican beaded lizard belong to a family called Helodermatidae. These lizards bite animals such as young rabbits to kill for food and other animals as

The tuatara is listed as an endangered animal by the International Conservation Union (IUCN). Like many other reptiles, this unusual reptile has suffered due to the loss of habitat and the introduction of species such as rats. The tuatara is now extinct on mainland New Zealand and exists only as a few scattered populations on the smaller offshore islands.

a form of defense. Gila monsters and beaded lizards have grooved teeth in their lower jaws. The venom or poison is made by a special gland in the lizards’ mouths. When they bite, the toxic chemical flows along the grooves and into their prey’s bloodstream.

OW? DID YOU KN The world’s longest lizard is the crocodile tree monitor. This reptile can reach several feet in length—most of it is taken up by the narrow tail. The prize for the biggest lizard in the world is usually given to the slightly shorter but much bulkier Komodo dragon.

223

Loggerhead Turtle The loggerhead is one of the largest marine turtles. This hard-shelled reptile takes its name from its stout head and beak, which may be used to crush giant crabs.

224


T

he head of an adult loggerhead is about 12 inches long. It uses its large eyes to spot shellfish in dark or murky water. The jaws are shaped like a huge beak, so these turtles can crush hard-shelled invertebrates, such as crabs and other shellfish.

Cycle of Life Female loggerheads return to the same nesting beaches on which they were born. They use their paddlelike limbs to crawl onto sandy beaches and dig a hole in the sand. In it they lay a clutch of about 100 eggs, cover them with sand, and then return to the ocean. A female may repeat this five to seven times in one nesting season. The effort is so great that females do not nest again for another two or three years. Loggerhead hatchlings are just 2 inches long when they emerge from their eggs and dig their way to the surface. This is usually at night when there are fewer predators around. The young loggerheads then crawl slowly toward the water. They often shelter among giant patches of seaweed before swimming out into the open ocean. Some travel thousands of miles from the nesting beach. As they grow, the young loggerheads feed on bigger and bigger prey. Loggerheads used to be killed for their attractive shells. Today, the trade in turtle shells is banned. However, many loggerheads die accidentally. They usually get caught in shrimp nets and drown.

Fact File Loggerhead turtle Caretta caretta Family: Cheloniidae Suborder: Cryptodira Order: Testudines Where do they live?: Atlantic Ocean, from Newfoundland south to Argentina, especially off southeastern United States; also Indian and Pacific oceans Habitat: Coastal, shallow water Size: Shell length measures around 41 in. (104 cm); weighs up to 1,200 lb. (544 kg) Coloration: Brown shell with red-brown, black, or fawn markings Diet: Shellfish such as clams, crabs, and mussels Breeding: Females lay around 100 eggs per clutch, with up to seven clutches in one year; eggs hatch after 55–70 days Life span: Up to 60 years Status: Endangered

Like other marine turtles, the limbs of the loggerhead are shaped like paddles to help them swim in the strong ocean currents.

225

Malaysian Tree Toad The Malaysian tree toad is one of the few in its family to live in trees. One unusual thing about this secretive species is that females from one part of its range are a completely different color than the rest.

226

Frogs and Toads

L

ike many other toads, Malaysian tree toads have warty skin and breed in the water. Females lay their eggs in forest streams or pools. In other ways, Malaysian tree toads are unlike other toads. They have smooth skin and slender bodies and long legs with webbed toes. Disc-shaped pads at the ends of the toes help the toads grip onto tree trunks and smooth branches up to 20 feet above the rain forest floor. Tree toads feed on a wide range of invertebrates, from ants, caterpillars, and grasshoppers to spiders and small beetles. They wait for insects to come into range and then grab them in their wide mouths. Tree toads themselves are eaten by predators such as birds. Like other toads, the Malaysian tree toad has special glands on its head behind each eye. These glands produce a foul-tasting fluid. Predators that swallow toads often spit them out because the fluid tastes so bad.

Fact File Malaysian tree toad Pedostibes hosii Family: Bufonidae Order: Anura Where do they live?: Borneo, Sumatra, the Malaysian Peninsula, and southernmost parts of Thailand Habitat: Low-level rain forest Size: Head–body length 2–4 in. (5–10 cm) Coloration: Usually brown or olive; females may have bright yellow spots Diet: Invertebrates Breeding: Females lay eggs in forest streams Life span: Unknown Status: Least concern

Spot the Difference There are several differences between male and female Malaysian tree toads. Females are twice the size of the males, so they can produce many eggs. Adults breed all year around. They gather by clear forest streams, where females lay strings of eggs on underwater plants. Males are a drab brown color. Females range from leaf green to grayish purple covered with yellow spots. Females found on the Malaysian peninsula are always spotted. Only about half of those found in Borneo have spots. The Malaysian tree toad is often called the yellowspotted tree toad because of the distinctive yellow spots that are seen on the females.

227

Mambas Mambas have a reputation for being some of the most aggressive snakes in Africa. These venomous snakes are often shy and will only attack when they feel threatened.

228

Snakes and Lizards

M

ambas are lithe snakes with an elongated head and large eyes. The western and eastern green mambas and Jameson’s mamba have green skin. This provides camouflage as they hunt in the treetops. The black mamba has gray-brown skin. It takes its name for the black skin inside its mouth.

Fact File Mambas Dendroaspis species Species: 3 green mamba species; 1 black mamba Family: Elapidae Suborder: Serpentes Order: Squamata

Fast and Venomous Mambas are swift hunters. A black mamba can travel at the same speed as someone running, even over rocky ground. Mambas prey on birds, mice, squirrels, and even other snakes. They bite their prey once or twice. The venom prevents the muscles of its victim from working. Once the prey has stopped moving, the mamba swallows its meal. Black mambas produce much more venom than green mambas. A single black mamba has enough venom to kill at least ten people. They only attack people when they feel threatened.

Where do they live?: Africa south of the Sahara Desert Habitat: Rain forest and savannah Size: Head–tail length 5–14 ft. (1.5– 4.3 m) Coloration: Green or gray-brown Diet: Rodents, bats, and birds Breeding: Females lay clutches of around ten eggs; eggs hatch after about 80 days Life span: Unknown Status: Locally common

Mamba Breeding Female mambas lay eggs in rotting vegetation inside termite mounds, or tree hollows. The warmth from the vegetation helps the young to develop. The hatchlings emerge three months later. They measure 16–24 inches. The hatchlings start to hunt for small rodents. Within one year, they may grow to 6 feet. Deforestation means that green mambas are moving to human settlements. They may be found in plantations, parks, and gardens. Black mambas are long, slender snakes that live among dusty rock piles, hollow tree trunks, and termite mounds in the African savannah.

229

Mantellas Mantellas are jewel-bright frogs of the Madagascan rain forest. The vivid colors of these amphibians advertise to other rain forest animals that they are poisonous and should not be eaten.

230

Frogs and Toads

M

antellas are tiny frogs from the rain forest of Madagascar off the eastern coast of Africa. The colorful skin of these amphibians acts like a warning signal to other animals that mantellas are poisonous and should not be eaten. Mantellas produce toxins in glands under their smooth skin. Some of these poisons can make animals such as birds and snakes very sick. Some mantellas are not poisonous but still have the protection of colorful skin!

Fact File Mantellas Mantella species Species: 12 Family: Mantellidae Order: Anura Where do they live?: Madagascar

Equator

Mantella Lifestyle Most mantellas prey on ants and termites. They sit next to the trails of these insects and pick off their prey as they pass. Mantellas accumulate small amounts of poison found in some ant species. This poison builds up in the frog’s body and forms the amphibian’s own poisonous secretion. Most mantellas lay up to 60 whitish eggs in moist leaf litter or other damp places. When the tadpoles hatch, heavy tropical rains wash them into pools or streams. One mantella species lays a few eggs in waterfilled tree hollows above the ground. The tadpoles feed on insects that fall into the water. Young mantellas are less poisonous than the adults, and have green skin with dark blotches for camouflage. Over two-thirds of the original rain forest on Madagascar has been cleared to make farmland or to sell timber. All mantellas are vulnerable to this deforestation.

Habitat: Rain forest Size: Head–body length 0.75–0.25 in. (2–3 cm) Coloration: Bright colors often with patches of brighter skin Diet: Invertebrates, including ants Breeding: Females lay small clutches of eggs on the ground or in trees; eggs hatch after 1 to 2 weeks Life span: 5–10 years Status: Varies according to species

The golden mantella is brilliant golden orange all over, apart from a patch of red under its back legs. This bright color deters would-be predators.

231

Marine Iguana Marine iguanas are the only lizards on Earth that live by the sea and swim beneath the surface to forage for seaweed. These endangered reptiles live only on a small group of islands off the coast of South America.

232

Snakes and Lizards

M

arine iguanas are distinctive reptiles. They have heavy bodies, muscular limbs, and a crest of tooth-shaped scales down their back and tail. Unlike other iguanas, they have blunt snouts. Marine iguanas graze on small algae or seaweeds that grow on rough rock. Their jaws have a flat front, which helps them gnaw at the algae-covered rocks. Tough scales on their lips protect their mouths from damage.

Life in the Ocean Marine iguanas have several adaptations that help them live by the ocean. Their tails are flat like rudders, and this helps them to swim in the sea. Their thick, curved claws allow them to grip onto the rocks even when they are pounded with heavy waves. Marine iguanas usually graze on seaweed when it is uncovered by tides. A few large males will dive underwater to graze. They can hold their breath for up to an hour and can swim to depths of 40 feet or more. The Galápagos Islands are situated on the equator, but the water is still very cold. This is because ocean currents carry water from the freezing Antarctic up toward the islands. Only the large males can store enough heat in their bodies to stay active in the cold water. Females, young males, and hatchlings have smaller bodies and would get cold too quickly. Marine iguanas swallow lots of salt water when swimming. Too much salt in the bodies would be poisonous, so

Fact File Marine iguana Amblyrhynchus cristatus Family: Iguanidae Suborder: Sauria Order: Squamata Where do they live?: Galápagos Islands off the coast of Ecuador Habitat: Rocky coastal regions Size: Head–body length 30 in. to 4 ft. (75–130 cm) Coloration: Gray with patches of red or turquoise Diet: Marine algae or seaweed Breeding: Females lay a clutch of between 1 and 6 eggs in tunnels on the shore; eggs hatch after about 95 days Life span: Up to 12 years Status: Vulnerable

The distinctive marine iguana is a common sight basking on rocks on the islands of the Galápagos archipelago off the coast of Ecuador.

233

Marine Iguana

the iguanas get rid of it by sneezing the salty water from their nostrils.

Day in the Life Large male marine iguanas bask in the Sun to warm their bodies before diving into the cold ocean waters to forage for seaweed.

234

Marine iguanas live in large groups called colonies. These lizards spend the first few hours of the day basking in the sunlight. Like other reptiles, marine iguanas are cold-blooded creatures. They need to warm up in the Sun to get enough energy to move about and get active. The females and youngsters then start to graze on seaweed, while the males

continue to bask in the hot midday Sun. Once the males are warm enough, they dive into the cold ocean waters to feed. After swimming, the males clamber back onto the rocky shore and bask while their food digests. The iguanas slow down and do not move greatly between the afternoon and late evening. Before sunset, they shelter among warm rocks, where they stay for the night. The iguanas often huddle together in large, closely packed groups at night to share the warmth of their bodies.

Snakes and Lizards

Island Races Most scientists think that the marine iguana is the descendant of different land iguanas that were swept out to sea from South America on bits of vegetation. Today, there are different races of marine iguanas on different Galápagos Islands. Those from the island of Fernandina in the west are large and dark gray. The waters off this island are rich in nutrients, which means there is a lot of seaweed around. The iguanas there can grow to be very large. Iguanas from the island of Genovesa in the north are small and black. The sea is not so rich there, so there is not as much seaweed on which to graze.

Breeding Season The breeding season of the marine iguana lasts from November to January. Males guard areas of rock in which the females live. The males bob their heads and display the red skin on the sides of their bodies. If these displays do not work, the males fight (see below). The winner then mates with the females. The females lay their eggs in warm sand away from the shore. Three months later the hatchlings scramble from the nest to the rocks where the other iguanas live.

Threats to Survival Scientists think that there are at least 50,000 iguanas scattered across the Galápagos Islands, but there may be more than double that number. The main threat to the survival of these reptiles is the introduction of species such as cats and dogs, which are common around towns. Until they have warmed up in the Sun, marine iguanas are slow and sluggish. Young iguanas are therefore easy pickings for dogs and cats. Dogs will also tackle the larger adults.

OW? DID YOU KN Marine iguanas can climb to heights of 250 ft. (80 m) up rocky hills on the Galápagos Islands. An average-sized adult can survive on about 1 oz. (28 g) of algae each day. Marine iguanas eat only red and green algae such as sea lettuce. They avoid brown algae, because it does not have enough nutrients. 235

Matamata The matamata is a freshwater turtle that lives in South America. This distinctive reptile is an ambush predator. It lies in wait in rivers and lakes, and sucks up passing fish and other small water-dwelling creatures.

236


T

he matamata is a bizarre turtle. In Venezuela, people call it la fea, which means “the ugly one.” It has a broad, flat, and triangular head when viewed from above. The head and long neck are fringed with thin skin flaps and strands. The matamata has tiny eyes and a broad mouth. Its nostrils are at the end of a short, bendy, trunklike snout. It has small, weak limbs and toes without webbing. The matamata’s oval shell is studded with knobby cone-shaped scales and looks rather like a rough piece of bark.

Ambush Predator The matamata ambushes its prey. It lies in wait in shallow, murky water. It does not need to hold its breath because its snout can stretch to the surface rather like a snorkel. The nostrils take in air while the animal remains submerged. The matatmata cannot see very well with its small eyes, but it can sense what is going on around it. The skin flaps around the turtle’s head move when fish and other prey swim close by. Fish are often attracted towards the wiggly strands on the matamata’s head, which look like worms. When prey gets close, the matamata stretches out its neck, opens its mouth, and quickly expands its throat. This sucks in water and any fish in it. The matamata then closes its mouth and forces out just the water. This turtle has no teeth or hard jaw edges to bite or chew prey, so it swallows its food whole.

Fact File Matamata Chelus fimbriatus Family: Chelidae Suborder: Pleurodira Order: Testudines Where do they live?: Northern parts of South America Habitat: Freshwater lakes, ponds, and slow-moving rivers Size: Head–shell length up to 26 in. (66 cm) Coloration: Reddish brown to black; younger matamatas often have red or pink throats Diet: Mostly small fish Breeding: Females lay around 20 hard eggs in riverbank nests; eggs hatch after about 30 weeks Life span: Up to 25 years Status: Common

The matamata’s head looks rather like a fallen leaf on the riverbed. This camouflages the matamata from predators such as caimans.

237

Mexican Burrowing Frog The Mexican burrowing frog is fairly common, but it is only seen during the breeding season. This secretive species spends most of its life in underground chambers, feeding on termites and their larvae.

238

Frogs and Toads

T

he Mexican burrowing frog is almost square in shape, with a short, fat leg at each corner. The spadelike hind feet are used to dig holes in the soil. Indeed, Mexican burrowing frogs spend most of their lives underground. They hide in chambers several inches beneath the surface. The frog’s head is tiny and blunt with a cone-shaped snout. It can force its tough snout through the walls of termite nests. The frog’s sticky tongue can change shape so it can poke it through the hole and catch termite adults or larvae.

Fact File Mexican burrowing frog Rhinophrynus dorsalis Family: Rhinophrynidae Order: Anura Where do they live?: Central America

Tropic of Cancer

After the Rains Mexican burrowing frogs leave their burrows when it rains. In Central America, the rains come in short, heavy bursts. The land soaks up water, fields and ditches flood, and temporary pools form. The males gather in the pools and start to call females. They puff up their body and make a “whooooo” call. Skin sacs inside their bodies blow up like balloons to increase the volume of the call. Females can hear the call from 0.5 mile away. Females mate with the loudest males. Females lay clumps of eggs, which float at the surface of the water. The tadpoles hatch after a few days but they stay in groups, even when they move around. This provides safety in numbers from predators such as herons and other waterbirds. To feed themselves, the tadpoles wag their tails together to waft water containing tiny food particles past their mouths.

Habitat: Lowland forests and coastal plains Size: Head–body length 2.5–3 in. (6.5–7.5 cm) Coloration: Dark gray with white spots and an orange or pink stripe down its back Diet: Ants and termites Breeding: Females lay up to 8,000 small eggs in clumps in water; eggs hatch after 3 days Life span: Up to 25 years Status: Common

Mexican burrowing frogs emerge from their burrows in heavy rains. The frogs feel the dampening soil and burrow out to find a mate.

239

Midwife Toads Midwife toads get their name for the way they look after their young. Males carry strings of eggs on their backs for weeks until they are ready to hatch.

240

Frogs and Toads

M

idwife toads look like most other toads. They are small and stocky with warty, dull-colored skin. There are four different species: the midwife toad, the Iberian midwife from northern Spain and Portugal, the southern midwife from southern Spain and Portugal, and the Majorcan midwife from the island of Majorca off the Spanish coast. All the midwife toads have excellent camouflage to hide from predators such as grass snakes. Most are active at night and feed by lunging to catch passing prey. Midwife toads are unlike all other toads in their interesting breeding behavior.

Fatherly Care Male midwife toads call at night or on rainy days in spring. The call is a tuneful “poo… poo… poo.” Females call back and move toward the deepest calls, which are made by the biggest males. After mating takes place, the female produces a string of eggs. The male then wraps the eggs around his back legs. The male is an attentive parent. He prevents the eggs from drying out by spending lots of time in a damp burrow. When the weather is very dry, he may take a dip in a pool to wet the eggs. Secretions from glands in his skin help protect the eggs from going moldy. By carrying the eggs, he protects them from predators. The male can feel the young wriggling when they are ready to hatch. He takes them to a stream or pond to release the tadpoles, which then feed on tiny water insects.

Fact File Midwife toad Alytes species Species: 4 Family: Discoglossidae Order: Anura Where do they live?: Europe from Britain down to southern Spain Habitat: Varies from woodland, fields, and parks to quarries and stone walls Size: Head–body length 1.5–2 in. (3.8–5 cm) Coloration: Pale gray, brown, or olive with scattered dark botches Diet: Invertebrates such as flies and slugs Breeding: Females lay up to 50 eggs; males carry the eggs in strings on their backs; eggs hatch after 3 to 8 weeks Life span: Up to 25 years Status: Varies according to species

Male midwife toads carry strings of eggs on their back legs. The eggs stay in place there for the next one to two months as the young develop.

241

Milksnake The milksnake is an unusual reptile. It comes in many different sizes and color combinations depending on where it lives. Milksnakes can be found in a wide range of habitats, from humid tropical rain forests to cool mountaintops.

242

Snakes and Lizards

M

ilksnakes are found across a wide range. They live in southern Canada and most of the United States, except deserts and high mountains. Milksnakes are also found throughout Central America south to the foothills of the Andes Mountains in Ecuador. In general, the largest adult milksnakes are found in warmer, tropical regions farther south. The smallest live in the northernmost parts of the snake’s range. There is one exception, however. The milksnakes found in warm, subtropical Florida are much smaller than milksnakes from the northeastern United States. The reason is that milksnakes in Florida are burrowers and live most of their lives in rotting tree stumps. A big snake would find this lifestyle difficult.

Seasonal Habits Milksnakes live slightly different lives depending on where they live. Milksnakes from tropical areas are always active because the temperature is very warm throughout the year. Milksnakes from temperate regions avoid the cool winters by entering a sleeplike state called hibernation. Milksnakes hibernate for several months. They find dry, sheltered places such as woodland rabbit burrows, holes in trees, stone walls, and the cellars of buildings. Eastern milksnakes often hibernate in groups of up to twenty-eight snakes. They huddle together to share their warmth. Female milksnakes may also group together early in the summer to lay their eggs. In cooler

Fact File Milksnake Lampropeltis triangulum Family: Colubridae Suborder: Serpentes Order: Squamata Where do they live?: From Canada in North America to Ecuador in South America Habitat: Varies from damp forests and desert edges to sandy beaches and rocky mountains Size: Adult head–tail length 20 in. (50 cm) to 6.5 ft. (2 m) Coloration: Usually blotched or striped with red, black, and white/yellow; some are brown, gray, or even black Diet: Small mammals such as mice; lizards; other snakes Breeding: Females lay between 4 and 15 eggs; eggs hatch after 40–60 days Life span: Usually 10–15 years Status: Common

Milksnakes are cylindrical snakes with small head scales and glossy body scales. Some milksnakes may grow to more than 6 feet long.

243

Milksnake

OW? DID YOU KN Kingsnakes are close relatives of the milksnake. Many kingsnakes are striped like milksnakes. To add to the confusion, some milksnakes are sometimes called kingsnakes. Milksnakes got their name because farmers once thought that these reptiles stole milk from cows. Milksnakes are often found in barns, where they hunt the mice that live there.

The red milksnake is commonly found in the easternmost parts of its range, particularly in Florida. These snakes are much smaller than most milksnakes, rarely exceeding 20 inches in length. 244

habitats, they may lay the eggs in rotting sawdust or manure heaps, which keep the eggs warm as the young inside develop.

Color Variations Most milksnake hatchlings are red with black-and-white stripes. This distinctive color pattern is similar to coral snakes, which are often found in the same places as milksnakes. Coral snakes are venomous, but milksnakes are not. In coral snakes, red and yellow bands meet, while red and black bands meet in the case of milksnakes. An easy way to remember the difference is the following mnemonic: “Red to yellow, kill a fellow: Red to black, venom lack.” For both, the bright color pattern acts as a warning signal to potential predators. The predators recognize the possible danger of being poisoned if they eat the snakes. However, hatchlings and very young milksnakes often fall victim to predators that include bullfrogs, hawks and other birds of prey, raccoons, and other snakes.

Snakes and Lizards

One or many? There are about 25 forms of milksnake. They differ in size, color, stripe pattern, and where they live. The forms include the Mexican, Honduran, Ecuadorian, Pueblan, and eastern milksnakes. The eastern milksnake (shown below)â•‹is gray with brown blotches down its back. This coloration camouflages the snake against the leaf litter in which it is found. Some

Some milksnakes become darker in color as they grow older. Large adult milksnakes have fewer predators. The darkening happens because black pigment spreads through the red and white scales. One form—the black

scientists think that milksnakes should be named as a different subspecies (types within the same species). Subspecies are isolated from each other because they live in different places. But the different milksnakes often overlap in range. The variations in size and pattern between forms are gradual so it is very tricky to say when one form ends and another begins.

milksnake from Colombia—becomes completely black, but most just get darker. The dark color helps the snakes to absorb heat more easily when basking. It also makes them less obvious to predators and prey. 245

Monitor Lizards Monitor lizards are long-bodied lizards with a wide distribution, from Africa east to the islands of the Pacific Ocean. These lizards make their homes in many different habitats and come in a range of sizes. The family includes some of the world’s biggest lizards.

246

Snakes and Lizards

M

ost monitor lizards have similar body shapes, with long necks and bodies and thick, strong legs. Each leg has five toes, which are tipped with long, sharp, curved claws. Monitors have long, muscular tails. If the monitor damages its tail or if it breaks off, it will not regrow, unlike other lizards. The head of a monitor lizard is generally long with a pointed snout. Its eyes have large, round pupils. Monitors have long, forked tongues, which they flick out while moving along. The teeth are sharp and point slightly backward.

Monitor Meals Depending on the size of the monitor lizard and where it lives, these predators eat a wide variety of animals. Coastal monitors eat mostly fish and crabs, while monitors that live in trees usually eat birds and their eggs. Monitors generally eat whatever food or prey is available. The lizards find their food using their keen sense of smell. They have nostrils to smell, but they also use their tongue to detect scents. Monitors are swift runners. Once they catch their prey, they may swallow it whole or tear it into chunks with their strong claws and teeth. They can eat large chunks of meat because the lower jaw and the bones in their throats are loose. Monitors develop fatter, rounded tails when they are well fed. The tail acts as a store of fat, which is used up when there is not much food around or when monitors are breeding.

Fact File Monitor lizards Varanus species Species: 57 Family: Varanidae Order: Squamata Where do they live?: Africa, Asia, Australia, and some islands in the Pacific and Indian oceans

Equator

Habitat: Varies from coastal swamps and grassland to barren desert and humid rain forest Size: Head–body length 10 in. (25 cm) to 15 ft. (4.75 m); weighs from 0.3 oz. (10 g) to 330 lb. (150 kg) Coloration: From sandy brown to dark green, with dark and light blotches over the body Diet: Small mammals, lizards, crabs, insects, and birds’ eggs Breeding: Females lay between 7 and 51 eggs in burrows; eggs hatch after 2 to 10 months Life span: 15–45 years

Aâ•‹lace monitor basks in the warm sunshine.


Lace monitors are among the largest lizards in Australia, where they are known as goannas.

247

Monitor Lizards

OW? DID YOU KN At 15 ft. (4.75 m), the world’s longest lizard is the crocodile tree monitor. Nearly two-thirds of its length is taken up by its thin, whiplike tail, which it uses to help it balance while climbing in the treetops. Monitor lizards are called goannas in Australia. Some goannas eat poisonous snakes. In the past, Aborigines in Australia thought that the goannas were immune to the snakes’ venom. So they killed goannas to make an oil that was used as a medicine.

A monitor lizard uses its sharp, curved claws to climb up a tree in search of food such as birds’ eggs.

Dangers to Monitors The greatest threat to monitor lizards is the destruction of their habitat, but monitors can adapt to live in different habitats. Full-sized adults have few predators. Giant monitors such as the Perentie monitor and Komodo dragon are easily the largest predators in their habitats. However, the eggs, hatchlings, and young are at risk from predators ranging from larger monitors to birds of prey. Monitors are also at risk from poisonous predators such as the cane toad and various snake species. When it faces danger, a monitor hisses, sways its body, and puffs up its throat. Monitors often lash out with their powerful tails, and they may even vomit on their attacker.

Monitors at Risk In the past, many monitor species were hunted for their meat and skins. Some body parts were also used in local medicines. Some of the rarest species are now protected in many countries, but others are still killed for their skins. For example, the skins of the Nile monitors and other water monitors are used to make bags, belts, and shoes. Crocodile tree monitor skins are made into drumheads. 248

Snakes and Lizards

In the water Monitor lizards are excellent swimmers. They flatten their legs against the sides of their bodies and wave their tails to move through the water. They have big lungs and can hold their breath underwater for up to thirty minutes. Monitor lizards swim in both freshwater and oceans, often moving between nearby islands. Some monitors are particularly well adapted for life in the water. Merten’s water monitor

lives in northern Australia. It has a tall, flattened tail to help it glide through the water. Its nostrils are on the top of its snout, which makes breathing while in the water easier. The Nile monitor (above)â•‹has similar adaptations. It lives in the River Nile in Egypt. However, both monitors spend some time on the ground. They live in dry habitats, climbing trees and digging burrows like other monitors.

249

Monkey-tailed Skink The monkey-tailed skink is the largest skink in the world. It lives in the trees of the Solomon Islands rain forest. Unlike other members of the skink family, this species has a prehensile tail, which means it can use it to grip onto branches.

250

Snakes and Lizards

T

he monkey-tailed skink has a stout body and well-developed legs. The head of this lizard is flat and triangular and ends with a blunt nose. Males have wider heads and slimmer bodies than the females. The tail of the monkey-tailed skink makes up about half its total length and tapers to a blunt tip. The body is covered with rows of large scales. The skink is green in color to match the plants found in the habitat in which it lives. Some skinks have dark stripes along their backs and sides. This gives them their alternative common name of zebra skink.

Old Rain Forest The monkey-tailed skink is very choosy about where it lives. Most can be found on ten mountainous tropical islands in the Solomon Archipelago and two islands that are part of Papua New Guinea. The temperature on these islands is not as hot as most tropical regions because it is cooled by moist ocean winds. This also makes the islands damp, so lots of trees grow there. The monkey-tailed skink prefers to live on older trees in the forest, including the strangler fig. These trees have dense leaves, and other plants grow on them, including climbing vines, ferns, and orchids. This dense vegetation provides cover for the skinks. They can hide from predators such as eagles while they feed on the leaves. The skink has sharp claws and rough scales on its toes, which it uses to grip the branches of

Fact File Monkey-tailed skink Corucia zebrata Other common names: Giant skink, zebra skink, or Solomon Islands green tree skink Family: Scincidae Suborder: Sauria Order: Squamata Where do they live?: Solomon Islands and Papua New Guinea Habitat: Damp rain forest Size: Head–tail length up to 30 in. (76 cm) Coloration: Olive green to gray-green with darker blotches Diet: Fruits and leaves of certain plants; occasionally birds’ eggs Breeding: Females give birth to 1 or (rarely) 2 young once every two years Life span: Up to 15 years Status: Vulnerable

The monkey-tailed skink uses its long prehensile tail to grip onto the branches as it moves through the trees in the rain forest of the Solomon Islands.

251

Monkey-tailed Skink

Monkey-tailed skinks are the largest members of their family. They spend all of their lives in the trees, spending most of the day hiding in tree hollows and then emerging at night to feed on green leaves.

trees in the rain forest. These lizards also use their tails to hold on to the trees, wrapping them around the branches. The grip is so powerful that the skink can let go with forelimbs or hind limbs and still not fall.

Special Diet Leaves make up most of the monkeytailed skink’s diet. They prefer to eat the leaves of plants that grow in the trees, such as Devil’s ivy and the Swiss cheese plant. Skinks may eat fruits or even birds’ eggs that they find in the treetops, but their bodies are adapted for eating tough leaves. The skink has short, square teeth and strong jaws 252

to crush the leaves. It also has wide intestines, with lots of bacteria inside. These microorganisms help to digest the leaves to release their nutrients. Young skinks are born without the bacteria. They take in the bacteria by eating the feces of adults.

Skink Threats Habitat destruction is one of the biggest threats to the monkey-tailed skink. The mature forests in which these lizards are found contain many large trees that some people want to cut down to sell for valuable timber. The other threat to monkey-tailed lizards is the pet industry. Many pet collectors keep monkey-tailed skinks because they are interesting lizards. They eat common plants such as dandelions, which means that they are also relatively easy to look after.

Snakes and Lizards

OW? DID YOU KN Monkey-tailed skinks are most active at night. Between January and April, the weather is so grey and the sky so dark that the lizards come out by day, too. At night, the male skink patrols the area in which his colony lives. He spreads a smelly wax on the trees. This tells other males to stay away from his territory.

When people take skinks from the wild, however, the colonies drop in size. It can be many years for the lizard population to recover. This is because females have very few young each year. It takes around three years for the young skinks to mature into breeding adults. Adults generally live for around twenty-five years.

Young skinks Monkey-tailed skinks do not lay eggs. Instead, the female keeps the young inside her body while they develop. She basks in the Sun to keep them warm. After about seven months she gives birth to one or two young, that are 12 inches long. The young grow up in a colony made up of a male and several females and their young. The male defends his colony from other males. The females care for the young. The skinks rest in tree hollows during the day and emerge at night to forage for food. The young make a chirping noise if they are attacked by predators. After three years, the young leave their colony and breed with skinks from other colonies.

253

Mudpuppy Mudpuppies are distinctive North American amphibians with blunt, doglike mouths. They live in a wide range of freshwater habitats, from flowing rivers to weed-choked, water-filled ditches.

254


T

he long body of the mudpuppy is flattened from top to bottom. It has small legs and a broad, blade-shaped tail for swimming. To breathe under the water, the mudpuppy has three branched gills on each side of its head. The branching gives the gills a large surface area to absorb oxygen in the water. External gills are a common feature of amphibian larvae, but the mudpuppy is one of several salamanders that retains its external gills when it is an adult, too.

Fact File Mudpuppy or waterdog Necturus maculosus Family: Proteidae Order: Caudata Where do they live?: Southeastern Canada and eastern USA

Mudpuppy World Most mudpuppies are found in canals and waterfilled ditches choked with plants or mud. They also live in fast-flowing rivers with gravel bottoms, and lakes with clear, cool water. In clear water, mudpuppies hide during the day from predators such as pike and waterbirds. At night they emerge to forage for food. In muddy water, mudpuppies are active by day, too. Mudpuppies have tiny eyes and cannot see well. They hunt using their sense of smell. Typical prey includes crayfish, fish and their eggs, insects, and worms. Mudpuppies mate in winter, and females lay their eggs in shallow water in late spring. Females make a nest under rocks, logs, or sunken trash. They attach each egg singly to the underside of the roof of the nest. The female guards her nest until the eggs hatch. The stripey larvae hide under leaves after hatching. It takes about five years before they can breed themselves.

Tropic of Cancer

Habitat: Streams, rivers, lakes, and water-filled ditches Size: Head–tail length 8–20 in. (20–50 cm) Coloration: Brown with light speckled markings Diet: A range of freshwater animals Breeding: Females lay between 60 and 120 eggs, which hatch after 1 or 2 months Life span: Up to 25 years Status: Least concern

The most distinctive feature of the mudpuppy is its bushy, red external gills, which it retains from its larval stage and uses to breathe under the water.

255

Namaqua Chameleon The Namaqua chameleon thrives in the deserts of southwestern Africa. This lizard uses a variety of survival and hunting skills to cope with the challenges of this harsh environment.

256

Snakes and Lizards

N

amaqua chameleons are short, solid lizards with large, knobby heads and strong jaws. The young chameleons find shelter in bushes, but adults generally roam over the sand. The chameleons can run fast to chase prey such as beetles and lizards and to escape predators such as monitor lizards and vipers. However, their skin is a similar color to the sandy soil so they rely on camouflage for ambush and defense. The chameleon’s eyes swivel to watch prey. When a young snake slithers close, the chameleon flicks out its long, sticky tongue to strike the snake on the head. The tongue pulls the snake close enough for the chameleon to crush its head in its jaws before it can strike back.

Survival Skills Daytime temperatures soar to 150˚F in the deserts of southwestern Africa but drop to freezing after dark. At night, the chameleon keeps warm in rodent burrows. In the morning, they emerge to bask in the Sun’s rays. They find shade under a bush during the heat of the midday Sun.The lizard also opens its mouth, so the moisture inside evaporates. This cools the air inside the mouth, which helps to cool the lizard itself. In the mornings, a cool fog blows onto land from the Atlantic Ocean. The chameleons stand in the fog, and the water vapor condenses on their skin. It trickles along grooves between the scales toward the lizard’s head, and the chameleon licks it up.

Fact File Namaqua chameleon Chamaelao namaquensis Family: Chamaeleonidae Suborder: Sauria Order: Squamata Where do they live?: South Africa and Namibia Habitat: Sand dunes in deserts and scrubland Size: Head–tail length 10 in. (25 cm) Coloration: Yellow or gray to pinkish brown with scattered spots Diet: Invertebrates such as beetles and locusts; small snakes and lizards Breeding: Females lay between 6 and 22 eggs up to 3 times a year; eggs hatch after 3 to 4 months Life span: 5–8 years Status: Common

The Namaqua chameleon basks in the Sun to warm its body. Its skin is black when it is cold to absorb heat well. The lizard’s color gets lighter as it warms up.

257

Natterjack Toad The Natterjack toad is a short, stubby amphibian with a very loud croak. It typically lives in sandy habitats in western Europe, but moves to shallow ponds in the spring to breed.

258

Frogs and Toads

T

he natterjack is a typical toad. It spends most of the summer resting under large stones or in the burrows it digs in the sand or soil. Natterjacks emerge at night to feed when it is cooler and when fewer predators can spot them. Those toads that live in coastal sand dunes may visit the beach to feed on the washed-up remains of sea creatures and beach-dwelling creatures such as sandhoppers. In cooler parts of Europe, such as Britain, natterjacks enter a sleeplike state called hibernation over winter. They shelter in burrows while the weather is cold and emerge in spring to breed.

Calling for Mates Male natterjacks breed in shallow ponds between March and June. The exact timing depends on how warm it is in the region in which they live. The water is often slightly salty in these breeding ponds. Males inflate their throat skin and make a loud “rrrRup” noise. Most calls can be heard in the afternoon and early evening, usually after rain. Females are attracted to the loudest calls. After mating, the females lay their eggs in double strands in warm parts of ponds. She then leaves her eggs. After about one week the tadpoles emerge. Over the next four months, the tadpoles gradually change into toads. At first, they feed on algae and water plants. They develop different teeth to eat animals such as tiny water invertebrates.

Fact File Natterjack toad Bufo calamita Family: Bufonidae Order: Anura Where do they live?: Western Europe Habitat: Sandy heathland with loose soil and sand dunes; usually near coastal regions Size: Head–body length 2.5 in (6–7 cm) Coloration: Pale brown, olive green, or gray, with red, brown, or green warts and a yellow stripe running down the back Diet: Invertebrates such as moths, snails, spiders, woodlice, and worms Breeding: Females lay between 1,500 and 7,500 eggs, which hatch after 5 to 8 days Life span: 12–15 years Status: Least concern

The natterjack toad is a compact toad with short legs. This amphibian is not a great swimmer. It often moves around by running, rather than hopping.

259

Newts Newts and their close relatives the salamanders are the most lizardlike of all the amphibians. They start their lives as larvae but gradually change their body shape to become land-living adults. Adult newts return to the water for part of the year. Males and females meet there to breed.

260

N

ewts are always found living in moist places. European species range from the Alpine salamander, that lives in streams in the high Alps, to the banded newts that live in the damp forests and grasslands of Turkey and Israel. In North America, these amphibians are divided into eastern and western newts, The red “eft” is a land-living stage in the development of the red spotted newt. Larvae develop into efts, which then tranform into adults.

Fact File depending on which side of the Rocky Mountains they live. China, Japan, Vietnam, and countries in South Asia are home to some of the rough-skinned types, such as crocodile newts and warty newts.

Life Cycle Most newts gather in pools, water-filled ditches, and slow-moving streams to breed. Newts of many species change color during the breeding season. For example, male alpine newts are usually green-brown, which acts as camouflage against predators. During the breeding season, however, these newts develop a blue back and sides, with a black-and-white spotted stripe. The undersides of both males and females turn bright red-orange. Some male newts grow crests along their backs and webs between their toes so they can swim and display to the females at the same time. After mating takes place, the female lays her eggs. She wraps each egg in a leaf to hide it from egg-eating predators such as fish. The larvae that hatch have long tails but no legs. They swim and feed on water animals such as small tadpoles. In the metamorphosis process, the newts leave the water and change into landliving amphibians. Unlike frogs and toads, the newts keep their long tails. Young eastern newts are called efts. They are bright red or orange. They are the intermediate stage between the larva and adult forms. Efts spend up to three years on land before returning to pools to breed, at which time they change into adults.

Newts Genera: 10 Species: 47 Family: Salamandridae Order: Urodela/Caudata Where do they live?: Europe, East Asia, the Middle East, and North America

Equator

Habitat: Ponds, rocky streams, and damp forest in lowlands and high mountains Size: Head–body length up to 12 in. (30 cm) Coloration: Varies from black to red; some species are brightly colored Diet: Invertebrates such as slugs and worms; other amphibians; fish eggs Breeding: Varies according to species; females of some species produce several hundred eggs, while others bear just 2 live young Life span: Up to 15 years Status: Varies according to species

261

Newts

Defense Mechanisms Newts have several adaptations for defense against potential predators such as snakes and waterbirds. Many species produce strong toxins in their skin that act as a chemical defense. To cause damage, the toxins have to enter the body of the predator, either by being swallowed or through a break in the skin.

Poisonous newts have bright colors to advertise to predators how dangerous they are. For example, mandarin newts have black skin with yellow or orange patches on the bumps where the toxin is produced. The efts of the eastern newts have bright colors because they also produce toxic chemicals. Some newts are extremely toxic—the rough-skinned newt of the Pacific Northwest produces enough toxin to kill an adult human. However, the garter snake can still eat this newt because the snake is immune to this poison. Sharp-ribbed newts and spiny newts use physical defenses to avoid being eaten by predators. When swallowed, these newts force out their The mating behavior of newts and salamanders (from top to bottom): red-bellied newts, brook salamanders, eastern newts, and smooth newts.

262

Newts

Newt or salamander? The family Salamandridae also includes the land-dwelling European salamanders. Generally, these amphibians return to water only to breed. Most of them have short tails that are roughly cylindrical and small legs with stubby toes. However, it is not always clear from the appearance or

sharp ribs through special holes in their skin. The ribs can injure the attacker and allow toxin to enter their bloodstream. Many newts, such as the fire-bellied newt, try to avoid being damaged by predators even if they are not eaten. They take up defensive postures. They may curl up their tail or bend over backward to show off their brightly colored underside.

lifestyle of these creatures whether they are newts or salamanders. For example, the brook salamander (below) rarely leaves the cool mountain streams in which it breeds, while the black knobby newt spends most of its life in warm Asian rain forests or marshes.

OW? DID YOU KN Iberian ribbed newts have been sent into space on six separate missions. Scientists studied how the development of these amphibians was affected by the low gravity conditions of space. Adult newts that lose a limb can regrow another one in about three months. Newts can also regrow eyes, jaws, nerves, and intestines. 263

Night Lizards Night lizards take their name because most people assume they are active at night. In fact, these secretive lizards emerge during the day to forage for ants, beetles, and other invertebrates.

264

Snakes and Lizards

M

ost night lizards are small reptiles with fairly short legs and tail. Many species are covered with small scales with a few large, pointed scales in between. The head has larger scales. That gives night lizards a prickly appearance. The size of the scales can be used to tell different species apart. For example, the Cuban night lizard from the genus Cricosaura is the only night lizard with two scales on top of its head, above its nose. Night lizards have large eyes. Like geckos, they lack eyelids so they clean their eyes by licking them. The large eyes were one of the reasons why people thought these reptiles were nocturnal. In fact, most species are most active during the day. They are rarely seen, however, because they live in crevices, hidden among leaves, and in other dark, secluded spaces. The bodies of night lizards are often flattened from top to bottom.

Staying Put Night lizards prefer to live within a small area and do not move far in search of food. Some individuals may spend their entire lives under the same log or rocks or on the surface of one plant. The desert night lizard lives on agave and yucca plants in the deserts of the United States and feeds on passing invertebrates such as ants and beetles. Tropical night lizards of southern Mexico and Guatemala eat the figs that fall into the caves in which they live.

Fact File Night lizards Genera: 3 (Cricosaura, Lepidophyma, and Xantusia) Species: 26 Family: Xantusiidae Suborder: Sauria Order: Squamata Where do they live?: Western USA, Central America, and Cuba

Tropic of Cancer

Habitat: Rock crevices and caves; damp logs, leaf litter, and under tree bark in forested areas Size: Head–body length 1.5–7 in. (4–16 cm) Coloration: Pale brown, olive green, or gray; some individuals have small yellow spots Diet: Invertebrates such as ants, beetles, and cockroaches; some species eat flowers, fruits, and seeds Breeding: Females bear between 1 and 9 live young Life span: 12–15 years

The granite night lizard has a flat body, broad head


and soft skin, which is covered with dark spots on a pale yellow or cream background.

265

Olm Olms live in water deep inside caves beneath parts of Europe. These thin, ghostly amphibians are perfectly adapted to their cool, dark, and wet environment.

266


O

Fact File

lms look like white eels with swollen heads and no eyes. They have long, tapering bodies with small, spindly legs. Similar to several other salamander species, adult olms retain the red, feathery gills from their larval stage. Like the larvae, the adult olms continue to live and breathe underwater.

Other comon names: White salamander or human fish

Living in Caves

Where do they live?: Southern Europe near the Adriatic coast, from Italy to Bosnia

Olms live in the water that runs through caves beneath limestone mountains. In the caves, the temperature of the water is very cold. Even in the summer, it never exceeds 48˚F. Olms grow slowly because of the cold conditions. It takes up to fourteen years for the larvae to transform into adults. Since they are not very active, olms do not need to feed often. Indeed, one olm survived for more than ten years without eating at all. Olms thrive in clean water. Chemicals from garbage dumps, farms, and factories are building up in the water in some areas and poisoning the olms there. Olms lack skin pigment because they live in total darkness. They look white or pink because their internal organs show through their colorless skin. Predators might spot an olm that strays near the cave entrance because of its pale appearance. Light-sensitive blobs in its skin tell the olm to retreat to the safety of the cave. They sense their surroundings using smell and touch. They can also detect where they are from the magnetic fields created by rocks deep inside Earth. Olms are the only vertebrates to live underground for their entire lives. It is completely dark inside

Olm Proteus anguinus

Family: Proteidae Order: Caudata

Tropic of Cancer

Habitat: Underground streams and rivers in caves Size: Head–tail length 8–12 in. (20–30 cm) Coloration: White with bright red, feathery gills Diet: Insect larvae and freshwater shrimps Breeding: Females lay up to 70 eggs, which hatch after about 4 months Life span: Up to 60 years Status: Vulnerable

the caves, so the olms do not need any eyes.

267

Painted Turtle The painted turtle is found in rivers, streams, and lakes across North America. It keeps warm in the cold evenings and part of the winter by burying itself in mud at the bottom of these watery environments.

268


P

ainted turtles are small reptiles with smooth, oval shells and stripy heads. There are four different (subspecies) types. The eastern painted turtle lives in eastern North America and has colored lines on the top of its shell. The midland painted turtle lives farther west has a dark patch on the underside of the shell. The western painted tortoise is found over a wide area, from British Columbia south to Mexico. It has an attractive, branched pattern on the underside of the shell. The southern painted turtle has a yellow or red stripe running down the center of its shell.

Turtle Year Painted turtles bask in the morning to get the energy they need to hunt for food. In the afternoon, they bask while digesting their food. In the evening, the turtles burrow into the soft, muddy riverbed. They can hold their breath overnight. In areas with very cold winters, painted turtles hibernate (sleep through the winter) beneath the mud. They slow down their breathing rate and can remain underwater for up to four months. In June, the turtles emerge to mate. The females dig shallow nests in soft soil where there is little risk of flooding. The hatchlings that emerge are about 1 inch long. They crawl to the water to avoid predators such as bullfrogs, herons, and mink. As the turtles grow they become too big for these predators. Instead, they face new threats such as alligators and bald eagles.

Fact File Painted turtle Chrysemys picta Family: Emydidae Suborder: Cryptodira Order: Testudines Where do they live?: Central and eastern United States, southern Canada, and northern Mexico Habitat: Slow-moving streams, rivers, and lakes Size: Shell length up to 10 in. (25 cm) Coloration: Green to black shell with different colors and patterns on top and bottom; head and forelimbs have yellow and red stripes Diet: Young eat insects, small fish, tadpoles, and other small aquatic creatures; adults eat water plants Breeding: Females lay up to four clutches of between 2 and 20 eggs each year, eggs hatch after 10–11 weeks Life span: Up to 20 years Status: Common

Painted turtles spend most of their time in the water, but they come ashore in groups of two or more to bask on logs in the sunlight.

269

Panther Chameleon The panther chameleon is a colorful lizard from the island of Madagascar. The bright skin color and habit of living at the edge of the forest makes this species a very conspicuous chameleon.

270

Snakes and Lizards

T

he panther chameleon is a typical chameleon, with a stout body, limbs adapted for gripping branches, and a curling, prehensile tail. The eyes sit on turrets and can swivel independently. Males usually have large scales on their noses, which form a tough ridge. They use this armor during fights over females and their territories. Males vary much more widely in color than females. For example, some males are emerald green with yellow lips, while others are turquoise blue with orange eye turrets. The color combinations depend on where the males live. The colors of chameleons change dramatically during the breeding season. Males turn bright red or orange-pink with purple heads to scare rival males. Females turn pale salmon pink to show that they are ready to mate or dark brown with pink blotches if they are already carrying eggs. Females lay their eggs in shrub roots where the soil is soft and moist. The hatchlings are tiny for such a large species. They measure just 1.5 inches in length.

Panther World The panther chameleon lives in northern Madagascar, from sea level up to about 3,900 feet. It is one of the few species that thrives following deforestation. In Madagascan myths, panther chameleons are important animals. Local people never eat them and are careful to swerve and avoid them when they cross the road.

Fact File Panther chameleon Furcifer pardalis Family: Chamaeleonidae Suborder: Sauria Order: Squamata Where do they live?: Madagascar and small populations on Réunion Island and Mauritius Habitat: Shrubs and trees at the edge of forested areas Size: Head–tail length 15–22 in. (38–56 cm) Coloration: Males vary from blue to green or pink; females vary from gray-fawn to pink; both males and females have a side stripe of white or blue, with oval blotches Diet: Large insects, small mammals, lizards such as geckos and frogs Breeding: Females lay 12–45 eggs up to 4 times a year; eggs hatch after 6 to 13 months Life span: Five to seven years Status: Common

The panther chameleon is a colorful lizard that thrives in shrubs, fields, and gardens on the island of Madagascar off the eastern coast of Africa.

271

Pipe snakes The heads and tails of the wormlike pipe snakes are almost identical. These pipe-shaped reptiles live in damp, tropical habitats in areas of Asia and South America.

272

Snakes and Lizards

P

ipe snakes have cylindrical bodies tipped at either end with a head and tail that look almost identical. This unusual body shape gives these snakes their alternative common name—the two-headed snake. Pipe snakes are burrowing reptiles that usually live in damp soil, mud, and the leaf litter on forest floors. They slither and swim through flooded clearings, water-filled ditches, and marshes. They are also often found in flooded paddyfields where farmers grow rice.

Putting Off Predators Pipe snakes have many predators, from birds and lizards to other snakes. They have different adaptations to help them avoid predators. The first is having a tail that is the same shape as the head. Predators often attack the head first as this is the control and sense center of the animal. If the brain is damaged, the victim is much easier to subdue and eat. With pipe snakes, however, predators are confused about which end is the head. If they strike the tail, the snake can still escape. Red-tailed pipe snakes raise their red-tipped tails to predators while they tuck their heads into their coils. The display makes sure that predators notice the tail and not the head. South American pipe snakes use bright colors to pretend that they are poisonous even though they are harmless. The red and black stripes mimic those of the South American coral snakes. Coral snakes are highly venomous members of the cobra family.

Fact File Asian and South American pipe snakes Other comon names: Two-headed snake or false coral snakes Genera: Cylindrophis and Anilius Family: Cylindrophiidae and Aniliidae Suborder: Serpentes Order: Squamata Where do they live?: Asian pipe snakes live in Southeast Asia, from China to Indonesia; South American pipe snakes live in northeastern parts of South America Habitat: Forests and grasslands Size: Head–tail length 27.5–39 in. (70–100 cm) Coloration: Asian pipe snakes are purple–brown with cream bars and red under the tail; South American species have black and red stripes Diet: Snakes and eels Breeding: Females bear 3–15 live young 40–60 days after mating Life span: Unknown Status: Common

The red-tailed pipe snake adopts its defensive posture by raising its red-tipped tail so that it looks like the snake’s head.

273

Pipe snakes

The red-tailed pipe snake is a black snake with white bands and a redtipped tail. These snakes eat a wide

Predators know to avoid coral snakes because the bright colors advertise how dangerous they are.

variety of prey, from eels and lizards to other snakes. They kill their prey by

Size Matters

squeezing their bodies until they cannot

Many snakes can dislocate their jaws and flex their skulls open to eat prey many times their own size. The pipe snake has fixed jaws. Its teeth are small and cannot tear chunks of flesh from their victims. As a result, the pipe snake has to size up its prey carefully to check that it will fit through its jaws and into its stomach. Similar snakes, called blind snakes and thread snakes, eat lots of small prey such as insects and worms. Young pipe snakes also eat this type of prey, but adults prefer larger meals. They feed exclusively on slender prey without legs that are as long or longer than themselves. These body shapes fit inside the long bodies of the pipe snake. Adult pipe snake prey includes blind snakes, freshwater eels, and worm lizards. The pipe snake has small eyes, so it hunts using its senses of touch, smell, and hearing. It captures its prey in its teeth and then coils its body around the victim to squeeze it to death. When the prey has stopped breathing, the pipe snake swallows its meal whole.

breathe.

OW? DID YOU KN Red-tailed pipe snakes lose most of their bright color with age. Hatchlings have a red bar and narrow red or orange stripes down their backs. The colors fade to cream, and the stripes often turn to blotches, but the tail always stays red. Fishermen in some parts of Cambodia catch a variety of marsh snakes, including redtailed pipe snakes, for food.

274

Snakes and Lizards

Threats to Survival Most pipe snakes have little contact with people. They prefer to live in low-lying forests near water, but a few wander into nearby towns and villages and some are seen by farmers in the paddyfields of Southeast Asia. Scientists know very little about

pipe snake populations in South America or Asia. The International Conservation Union (IUCN) do not include any pipe snakes on their Red List of threatened species. However, these reptiles probably endure the usual threats to survival because of habitat loss through deforestation.

snake relations The South American pipe snake (below) is descended from some of the oldest known snakes. Scientists have unearthed fossils of ancient snakes in rocks dating back more than 135 million years. The skeletons preserved in the fossils closely match the skeleton of the South American pipe snake. They have a small pelvis and

tiny spurs of bone, which are the remains of limbs that the ancestors of all snakes once had. Fossil evidence shows that pipe snakes once lived in North and South America and Europe up to about 50 million years ago. After this they died out across most of the range but remained in South America until today.

275

Plumed Basilisk The plumed basilisk is best known for its amazing ability to run across water. These striking reptiles use this ability only as an escape mechanism from predators such as birds of prey.

276

Snakes and Lizards

T

he plumed basilisk is a medium-sized lizard with long legs. Its body and tail are flattened from side to side. The tail takes up three-quarters of the basilisk’s length. All basilisks have fleshy crests on their heads. Males also have crests on the back and tail, and flaps of skin on their throats. These features make the males look bigger when they display to females or rival males during the breeding season.

Fact File Plumed basilisk Basiliscus plumifrons Other comon names: Green-crested basilisk and Jesus Christ lizard Family: Iguanidae Suborder: Sauria Order: Squamata Where do they live?: Central America

Running on Water Plumed basilisks live among the plants by rivers and streams in forested areas. When they are disturbed, these unusual lizards can escape from predators by running over water. They can do this because they have a fringe of rectangular scales along the toes of their back feet. The scales give the feet a wide surface area. They can rest on the water without breaking the surface—as long as the lizards keep moving.

Basilisk Routine Plumed basilisks forage for food during the day. They eat anything they can find, from flowers and fruits to slugs and snakes. They also catch fish or crabs. Plumed basilisks breed all year long, but especially during the cool, rainy season. After mating, the female scrapes out a burrow in the warm, damp soil or sand and lays up to seventeen eggs. The hatchlings are dull at first but develop crests and the distinctive green color as they grow.

Equator

Habitat: Tropical forests near water Size: Head–tail length up to 36 in. (91 cm) Coloration: Mainly green with black bars on the tail and light green or white spots on the flanks Diet: Plants, invertebrates, and small vertebrates Breeding: Females lay between 4 and 17 eggs, that hatch after about 2 months Life span: Up to 7 years Status: Common

The male plumed basilisk is a striking lizard, with its bright green color and the distinctive crests on the head, back, and tail.

277

Poison Dart Frogs Poison dart frogs are small, attractive amphibians that can be found in tropical parts of the Americas. These amphibians get their common name for the strong toxins that ooze from their skin. Native Americans who live in the Amazon rain forest rub the toxin on darts and use them to kill forest animals.

278

Frogs and Toads

P

oison dart frogs are tiny amphibians with jewel-bright colors. The bright skin colors warn predators that these frogs produce powerful toxins in glands under their skin. Poison dart frogs have long toes with slightly split ends, that help them to grip onto mossy tree trunks or branches in their rain forest habitat. Many species live in the fallen leaves alongside forest streams. They live anywhere from sea level up to 5,575 feet in the Andes Mountains.

Frog Habitats Poison dart frogs are found in the humid tropical rain forests of Central and South America, from Nicaragua and Costa Rica south to Bolivia and Brazil. A few species can be found on the islands of Hawaii, but these are introduced species. Poison dart frogs prefer to live close to the ground, but some species live in trees up to 20 feet from the forest floor.

Looking After Tadpoles Poison dart frogs have an unusual life cycle. The male guards and cleans off a leaf or other flat surface as a nesting site for the eggs. The male then fiercely guards his site from rival males. He also calls with load croaks to attract potential mates. After mating, the female lays her eggs on the site. Either the male or female frog guards the eggs until they hatch. The parent bends down, and the tadpoles wriggle onto the adult’s back.

Fact File Poison dart frogs Species: 214 Genera: 8 Family: Dendrobatidae Order: Anura Where do they live?: Central and South America, islands of the Caribbean, and Hawaii

Equator

Habitat: Rain forest Size: Head–body length up to 2.5 in. (6 cm) Coloration: Very bright colors, ranging from sky blue or yellow to red or black, often with patches of contrasting colors Diet: Invertebrates, including ants Breeding: Females lay clutches of 2 to 29 eggs on leaves; eggs hatch after 1 or 2 weeks Life span: Unknown Status: Varies according to species

The ruby poison frog is a poisonous amphibian from the Amazon rain forest in South America. The toxins ooze from the red spots on the frog’s back.

279

Poison Dart Frogs

The golden poison dart frog is considered to be the world’s

The tadpoles stick onto a patch of sticky mucus on the skin. Small species can carry just one or two, but others can carry many more. The adult then carries its young to a quiet place where the tadpoles can safely grow. This may be a stream, a pool, or the water collected in a tree hollow or in the center of a plant that grows on the branch of a tree. Sometimes poison dart frogs take their tadpoles to the water collected in broken bottles or other human trash. Once the adult dips its back into the water the mucus on its back dissolves, and the tadpoles swim free. Adults of some species may have to make several trips to transport all their young to water.

Parent Matters Poison dart frogs produce few eggs compared to most other amphibians. The parents look after their eggs and tadpoles to give them the greatest chance of survival. Poison dart frogs live in tropical forests where it is moist and there is plenty to eat. However, there are few pools in which to lay eggs, particularly on mountainsides, where water runs off the land, or in drier forests. Poison dart frogs that live in these habitats care for their young more than those that live in damp, lowland forests where the habitat is much wetter. They wet their eggs and young with water to make sure they stay damp so they can survive to become froglets.

most poisonous amphibian.

Many Frogs There are many different poison dart frogs in the family Dendrobatidae. They come in many different shapes, sizes, and color combinations. The largest genus in the poison dart frog family is Colostethus, or the rocket frogs. These are the least colorful members of the family, with brown backs and dark stripes on their sides. The second largest genus is Dendrobates. Species from this group are highly variable in color. Even

280

Frogs and Toads

within species, each individual poison dart frog has a distinct pattern of bands and spots. Some species, such as the dyeing poison dart frog, may be any color from yellow with black blotches to mottled blue with a black and white back. Others, including the strawberry poison dart frog, are mostly red. The most poisonous genus, Phyyllobates, live mainly in Central America. These frogs are typically black and yellow, or orange.

OW? DID YOU KN The species Phyllobates terribilis is the most poisonous frog in the world. It has enough venom in its skin to kill several people. The skunk frog was discovered in Venezuela in 1991 but is probably extinct already. This frog got its name for the noxious chemical that oozes from its skin. This foulsmelling substance is similar to the chemical that skunks spray over their enemies.

The female strawberry poison dart frog carries her tadpoles to individual feeding sites, where they will develop into small froglets.

Toxic Frogs Many poison dart frogs are highly poisonous. They do not make their own poison but accumulate the toxic chemicals from prey such as ants and termites. The toxins ooze through the frogs’ skin, so they taste bad when predators eat them. The predator then releases the foul-tasting frog immediately. Some predators have built up immunity to the toxins. One such predator is the Amazon ground snake. Poison dart frogs got their common name for the way in which Chocó Native Americans use the powerful toxins to coat the tips of arrows and blowdarts. They use these weapons to

kill animals for food. However, only three of the 175 species in the family are used for this purpose. The world’s most poisonous species, the golden poison dart frog, is one of them. It secretes a potent nerve toxin. This poison is extremely dangerous— just a single gram from 281

Poison Dart Frogs

DID YOU KNOW? The strawberry poison dart frog feeds her tadpoles with an egg that she lays in the water. The tadpoles of several species in the genus Colostethus have funnel-shaped, rotating mouths. When these frogs feed at the surface of the water, they rotate their mouths to the top. When they feed on stones on the bottom of the river or stream in which they live, they rotate their mouths back under the surface.

282

its skin could kill up to ten men. Scientists have recently discovered that chemicals in this frog’s poison have valuable medicinal properties, particularly as a powerful pain killer.

Captive Species Poison dart frogs are popular captive species thanks to their bright colors. In captivity, some species live up to 20 years old. These frogs need to

Mimics In many parts of Central and South America different species in the family Dendrobatidae live in the same areas and have similar colors. These species are usually dark with striking white or yellow stripes. These bright colors warn predators that these frogs are poisonous,

although not all of them are. The advantage to the nontoxic frogs is that they get the color protection without having to produce toxins. The advantage to the toxic frogs is that there are more frogs around with the same color as them, advertizing the dangers to predators.

Frogs and Toads

The dyeing poison dart frog is a large amphibian. On average, this species grows to about 2 inches in length, but the size and color varies between individuals.

be kept in humid conditions with a constant temperature of between 72 and 80°F. They eat a range of invertebrates, such as ants, small beetles, crickets, fruit flies, and spiders. Since these frogs build up toxicity from their food, most captive species should not be toxic to their owners. However, owners should still use extreme care when handling these fascinating amphibians.

Threats to Survival Many poison dart frogs are facing threats to their survival. Like many amphibians, the greatest threat is

habitat loss due to deforestation. People are clearing the rain forests to grow crops and build new homes. Many frogs are also threatened by an infection called chytridiomycosis. This disease was discovered in 1998. It is caused by a microorganism called a chytrid fungus. Another threat is overcollection for the pet trade. Poison dart frogs are popular among collectors, and this has led to a decline in the population of some species. As a result, most poison dart frogs are protected by laws in many countries.

283

PUFF ADDER The puff adder is one of the most common snakes in Africa and also one of the most deadly. This small viper is responsible for more deaths in southern Africa than any other snake.

284

snakes and lizards

P

uff adders are members of the viper family. They can be found in a variety of habitats, but not rain forests or deserts. They live in southern Africa but do not live in the western rain forests or north of the Sahara Desert. Puff adders also live on the other side of the Red Sea, in the Arabian Peninsula.

Deadly Venom Puff adders hunt at dusk or at night. Their prey include birds, small rodents, small snakes, and toads. Large puff adders eat guinea fowl, hares, and even very small antelope. They lie in wait and ambush victims. Their brownish body with dark gray and cream markings is well camouflaged among scrub, grass, or fallen leaves. The snake strikes when its victim comes within range. Long, hinged fangs inject large quantities of venom into the prey. The snake then releases its victim and follows it until the poison has eventually killed the animal. The bites of puff adders kill more people in southern Africa than those of any other type of snake. Their camouflage and habit of basking in the sunlight by paths mean that it is all too easy to step on one, which will cause it to strike. Most victims die through kidney failure. Puff adder venom is fairly slow-acting, however, so most people can reach medical help and receive a dose of antivenom—the antidote to the snake’s venom. Nine out of ten people recover from puff adder bites.

Fact File PUFF ADDER Bitis arietans Family: Viperidae Order: Squamata Where do they live?: Africa, south of the Sahara; also southern Morocco and the Arabian Peninsula Habitat: Woodlands, grasslands, and scrublands Size: 36 in. to 6 ft. (90 cm to 1.8 m) Appearance: Stout body with broad head. Tawny or brown with dark gray, cream-edged V- or U-shaped markings Diet: Small reptiles, birds, and mammals Breeding: Females lay 20–156 eggs, which develop inside the mother for 90–120 days before being born live Life span: Not known Status: Very common

Puff adders are large vipers, with thick bodies and flattened heads. Sluggish by nature, they crawl over the ground in a straight line like a caterpillar.

285

PYTHONS The python family contains some of the world’s biggest snakes. Unlike snakes with deadly venom, pythons use their huge, muscular bodies to squeeze their prey to death in a process known as constriction.

1

2

F

our out of five of the world’s largest snakes are pythons. These huge snakes are closely related to another family, the boas, which include the anaconda. Like boas, pythons kill their prey by squeezing them to death. Scientists have recognized about 30 species (different types) of pythons. Only the South American anaconda is bigger than the largest python species—the African and reticulated python.

3

Habitats Pythons and boas are close relatives, but the two groups live in different parts of the world. Pythons live in Africa, Asia, Australia, and New Guinea. Boas live in the Americas, although a few species are found in Africa and Asia. Five species of pythons live in Asia, and three live in Africa. All the other species inhabit Australia or New Guinea, an island to the north of Australia. Most pythons live in tropical regions. Most species live near water in these hot, humid areas. Many live in forests and spend part of their time in the trees. The green tree python spends all of its life in the trees. Outside the tropics, most pythons live in 286

4

5

Fact File PYTHONS

6

Family: Pythonidae Order: Squamata Where do they live?: Africa, Central and Southeast Asia, Australia, and New Guinea

7

Equator

8 Habitat: From tropical forests and grassland to scrub and arid deserts

1 Children’s python

5 Royal python

2. Amethystine python

6. Carpet python

3. Short-tailed python

7. Black-headed python

4. Green tree python

8. Indian python

deserts. In these areas, they do not hibernate in winter as many other snakes do. Instead, they may become inactive during cold or dry spells.

Breeding Habits Pythons reproduce by laying eggs. A female python lay eggs about six weeks after mating with the male. Pythons are very unusual among snakes in that they take care of their eggs. The female coils her body around her clutch of eggs. She warms them with her body, which helps them to develop. This is called incubation. As well as warming the eggs, the female also defends her eggs against predators.

Size: Head–tail length ranges from 6 in. to 33 ft. (40 cm to 10 m) Appearance: Broad, flat heads with powerful, muscular bodies. Color patterns vary from bold green or yellow to light brown with a pattern of darker brown and tan markings Diet: Amphibians, reptiles, birds, and smaller mammals Breeding: Females lay between 3 and 25 eggs, which hatch after 70 to 85 days Life span: Not known Status: Varies according to species

287

PYTHONS

While the eggs are incubating for eight to twelve weeks, the female rarely moves more than a few feet away from the clutch, even to eat, drink, or warm herself in the sun. Her care increases her offspring’s chance of survival. But the female loses weight and fitness at the same time, so she is unlikely to breed again until the following year. After the incubation period, the young snakes hatch from their shells. As soon as they have hatched, the female takes no further care of her young.

288

Hunting and Senses Pythons are predators like all snakes, but they do not use poison to kill their prey. Instead, they kill their victims by wrapping their body around the animal and then tightening their coils. Each time the victim breathes out, the snake tightens its grip. The prey eventually dies Large pythons often lie in wait and ambush their victims. Smaller snakes hunt more actively at night, when they go after smaller prey.

PYTHONS

through suffocation or being crushed to death. Once the victim is dead, the python senses the location of its victim’s head to swallow. Pythons sense their prey with the help of two small pits near their nostrils. These pits can detect the body heat of warm-blooded prey such as birds and mammals. The ability to sense heat is what helps pythons track down their prey under the cover of darkness.

OW? DID YOU KN Female pythons control the temperature of their eggs by loosening or tightening their coils around the clutch. The Indian python can raise the temperature of her eggs by twitching repeatedly to raise her body heat.

SUPER SizeD PYTHON Pythons vary in size. The world’s longest snake is the reticulated python, which measures up to 30 feet long and can weigh up to 440 pounds. These giant snakes are so big, they have been known to swallow mammals as big as gazelles.

Like other snakes in the family, pythons have colors and patterns that generally match their surroundings. The carpet python is named after the intricate blotches on its body, which may be tawny, red, gray, black, or brown.

Pythons continue to grow throughout their lives, so the oldest snakes are usually the biggest. These huge reptiles are able to tackle prey as large as deer, dogs, gazelle, and pigs. They have even been known to attack people.

289

RAIN FROG Rain frogs are a large group of frogs living mainly in Central and South America. These frogs live at ground level, often near streams, as some smaller species can dry out easily.

290

frogs and toads

W

ith more than 700 species, rain frogs are the largest group of frogs. Some people also call rain frogs leaf litter frogs, robber frogs, and whistling frogs. Rain frogs belong to a wider family called Leptodactylidae, which has more than 1,110 species. These smallish, often drab-looking frogs are difficult to identify, and scientists regularly discover new species. Unfortunately, some types of rain frogs are also dying out, because the places where they live are taken over by people. Global warming is also taking its toll, because some damp habitats are drying out.

Distribution and Habitats Rain frogs live only in the Americas. As a group, they range from the southern United States southward through Central America to Brazil and Argentina. Some rain frogs live on the Caribbean islands, with large islands such as Cuba holding many species. Rain frogs live in a variety of moist habitats, from rain forests to rocky outcrops and plantations. They also live in parks and gardens in towns and villages. Some species are common and widespread. Others are very rare and can be found only in one small location. Most rain frogs live on the ground. They hide on the forest floor under stones or in leaf litter, and many smaller species live near streams. A few species climb into bushes and trees to search for food. These frogs have toes with wide, sticky tips that help with climbing.

Fact File RAIN FROGS Family: Leptodactylidae Order: Anura Where do they live?: Southern United States through Central America to Brazil and Argentina, also on some Caribbean islands

Equator

Habitat: Rain forests, woodlands, plantations, and parks Size: 0.5 in. to 4 in. (1 to 10 cm) Appearance: Small, often brownish frogs with long hind limbs. Disks on their undersides help them cling to smooth surfaces Diet: Small invertebrates Breeding: Females lay from 3 to over 20 eggs on land. The young develop inside the eggs and then hatch as froglets Life span: Not known Status: Varies according to species

This brightly colored rain frog lives in Costa Rica. It belongs to the largest vertebrate group on Earth, Eleutherodactylus, with more than 700 species.

291

RAIN FROG

Many rain frogs have a round disk on their belly that helps them to grip smooth surfaces. Rain frogs are nocturnal (active at night). They emerge under the cover of darkness to forage for food such as insects.

Many Enemies

Shape, size, and color Rain frogs are small, compact frogs with long hind legs. The smallest species, a frog that goes by the Latin name Sminthillus limbatus, is just 0.4 inches long, and the largest is about ten times that size. Most rain frogs have smooth skin, but some have warty skin and resemble toads. Many rain frogs are agile, dainty amphibians with long limbs and toes. Some rain frogs are brown, with mottled markings. This coloration, known as cryptic coloration, helps the frogs to hide among dead leaves, stones, twigs, or garbage. Many have a dark stripe running through the eye, which makes it hard for enemies to recognize the head.

292

Being small with no defenses, rain frogs make an easy meal for many forest predators. Their enemies include snakes, such as vine snakes and young pit vipers, which lure the frogs closer by twitching the brightly colored tips of their tails. Spiders and larger frogs also hunt rain frogs, and larger rain frogs may eat smaller members of their own species. If a rain frog spots a predator, it often escapes by making one long leap and then staying perfectly still. This tactic tends to confuse the predator, which is often unable to spot the frog again.

Breeding Habits Male rain frogs are smaller than the females, and they are usually more brightly colored. During the breeding season, the males call to warn off rival males and attract the females. In contrast to frogs that lay their eggs in water, female rain frogs lay their

frogs and toads

eggs on land. They lay between three and twenty eggs in a cluster, usually in a shaded patch of soil or in dead leaves. Unlike eggs that are laid in water, these frog eggs are protected by a tough outer membrane (skin). The female usually stays with the eggs until they hatch. In a few species, it is the male that stays. The parent prevents the eggs from drying out and defends them against predators or parasites (animals which live on others) such as flies. Unusual among frogs, the embryos (unborn young) develop inside the eggs instead of hatching out as tadpoles. Nourished by the yolk, the embryos spend between fifteen and forty-nine days Male rain frogs call to attract females by expanding the vocal sac on their throats.

inside their tough-skinned capsule. They emerge as miniature versions of the adults.

Bright Colors A few rain frog species are more brightly colored than most. One species from Central America has a bright red spot on each thigh that appears as it leaps, but disappears when it lands. This is designed to distract predators while the frog makes its escape. Another species is brown with two bright orange stripes. It resembles a highly poisonous frog from the same region. Predators often think it is poisonous and avoid it, even though it is totally harmless.

OW? DID YOU KN The Caribbean island of Cuba has forty-eight species of rain frogs, including the very smallest species. Rain frogs form the largest group of any vertebrate (an animal with a backbone).

293

RATSNAKES Ratsnakes are a widespread group of snakes that usually kill their prey by constriction. They wind their muscular bodies around their prey and then squeeze so hard that the victim stops breathing.

294

snakes and lizards

T

here are about thirty-five species of ratsnakes belonging to the genus Elaphe. They live in North America as well as across Asia—there are Japanese, Persian, and Korean ratsnakes, for example. North American species include the common or American ratsnake, the corn snake, and the fox snake. The American ratsnake is common through the eastern half of North America. These snakes live in a variety of habitats, including forests, swamps, and wooded areas. American ratsnakes are active by day, especially early morning and late afternoon. In northern areas where winters are cold, they hibernate (spend the winter sleeping) for up to seven months of the year, hiding in hollow trees, caves, or buildings. They may share their hiding place with other snakes. American ratsnakes are expert tree-climbers. They use the ridged scales on their underside to grip the bark. They climb trees to prey on nesting birds and mammals such as squirrels.

Fact File AMERICAN RATSNAKE Elaphe obsoleta Family: Colubridae Order: Squamata Where do they live?: Eastern North America, including southeastern Canada, and the eastern and central United States Habitat: Forests and woodlands Size: 39 in. to 8.1 ft. (1–2.5 m) Appearance: Long and muscular. Color varies among the subspecies Diet: Frogs, lizards, nesting birds, and small mammals such as mice Breeding: Females lay between 10 and 40 eggs, which hatch after about 70 days Life span: Not known Status: Common

Life Cycle In cool, northern areas, American ratsnakes breed as soon as they emerge from hibernation in April or May. Southern ratsnakes have a longer breeding period. The female lays a clutch of ten to twelve eggs about forty days after mating. The pure white eggs stick together in a cluster. The eggs hatch after about seventy days, and the newborn young measure about 11 inches long. Ratsnakes, such as Elaphe taeniura shown here, belong to a group of snakes called the colubrids, which also includes garter snakes and grass snakes.

295

RATTLESNAKES Rattlesnakes are part of a small subfamily of vipers found only in the Americas. These highly venomous snakes warn enemies by shaking the rattles on the end of their tails.

R

attlesnakes are named for the loose scales on their tails, which make a loud rattling sound when shaken. They shake their rattle to warn animals, such as cattle, that might otherwise step on them. Rattlesnakes belong to a group of vipers called pit vipers. There are more than thirty species of rattlesnakes

296

and three species of pygmy rattlesnakes. The group includes the western diamondback, North America’s most dangerous snake, and the sidewinder, which is named after its unusual sideways movement. Other species include the Mojave, speckled, and banded rock rattlesnakes.

The Rattle The scientific name of the rattlesnake group, Crotalinae, comes from the Greek word for The western diamondback is one of the most aggressive rattlesnakes in the United States. This large snake with highly toxic venom is named for the diamond-shaped marks that run along its body.

Fact File rattle or castanet. The rattle is a unique feature of these snakes. It is made of horny segments that fit loosely together. The horny substance is called keratin, which is the same material that forms animal claws, hair, and horns. Each segment of the rattle was originally the skin of the scale covering the tip of the snake’s tail. In other snakes, this part is lost when the snake sheds its skin. In rattlesnakes, the dumbbell-shaped scale remains to become a new segment of the rattle. The rattle segments fit together loosely. Their irregular shape means they move more when shaken up and down, than when moved from side to side. This allows the snake to control its rattle and move silently when stalking prey. When it wants to make a noise, it raises its rattle in the air and shakes it back and forth. Many people believe that the number of segments in a rattlesnake’s tail is the same as its age in years. This is not quite true, but the number of segments does provide a general guide to the snake’s age. Most rattles are made of five to ten segments. A new segment is added each time the reptile molts—but young, fastgrowing snakes can molt up to four times a year. Over time, the end segments tend to fall off due to wear and tear. Rattlesnakes do not rattle to confuse or hypnotize their prey. Nor do males “serenade lady rattlesnakes,” as one early writer claimed. The rattle is used purely for defense, allowing the rattlesnake to make a noise to avoid being trampled by large beasts such as bison.

RATTLESNAKES Subfamily: Crotalinae Family: Viperidae Order: Squamata Where do they live?: North and South America, from southern Canada to northern Argentina Habitat: Open ground, including deserts, mountain, prairie, and scrubland Size: Varies from 20 in. to more than 2 ft. (50 cm to 1.5 m). Males usually slightly bigger than the females Appearance: Rattlesnakes have thick bodies. Most come with distinctive rattles on the end of their tails. Colors vary but usually dull brown with darker patterns on the scales Diet: Lizards and small mammals Breeding: Females lay between 4 and 25 eggs, which develop inside the body. On average the female gives birth to 10 live young Life span: Not known Status: Some species, such as the timber rattlesnake, are endangered. Others, such as the speckled rattlesnake, are fairly common

297

RATTLESNAKES

Many other snakes vibrate their tails when alarmed. Even without a rattle, this can make a loud noise if the snake is resting among dead leaves. Snakes also hiss and rub loose scales together as a noisy warning of their presence.

Breeding Habits Most rattlesnakes breed in late spring. The males track the females by following special scents called pheromones, which the females produce in preparation for breeding. If several males find the same female, they will fight for the right to mate. The largest snake usually wins the contest and mates with the female. As a result, male rattlesnakes are usually up to 15 percent larger than the females.

298

The fertilized eggs develop inside the female, and the live young emerge from her body at the end of summer, around four to six months after mating. Western diamondbacks give birth to between four and twenty-five young. The female remains with her young for up to sixteen days, until their first molt. Some experts think that snakes born at the same time can recognize their mother and one another throughout their lives. This may help the young snakes to follow the adults to the dens where they hibernate (sleep) in winter.

Hunting and Venom Like all vipers, rattlesnakes are venomous. They inject venom into their prey using hollow fangs,

RATTLESNAKES

RATTLESNAKE Habitats Rattlesnakes are found throughout the Americas and prefer to live in open habitats, such as deserts, mountain meadows, open grassland, rocky mountains, and scrublands. One species from South America lives in forest clearings. The sidewinder dwells in the deserts of southwestern United States. The snake moves over sand by throwing its body into curves that thrust it sideways. With its mottled markings, the massasauga inhabits swamps, prairie, and woodlands in northeastern United States and Canada. No rattlesnakes live in trees, but some types climb into shrubs

which are linked to special poison glands. The fangs are hinged and normally lie folded in the roof of the mouth. They swing forward to stab the victim when the rattlesnake strikes. Rattlesnakes detect their prey using two heatsensitive pits near their eyes. Their ability to sense heat means they can hunt warm-blooded prey (with a fairly constant body temperature) Rattlesnakes have a reputation for being aggressive toward people, but they will only strike to defend themselves when disturbed. Rattlesnakes give plenty of warning before they strike by shaking the noisy rattles on the end of

to hunt roosting birds. In regions with cold winters, rattlesnakes gather in dens to pass the cold months in a deep sleep known as hibernation.

such as birds and small mammals, but they will also feed on amphibians, reptiles, and insects given the opportunity. The heat-sensitive pits allow the snakes to hunt in complete darkness. They usually lie in wait to attack their prey.

OW? DID YOU KN The rattles of wild rattlesnakes are rarely more than a dozen segments long. The record for a wild snake was twentythree segments. The rattles of captive rattlesnakes are often longer because the snakes live a much quieter life. The record for a captive snake was twenty-nine segments.

their tails. 299

RATTLESNAKES

Rattle-less Rattlesnakes Not all rattlesnakes have rattles. One or two rare species that live on small islands in the Gulf of California cannot rattle their tails, even though they are descended from snakes with working rattles. Snake experts think that these rattle-less snakes reached the islands either by swimming or after being stranded on rafts of floating vegetation. Once on the islands, the snakes may have gradually lost their rattles so that they could climb trees to hunt birds more effectively. The rattle may also have been lost

300

because the islands did not hold large hoofed mammals that might trample them.

Growing Up Newborn rattlesnakes have no rattle. The rattle begins as a tiny button and develops in the first year or so as the young snake grows and molts several times. Young rattlesnakes may not A tightly coiled and rattling blacktailed rattlesnake is a rare sight. These snakes usually retreat when they are disturbed.

RATTLESNAKES

be able to sound a warning, but they are still extremely dangerous. When biting in defense, adults may deliver less venom or none at all. Young snakes do not have the same control and so they are just as deadly.

The Deadliest Rattlesnake

Rattlesnake bites are rare. The people who are

The western diamondback is considered to be the most dangerous snake in North America. More people die from bites from this snake than any other. It is dangerous because of its large size, and also the strength and quantity of its venom. Although they stand their ground and strike if provoked, these snakes are not as aggressive as people imagine. They would rather slither away, shaking their rattles to warn an enemy not to follow. Although the bite can kill a person, an antivenom is available. Captive diamondbacks are milked for their venom, which is used to make the antivenom.

bitten either step on the snakes, or prod or poke them on purpose. If you see a rattlesnake in the open, leave it alone and move far away.

OW? DID YOU KN The venom of most rattlesnakes acts on the blood. But the venom of the Mojave rattlesnake attacks the nerves. It works very quickly, which makes the Mojave very dangerous. The eastern diamondback rattlesnake is as venomous as the western diamondback, but it is rarer and found over a much smaller area. 301

RED SALAMANDER The red salamander is one of the most colorful amphibians in North America. The bright orange, scarlet, or crimson color of the young salamanders tends to darken with age.

302


T

hroughout the animal kingdom, bright colors warn potential predators that an animal might be poisonous. The predator recognizes these colors and avoids these species. Red salamanders are only mildly poisonous, but their coloration closely matches that of young eastern newts, which are highly poisonous. Scientists believe they benefit from resembling their poisonous relatives. Predators are fooled into avoiding red salamanders, too. When threatened, they arch their body and raise their tail just like young eastern newts. Red salamanders live in the eastern United States, where they can be found in damp places such as boggy fields and wooded areas. By day, they rest in burrows in soft mud beneath rocks and logs. They emerge to feed at night. Small invertebrates such as insects make up most of their diet. Large red salamanders go after bigger prey such as frogs and other salamanders.

Life Cycle Red salamanders breed in summer. The female’s eggs are fertilized by a capsule of sperm dropped by the male, which she is able to store for several months. She usually lays her eggs in fall or winter in a wet site such as a spring. Up to ninety eggs are glued to the underside of stones. She stays with the eggs until they hatch about twelve weeks later. The larvae (young) grow up in water. They develop slowly in the still water of pools, taking up to three and a half years to transform into adults.

Fact File RED SALAMANDER Pseudotriton ruber Family: Plethodontidae Order: Caudata Where do they live?: Eastern United States Habitat: Streams, springs, and bogs in meadows and wooded areas; young grow up in water Size: 3.75–7 in. (9.5–18 cm) Appearance: Stout with short, thick tail; orange to crimson body has small black spots; bright color darkens with age Diet: Small invertebrates and other salamanders Breeding: After internal fertilization, females lay 70–90 eggs, which attach to rocks; eggs hatch into aquatic larvae after 3 months Life span: Not known Status: Lower risk—least concern

Red salamanders have a stout build, with a thick body, small legs and a short tail. The upper body is speckled with small black spots.

303

RETICULATED PYTHON The reticulated python is one of the world’s biggest snakes and also one of the most feared since it has been known to kill people. Like other pythons, the reticulated python kills by constriction.

304

snakes and lizards

T

he reticulated python is the world’s second largest snake, after the anaconda. Like all snakes, these pythons never stop growing. They grow quickly during their early years, but the rate slows as they become adults. These snakes have a complex web of brown, black, yellow, and white markings on their large, muscular bodies. This provides camouflage as the python lies in wait for victims, hiding in water or among vegetation. It hunts medium to large mammals and birds. The prey is wrapped in the snake’s coils which then tighten and suffocate the victim.

Breeding Habits Reticulated pythons produce large numbers of eggs. Females have been known to produce more than 100 eggs at one time. The female coils around her eggs to warm and guard them. The hatchlings measure 24– 30 inches long. Reticulated pythons are able to breed when they reach about 9 to 10 feet long, which usually takes five or six years.

Pythons and Humans

Fact File RETICULATED PYTHON Python reticulatus Family: Pythonidae Order: Squamata Where do they live?: Southeast Asia Habitat: Fields, forests, plantations, riverbanks, and towns Size: Usually 15–18 ft. (4.5–5.5 m) but can reach up to 33 ft. (10 m) Appearance: Huge, muscular snakes with large broad head; markings come in complex brown, black, and yellow with white triangles Diet: Birds, reptiles, and medium to large mammals Breeding: Females lay between 60 and 100 eggs, which hatch after about 90 days Life span: Not known Status: Common, but becoming rarer because of hunting and habitat loss

Of all the constrictors, reticulated pythons are the most dangerous to people. Not only are they huge, but they are also drawn to towns and villages by plentiful prey, such as chickens and rats. There are accounts of reticulated pythons eating people, especially children, although this would be extremely rare. Reticulated pythons have large heads. The complex pattern on their bodies gives these snakes their common name—reticulated means “netlike.”

305

ROUGH-SKINNED NEWT The skin of the rough-skinned newt contains a poison powerful enough to kill a dog. This is one of the most poisonous newts in North America. Poison helps the newt defend itself from predators such as snakes.

306


R

ough-skinned newts live along the Pacific coast of North America, from southeastern Alaska to California, where they are found in damp forests in hilly or mountainous country. These shy amphibians emerge at night to hunt insects and worms on the ground, and tadpoles and frogs’ eggs in the water.

Warning Colors The rough-skinned newt is a poisonous species, and it advertizes this fact with its bright orange or yellow belly. Most snakes and other predators recognize the bright belly of these newts and know not to attack. If threatened by a predator, the newt arches its back and raises its head and tail to reveal the bright belly.

Breeding Habits Rough-skinned newts mostly live on land as adults, but return to water to breed. They usually breed in spring, but newts in high, cold mountains breed in fall. Fertilization (the fusing of egg and sperm) takes place inside the female, and a packet of sperm from the male fertilizes the eggs. After mating, the female lays her eggs one by one in the water, attaching them to submerged plants. The young hatch out as aquatic larvae. They grow, develop, and metamorphose (transform) to become land-dwelling adults. This usually happens by the end of summer. In the mountains, young pass the winter as larvae and become adults the following year.

Fact File ROUGH-SKINNED NEWT Taricha granulosa Family: Salamandridae Order: Caudata Where do they live?: Western North America, from southeastern Alaska to California Habitat: Damp forests and meadows in uplands; larvae grow up in lakes, ponds, and pools Size: Head–tail length 6–8.5 in. (15.5–22 cm) Appearance: Sturdy newt with rough, warty skin; dark brown or black upper body, orange or yellow underside, sometimes with dark markings Diet: Insects, frogspawn, tadpoles, and worms Breeding: After internal fertilization, females lay eggs one at a time and fix them to water plants Life span: Not known Status: Lower risk—least concern

Rough-skinned newt have thick bodies, short legs, and large heads. The upper body is dark to conceal it from above. The underside is orange or yellow.

307

SALAMANDERS One of the three main groups of amphibians, salamanders have long, slender bodies. Different species lead very different lives, with some kinds living on land and others living in the water.

S

alamanders and newts are one of the three main groups of amphibians. They are more closely related to the caecilians than they are to the frogs and toads. Amphibians were the first

308

group of vertebrates (animals with backbones) to leave the sea and live on land. They evolved from a group of fishes that had developed lungs and fleshy, leglike fins. Salamanders and newts are the group of amphibians that most closely resembles those fishy ancestors, with their long, slender bodies and powerful tails. The marbled salamander is a medium-size species that can reach up to 4.25 inches in length. The white bars across the black body and tail are a distinctive feature of these salamanders.

Fact File There are more than 400 species of newts and salamanders, which make up the scientific order (group) called Caudata. Some species are aquatic (water-dwelling), while others are terrestrial (live on land). Most land-dwelling species live at ground level, but some are good climbers and can be found in trees. Some species live in dark caves and underground streams. As adults, newts live on land, but they always return to water to breed. Apart from this behavior, there is no scientific difference between newts and salamanders. Salamanders and newts mainly live in damp places in cool, temperate regions of the world. Most are found in the Northern Hemisphere, especially parts of Central Asia, Europe, and North America. Many small, agile species inhabit parts of Central and South America. They are found in North Africa but not south of the Sahara Desert. There are no salamanders in Southeast Asia or Australia.

Shape and Movement In terms of their appearance, salamanders and newts resemble the intermediate stage between the other two groups of amphibians—the caecilians, and frogs and toads. Unlike frogs and toads, which have squat bodies with no true tail, salamanders and newts have a long, slender body and thick tail. Unlike legless, worm like caecilians, most salamanders have four limbs. These legs are not as strong as the back legs of frogs. Some aquatic salamanders have only small front limbs and no back legs.

SALAMANDERS AND NEWTS Order: Caudata Families: Over 400 species in 10 families Where do they live?: North and South America, Central Asia, Europe, and North Africa

Equator

Habitat: Generally moist places such as brooks, ponds, and streams Size: Varies from 5 in. (13 cm) to the 6 ft. (1.8 m) giant salamander Appearance: Most salamanders and newts have small heads, with long, slender bodies, short legs, and long, thick tails. Most species have four legs, but some have only 2 legs or very short legs. Skin is smooth Diet: Small species eat invertebrates (animals without backbones); larger species eat small frogs, reptiles, and rodents Breeding: Females lay eggs in the water, which mostly hatch out as larvae; in some species the eggs develop inside the mother; others retain larval features as adults Life span: Not known Status: Varies according to species, from common to scarce

309

SALAMANDERS

The small group called the sirens have only front limbs, while another group, called the amphiumas, have tiny, almost useless limbs. Salamanders and newts cannot leap like frogs. Land-dwelling species generally move in two different ways. When moving slowly, they walk on all fours, holding their body off the ground. When frightened they throw their body into a series of S-shaped curves, in a similar way as caecilians, legless lizards, and snakes. Salamanders and newts have fairly small heads with little eyes. Their most important sense is smell. Salamanders and newts use scent to track their food and also to find a mate.

1

Breathing Like other amphibians, most salamanders breathe using lungs and through their moist, smooth skin. Some species use their skin to breathe more than others. Whether in water or on land, salamanders often raise and lower their throat in a pumping action. This helps

OW? DID YOU KN Some salamanders can shed their tail when attacked. The twitching tail distracts the enemy, while the salamander makes its getaway. Californian newts give off a highly poisonous fluid to defend themselves against attack.

These illustrations show various species of salamanders and newts: western Chinese

2

mountain salamander (1); Japanese clawed salamander (2); black crocodile newt (3);

5 3

mudpuppy (4); olm (5); greater siren (6); and the two-toed amphiuma (7).

4

6 7

310

SALAMANDERS

to move air in and out of the lungs. The gas oxygen also enters the body through the lining of the mouth, which is rich in blood vessels. Waste carbon dioxide gas, the by-product of respiration (process of breathing and respiring), passes out through the mouth. Most young salamanders breathe using large, feathery gills on the sides of their head. Some salamanders and newts keep these gills as adults.

Feeding Techniques All salamanders and newts are carnivorous— they eat meat. These animals catch live prey by picking up scent molecules from the air or by spotting movement. Salamanders and newts feed on whatever prey is most abundant. The size of prey varies according to the size of the salamander. So, newly hatched salamanders feed on smaller aquatic creatures, while the larger

The barred tiger salamander is a large species, with a broad head and protruding eyes. The dark skin is covered with large yellow blotches, which advertizes that it is poisonous to predators.

land-dwelling adults hunt vertebrates (animals with backbones)â•‹including frogs and mice. Many species eat smaller salamander species, and some are cannibals, which means they eat members of their own kind. Aquatic salamanders open their mouths to let in water and their small prey. Salamanders that live on land creep up on their prey. When in range, they dart out their long, sticky tongues.

Reproduction Salamanders and newts vary in their breeding habits. Most have a life cycle that involves three distinct stages: egg, larva (young), and adult. 311

SALAMANDERS

Adult

Adult

Terrestrial salamander ONâ•‹LAND

Eft stage

Larval stage in egg

Amphibious newt

Egg mass

INâ•‹WATER

Adult with gills

Aquatic axolotl

Egg

Gilled larva

Courtship in water

Some hatch out from eggs as water-dwelling larvae, which breathe using feathery gills. When the larvae are full-grown they metamorphose, which means they transform into a new adult form. During this process, the salamanders and newts lose their gills and start to breathe air through their skin and their newly formed lungs. Not all species undergo this amazing transformation. This depends on whether the species lives on land or in the water. Newts mostly live on land as adults, but breed in water, and are known as amphibious species. Larvae pass through an intermediate stage, called an eft, before becoming adults. 312

Freeswimming larva

Egg mass

These illustrations compare the life cycles of salamanders and newts. Many salamanders live entirely on land, newts return to the water to breed, and the unusual axolotl is completely aquatic.

OW? DID YOU KN Some newts become more brightly colored in the breeding season to attract mates. Some salamander species that live in caves have tongues that are almost as long as their bodies.

SALAMANDERS

Land-dwelling salamanders lay relatively few large eggs in damp soil. The eggs contain a rich supply of yolk, which feed the larvae as they develop inside the egg. The larvae then hatch out as miniature versions of the adults. Female salamanders often guard their eggs. In a few species, the eggs develop inside the female so that she gives birth to well-developed larvae or fully formed young. Aquatic salamanders live and breed in the water. Females produce large numbers of small eggs, which then hatch into free-swimming larvae. Some aquatic species can breed while keeping the features usually associated with the larvae, such as gills. This is called neoteny. The axolotl of Mexico is the best known example of an animal that shows neoteny.

Who’s Who Among Salamanders The 400 or more species of salamanders are grouped into ten families. The largest group is the lungless salamanders, which contains about 285 different species. As their name suggests, these species of salamanders do not have lungs and breathe through their skin, mouths, and throats. The next biggest group is that of the newts and European salamanders, which contains fifty-five different species. This group includes the poisonous black-and-yellow fire salamander. Mole salamanders number around thirty species, including the extraordinary axolotl. The giant salamander group includes the North American hellbender. Four species of

sirens spend all their lives in the water, where they breathe using their special feathery gills. Finally, the three species of amphiumas have eel-like bodies with tiny limbs.

EFFECTIVE Defense

Salamanders such as the northern spring salamander are shy, secretive animals that are mainly active at night. A nocturnal lifestyle reduces the risk of being hunted by predators. Many species have dull, mottled colors that blend in with their surroundings. Some defend themselves by producing foul-tasting or poisonous fluid from glands on their heads or tails. These species are often brightly colored. Predators see the warning colors and avoid the salamanders. A few are brightly colored but non-poisonous. They escape attack by mimicking (copying) poisonous species.

313

SALTWATER CROCODILE This fearsome predator is the world’s biggest and most dangerous crocodile. Famous for their attacks on people, saltwater crocodiles have more to fear from people who kill them for their valuable skins.

314

crocodilians

T

he saltwater crocodile is found in a variety of habitats, including estuaries, rivers, swamps, and the open ocean. They are the most aquatic of all the crocodiles and spend little time on land. Some even have barnacles growing on them, which is a sure sign they spend a lot of time in water.

Crocodile Attacks Saltwater crocodiles are believed to kill as many as 1,000 people every year. They also attack small boats, even after the crew have been thrown into the water. Experts think that the crocodiles mistake small boats for rivals entering their territory. People also kill saltwater crocodiles, mainly for their valuable skins. So many were slaughtered in the second half of the twentieth century, that their numbers fell steeply. Saltwater crocodiles are now protected by law, and the population is carefully controlled.

Fact File SALTWATER CROCODILE Crocodylus porosus Family: Crocodylidae Order: Crocodylia Where do they live?: From eastern India through Southeast Asia to Australia, and on Pacific islands Habitat: Coastal waters, lakes, rivers, swamps, and open ocean Size: Around 16–23 ft. (5–7 m) Appearance: Large gray or brown crocodile with broad snout and strong jaws Diet: Aquatic animals including fish to the size of sharks; mammals to the size of buffalo Breeding: Female lays 60–80 eggs, which she guards until the young hatch about 3 months later Life span: Not known

Breeding Habits

Status: Lower risk—least concern

Males become territorial during the breeding season, and fights often break out for the chance to mate. After mating, the female builds a mound of plant debris on the river bank. She lays sixty to eighty eggs in this nest, which she guards against enemies such as monitor lizards. The young hatch after three months. The female then carries the hatchlings down to the water in her mouth. She continues to care for them for several weeks. All along the jaws of a massive saltwater crocodile are large, triangular teeth that are very efficient at tearing flesh from its prey.

315

SAND LIZARDS Sand lizards are a group of small, agile lizards suited to living in deserts. Unlike most desertdwellers they are active by day, darting here and there to catch insects.

316

snakes and lizards

S

and lizards are closely related to the African desert lizards. Both are members of the large lizard family Lacertidae. They are slender lizards with long legs and tails and pointed snouts. Sand lizards and African desert lizards live on the ground but prefer different habitats. Desert lizards inhabit sandy parts of southwestern Africa, including the Namib Desert. They have fringes of hairlike scales between their toes that act like flippers, allowing them to run across loose sand. Despite their name, sand lizards prefer rocky or gravelly ground. They lack the toe fringes of the desert lizards. Namaqua sand lizards dart among the ancient Welwitschia plants that dot the landscape, searching for insects. This speedy lizard can be active during the hottest parts of the day. When the sand gets too hot, it raises its tail off the sand and does a shuffling “dance,” raising one front leg and the opposite back leg, then switching legs.

Feeding and Breeding Most sand lizards and desert lizards eat insects such as beetles, grasshoppers, locusts, and termites. One species feeds on smaller lizards, and the shovel-snouted lizard also eats seeds. These lizards lay small clutches of eggs in burrows or holes under rocks. Some may breed at any time of year. Most species lay between three and eight eggs, while the wedge-snouted sand lizard lays just one. The eggs usually hatch after about two months.

Fact File SAND LIZARDS AND AFRICAN DESERT LIZARDS Pedioplanis (sand lizards) Meroles (desert lizards) Family: Lacertidae Order: Squamata Where do they live?: Southern Africa Habitat: Rocky and sandy deserts Size: 6–8 in. (15–20 cm) Appearance: Small, slender lizards with long legs and tails and pointed snouts. Color varies from buff and brown to reddish with light or dark markings. Desert lizards have fringes of fine scales between their toes Diet: Varies from seeds and small insects to smaller lizards Breeding: Females lay clutches of up to 8 eggs that hatch after about 60 days Life span: Not known Status: Very common in suitable habitats

Sand lizards are beige, brown, or reddish in color, with lighter or darker markings that blend in with sandy surroundings, camouflaging the animals.

317

SANDFISH The sandfish is an unusual lizard that lives in loose sand in deserts. It tunnels through the sand with a swimming motion, flexing its body and tail from side to side.

318

snakes and lizards

S

andfish live in hot deserts in North Africa and western Asia, ranging from Morocco in the west to Iran in the east. They live in the loose sand of wind-blown dunes, often near oases.

Desert Dwellers The sandfish is well suited to a burrowing lifestyle. The short, wedge-shaped head; slender, flattened body; and smooth, tight-fitting scales create a streamlined shape that glides through sand. The toes have tiny fringes that act like flippers, pushing against soft sand. Male sandfish are larger than the females. These lizards start to breed in May. After mating, the female lays a clutch of about six eggs, which take about two months to hatch.

Fact File SANDFISH Scincus scincus Family: Scincidae Order: Squamata Where do they live?: North Africa, Middle East, and western Asia Habitat: Sandy deserts Size: 8.75 in. (22 cm) Appearance: Small lizard with wedge-shaped head and short tail; color is brownish-yellow with yellow or brown spots and streaks Diet: Some plant matter; insects, spiders, scorpions, and small lizards Breeding: Females lay about 6 eggs, which hatch after about 2 months

Hunters and Hunted


Sandfish “swim” through the sand much like a fish swims in water. They can quickly dive below the surface to escape predators. And they can surface just as quickly to seize prey such as insects, spiders, scorpions, and smaller lizards. In turn, sandfish are eaten by many desert creatures, including horned vipers, fennec foxes, and monitor lizards. Sandfish are also hunted by people who live in the desert. Children are often given the job of catching these reptiles by digging them from the sand. The lizards are either roasted and eaten immediately, or dried.

Status: Common in suitable habitats

The sandfish is suited to a desert life. Grooves on the head direct sand away from the eyes, and the ears are covered by fringed scales to keep out sand.

319

SEA SNAKES AND SEA KRAITS Most people think that snakes are land-dwelling reptiles, but some species spend all of their lives in the ocean. Sea snakes use their highly toxic venom to kill their prey.

S

ea snakes belong to the family of poisonous snakes that includes landdwelling mambas and cobras. Scientist divide sea snakes into two groups—the “true” sea snakes and sea kraits. There are about fifty

320

species of true sea snakes and five species of sea kraits. Both groups are well suited to a life in the ocean, but true sea snakes are completely at home in the marine environment. These snakes never venture onto land and are helpless there. By contrast, sea kraits regularly come ashore to mate and lay their eggs, or just to bask in the sun. Sea snakes live in the warm, tropical waters of Unlike sea kraits, all sea snakes are completely aquatic reptiles and never leave the warm, tropical waters in which they are found.

Fact File the Indian and Pacific oceans, from the Arabian Gulf, through Indian and Southeast Asian waters, to New Guinea and Australia. One species, the yellow-bellied sea snake, has a wider distribution and is also found on the opposite side of the Pacific Ocean, off the coast of North and South America. Most sea snakes keep to fairly shallow, inshore waters, but the yellowbellied sea snakes lives far out to sea.

Suited to the Sea The long body of a sea snake is flattened from side to side, especially toward the tail, which is oar-shaped. The scales on the underside are narrower than those of land-dwelling snakes. They form a ridge that acts like the keel of a boat, helping to stabilize the reptile as it swims. Sea snakes sweep their body and tail from side to side to move. The oar-shaped tail pushes against the water, driving the snake forward. Sea snakes have glands (special cells) under their tongues that remove excess salt absorbed from the seawater. Sea snakes vary in color. Most are gray, brown, or olive and blend in with the seabed. Some species have black and white bands, while the yellow-bellied sea snake is black and yellow. Conspicuous markings warn enemies that the snakes are poisonous and should be left alone.

SEA SNAKES AND SEA KRAITS Family: Elapidae Subfamilies: Hydrophiinae and Laticaudinae Order: Squamata Where do they live?: Coastal waters of Indian and Pacific Oceans, from Arabian Gulf and India through Southeast Asia to Australian waters; yellow-bellied sea snake more widespread Habitat: Shallow waters, including river estuaries; yellow-bellied sea snake open ocean Size: 18 in. to 9 ft. (45 cm to 2.7 m) Appearance: Marine snakes with sidewaysflattened bodies and paddle-shaped tails; some species have small heads and thick bodies. Colors vary from brown, gray, or olive, some species have black and white bands and one species is a striking black and yellow color Diet: Crustaceans, eels and other fish, and fish eggs Breeding: True sea snakes mate in the water and give birth to between 2 and 18 live young at sea. Sea kraits breed on land and lay between 6 and 20 eggs on beaches Life span: Not known Status: Mostly common

A Seafood Diet Like their land-dwelling relatives, sea snakes are formidable predators. They use highly toxic venom to overcome slippery prey such as fish. 321

SEA SNAKES AND SEA KRAITS

All species of sea snakes hunt in the water. Some species, such as olive sea snake, feed on a variety of prey, including crabs, cuttlefish, prawns, and squid. Most prefer just one type of food—usually slow-moving fish that can be trapped in rocky crevices. Eels are the favorite prey of many sea snakes. The long and slender bodies of these fish fit comfortably inside the snake’s long, thin stomach. Sea snakes look for eels as they cruise over the seafloor. Some hold onto their prey after striking, until their venom takes effect. Others release their victim and The yellow-bellied sea snake is one of the few reptiles that lives out in the open ocean, where it hunts fish and other small prey.

322

OW? DID YOU KN Turtle-headed sea snakes have blunt, cone-shaped spines on their snouts. Eyelash sea snakes have raised scales over their eyes that resemble spiky eyelashes. No one knows the purpose of these unusual scales. Yellow-bellied sea snakes can swim almost as well backward as they can forward. They do this by reversing their normal forward-swimming movements.


Breathing Like all reptiles, sea snakes and sea kraits such as the banded sea krait (below) take in oxygen from the air using lungs. They do not have gills like fish, so they must surface to breathe every so often. Their nostrils are located on top of their heads so they can breathe without lifting their heads from the water. Special valves cover the nostrils. These valves close tightly when the snake dives. Like other snakes, sea snakes have only one working lung. The lung is long and slender so that it fits inside the body. In sea snakes, this working lung is very big.

Part of it extends backward, forming an air store that supplies the snake when diving. The large lung may also help with buoyancy (keeping afloat). Some sea snakes also absorb oxygen dissolved in water through their skin. They may take in one-fifth of their oxygen in this way. Sea snakes usually look for food in shallow water and come up to breathe every thirty minutes or so. Sea kraits surface more often, usually about every five minutes. However, some types of true sea snakes can dive to depths of 550 feet and stay under for up to two hours.

323


track it as it dies using their keen sense of smell.

Life Cycle True sea snakes have different breeding habits than the sea kraits. True sea snakes mate in the water and do not come on land, not even to give birth. Most species mate on the seabed, but yellow-bellied sea snakes mate at the surface. The eggs develop inside the female, and she gives birth to live young. The female produces just three or four young—a smaller number

324

than most snakes. More offspring would weigh the female down and hinder her ability to hunt. Sea kraits come ashore to mate and again to give birth. Yellow-lipped sea kraits migrate long distances to reach their breeding grounds on remote beaches. They come ashore to mate The venom of the banded sea krait ranks among the most toxic in the world. These snakes are very docile (not aggressive), however, so there is little chance of a person being bitten.


An ocean-going snake The yellow-bellied sea snake is the only snake that ventures out into the open ocean. These distinctive black and yellow reptiles gather out at sea at sites where the ocean currents meet, and seaweed and other debris collects. The snakes prey

and remain on land for hours before returning to the sea. When the female is ready to lay her eggs, she swims ashore again, and lays a clutch of about a dozen eggs in a moist cave above the high-tide mark. Several females may share the same cave. Other sea kraits lay their eggs in the sand or under foliage. The eggs of yellow-lipped sea kraits hatch after sixteen to twenty weeks.

on small fish that live in this flotsam. They may drift out into very deep water with ocean currents. The bright colors of yellow-bellied sea snakes warns potential predators that they are poisonous, and they also have unpleasant-tasting flesh.

OW? DID YOU KN Turtle-headed sea snakes eat only fish eggs. They search rocky crevices for the eggs laid by blennies and gobies. They have special muscles in their mouth to suck up the eggs. “Thin-necked” sea snakes have slender heads and necks. They can thrust their heads right inside the narrow burrows of eels to catch the slender fish.

A Freshwater Sea Snake The Lake Taal sea krait is a contradiction in terms—a sea snake that lives in fresh water. The home of this unusual sea snake is a freshwater lagoon on the volcanic island of Luzon in the Philippines. Scientists believe Lake Taal was formed by a violent volcanic eruption in ancient times. The eruption created a large

hollow, which was then flooded by seawater. Sea snakes entered the lagoon via a channel that was later closed by a further eruption, trapping the snakes inside. The lagoon gradually became less salty as it filled with rainwater. The snakes survived and adapted to life in fresh water. The 325

SHARP-RIBBED NEWT The sharp-ribbed newt is a fierce predator, hunting out tadpoles, fish, and worms. Poison glands protect these newts from attack, as do the sharp ribs, which stick out through their skin.

326


S

harp-ribbed newts are common over much of Spain and Portugal, and across the Mediterranean in Morocco. These amphibians spend almost all their lives in water. They live in stagnant pools, streams, and water-filled ditches, where they hide in the mud at the bottom and surface for air. At night they hunt for fish, insects, and worms, and will even eat their own kind.

Poisoned Ribs This newt has a mottled greenish-gray body, with a row of large orange warts down each flank. These are poison glands positioned over the tips of the sharp ribs that lie just beneath the skin. When captured by a predator, the newt arches itself. This tightens the skin over the orange warts, and the tips of the ribs pierce the skin through the poison glands, releasing poison. The newt writhes around, repeatedly stabbing its attacker with its poisoned ribs. With such a ferocious defense, it is not surprising that most predators leave it alone.

Life Cycle Sharp-ribbed newts breed between September and March. A few days after mating, females lay between 200 and 300 eggs in clumps, fixing them to stones or water plants. After five to fourteen days, the eggs hatch into larvae. They feed and develop for between 50 and 150 days before transforming into adults. The time taken to develop depends on the water temperature.

Fact File SHARP-RIBBED NEWT Pleurodeles waltl Family: Salamandridae Order: Caudata Where do they live?: Spain and Portugal (except northern areas) and northern Morocco Habitat: Water-filled ditches, pools, lakes, and sluggish rivers Size: 6–12 in. (15–30 cm) Appearance: Large, stocky newt with large, flattened tail; gray-green skin with a row of orange warts running along its sides Diet: Invertebrates, tadpoles, and small vertebrates Breeding: After internal fertilization (when eggs fuse with sperm), female lays between 200 and 800 eggs in clumps, which are fixed to water plants; the larvae take up to 150 days to transform into adults Life span: Not known Status: Near threatened

At up to 1 foot long, the sharp-ribbed newt is one of Europe’s largest amphibians. It has a stout body and a long tail, which is flattened from side to side.

327

SIDEWINDER The sidewinder is a rattlesnake that lives in the deserts of southwestern United States, including Death Valley. It takes its common name for the looping, sideways movement that it uses to slither over loose sand.

328

snakes and lizards

F

ew animals can tolerate the desert heat, and the sidewinder is no exception. During the hottest part of the day, this snake burrows into the sand to keep cool. With much of its pale, mottled body covered by sand, it is almost invisible. However, the top of the head shows above the sand. The snake then emerges at night to hunt for food. The sidewinder is unusual among snakes because it does not have a home range where it lives, hunts, and patrols. Instead, it wanders the desert randomly searching for prey.

Hunting Techniques Lizards are the sidewinder’s favorite food, especially whiptails, which move quickly by day but are very sluggish at night. Sidewinders also hunt birds and rodents. The snake kills by biting its prey with poisoned fangs. Its venom is not as powerful as that of most other rattlesnakes. If it gets the chance, it will also strike from its daytime burrow. It holds onto its prey until its venom takes effect, so it does not need to move out into the open, where it would be more noticeable.

Fact File SIDEWINDER Crotales cerastes Family: Viperidae Order: Squamata Where do they live?: Southwestern North America Habitat: Deserts with sand dunes Size: 24–30 in. (61–76 cm) Appearance: Smallish, slender rattlesnake with flat head and raised scales over the eyes. Body is yellow, beige, pink, or grayish with darker blotches and speckles Diet: Lizards and mice Breeding: 5 months after mating, the females give birth to 5–18 live young in late summer Life span: Not known Status: Common

Breeding Behavior Sidewinders mate in April or May. Five months later, five to eighteen live young are born. Young sidewinders have an unusual hunting technique—they use their tails to lure lizards closer. The young snake moves its tail slowly over the sand so that it resembles a crawling insect. The sidewinder moves by throwing its body diagonally across the surface, leaving a trail of parallel J-shaped markings on the loose sand.

329

SIRENS Sirens are unusual salamanders that have tiny front legs and no back legs at all. These eel-like amphibians live in the mud at the bottom of swamps and pools. They are rarely seen and therefore poorly understood.

330

snakes and lizards

W

ith their long, slender bodies, sirens look more like eels or snakes than amphibians. Growing up to 35 inches long, they are among the largest amphibians in North America. There are just four species—the greater siren, the lesser siren, and two species of smaller dwarf sirens. Sirens live in marshes, ponds, swamps, and waterfilled ditches, spending most of their time burrowed in the mud and vegetation at the bottom. Sirens never come on land, even if their pond or swamp dries out. Instead, they burrow down into the mud. As the mud dries, the slime covering their skin hardens, forming a cocoon that keeps the animal moist. The siren enters an inactive stage called estivation. Its body processes slow down and it survives on fat stored in its tail. When rainwater fills the pool, the siren returns to life. Lesser sirens can survive several months of drought. Greater sirens stay up to five years in this inactive state.

Breeding and Feeding Sirens are most active in summer, emerging at dusk to hunt for young insects, snails, and other aquatic creatures. Scientists know little about the breeding habits of these unusual amphibians. Experts think that the eggs are fertilized by the male (when egg and sperm fuse) outside the female’s body. Both lesser and greater sirens lay large quantities of eggs. The eggs are probably laid in late winter and hatch about two The siren breathes under the water using the

Fact File SIRENS Siren lacertina (greater siren) Siren intermedia (lesser siren) Family: Sirenidae Order: Caudata Where do they live?: Southeastern North America

Tropic of Cancer

Habitat: Swamps, ponds, and water-filled ditches Size: 7–35 in. (18–90 cm) Appearance: Slender amphibians with large, feathery gills on the head; long tail, tiny front legs, and no back legs; dark brown or olive with darker spots, young may have red patch on the snout and side of head Diet: Plants, amphibian eggs, crayfish, insect larvae, and snails Breeding: Lesser siren lays between 200 and 550 eggs, greater siren lays up to 1,400 eggs singly or in groups. Eggs hatch after 8 weeks Life span: Not known Status: Lower risk—least concernÂ�

feathery gills on its head. The gills are often so large that they hide the tiny front legs.

331

SKINKS Skinks are one of the largest lizard families. Most species live on the ground, but some prefer to climb in the trees and others burrow in the sand or soil.

T

here are at least 1,400 species of skinks in the family Scincidae. Experts divide this large family into between 115 and 124 smaller groups called genera. Skinks are found in every continent except Antarctica, and they have even

332

become established on some remote islands far out to sea. Skinks are the most abundant reptiles in Australia, with more than 370 species. These fast, agile lizards are also common in Africa, India and Southeast Asia. The current distribution of skinks suggests that they may have evolved on southern continents, and then spread northward and westward. The common garden skink is often seen basking on top of rocks or paths in gardens and parks across southern Australia.

Fact File Shape and Size

SKINKS

Skinks are generally long, slender lizards with short legs and a tapering tail. Some skinks have tiny legs, however, and a few species have no legs at all. Most skinks measure 3 and 13 inches from head to tail, but some are much larger. The shape of the tail also varies. Some species have long tails that can be twice the length of the body. The stump-tailed skink of Australia has a short, fat tail that resembles its head. This serves to confuse predators, which strike at the wrong end of the skink. The tail also functions as a food store. Most skinks have rounded bodies covered with smooth, flat, overlapping scales. Some species have ridged scales that may help them move about in their surroundings. The heads of most skinks are small and wedge-shaped, with large, bony plates protecting the top of the skull. The snout is often long and pointed. Skinks can replace teeth lost through wear and tear. New teeth move up from the inner jaw to fill gaps created by the missing teeth. Most skinks have short, wide tongues that are covered with tiny bumps.

Family: Scincidae

Burrowing Skinks Many skinks live under the ground, burrowing through the soil or sand. Their bodies are well suited to this lifestyle. Most have eardrums set deep within the head, with a small opening to keep out the sand or soil. The eyes have seethrough lower lids that protect the eyes from dirt but also allow them to see underground.

Order: Squamata Where do they live?: Every continent except for Antarctica

Equator

Habitat: Varies according to species but includes deserts, forests, and grassland; often found along rivers and streams. Some are good burrowers, some live in trees, while others are good swimmers Size: Usually around 5 in. (12 cm) but some larger species reach up to 14 in. (35 cm) Appearance: Slender lizards with wedge-shaped heads, tapering tails, and short legs Diet: Some species eat plants but most prey on small invertebrates (animals without backbones) such as insects, slugs, and worms Breeding: Some females lay eggs, while others give birth to live young Life span: Not known Status: Varies from common to endangered

333

SKINKS

Like most skinks, the burrowing species have small, wedge-shaped heads. The slender bodies of these reptiles are covered with hard, smooth scales that help the animal slide easily through the soil or sand. Some burrowing skinks have small, weak legs and burrow by wriggling their long, bodies in the same way as a worm. In this form of movement, legs are of little use, and can

OW? DID YOU KN A bright blue tongue gives the blue-tongued skink its common name. When threatened, it sticks out its startling tongue and hisses loudly. It also has a powerful bite. An unusual skink from the island of Madagascar off the coast of Africa lives on the beach. It hunts crabs and small fish in rockpools and is mainly active at low tide.

1

2

even be a hindrance, so the burrowing skinks have no front legs, or even no legs at all.

Shedding the Tail Many skinks shed their tail when they are attacked by a predator. The reptile can survive without its tail, which often breaks off quite cleanly. The tail distracts the enemy’s attention while the skink escapes. For this reason, tails are often brightly colored. For example, the African fire skink has a red-and-black body and a blueand-black tail. An enemy that focuses on the tail may well lose sight of the skink when the tail breaks off. For the same reason, young pinktailed skinks of Baja California have a brownand-cream striped body and a bright pink tail. 1 Five-lined skink

5 Fire skink

2. Berber skink

6. Blind burrowing skink

3. Cape skink

7. Monkey-tailed skink

4. Spiny-tailed skink

8. Three-toed skink

5 3

4

6

7

8

334

SKINKS

Suited to different habitats Skinks live in many different habitats, including deserts, forests, and grasslands. Most species live on the ground, but a few kinds are good climbers and forage in trees. Tree-dwelling skinks from Asia and Southeast Asia have long, tapering tails to help them balance when climbing. One species, the large Solomon Islands tree skink, has a prehensile (gripping) tail like a monkey, which it curl around branches. Many tree-dwelling skinks have a flat pad under the toes that helps them climb. Cat skinks from hilly forests in India have sharp claws for climbing but, like cats,

they are able to retract their claws to run over the ground. Some skinks spend much or part of their time in water. Eastern water skinks (below) live by streams and waterways and feed on insects and worms, and the occasional berry. The diving skinks of Madagascar live in forest streams. Their nostrils are high on their snouts so they can breathe while swimming. These skinks are expert divers and strong swimmers. They can swim against the current to prey on creatures hiding under stones on the riverbed.

335

SLIMY SALAMANDER The slimy salamander is named for the sticky, poisonous slime that it produces to protect itself from predators. The male slimy salamander performs an elaborate “dance” to win his mate.

336


S

limy salamanders live in moist forests and wooded hillsides in eastern North America. They spend their days resting in burrows under rocks or logs. At night, they emerge to hunt for insects such as ants and beetles. The slime glands that give these salamanders their common name are in their tails. When a predator strikes, the salamander raises its tail and unleashes a gluelike, poisonous slime. The sticky slime is a good defense, but slimy salamanders are still prey for some birds, snakes, small mammals, and other salamanders.

Courtship Dance Slimy salamanders identify their mates by scent and also through an elaborate courtship display. After approaching a female, the male does a complex “dance,” raising and lowering his back legs in turn or both together. If he lifts both hind legs at once he props himself up with his tail. Then he lifts and lowers his front legs. Moving closer, he rubs himself against the female and gently bites her. Finally, the male nudges the female’s belly and the pair walk forward together. He drops a capsule of his sperm, which she picks up with her reproductive organ. The sperm in the capsule fertilizes the female’s eggs inside her body. The female then lays up to three dozen eggs in clusters, sticking them to an overhanging rock or tree stump. She remains with the eggs until they hatch two to three months later.

Fact File SLIMY SALAMANDER Plethodon glutinosus Family: Plethodontidae Order: Caudata Where do they live?: Eastern and southeastern United States Habitat: Damp forests, pine woods, and ravines Size: 4.5–8 in. (11–20 cm) Appearance: Slender salamander with long tail; black or dark gray with small silver spots Diet: Small invertebrates such as insects and worms Breeding: After internal fertilization, females lay 5–34 eggs, which are fixed to rocks. Eggs hatch after 2 to 3 months Life span: Not known Status: Lower risk—least concern

The slimy salamander has a slender body with small, strong legs. The long, cylindrical tail is about the same length as the head and body.

337

SLOW WORM Slow worms are often mistaken for snakes, but they are actually legless lizards. They are found in gardens and parks across Europe and highly prized by gardeners because they eat pests.

338

snakes and lizards

S

low worms are legless lizards that are found across much of Europe and into western Asia. They often live in damp places with low-growing vegetation, such as in cemeteries, hedges, overgrown gardens, and along railway lines. Slow worms are shy, nocturnal (active at night) creatures. By day, they hide in ready-made burrows or under rocks or concrete slabs. At night, they emerge to feast on earthworms, insects, slugs, snails, and spiders. They track their prey by scent, flicking out their tongue to gather scents in the air. Slow worms have many enemies, including birds, cats, snakes, and weasels. They have strong jaws but rarely bite. Instead, they shed their tails to confuse predators. Slow worms can live without their tails, which grow back slowly. Many adult slow worms have stumpy or regrown tails, resulting from attacks by cats.

Life Cycle Slow worms hibernate (spend the winter sleeping) in vacant rodent burrows. Many slow worms may hibernate together. They emerge by March, and mating takes place in May or June. The male pins down the female by biting her head and twisting his body around hers. Mating can last up to ten hours. Females give birth to six to twelve young from August to October. They are born inside a membrane (skin) from which they escape by wriggling energetically. Males can breed from the age of three; females breed from five years.

Fact File SLOW WORM Anguis fragilis Family: Anguidae Order: Squamata Where do they live?: Most of Europe into western Asia and northwestern Africa Habitat: Damp places, including gardens, hedges, parks, riverbanks, and woodlands Size: 12–20 in. (30–50 cm) Appearance: Legless lizard with narrow head, small eyes, and long tail. Shiny skin is a brown or coppery color; females have a thin, dark line running down the back Diet: Invertebrates (animals without backbones) such as insects, slugs, snails, spiders, and worms Breeding: Females give birth to 6–12 live young around 8–12 weeks after mating Life span: Up to 12 years in the wild; up to 54 years in captivity Status: Common

Slow worms have a slender, snakelike body but the unmistakable head of a lizard. Many people kill these lizards thinking they are snakes.

339

SMOOTH NEWT Smooth newts are named for their smooth, velvety skin. Like other newts, they breed in the water where the male performs an elaborate mating “dance” to attract his mate.

340


S

mooth newts are small amphibians with compact bodies, well-developed legs, and large tails. This species is the most abundant newt in northern and central Europe, ranging from Britain eastward into western Asia. They are so common that they are also called common newts. Like other newts, smooth newts live on land as adults but return to water to breed. On the land they live in damp fields, gardens, and wooded areas. They are often seen in flooded gravel pits, village ponds, and water-filled ditches. Smooth newts are shy creatures, hiding under stones and logs by day. At night they emerge to hunt small invertebrates (animals without backbones) such as insects, slugs, and worms.

Differences in Appearance Smooth newts are yellow-brown or olive with dark spots. Outside the breeding season, the males and females are difficult to tell apart. Both are a similar size—around 4 inches from the head to tail—with a similar coloration. However, the males have a single dark stripe running down the center of the back, while the females have two dark stripes that run either side of the center line. Both sexes have a yellow or orange belly. When the newts breed in the spring, however, the male is much darker on the back. The male also develops brighter colors on his belly. He also develops a high, wavy-edged crest running along his back, which makes him more attractive to females.

Fact File SMOOTH NEWT Triturus vulgaris Family: Salamandridae Order: Caudata Where do they live?: Northern and central Europe eastward into western Asia Habitat: Damp fields, gardens, and woodlands; larvae grow up in ponds Size: 4.5 in. (11 cm) Appearance: Small newt with smooth skin; yellowish-brown with dark spots and yellow or orange undersides; breeding males develop a high, wavy crest Diet: Insects, slugs, worms, and other small invertebrates (animals without backbones) Breeding: After internal fertilization, females lay 200–300 eggs, one at a time, fixing them to water plants; larvae hatch after 10–20 days Life span: Not known Status: Lower risk—least concern

Outside the breeding season, smooth newts spend most of their time on the land. They hide under large stones or in compost heaps, emerging at night to feed.

341

SMOOTH NEWT

Adult smooth newts live on the land but return to the water to breed. They prefer standing water with plenty of

The high, wavy crest of the male is useful as well as decorative. When they are underwater, newts can add to their oxygen supply by absorbing oxygen through their skin. The tall crest of the male increases the surface area through which oxygen can be absorbed. This gives the male more time underwater before coming up for air, which in turn increases his chance of breeding success.

dense vegetation, such as the edges

Breeding Time

of lakes and

Adult smooth newts breed in the water, such as freshwater ponds. When the female enters the water,

ponds, and water-

342

the male immediately swims in front of her, blocking her way. He curls his tail against his flank and waves it energetically, wafting a special scent toward the female. Having gained her interest, he turns and slowly moves away in front of her, waving his tail. If she follows, nuzzling his tail with her snout, he drops a capsule of sperm, which she picks up with her reproductive organ. The pair may repeat this courtship “dance” several times before the female loses interest and swims away. After mating, the female lays


between 200 and 300 eggs in water, at the rate of three to seven eggs per day. She attaches each egg to submerged plants. The eggs hatch into larvae after a maximum of twenty days. The larvae (young) look nothing like the adults. These aquatic creatures have feathery gills on their heads, which they use to breathe in water just like a fish. The larvae also have powerful tails for swimming, but they do not have legs. These develop as the larvae grow in the pond, where they feed on invertebrates and crustaceans. By summer’s end, they have usually metamorphosed (transformed) into adults. During the transformation, the newts lose their gills and develop lungs for life on the land. However, the larvae that hatch late in summer spend winter in the pond and become adults the following spring.

Close relatives Smooth newts belong to a family of about a dozen newts that are widespread in Europe, North Africa, and western Asia. Palmate and alpine newts live on hills and mountains, which are littered with tiny lakes where they can breed. Smooth newts are often mistaken for palmate

newts. However, smooth newts have conspicuous spots on their throats, while palmate newts have pale, unspotted throats. The group also includes the great crested or warty newt. Larger than the smooth newt, the male great crested develops a tall, jagged crest along his back during the breeding season. In the same way as smooth newts, he attracts females with an elaborate courtship dance. Adult smooth newts look quite different on land than in the water. Sometimes, they can be mistaken for lizards. However, newts move much more slowly than the fast-moving lizards. Lizards have five toes on each front foot, with small claws and scaly skin. Smooth newts have only four toes, with no claws and softer skin that lacks any scales.

Black spots cover the throat and flanks of the smooth newt and extend on to the orange or yellow belly. These colors camouflage the newt, helping it to hide from predators.

343

SNAKES There are around 3,000 different species of snakes, making up around 40 percent of all reptiles. Snakes are unusual because they lack limbs, but they manage to move around with ease. Snakes are some of the most efficient predators on the planet.

A

long with lizards and worm-lizards, snakes form one of the three main groups of reptiles. The other two groups are crocodilians, and turtles and tortoises. There are around 3,000

344

different snake species in the world, and they are divided into eighteen families. The largest family, Colubridae, includes over 1,500 species. The most obvious feature of a snake is its lack of limbs. However, snakes still manage to move and capture prey with deadly efficiency. Snakes are a successful group of reptiles. They live in almost every habitat on Earth except the polar regions and the ocean depths. They live in forests, grasslands, deserts, freshwater lakes and rivers, and in the oceans. Some spend their lives The garter snake is a common sight in gardens and parks across the United States. Indeed, it is the most widely distributed reptile in North

Fact File in trees, while others live under the ground. Snakes are most abundant in hot, tropical, or subtropical parts of the world. Southeast Asia, Central and South America, and Australia have many snakes. In cool, temperate places snakes are active only during the summer. They pass the cold winter months in the sleeplike state of hibernation. There are no snakes in Antarctica. Snakes have also failed to reach and colonize many remote islands, including New Zealand.

Senses and Feeding Snakes sense the world in a different way to people. Most have poor eyesight and can only see moving objects. Their hearing is also poor, but they can hear some sounds. They can also pick up vibrations passing through the ground. Snakes have a keen sense of smell. The forked tongue of a snake flickers out to collect scent molecules floating in the air. The tongue then touches two tiny pits in the roof of its mouth. Called the Jacobson’s organ, these pits can identify scents. Boas, pit vipers, and pythons have an extra sense—two small pits on their snout that detect the body heat of warm prey. This super-sense allows them to pinpoint the position of prey in total darkness. Depending on the size and species, snakes prey on animals from the size of ants up to antelopes. They use various methods to tackle their prey. Some snakes simply grab the victim in their jaws and swallow it. Snakes called constrictors coil their body around the prey and squeeze it to death. Cobras, colubrids, and vipers use venom to kill their victims.

SNAKES Order: Squamata Suborder: Serpentes Families: 18 families, with 2,900 species: Acrochordidae (file snakes); Aniliidae and Cylindrophiidae (pipe snakes); Anomalepidae (dwarf blind snakes); Anomochilidae (dwarf pipe snakes); Atractaspididae (stiletto snakes); Boidae and Bolyeriidae (boas); Colubridae (typical snakes); Elapidae (cobras); Leptotyphlopidae (thread snakes); Loxocemidae and Xenopeltidae (sunbeam snakes); Pythonidae (pythons); Tropidophiidae (dwarf boas); Typhlopidae (blind snakes); Uropeltidae (shield-tailed snakes); Viperidae (vipers and pit vipers) Where do they live?: Almost every continent apart from Antarctica

Equator

Habitat: Varies, but includes deserts, forest, grasslands, and the open ocean Size: 3 in. (8 cm) to 23 ft. (7 m) Appearance: Legless reptiles with an obvious head and a long, often slender, body and tail. Mostly dull colors with more striking markings Diet: Invertebrates, amphibians, reptiles, birds, and small mammals Breeding: Some snakes lays eggs; others give birth to live young Life span: Not known Status: Varies depending on species

345

SNAKES

Poison glands in their head are linked to two long teeth called fangs, which inject the prey with venom when the snakes strikes. Snakes have flexible jaws. This allows them to open their mouth very wide to swallow large prey.

Moving Along Despite their lack of legs, snakes manage to move about effectively. When moving over the ground, most snakes flex their body to form a series of S-shaped curves. The underside of each

Size, shape, and color Snakes vary in size, shape, and color, and they have different patterns on the body. At just 3 inches in length, blind snakes are some of the smallest snakes. They are so thin that they would fit inside a pencil if the lead was removed. Boas and pythons are the largest snakes and grow to 33 feet. Some snakes, especially those that climb trees, are long and slender. Others, such as burrowing snakes, are squat with a short tail. Still others have bodies that are adapted for swimming in the oceans or tunneling through loose sand.

346

Many snakes are dull and marked with blotches, bands, or stripes. This provides camouflage, helping the snake blend in with its surroundings. A few snakes are brightly colored, with bands of black, white, red, or yellow. These so-called “warning colors” tell potential enemies that the snakes are poisonous. A few non-poisonous snakes have the same colors, which fool their enemies into leaving them alone. One example is the milk snake (below), which has the same coloration as the poisonous coral snake.

SNAKES

curve pushes against the ground. As the snake moves forward, more scales push against the same points on the ground. This produces a smooth, flowing movement. A similar technique is used when swimming. Large, heavy snakes such as boas and pythons move in a straight line like a caterpillar. The snake hooks the edges of its lower scales against uneven ground to pull its body along. When moving through a narrow tunnel, the snake contracts its body into tight loops that press against the tunnel. It then reaches forward with its head and neck, anchors itself, and pulls up the rest of its body. It uses a similar technique to climb trees. Sidewinders use a sideways looping motion to move over loose sand.

OW? DID YOU KN Some snakes have large scales on their snout or that stick out over their eyes. These species are often called horned snakes. Saw-scaled vipers and horned vipers have ridged scales that they can use to produce sound.

4

1

These illustrations show four species of snake: the sand snake (1); the common death adder (2); the

2

southern hognose (3); and the Indian cobra in threat pose (4).

3

347

SNAKES

Breeding and Young The breeding habits of snakes vary according to species. They are also linked to habitat. In the tropics, snakes breed at any time of year. In dry areas, breeding often coincides with the rainy season, when food is plentiful. In temperate (mild) areas, snakes often breed in spring as soon as they emerge from hibernation. The green tree python lives in the humid rain forests of Indonesia, Papua New Guinea, and northern Australia. It spends all its life in the trees, where it hunts small mammals such as rodents.

348

Some snakes reproduce by laying eggs, which they guard until they hatch. In other snake species, the eggs develop inside the female’s body, and she gives birth to live young that resemble miniature versions of the adult snakes.

Skin and Scales Like all reptiles, snakes are covered with scales. The shape, size, and texture of these scales varies on different parts of the body and also according to species. Some species of snakes have ridged scales that help them climb trees or slither over the ground.

SNAKES

Inside snakes

The beauty rat snake is equally at home on the ground or climbing trees. These lithe snakes can reach lengths of up to 8 feet or more.

Snakes shed their skin as they grow. Called sloughing, this allows worn or damaged skin to be replaced and also helps the snake get rid of parasites (animals living on them). Only the outer layer of epidermis (skin) is shed. Even the skin over the eyes is shed. A snake that has shed its skin has particularly bright markings.

OW? DID YOU KN

Like all other reptiles, snakes are vertebrates. This means they have a bony inner skeleton, which includes a skull and backbone. However, the lack of limbs and long, slender shape means that the body of a snake is a bit different than most other reptiles. The vital organs are elongated to fit inside the body. Twin organs such as kidneys are arranged one behind the other, rather than side by side as in most animals. Most snakes have only one working lung. The stomach is a long tube taking up about one third of the body. The intestines are not as coiled up as in most animals.

Heart

Liver

Right lung

Kidney

Small intestine Kidney

Stomach

Some snakes feed on many kinds of different prey. Others specialize in capturing just one type of food, such as birds’ eggs or rodents. Young snakes often feed on different types of prey than the adults. They move on to adult food when they reach a certain size. 349

SPADEFOOT TOAD The spadefoot toads are a small family of burrowing toads that spend most of their lives underground. The rapid life cycle of these amphibians allows them to survive in very dry places such as deserts.

350

frogs and toads

S

padefoot toads are named for the horny, spadelike growths on their hind feet. These act as shovels, allowing them to burrow into the soil. These toads are mostly nocturnal, spending much of the time in burrows and emerging to feed at night.

Surviving Drought There are two groups of spadefoot toads—European and American species. Most live in dry places such as deserts. Their burrowing habits allow them to survive dry periods in tunnels below the surface. In very dry weather, spadefoot toads survive by entering a deep sleep, called estivation, which is similar to hibernation.

Fact File SPADEFOOT TOADS Families: Pelobatidae (Eurasian spadefoot toads) and Scaphiopodidae (American spadefoot toads) Order: Anura Where do they live?: Central and North America, Europe, North Africa, and western Asia

Tropic of Cancer

Race Against Time Spadefoot toads have developed a rapid breeding cycle to survive years of drought. After a sudden downpour, the toads quickly emerge to breed in temporary pools. The eggs and tadpoles develop rapidly. The eggs hatch in just a few days, and the tadpoles transform into adults in just a few weeks. As the pool dries up, the toadlets burrow into the mud to wait for the next rain.

Poisonous Defense Spadefoot toads have a smooth skin and lack the large poison glands of true toads. If handled, they can release a poisonous fluid through their skin, which can give people skin irritations and make them sneeze.

Habitat: Deserts, sand dunes, sandy heathlands, and scrubland Size: Usually no longer than 4 in. (10 cm) Appearance: Compact bodies with large eyes; smooth skin, which is brown or green; spadelike growths on hind feet give these toads their common name Diet: Small invertebrates (animals without backbones) Breeding: Females lay eggs that hatch and develop very quickly Life span: Not known Status: Varies according to species

Spadefoot toads are mostly dull green or brown in color. These colors blend in with their surroundings, which makes it hard for predators to spot them.

351

SPOTTED TURTLE The yellow-spotted river turtle is named for the bright yellow spots on the sides of its head. These South American turtles are becoming rare because people have hunted them for their meat and eggs.

352

TURTLES, TERRAPInS, TORTOISES

T

he yellow-spotted turtle is one of the largest river turtles in South America. Its oval-shaped shell can measure more than 2 feet in length. Apart from the spots on the head, which are brightest in younger individuals, yellow-spotted turtles have dull colors that blend in with their environment. Yellow-spotted turtles live in lakes and slow-moving rivers in northern South America. During the rainy season, when the rivers overflow their banks, the turtles swim into the flooded forest rather than staying in the fast-flowing rivers. They spend most of their time in the water but sometimes come ashore to sunbathe in groups on sandbanks.

Breeding and Enemies Yellow-spotted turtles breed in the dry season. Males and females mate in the water. Later, the female comes ashore at night to lay a clutch of fifteen to forty eggs high on a sandbank, shifting the sand to cover them with her hind feet. The young hatch about two months later. Yellow-spotted turtles and their eggs are at risk from many predators. Tegu lizards and birds such as crested caracaras raid their nests for eggs. People also take the eggs and hunt the adult turtles for their meat. Spotted turtles are now rare, and in many countries it is illegal to hunt them. They are still targeted by poachers, however, because the larger Arrau River turtle—once the favorite prey of poachers—is now almost extinct.

Fact File spOTTeD TUrTLe Podocnemis unifilis Family: Pelomedusidae Order: Testudines Where do they live?: The Amazon River Basin in South America Habitat: Lakes and slow-moving rivers and streams Length: Shell up to 27 in. (69 cm) long Weight: 20 lb. (9 kg) Appearance: Dark brown or black shell is oval in shape; yellow or orange spots on the head fade as these turtles grow older Diet: Water plants, fruits, and snails Breeding: Females lay a clutch of 15–40 eggs, which hatch after 63 days status: Vulnerable

Yellow-spotted turtles feed on water plants such as water hyacinths, and also like fruits that fall into the water. They will also eat snails.

353

SURINAM TOAD The Surinam toad is an odd-looking amphibian with a very flat, rounded body. The breeding habits of this toad are also rather unusual. The female carries her eggs on her back until they hatch into tiny toads.

354

FROGS AnD TOADS

S

urinam toads live in dark, murky streams and swamps in northern South America and on the Caribbean island of Trinidad. They spend their lives in water, where their webbed hind feet make them very strong swimmers. They hunt fish, tadpoles, and other water creatures. The toad uses long, sensitive fingers on its front feet to feel for prey among the debris on the bottom. It can also detect tiny ripples caused by swimming creatures. The toad opens its large mouth to gulp in water and the prey, and uses its long fingers to push the meal into its mouth.

Fact File sUrINAM TOAD Pipa pipa Family: Pipidae Order: Anura

Clawed toad Where do (pipidae) they live?: Northern South America and Trinidad

Equator

Breeding Behavior Surinam toads are famous for their unusual breeding habits. The males call from below the water, producing a loud buzzing sound. A female that is ready to breed develops a pad of spongy material on her back. The male clasps her back legs from behind and above. The pair then turn somersaults in the water. At the top of every loop, the female lays one to three eggs, which the male then fertilizes and positions on her back. They repeat this process until up to 100 eggs are laid. Over the next day, the eggs sink into the spongy flesh on the female’s back until they are almost invisible. Each egg develops in a separate pocket of her flesh. The tadpoles develop inside the eggs and are carried around by the mother until fully developed. Three to five months later, the young toads hatch out.

Habitat: Backwaters, lakes, and dark, murky streams Length: 5–8 in. (13–20 cm) Appearance: Flat body with small, triangular head; large hind limbs have webbed feet; thin front limbs have long fingers; dark-gray mottled upper body, with pale underside Diet: Tadpoles, fish, and other small aquatic creatures Breeding: The female carries between 80 and 100 eggs on her back; eggs hatch after 11–19 weeks status: Common—least concern

The Surinam toad is very flat, with a small, flat head and upward-pointing eyes. The large, powerful hind legs have huge, flipperlike webbed feet.

355

TEGU Tegus are among the world’s largest lizards. They live in the tropical forests of South America, where they tackle prey as large as snakes and small mammals.

356

SnAkES AnD LIzARDS

T

Whiptails & Racerunners Fact File(teiidae)

egus are strong, sturdy lizards with cylindrical bodies, stout limbs, and thick tails. Their bodies are covered with small, shiny scales. There are at least six species. The common, or black-and-white, tegu is the most common species. It is found over a huge area of northern South America.

Predators and Prey Tegus eat a variety of prey, from large insects to small mammals. They also raid farms in local villages to steal chickens’ eggs. They bask in sunlight to warm up and usually hunt in the late afternoon. Tegus themselves are hunted by birds of prey, cats, and snakes. The young are more at risk from predators than the full-sized adults. People also kill tegus for their meat and skin and also because they steal eggs.

Forest Breeders Tegu matings are timed so their eggs hatch in the rainy season when there is plenty of food. Courtship is quite dramatic. The male approaches the female with a stifflegged walk, puffing himself up and snorting. He grabs the female and pins her down for mating. Females lay up to thirty eggs in a burrow, under leaves, or most often in a termite mound, which they tear open with their claws. The termites soon repair the mound, and seal in the eggs. The young tegus hatch and break out of the mound about three months later.

COMMON TeGU Tupinambis teguixin Family: Teiidae Order: Squamata Where do they live?: South America Equator

Equator

Habitat: Clearings in rain forests and near villages Length: Up to 43 in. (109 cm) from head to tail Appearance: Large, powerful lizard with long head and thick tail; body is covered with small, shiny scales; adults are black, white, and yellow; young are bright green Diet: Birds and their eggs, insects, lizards, small mammals, and snakes Breeding: Females lay 7–30 eggs, which hatch after 12 weeks status: Common in suitable habitat

Tegus are widespread in the rain forests of South America. They dig burrows for themselves or take over the burrows of other animals.

357

TERCIOPELO The terciopelo is a member of the viper family. It is one of the most dangerous snakes in Central and South America. Every year, many people die from the bites of these poisonous snakes.

358

SnAkES AnD LIzARDS

T

here are several reasons why terciopelos are so dangerous. First, these snakes commonly live alongside people. They are attracted to towns and villages because they contain abundant rats and mice, on which the terciopelos feed. In the wild, terciopelos live in forests, but their numbers actually increase when the land is cleared for farming. They have long fangs and strike rapidly. Most important, they are highly venomous. Their venom is quick-acting. It attacks the blood cells of their prey, causing death through severe internal bleeding. Terciopelos also have superb camouflage, making them very difficult to spot. With brown or tan colors and pale triangular markings, they blend in perfectly with the leaf litter. This means it is all too easy to step on one without seeing it. Terciopelos are aggressive snakes and do not hesitate to defend themselves. They can strike from a coiled position over long distances. Even a snake that appears to be retreating may suddenly turn on an enemy and strike quickly, injecting large amounts of venom. Together with its relative, the common lancehead, the terciopelo kills hundreds of people every year. In recent years, the number of deaths has dropped as medical care has improved in Central and South America, and also as more people have taken to wearing thick footwear. Even so, in a small country such as Costa Rica, terciopelos still kill about thirty people a year.

Fact File TerCIOpeLO Bothrops asper Family: Viperidae Order: Squamata Where do they live?: Central America to northern South America Habitat: Fields, forest clearings, plantations, riverbanks, and villages Length: 4–8 ft. (1.2–2.5 m) Appearance: Large, stocky snake with triangular head; brown or tan with pale triangular markings Diet: Invertebrates, birds, lizards, and small mammals, especially rodents Breeding: Females give birth to a litter of 18–40 young 6 or 7 months after mating status: Very common

A terciopelo coils up into a defensive position ready to strike out and attack. These snakes are responsible for hundreds of lethal snakebites every year.

359

TERCIOPELO

Distribution and Habitats The terciopelo is a large, stocky snake that grows to 8 feet long. With its triangular-shaped head, it closely resembles its pit viper relative, the common lancehead. People used to think the two snakes were the same species, but they are found in different areas.

Ground dweller In the wild, terciopelos mainly live in lowland forests. In some places, however, such as on the island of Trinidad, they live in the hills. In dry places, they live near water, which brings them into contact with people. They do well on sugarcane and banana plantations where rodents are plentiful. Terciopelos are nocturnal (come out at night). Adults live on the ground, where they hunt rodents. Heat-sensitive pits on their heads allow them to detect prey in the dark.

360

OW? DID YOU KN The terciopelo gets its name from the texture of its scales. Terciopelo is Spanish for “velvet.” The terciopelo’s relative—the common lancehead—is also called the fer-de-lance. It is named for the pointed shape of its head. Fer-de-lance is French for “lancehead.” The common lancehead is also called the yellow-beard because of its pale-colored throat. Another snake called the fer-de-lance lives on the Caribbean island of Martinique.

Snakes and Lizards

The terciopelo lives in Central and South America, from the eastern coast of Mexico south to Venezuela and northern Ecuador. The common lancehead is found farther east and south. Both species inhabit certain Caribbean islands.

Breeding Terciopelos do not reproduce by laying eggs. Like most other vipers, they give birth to live young about six months after mating. The young snakes eat a wider range of prey than the adults, including insects, frogs, and lizards. The tip of the young snake’s tail is pale yellow in color. By moving the tail over the ground, the tip of the tail looks like a crawling insect. This lures prey such as lizards, which are injected with a fatal dose of venom. Young terciopelos often climb into shrubs to hunt prey such as birds. The tail tip darkens as the young snake becomes older. Terciopelos are able to breed when they reach about Â�3 feet long.

The Breeding Season Terciopelos breed at a particular time of year. However, the breeding season varies on either side of the Andes Mountains that run down Central

The female terciopelo is much longer and heavier than the male, with a bigger head, thicker body, and longer fangs.

and South America. Snakes that live east of the Andes Mountains mate in March and give birth in September or November. Snakes that live on the Pacific side of the Andes mate in September or November and give birth the following year, from April to June. In each case, mating is timed so that the young are born in the rainy season, when food is much more plentiful. Females that live along the Atlantic coast produce larger numbers of offspring than their Pacific-coast cousins. On average, the Atlantic-coast females produce more than forty young. Pacific-coast females bear only eighteen young. 361

THORNY DEVIL Thorny devils are desert-dwelling lizards of Australia. The thornlike spines of these creatures are a form of defense against predators and also channel moisture into the mouth. These lizards feed exclusively on ants.

362

SnAkES AnD LIzARDS

T

he deserts of western and central Australia are home to a lizard called the thorny devil. The spines of this unusual lizard deter attackers, but they also have another purpose. Water is almost impossible to find in the dry, sandy areas in which this lizard lives. Grooves between the spines channel the dew, which condenses on the lizard’s body into its mouth. This supplies almost all of its needs for drinking water.

Life in the Burrow Thorny devils live on the ground in underground burrows. They venture out by day to hunt ants. They can lick up twenty-five to forty-five ants per minute and eat 2,500 in a single sitting. Thorny devils move very slowly. They rely on their reddish-brown color to conceal them from predators. They can withstand great heat and are active when most other reptiles are hiding in the shade. Even so, they remain below ground during the hottest months of the southern summer (January and February). They also do not move around much during the coldest months (June and July). For much of the year, thorny devils stay close to their burrows. These lizards are most active in spring and early summer. At this time they roam more widely, probably in search of mates. Little is known about the breeding behavior of thorny devils. However, females are known to lay a single clutch of between three and ten eggs in a deep, cool, south-facing burrow.

Fact File THOrNY DeVIL Moloch horridus Family: Agamidae Order: Squamata Where do they live?: Western and central Australia Habitat: Deserts Length: 6–7 in. (15–18 cm) Appearance: Stocky lizard covered with large, thornlike spines. Color varies from dark red to brown, with paler, wavy-edged stripes Diet: Ants Breeding: Females lay 3–10 eggs in burrows, which hatch after 90– 132 days status: Common in suitable habitat

The thorny devil has thornlike spines all over its body, with larger spikes on its head and back and smaller ones on its legs.

363

TIGER SALAMANDER These large, colorful salamanders are some of North America’s best-known amphibians. There are several varieties with different colors and markings.

364

nEWTS AnD SALAMAnDERS

T

iger salamanders are found over much of central and southern North America. They live in many different habitats, including deserts, forests, meadows, and scrublands, from sea level up to 11,000 feet. In cold places they hibernate in winter. Tiger salamanders live on the ground near water, usually hidden among plant debris. They are nocturnal, emerging at night to hunt earthworms, insects, small amphibians, and mice. In dry weather, they may travel to pools that are drying up to prey on tadpoles and insect larvae.

Life Cycle The breeding habits of the tiger salamander depends on where they live. Most breed in early spring soon after they emerge from hibernation. They mate in water, usually after rain. The female lays a mass of about fifty eggs that stick to underwater plants. Some females produce more than 5,000 eggs in a single season. The larvae grow up in the water, hunting small aquatic creatures. Some large larvae feed on tadpoles and even on larvae of their own kind. In warm, lowland pools the larvae usually change into adults in two to three months. In deserts, they mature before their pool dries up, usually in five to six weeks. In mountains, the larvae often pass the winter and become adults in the spring. Some larvae never mature into land-living adults but remain in pools. They can breed but keep the appearance of larvae.

Fact File TIGer sALAMANDer Ambystoma tigrinum Family: Ambystomatidae Order: Caudata Where do they live?: North America, including southern Canada and central Mexico Habitat: Deserts, forests, meadows, mountains, and scrublands Length: 7–14 in. (18–35 cm) Appearance: Large, stocky animal with broad head, short limbs, and a thick tail. Color varies from black or gray to dark brown, with yellow or cream markings Diet: Invertebrates, mice, tadpoles; some eat other salamanders Breeding: Internal fertilization; females lay clumps of 50 eggs, which hatch after 20–50 days; larvae grow up in water status: Generally common, but some types are rare

Tiger salamanders have stout, cylindrical bodies with large heads and thick tails. There are at least six subspecies, which vary in color.

365

TOKAY GECKO This large, colorful lizard is named for its loud, barking “toe-kay” call. It lives in the forests of Southeast Asia but sometimes wanders into people’s homes.

366

SnAkES AnD LIzARDS

T

he tokay gecko is common throughout much of Southeast Asia. It lives in forests, where its large toe pads and ridged soles help it to climb trees. Tokay geckos are also common in towns and villages, where almost every building has its own gecko. People think that these lizards bring good luck. They certainly help to reduce pests, as they feed on insects and mice. Tokay geckos are active at night. They spend the day hidden in cracks or under loose bark and emerge at night to feed. Creatures of habit, they emerge at the same time every night and move to a regular hunting position. They often lie in wait near spotlights to catch moths and other insects that are attracted to the light. Tokay geckos are large lizards and have few enemies, but they may fall victim to some snakes. If attacked, they will put up a fight. They may even shed their tail to escape (the tail grows back again in three weeks.) They can deliver a painful bite and are hard to shake off once they have siezed something with their jaws.

Breeding Male tokays have larger heads than the females. They are territorial and mate with several females who share their “patch.” In most areas, tokays breed at any time of year. After mating, females lay two round, hardshelled eggs under bark. Several females lay their eggs in the same place. The eggs hatch out in anything from sixty to two hundred days.

Fact File TOKAY GeCKO Gekko gecko Family: Gekkonidae Order: Squamata Where do they live?: Southeast Asia Habitat: Forests, plantations, and buildings in towns and villages Length: 8–14 in. (20–36 cm) Appearance: Large, heavy-bodied gecko, with big head and large orange or yellow eyes; feet have wide toe pads; skin is bluish grey with pale or rust-colored spot; young are more boldly marked than the adults, with dark gray skin covered with large white spots and black-andwhite striped tails Diet: Insects, lizards, small birds, and rodents such as mice Breeding: Females lay two (rarely three) hard-shelled eggs, which hatch after about 100 days status: Common

Experts think that the distinctive call of the tokay gecko helps neighboring reptiles to keep their distance so they do not compete for food.

367

TOMATO FROG The tomato frog lives on the island of Madagascar. The attractive markings and bright colors of this amphibian have made it popular among collectors, and it is now rare in the wild.

368

FROGS AnD TOADS

T

he tomato frog has an effective defense if its bright tomato color does not deter predators. When handled, the frog puffs itself up and releases a white slime from its skin. The slime may be poisonous or unpleasant-tasting to predators, and it gives people a skin rash. Tomato frogs belong to a family called the Microhylidae. About sixty species live on the island of Madagascar. They have varied habits, with some species living in trees and others in burrows.

Range and Habits The natural habitat of the tomato frog is forest clearings in northeastern Madagascar. It also lives in the towns and villages that have developed there. Tomato frogs live on the ground and sleep in burrows. They are mostly active at night but may be seen around dawn and dusk, snapping up crickets and worms at the burrow entrance.

Breeding Behavior Tomato frogs breed in pools, swamps, and water-filled ditches. After mating, females lay more than 1,000 eggs, which float on the surface. The tadpoles have flattened bodies. They filter food from the water using the mouth located at the very front of the head. Within about forty-five days they metamorphose (transform) into froglets. The young frogs lack the bright colors of the adults, being dull yellow with darker flanks.

Fact File TOMATO FrOG Dyscophus antongilii Family: Microhylidae Order: Anura Where do they live?: Madagascar Habitat: Forest clearings and wooded scrubland; gardens and plantations; larvae live in pools Length: Males to 2.5 in. (6 cm); females to 4 in. (10 cm) Appearance: Large red frog with narrow head and large eyes; skin smooth apart from a ridge running down each flank; flanks and hind limbs may have small, dark flecks Breeding: Females lay more than 1,000 eggs in pools and ditches; tadpoles gradually change into the adult frogs over 45 days Lifespan: Wild frogs live for 6–8 years; longer in captivity status: Near threatened

Tomato frogs have large, prominent eyes. They are named for their tomato-red color, which acts as a warning signal to put off predators.

369

TORTOISES Tortoises are land-dwelling reptiles. The main feature of these slow-moving creatures is their shells, which provide protection against predators. They are very easy to care for, so they are commonly kept as pets.

T

ortoises and turtles make up the order (major group) called Chelonia, or shelled reptiles. Tortoises live exclusively on land, while turtles and terrapins spend part or all of their lives in fresh or salt water. There are around 240 different chelonians, but only thirty-eight species belong to the tortoise family.

Shape and Size The most obvious feature of all the chelonians is their shells. The shell is made up of a bony inner layer and a horny outer layer. The horny layer consists of plates called scutes. The upper shell is called the carapace, and the lower shell is called the plastron. The shell is the tortoise’s main defense against predators. When danger threatens, the tortoise withdraws its head and legs into its shell so that the whole body is protected. The disadvantage of the shell is that it makes the tortoise ungainly and slow-moving. Various tortoise species have shells of different shapes. Most shells have a fairly smooth surface, while a few are knobbly. In most species, the shell is domed, but the pancake tortoise has a flat shell. 370

The legs of the tortoise are strong and sturdy and support the weight of the shell. The head is small and sits at the end of a long, flexible neck. Most tortoises are brown, yellow, or olive-green, often with patterns on their scaly skin and shells. The colors and patterns camouflage the tortoise, helping it to blend in with its surroundings. Tortoises vary in size. The world’s largest tortoise is the giant tortoise of the islands of Aldabra in the Indian Ocean. The carapace of these huge reptiles can measure up to 4.5 feet long and can A leopard tortoise (top), Galápagos giant tortoise (middle), and two mating gopher tortoises (bottom).

Fact File weigh up to 550 pounds. At the other end of the scale, the speckled Cape tortoise is the world’s smallest tortoise at just 2.5 inches in length.

Tortoises Family: Testudinidae Order: Testudines (Chelonia) Tortoise (testudinidae)

Lifestyle Tortoises live exclusively on land, but they often wallow in muddy pools to cool off in very hot weather. Most tortoises live in the warm, humid tropics. Those that live in the cooler temperate regions pass the cold winter months in a deep sleep called hibernation. Tortoises can be found in a variety of habitats, including forests and grasslands, but many live in deserts and dry scrubland. Desert tortoises can survive on very little water. Many species spend the hottest and driest months in a summer sleep, similar to hibernation, called estivation. Tortoises mainly eat plants, but some species also eat slow-moving creatures such as caterpillars, snails, and worms. They find their food using sight and smell.

Where do they live?: Africa, Asia, Europe, and the Americas Habitat: Varies from deserts and scrublands to grasslands and forests

Equator

Equator

Length: Carapace measures 2.5 in. (6 cm)– 4.5 ft. (1.4 m) long Appearance: Shelled reptiles with sturdy legs, small head, and long neck; color varies from brown and black to yellow or green, with darker or paler streaks or rings on the upper shell Diet: Plants; some species eat slow-moving animals such as insects and worms Breeding: Females lay 1–50 eggs in a pit dug in the earth; eggs hatch after 2–15 months Status: Varies from common to rare Lifespan: Some species have been known to live for more than 100 years

The desert tortoise lives in burrows in order to escape the heat of the Mojave and Sonoran deserts, in the United States.

Tough plant food is torn off and ground up in the tortoise’s horny, beaklike mouth. Tortoises reproduce by laying eggs. Some species produce several clutches in one year. During the mating season, the males fight for the right to mate with the females. The males charge and ram one another as each one tries to flip his rival onto his back. The defeated male will be helpless until he can right himself. 371

TORTOISES

After mating, the females lay their hard-shelled or leathery eggs in a hollow in the ground, which they dig with their powerful feet. The females then refill the hole to hide the eggs from predators. The eggs hatch after two to fifteen months, and the hatchlings dig their way out.

Where Do Tortoises Live? Tortoises are a widespread group of reptiles. Many species live in Africa, but they are also found in Asia, Europe, and the Americas. Africa is home to the greatest number of tortoise species. The largest African species is the spurred tortoise, which measures up to 30 inches long. It lives on the edges of the Sahara

Long-lived reptiles Tortoises are some of the world’s most long-lived animals. Scientists know about their long life from individuals kept as pets. Mediterranean spurthighed tortoises are known to live for up to 160 years. In 1776, a giant tortoise from Aldabra was moved to a nearby island. It survived for 142 years but was fatally injured in an accident in 1918. The tortoise was a large adult when it was moved, so it must have been nearly 200 years old when it died.

372

OW? DID YOU KN The pancake tortoise of East Africa has a flat body, which allows it to retreat into rocky crevices and hide from predators. It wedges its shell behind a rock and becomes almost impossible to dislodge. The plowshare tortoise of Madagascar has a large prong on the front of its shell. The males use these prongs in the mating process.

Desert and survives drought by hiding in its burrow. The tiny speckled Cape tortoise lives in rocky places in southern Africa. The island of Madagascar off the east coast of Africa holds four species that are now rare because of hunting and habitat loss. Species there

TORTOISES

include the attractive radiated tortoise, which has starlike patterns on its shell. Spur-thighed tortoises are found in Africa and southern Europe. They are named for the distinctive spurs (horny spines) on their hind limbs. The biggest European tortoise is called the marginated tortoise and lives in Greece. This tortoise measures up to 1 foot in length.

Pinta

Fernandina

San Salvador Santa Cruz

Isabela

Santa Maria Española

San Cristobal

Asian and American Tortoises Seven species of tortoises live in Asia. They include the attractive star tortoise, with a shell pattern similar to the radiated tortoise. Elongated tortoises have an unusual, ovalshaped shell. The Burmese brown tortoise is the largest Asian species. The shell of this tortoise measures up to 18 inches in length. New World tortoises include four species of gopher tortoises, which live in North America. Gopher tortoises make their homes in burrows. In South America, the Amazon River Basin is home to two forest species called the redfooted and yellow-footed tortoise. Both feed on a variety of plant material, including leaves and fruits. The yellow-footed tortoise is the larger of the two species, with a shell measuring up to 29 inches in length. The most southerly tortoise in the Americas is the Chaco tortoise of Chile and Argentina. This tortoise retreats to its burrow to hibernate (sleep) over the winter. The Galápagos Islands off the coast of Ecuador are home to ten subspecies of giant tortoises. Each one measures up to 4 feet long.

The “domed” and “saddleback” shells of the giant tortoises of the Galápagos Islands have evolved to suit the conditions on each island.

The Most Northerly Tortoise Horsfield’s tortoise is found the farthest north of any tortoise, living on the plains of Kazakhstan in central Asia. This tortoise spends much of its life asleep. It survives the long, dry winter in hibernation. In spring, it emerges to feed and breed, before retreating to its burrow again in July to survive the summer drought.

OW? DID YOU KN Hinged tortoises of Africa live in forests, grasslands, and semideserts. The rear end of the shells of these tortoises are hinged. They flap down to provide extra protection against predators. The Burmese brown tortoise is unusual because it provides some parental care. The female guards her nest for a few days after she has laid her eggs.

373

TREEFROGS Treefrogs are a large family of frogs. As their name suggests, treefrogs live mostly in the treetops. Sticky pads on their toes help them to clamber among the branches.

374

FROGS AnD TOADS

W

ith more than 830 species, the treefrog family (Hylidae) comprises about one-fifth of all the frog species. Treefrogs live on every continent apart from Antarctica. Many treefrogs are native to the Americas, while just one species is found in Africa. Most treefrogs live in tropical rain forests. Some prefer cooler, drier habitats, such as the Australian “outback.” Most of the tropical treefrogs are nocturnal, which means they emerge at night. This helps them retain moisture. They spend the day hunched up with their legs tucked beneath them—a position that minimizes water loss. Some Australian treefrogs live in very dry places. These so-called water-holding frogs survive periods of drought by burrowing underground and shedding their outer layers of skin to form a watertight cocoon around their bodies.

Treefrog Types The treefrog family is divided into four subgroups. Each one is distinguished by physical features and different lifestyles. The largest group is the typical treefrogs from northwestern Africa, Asia, Europe, and the Americas. These frogs have horizontal pupils and live in trees. The group also includes cricket frogs and chorus frogs, which live by lakes and pools, and four species of Mexican burrowing frogs. The second group in the treefrog family is called the casque-headed frogs of Central and South America. The pine barrens treefrog lives in the swamps and

Fact File TreeFrOGs The treefrog family (Hylidae) has around 835 species divided into four subfamilies: Hemiphractinae (casque-headed frogs and marsupial frogs), Hylinae (chorus frogs, cricket frogs, and other treefrogs), Pelodryadinae (Australian treefrogs), and Phyllomedusinae (leaf frogs) Order: Anura Where do they live?: Every continent except Antarctica

True tree frog (hylidae)

Equator

Equator

Habitat: Tropical forests; some live in temperate and dry regions Length: 0.75–5.5 in. (2–14 cm) Appearance: Small, slender frogs; color ranges from gray and green to brown; toes have rounded, sticky tips Diet: Tadpoles eat plants; adults eat insects, spiders, slugs, and worms Breeding: Females of most species lay their eggs in pools, streams, and ditches; some carry their eggs on their backs status: Mostly common; some species are rare

bogs of the southern United States. These frogs are facing extinction due to the loss of their habitat.

375

TREEFROGS

DID YOU KNOW?

Breeding Time

They have bony skulls like helmets and eyes with horizontal pupils. The third group is the Australian Two species of American treefrogs. This group contains about treefrog look 135 species that live in Australia and so similar that scientists can only on islands of the South Pacific. They tell them apart have horizontal pupils. Some live on by their different the ground, including water-holding calls. frogs of Australian deserts. Gladiator frogs of Central and South The fourth group is the leaf frogs America lay their from Central and South America. eggs in basinshaped nests These frogs are large, tree-dwelling at the edges species with vertical pupils. The leaf of streams. The male stays nearby frog group also includes the striking to guard the eggs and distinctive red-eyed leaf frog, and tadpoles. which is often featured in natural history television programs.

Treefrogs that live in tropical rain forests usually breed at any time of year. Desert-dwelling frogs breed after the rainy season, while the frogs of the cooler temperate regions breed in the spring. The males form territories and call to attract the females. Each species has a slightly different call. When they mate, the male clasps the female just behind her armpits. Most species lay their eggs in quiet pools, slow-moving streams, and water-filled ditches. A few lay in fast-flowing water, and some use the tiny pools that form by waterfilled tree-holes or cup-shaped plants called bromeliads.

2

1

4 1 Casque-headed frog 2. Common European treefrog 3. Riobamba marsupial frog 4. American green treefrog 376

3

Frogs and Toads

Size, shape, and color Treefrogs are well-suited to a life in the trees. The most obvious feature is the sticky pad at the end of each toe. Each pad acts like a suction cup to grip onto rough bark or smooth leaves. Treefrogs move slowly, but they leap to escape from their predators. Most are slender, with lightweight bodies suited to climbing. Larger species have huge toepads. Most treefrogs are green or brown to blend in with the foliage. Some have bright marks that break up their outline and make it hard for predators to spot them. Some have bright spots on their thighs that appear as they leap and then disappear again, which confuses predators. Some treefrogs change color to match their surroundings or to give off signals.

The tadpoles of most treefrogs grow up in water and feed on water plants. Leaf frogs lay their eggs on the leaves that overhang pools. Their tadpoles drop into the water when they hatch. Casque-headed treefrogs carry their eggs on their backs, sometimes in pouches. The young may be released as mature tadpoles or as tiny frogs.

Temperate Treefrogs

The red-eyed

Treefrogs from temperate regions survive the cold winter months by hibernating. Their bodies contain a natural antifreeze that allows them to survive subzero temperatures. The spring peeper lives as far north as southeastern Canada. This frog is named for its peeping call, which announces the arrival of spring.

leaf frog is one of the most familiar members of the treefrog family.

377

TUATARA Tuataras are the sole-surviving members of an ancient group of reptiles that thrived more than 200 million years ago. Today, tuataras live only on a few small islands off New Zealand.

378

TUATARAS

T

uataras look like lizards, but they are the only survivors of a completely different group of reptiles called the beak-heads. The ancestors of tuataras lived on Earth around 220 million years ago. Fossils show they once thrived in Africa, Europe, and South America but had died out everywhere—except on New Zealand—by sixty million years ago. When people called Maoris landed on New Zealand around 1,000 years ago, they brought animals such as rats with them. Tuataras on the mainland died, but they survived on about thirty small offshore islands.

Fact File TUATArA Sphenodon punctatus Family: Sphenodontidae Order: Rhynchocephalia Where do they live?: Small islands off New Zealand Tuatara

What Makes Them Different? Unlike other reptiles, tuataras have two rows of teeth in their upper jaw, which mesh with a single row in the lower jaw. This helps them to grind up tough food. Tuatara hatchlings have a primitive third eye on top of their head that may be sensitive to light. Unlike most lizards, tuataras have no external openings to their ears.

Feeding and Breeding Tuataras live in wooded areas of their island habitat. They stay in burrows by day and emerge at night to feed on invertebrates, lizards, and young birds. Tuataras breed in summer, and the males raise their crests to attract the females. After mating, the eggs start to develop inside the female, but are not laid until the following spring. Females lay eggs every two to five years.

Habitat: Coastal forests, usually near the burrows of seabirds Length: 20–31 in. (50–80 cm) Appearance: Large head, squat legs, long tail, and spiny crest on head and back; color ranges from green and gray to black with speckled markings Diet: Insects, frogs, lizards, and the occasional birds’ egg and chick Breeding: Females lay 6–15 eggs, which hatch after 11–15 months status: Lower risk—least concern

“Tuatara” is a Maori word meaning “peaks on the back.” The name refers to the spiny ridge that runs along the reptile’s head, back, and tail.

379

TURTLES Turtles are a major group (order) of reptiles that includes terrapins and tortoises. All the members of this group have a shell that provides protection against predators. Various species live in freshwater, saltwater, or on the land.

1

R

eptiles with shells belong to the order Chelonia, or Testudines. Members of this group include the tortoises, turtles, and terrapins. In Britain, the word “turtle” is used only for species that live in the oceans. In North America, the word “turtle” refers to any

1 Leatherback turtle

3. Loggerhead turtle

2. Hawksbill turtle

4. Green turtle

2

3 4

380

Fact File species that lives in water. “Turtle” also refers to the entire group of shelled reptiles. In Britain, freshwater turtles are often called terrapins.

Turtles

Body Basics

Habitat: On land; freshwater and saltwater

The most recognizable feature of these reptiles is their shell. It is is made up of an upper section, called the carapace, and a lower section, called the plastron. The outer layer is made up of horny, fused plates called scutes. The hard shell protects the turtle from predators and the weather. All turtles can draw their heads, limbs, and tails inside their shells. Turtles pull their heads inside their shells in one of two ways. Members of the largest group of hidden-necked turtles pull their heads and necks back vertically to form a tight S-shape. This group includes tortoises. Side-necked turtles pull their head to one side. This group includes snake-necked turtles, some of which have a very long neck. There are about 240 species of shelled reptiles, divided into twelve families. The largest family are the freshwater turtles, with eighty-six species. The thirty-eight species of land-living tortoises have sturdy legs to support their heavy weight. There are twenty-six species of softshell turtles with flexible, leathery shells. Marine turtles include six species of sea turtles and the leatherback turtle.

Lifestyle Turtles vary in their feeding habits. Tortoises and many freshwater turtles (terrapins) usually eat plants. Most marine and some freshwater

Order: Testudines (Chelonia) Where do they live?: Worldwide except the polar regions

Length: Carapace measures 2.5 in. (6 cm) to 6.5 ft. (2 m) long Weight: 5 oz. (140 g) to 2,000 lb. (900 kg) Appearance: Shelled reptiles with small heads, long necks, and powerful limbs; color ranges from yellow and olive-green to brown and black, with dark or pale markings Diet: Varies according to species, including plants and invertebrates Breeding: Females lay between 1 and 100 or more eggs in hollow dug in earth or sand; eggs hatch after 2–15 months Status: Some species are common; some are rare Lifespan: Some live for 100 years or more

turtles eat other animals. Sea turtles prey on creatures such as jellyfish. Lacking teeth, all turtles use their sharp, beaklike jaws to slice through their food. Most turtles rely on their sense of smell to find food and also to locate mates. Scents are identified with the help of the Jacobson’s organ in the roof of the mouth, which sends signals to the brain. Turtles can pick up scents underwater. They see well, and have color vision. Hearing is less important, which may explain why turtles make little noise.

381

TURTLES

Many turtles have small, fleshy tentacles, called barbels, on their chin, which are used to find food. Barbels are touch-sensitive, allowing the turtle to probe for food as it swims along the bottom or in murky water. All turtles reproduce by laying eggs on land. Marine turtles migrate long distances across entire oceans to reach the beaches where their species breeds. Clutch sizes vary according to species. Some lay a single egg, while others lay

382

more than 100 eggs. After mating, the female digs a pit in the soft earth or sand with her hind limbs. She lays her eggs in the pit and then refills it. Eventually, the young turtles break out of their shells and dig their way to the surface.

The red-eared slider terrapin lives around the the Mississippi River south to the Gulf of Mexico.

TURTLES

Body parts The skeleton of a turtle is quite unlike that of any other animal. Turtles have long, mobile necks to support their small heads. The short tail is also mobile, but the backbone and ribs are fused to the bottom of the carapace. This means the ribs do not help with breathing. Instead turtles have special leg muscles that help to draw air into the lungs and expel waste air. Lacking the gills of fish, aquatic turtles have to surface to breathe air. However, some turtles have special organs in their throat, which extract oxygen from water. Others have long nostrils that act as snorkels. Land tortoises have stout, pillarlike legs. Aquatic species have webbed feet or limbs shaped like flippers (see right).

The First Turtles The ancestors of modern turtles appeared on Earth about 280 million years ago. Very early species had flexible shells. By about 200 million years ago, turtles had developed hard shells. These early turtles lived in water and looked a lot like modern species, but they had teeth. Over time, the turtles lost their teeth and developed beaklike mouths. Around 90 million years ago, the largest chelonian ever known, called Archelon, roamed the seas. With a

The legs are scaly and the feet are clawed. Tortoises have short claws that become blunt as they walk, while aquatic turtles have longer claws.

shell measuring at least 12 feet long, Archelon was a third longer than the largest living species, the leatherback turtle.

OW? DID YOU KN Snapping turtles lie in wait for their prey on the beds of shallow lakes and rivers. They snap up prey with their strong jaws. Leatherback turtles make the longest migration of any turtle, from their feeding grounds to the remote beaches on which they breed. They have been known to migrate over 12,000 miles. 383

VIPERS Vipers make up a large family of snakes. The best-known are the rattlesnakes from the Americas. Every year, hundreds of people die from the bites of these venomous snakes. Vipers such as this adder have raised scales that look like horns. They break up the outline of the snake’s head, making it harder for predators to see.

384

A

ll vipers are extremely poisonous. They use their venom to kill prey and defend themselves from attack. The long, hollow fangs that inject the venom are located on a hinged bone in the upper jaw. When not in use, the fangs fold back against the roof of the mouth and are covered by a fleshy sheath. As the snake strikes, the fangs swing forward to stab the prey and inject the lethal poison. Vipers are lithe, thick-bodied snakes with short, thin tails. Poison glands on either side of the jaw make

Fact File the head wide. Vipers vary in size from just 11 inches to more than 6 feet in length.

Vipers Family: Viperidae Order: Squamata (suborder Serpentes)

The Viper Family Vipers are found nearly all over the planet. They survive in many different habitats and can be found farther north and south than any other snakes. The adder is the most northerly species, while the Patagonian lancehead is the most southerly. Vipers also live at higher altitudes than any other snakes—up to 16,000 feet in the case of the Himalayan pit viper. Various viper species live in Africa, Asia, Europe, and the Americas. Vipers are notably absent from Australia and the island of Madagascar. The viper family contains about 250 species, making up about one-twelfth of all snakes. The family is divided into two main groups: “true” vipers and pit vipers. There are also six species of night adders and the Fea’s viper, which is an unusual snake from the remote Himalayas. Night adders live in Africa and specialize in hunting toads. Like Fea’s viper, they have smooth scales on their bodies and large scales on their heads.

Pit Vipers Two-thirds of all vipers are pit vipers. Members of this group are found in Asia, eastern Europe, and the Americas. Pit vipers are named for the heat-sensing pits on their heads. These are used to detect the body heat of prey such as birds and mammals. The ability to detect heat allows the snake to hunt in total darkness. Many pit vipers are night hunters. They live in various

Viper (viperidae)

Where do they live?: Africa, Asia, Europe, and the Americas Habitat: Varied, including Equator desert, forests, grasslands, mountains, scrub, and swamps

Equator

Length: 11 in. (28 cm) to 6.3 feet (2 m) long Appearance: Thick, muscular bodies with small tails and wide heads; venomous fangs; color ranges from brown to green, with pale or dark camouflage markings Diet: Insects and other invertebrates, frogs, lizards, birds and their eggs Breeding: Females of some species lay eggs; most carry their eggs inside the body and then give birth to live young Status: Some species are common; others are rare

habitats, including deserts, forests, and swamps. Pit vipers include the familiar rattlesnakes, which are named for the “rattle” of loose scales on their tails. Rattlesnakes shake their rattles to warn away intruders, such as cattle, that might tread on them. There are about thirty species of rattlesnakes, and they live in the Americas. Pit vipers feed mainly on warm-blooded prey. They track down this prey using their heatsensing pits. Rattlesnakes eat a wide range

385

VIPERS

of prey, including insects, fish, frogs, young alligators, hares, and ground squirrels.

Coping with the Cold Vipers that live in cold places spend the winter months in hibernation. They emerge in the spring and warm their bodies by basking in the sunlight. Their dark skin quickly absorbs heat. Vipers are usually well-camouflaged and can risk basking in the open. These snakes are

386

OW? DID YOU KN Some pit vipers are able to detect tiny temperature differences of just 0.001°C, This allows them to pinpoint their prey in pitch darkness. South American pit vipers are called cuatro narices, which is the Spanish for “four-nostrils.” They take this name for the heat-sensing pits near their nostrils.

The viper’s heat-sensing pits are found on either side of the head, between the eye and the nostrils.

VIPERS

True vipers About one-third of vipers are Old World adders or “true” vipers. They are found throughout Africa, Asia, and Europe. True vipers are short and stocky, with wide, triangular or pear-shaped heads. They have “keeled” or ridged scales. True vipers live in various habitats, including deserts, forests, mountains, and scrub. Many species are very well camouflaged. Species such as the Gaboon viper (see right) of Africa have brown, yellow, and black markings to conceal the snake in the forest leaf litter. Some tree-dwelling vipers are green to blend in with their surroundings. Many adders have raised scales that look like horns on their heads, either over the eyes or on the snout. These ridges help to protect the eyes or nostrils from sand and dust and also break

also stocky, which helps to retain body heat. Female vipers that live in cold places carry their developing eggs inside them and give birth to

up the outline of the snake’s head so that it is hard to spot. Saw-scaled and carpet vipers can produce a rasping sound by rubbing their keeled scales together. They do this to frighten away intruders. Old World adders and vipers eat a variety of different prey, including birds, lizards, and small mammals such as rodents. In most species, females carry the eggs inside their bodies, and the young hatch as live snakes. A few reproduce by laying eggs.

live young. They can regulate the temperature of the young by basking. Some species also feed their young using their own blood.

387

VIVIPAROUS LIZARD The viviparous lizard lives farther north than any other lizard. It can even be found within the Arctic Circle. It has unusual breeding habits, giving birth to live young instead of laying eggs.

388

SnAkES AnD LIzARDS

T

he viviparous lizard belongs to a large family of lizards called the Lacertidae. This slender, longtailed lizard lives throughout Europe and central Asia from Britain eastward to Japan. Within this vast area, viviparous lizards thrive in many different habitats, including bogs, coastal regions, ditches, meadows, moors, and mountains up to 8,200 feet. Viviparous means “bearing live young,” and this helps these lizards survive in cold, northerly climates. Viviparous lizards pass the cold winter months in hibernation. In the northernmost part of their range, they may spend up to eight months of the year asleep.

Feeding and Breeding Viviparous lizards feed mainly on invertebrates. In turn, they are eaten by birds, larger lizards, small snakes, and mammals such as weasels. Their main form of defense is escape, and can shed their tail in an attempt to do so. Viviparous lizards live in colonies centered on a good basking area. Mating takes place soon after the lizards emerge from hibernation. Unlike all other lacertids, female viviparous lizards give birth to live young. Up to eleven young develop inside the female. As the mother basks in the sun, she warms the young inside her. This helps them to develop quickly. In a few places, however, viviparous lizards lay eggs, which hatch in four to five weeks.Young are born inside a transparent membrane (skin) from which they emerge within minutes.

Fact File VIVIpArOUs LIZArD Zootoca vivipara Family: Lacertidae Order: Squamata Where do they live?: Most of Europe eastward across Asia to Japan Habitat: Cliffs, ditches, dunes, hedges, marshes, and moors Length: 6 in. (15 cm) Appearance: Small lizard with short legs and long tail; color ranges from olive to gray, with white, yellow or orange belly; females have a single dark stripe running down the back; males are much darker Diet: Insects and their larvae, and spiders Breeding: Most females give birth to 3–11 live young after a gestation period of 8–13 weeks; some lay eggs Lifespan: Up to 12 years status: Common in suitable habitat

The color of the viviparous lizard varies according to the place in which it lives. Most are brown, but these lizards can also be gray, olive, and black.

389

WALL LIZARDS Wall lizards get their common name for their habit of basking on walls in the sunshine. Also known as the lacertids, some species in this large family can be found in remote deserts, while others live alongside people in towns and villages.

390

SnAkES AnD LIzARDS

T

he family of lizards called the Lacertidae are known by many common names, including the wall lizards, sand lizards, and Old World lizards. There are about 280 species in the group. They live in Africa, Europe, and right across Asia, from the Middle East to Japan. These reptiles are mostly medium-sized, slender lizards with long legs and a long tail. The scales on their backs are small and beadlike, while the scales that cover the head and underside are much larger. Many lacertids are well-camouflaged with dull browns and grays. Others are brightly colored, especially the males during the breeding season. Some species from the islands of the Mediterranean Sea are a brilliant shade of green or blue and are striking to look at.

Fact File WALL LIZArDs Family: Lacertidae, 279 species in 26 genera Order: Squamata Where do they live?: Africa, Wall & Sand lizards (lacertidae) Europe, and Asia

Equator

Equator

Habitat: Varied, including forests, grasslands, mountains, deserts, towns, and villages

Feeding Habits

Length: 4–32 in. (10–80 cm)

Wall lizards feed mostly on invertebrates such as insects, slugs, and spiders. Some species vary their diet throughout the year as different insects become more and less available. For example, they may switch from beetles to ants or mayflies when these insects hatch in the summer. Some wall lizards eat plants as well as insects. Island species feed almost entirely on fruit, flowers, and pollen. Others are brave enough to steal scraps of food from predators. For example, some wall lizards live near seabird colonies and scavenge the scraps of fish dropped by the birds. The brave Lilford’s wall lizard even steals the scraps from falcons’ nests.

Appearance: Slender, long-tailed lizards with small scales on the back and larger scales on the head and belly; many species are camouflaged in shades of brown, black, green, or yellow; other species are bright green or blue

The common wall lizard is a small, slender reptile that lives throughout Europe and has also been

Diet: Earthworms, insects, slugs, spiders, and other invertebrates; some species eat small lizards; others eat plants Breeding: Females of most species lay 4–20 soft-shelled eggs, which hatch in 30–45 days. The viviparous lizard gives birth to live young; five species reproduce without mating status: Varies from common to scarce

introduced to North America.

391

WALL LIZARDS

DID YOU KNOW?

The Ibiza wall lizard lives in the shrublands of rural Spain.

The African bluetailed tree lizard leaps from tree to tree using its flattened tail to slow its fall like a parachute. Asian grass lizards have incredibly long tails—up to four times as long as their bodies. The alpine meadow lizard of East Africa lives at a greater altitude (height) than any other African lizard—up to 14,750 feet on the mountain peaks of Kenya.

392

Life Cycle Most wall lizards breed in the spring, but some tropical species breed at any time of the year. Males become more brightly colored during the mating season. They also form a territory, in which each male defends a “patch” of land that contains several females. The male uses scent to mark the borders of his territory. Then he takes up an aggressive stance to warn away his rivals. He lifts his head and puffs his throat as an threatening display. These visual signals usually work, but if not a fight will break out. Tails are often broken as each male tries to bite the other. Finally, the loser is chased away.

Almost all wall lizards reproduce by laying eggs. Females lay clutches of between four and twenty soft-shelled eggs in short burrows. The eggs hatch within forty-five days. The viviparous lizard is an exception. In this species, the female carries the eggs inside her body and gives birth to living young. Indeed, the word viviparous means live-bearing. Females from a few species from the Caucasus region of Eurasia can produce offspring without mating. This highly unusual method of reproduction is called parthenogenesis. This practice was first discovered in lacertids. Several other lizard species are also known to reproduce in this way.

Escaping Danger Many predators feed on wall lizards, including birds, larger lizards, and snakes. Wall lizards rely mostly on speed and agility to escape from predators. If seized, they can shed their tail, which continues to wriggle as a distraction while the lizard escapes. The lizard does not lose its tail for good—it simply grows back again about three weeks later.

Snakes and Lizards

adapt to the habitat Wall lizards are found in many parts of Africa, Asia, and Europe, from tropical rain forests and arid deserts, through temperate grasslands, to the cold tundra far north of the Arctic Circle in the case of the viviparous lizard. Many unique species live on islands, for example, in the Mediterranean and on the Canary islands west of Africa. Many wall lizards, such as the Balkan wall lizard below, can be seen basking on walls in towns and villages to warm up. Some species never stray far from people, while others prefer to hide in the dense vegetation of the rain forest or beneath the scorching desert sand. Desert-dwelling wall lizards include the

sand-swimmers of the Namib Desert in southwestern Africa. Some desert species have fringed scales on their toes that allow them to run over sand. They dive into loose sand to escape predators and avoid the strong heat of the midday Sun. Forestdwelling wall lizards have features that help them to climb trees. For example, the African blue-tailed tree lizard has rough scales under its tail that grip the tree bark. Several African keel-bellied lizards can grip twigs with their tail, which acts as a fifth limb. Asian grass lizards are also strong climbers, and can climb tall grass stems. They can wriggle their whole body to “swim” through the grass at speed.

393

WATER FROGS Water frogs are one of the largest families of frogs and toads. Found in most parts of the world, the family includes familiar species including the common European frog and the North American bullfrog.

394

FROGS AnD TOADS

W

ater frogs belong to a large family called the Ranidae. They are also called “typical” frogs, true frogs, and ranids. Water frogs are some of the most important species because of their wide distribution and also because they are so common. Most water frogs have slim bodies with narrow heads, long, powerful hind legs, and webbed feet. Members of the family vary in size from the microfrog of southern Africa, which measures just 0.75 inch long, to the African Goliath frog, which grows to 1 foot or more. Most water frogs have narrow waists and smooth skin. Many have a pair of ridges running down the sides of their backs. Within this huge family, there are many species that differ from the general description. Some are plump or squat, rough-skinned, and toadlike, while others are unusually slender.

Distribution and Way of Life Water frogs live almost everywhere frogs are found. They are particularly abundant in the Northern Hemisphere. One species, called the North American wood frog, lives inside the Arctic Circle. Water frogs are found on every continent except Antarctica. There are relatively few species in South and Central America and Australia, and there are none in New Zealand. As their name suggests, the water frogs live beside freshwater, which they use as an escape route from predators and as a source of food for themselves. The bullfrog is one of the largest species in the

Fact File WATer FrOGs Family: Ranidae is made up of 729 species divided into eight subfamilies: Raninae, Dicroglossinae, Platymantinae, Tomopterninae, Ptychadeninae, Petropedetinae, Pyxicephalinae, and Ranixalinae Order: Anura Where do they live?: The Americas, Africa, Australia, Europe, and Asia including Southeast Asia True frog (ranidae)

Equator

Equator

Habitat: By water and in fields, meadows, woods, forests and gardens, also some in drier areas Length: 0.75–12 in. (1.8–30 cm) Appearance: Mostly slim, smoothskinned frogs with pointed heads, long hind limbs, and webbed feet. Most are green or brown, with darker markings Diet: Insects, spiders, and other invertebrates Breeding: Most lay thousands of eggs in water that hatch into tadpoles and later transform into adults status: Varies from common to endangered

family of true frogs. These large frogs spend almost all of their lives in the water.

395

WATER FROGS

DID YOU KNOW? The semaphore frogs of Southeast Asia communicate by sticking their legs out to one side and spreading their toes to show the bright blue webbing between them. Semaphore frogs live by fast-flowing streams. They probably developed this visual signal because vocal calls could not be heard over the water. The sand frogs of southern Africa spend the dry months of the year in underground burrows. They emerge to breed in the temporary pools that form after heavy rain.

396

Water frogs live by lakes, ponds, rivers, and streams as well as gardens, fields, forests, lakes, meadows, ponds, and woodlands. A few species live by the semi-salty water of the coastal regions or by warm springs. Some species also live in burrows and look like burrowing toads, while others climb trees and have large, sticky toepads that help them grip. Adult water frogs are predators and feed on insects, spiders, and other small creatures. These frogs gather at the start of the breeding season, with the males calling to attract the females. The male grips

the female’s body with his front legs to mate. He fertilizes the female’s eggs as they are laid. The eggs are usually laid in the water in large clumps. Each egg is surrounded by jelly to protect it. Females can lay thousands of eggs, but most die or are eaten by predators. Only a small fraction of the eggs survive to become adults. Most young pass through the tadpole stage before becoming adults. In a few species, however, the eggs hatch directly into froglets. An American bullfrog hides in the tall grass to escape predators.

Frogs and Toads

Water Frog Subfamilies There are 730 species of water frogs in the family Ranidae. There are eight subfamilies. The largest family, the Raninae, has more than 250 species. They can be found across Africa, Australia, the Americas, and Eurasia. The group includes the most familiar species, including the American bullfrog and the common European frog. It also includes rare species such as the long-toed stream frogs of southern Africa, and the torrent frogs of China and Southeast Asia. The subfamily Dicroglossinae includes more than eighty species that live in Africa, Asia, and the island of Fiji. The group includes the massive Goliath frog, the crowned bullfrog of Africa, and the Indian bullfrog, which has fierce, predatory tadpoles. The group also contains rice-paddy frogs that are common in paddies and villages throughout southern Asia. Another large subgroup, called the Petropedetinae, contains more than 100 species of frogs from southern Africa. The largest is just 2 inches long. The subfamily Platymantinae has many species that are unique to one island or group of islands, such as the Solomon Islands frogs (see the box right).

true colors Most water frogs are brown or green in color, with darker or paler markings that help to conceal their bodies among the stones, earth, or vegetation. The shape, markings, and color of the Solomon Islands leaf frog (shown below) look exactly likeâ•‡ a dead leaf. This helps to camouflage the body of the frog against the leaf litter. Some common water frogs have a dark “mask” around their eyes, which stretches from the snout to the neck. A few species are more brightly colored. For example, the palm frog has a jade-green back, yellow feet, and large blue eyes. It lives among the trees of tropical and subtropical forests in Papua New Guinea and the Solomon Islands.

397

WHIPTAILS Whiptails, racerunners, and jungle racers belong to a large family of lizards called the teiids. These alert, fast-moving lizards live in a wide range of habitats in the Americas.

398

SnAkES AnD LIzARDS

W

hiptails belong to a family of lizards called the Teiidae. There are two main groups in this family—the racerunners and the jungle racers. There are about sixty species of racerunners that live in the Americas. Around thirty-three species of jungle racers live in Central and South America. The family also includes the tegus—large lizards from South America. In total there are about 120 different kinds of teiids. These medium to large reptiles have the typical lizard body shape, with a narrow, pointed head, long legs, and a long tail. They range in size from the little striped whiptail, which measures just 2 inches long excluding the tail, to the large tegus, which measure 2 feet long excluding the tail. Racerunners are usually striped in dull colors, but some tropical species have bright green or blue markings. Jungle racers are powerful lizards, and they can often be heard crashing through the undergrowth. Tegus are large lizards found in South America. The family also includes the caiman lizard and the crocodile tegu, which are semiaquatic species. Some scientists also place the group of spectacled lizards, with 179 species, within the Teiidae family.

Fact File WHIpTAILs AND OTHer TeIIDs Family: Teiidae, 120 species in nine genera: Cnemidophorus (racerunners), Ameiva (jungle racers) Callopistes (false tegus), Crocodilurus (the crocodile tegu), Dicrodon (deserts tegus), Dracaena (caiman lizards), Kentropyx (whiptails), Teius, and Tupinambis (tegus) speCTACLeD LIZArDs Family: Gymnophthalmidae (179 species in 34 genera) Order: Squamata Where do they live?: The Americas, including some Caribbean islands Whiptails & Racerunners (teiidae)

Equator

Equator

Habitat: Deserts, forests, farms, scrub, villages, and coastal regions Length: 2 in. to 2 ft. (5–61 cm) long

Breeding Behavior All teiids reproduce by laying eggs. In cold places, these reptiles breed as soon as they emerge from hibernation in the spring. Tropical species breed at any time of the year but mostly to coincide with the rainy season. The long, slender body of the plateau striped whiptail has several white stripes down its back and

Appearance: Medium to large lizards, dull brown or cream with stripes; some have green or blue markings Diet: Small invertebrates Breeding: Females lay 3–30 eggs; some reproduce without mating status: Varies from common to endangered

sides. The underside is white or pale blue-green.

399

WHIPTAILS

Habitat and lifestyle Whiptails, such as the four-striped whiptail shown below, are diurnal reptiles, which means they are active during the day. Early in the morning, these lizards bask in the Sun to raise their body temperature and hunt for food. Whiptails often live in forest clearings, including those around farms and villages. In such places, there are plenty of good basking

spots, as well as cover to conceal the lizard if danger threatens. Jungle racers live in forest clearings and grasslands in tropical regions. Tegus also live in the open forest, as well as along the banks of rivers and streams. Some racerunners inhabit deserts and scrubland, including in North America. Desert species hunt in the morning and at dusk and spend the hottest part of the day in cool, shady burrows. Other racerunners live by the coast on the islands of the Caribbean. In the far north and south of their range, whiptails hibernate in winter and may only be active for six months of the year. Whiptails eat mainly insects and other small creatures. Tegus eat a range of prey including fruit, snails, fish, frogs, other lizards, and carrion (dead meat). The teiids have good eyesight, which helps them spot food from a distance. Like snakes, these lizards also have long, forked tongues to help them gather scents in the air. The lizard then “smells” the scent by touching the tongue on the Jacobson’s organ in the roof of its mouth.

This is when food is most abundant. Females lay between three and thirty soft-shelled eggs. Some racerunners can produce young without mating in a process called parthenogenesis. All the lizards of such species are 400

female, and they lay fertile eggs without mating. Parthenogenetic species include the desert grassland whiptail of Arizona. Females lay up to four eggs that hatch into young with bright blue tails.

Snakes and Lizards

OW? DID YOU KN The caiman lizard and the crocodile tegu live by the rivers and streams of the Amazon River Basin. The crocodile tegu has a flat tail like a crocodile, which it sweeps from side to side to move through the water. It eats frogs, fish, and other water creatures. Caiman lizards have two rows of scales running down their backs and

Rainbow whiptails are brightly colored lizards that live in Colombia.

Spectacled Lizards The spectacled lizards are named for their fused lower eyelids, which look a little like spectacles. There are around 179 species, some of which are called shade, creek, root, or cave lizards. Being small, spectacled lizards are sometimes called microteiids. These shy creatures dwell on the ground in the leaf litter or under rotting tree stumps. They can be very hard to spot. Many have short limbs. Some are legless and these can only move by wriggling like a worm. Spectacled lizards eat caterpillars, grubs, and worms. They breed by laying small clutches of eggs.

401

WORM LIZARDS Worm lizards, or amphisbaenians, are slender, legless reptiles. Like earthworms, they spend their lives in underground burrows. Scientists know very little about these unusual creatures.

402

SnAkES AnD LIzARDS

A

mphisbaenians are commonly called worm lizards, but they are neither worms nor true lizards. Scientists think that their closest relatives are snakes and lizards. Experts in classification place the unusual worm lizards in the same order (Squamata). Snakes, lizards, and worm lizards are thought to be descended from common ancestors. At first glance, amphisbaenians look exactly like earthworms, with their long, thin bodies and pink skin. Most worm lizards do not have any legs, but three species have tiny forelimbs. Worm lizards have blunt heads and short, round tails. The word amphisbaenian is a Greek word which means “to go both ways.” The name may refer to the fact that it is often difficult to tell the tail ends from the heads of these creatures.

Living Underground Like earthworms, amphisbaenians are well-suited to their underground lifestyle. They have square scales arranged in rings around the body. The tiny eyes are covered by scales and show up as dark spots. Worm lizards can tell light from dark, but their eyes cannot produce a visible image. They have no external ear openings, and their nostrils point backward so soil does not enter while burrowing. Most species are pink or white, but some have darker markings. Worm lizards spend their entire lives in tunnels. Some species appear on the surface after heavy rain.

Fact File WOrM LIZArDs The suborder Amphisbaenia consists of three families: Amphisbaenidae (155 species) Trogonophidae (shortheaded worm lizards, six species) and Bipedidae (two-legged worm lizards, three species) Order: Squamata Where do they live?: The Americas, Africa, southern Europe, Middle East Habitat: Varied, including rain forests, woodlands, grasslands, and deserts Length: Up to 30 in. (75 cm) long Appearance: Long, slender, wormlike white or pink reptiles; some species have dark markings; most lack limbs; eyes show up as dark spots Diet: Insects and earthworms; large species also eat small vertebrates Breeding: Most lay eggs, a few give birth to live young status: Mostly not known

The worm lizard Amphisbaena vanzolinii is a legless amphibian. The eyes of this wormlike amphibian are dark spots that can tell light from dark.

403

WORM LIZARDS

Most are only seen above ground if rain floods their burrows. They move through their tunnels by sliding their loosely attached skin forward over their bodies, like pulling down the sleeve of a sweater. Then they brace their scales against the sides of the tunnel and pull the inner cylinder of their body forward. When they move quickly, this two-stage process produces a rippling effect.

Three Families Unlike most species, the ajolote has two small forelimbs, which it uses to burrow through the soil.

404

Amphisbaenians have only a limited ability to control the temperature of their bodies. For this reason, they are found only in warm regions. Various species live in rain forests, woodlands, grasslands, and dry places around the world, including deserts. There

are 164 species of worm lizards. Experts divide the group into three families, of which the largest, the amphisbaenids, contains 95 percent of the group. Members of this large family are mostly found in tropical South America, southern Africa, and parts of North America, North Africa, southern Europe, and the Middle East. The Florida worm lizard is the only amphisbaenian found in the United States. The second family is the shortheaded worm lizards (also called the trogonophids). There are six species in this small family. The bodies of this small group of worm lizards are roughly triangular in cross-section. They specialize in digging through loose, sandy soil and are found in scattered parts of North and East Africa, the Arabian Peninsula, and on Socotra Island in the Indian Ocean. The third family, the bipedids, contains just three species, which differ from all the other worm lizards in having small but strong front legs. These tiny forelimbs are found near the head and come with long claws to help burrow through the soil. These two-legged amphisbaenians are found only in western Mexico.

Snakes and Lizards

Way of Life Worm lizards move about their burrow networks to find food and their mates. Most worm lizards feed on invertebrates such as insect grubs and earthworms. Some large species also prey on small vertebrates, such as lizards. Amphisbaenians usually eat creatures that fall into their tunnels. They also lie in wait just below the surface to ambush small creatures walking on the surface. When they sense movement above, they break through the surface

Tunnelling techniques Worm lizards have hard, ridged skulls to tunnel through the soil. Many have pointed heads to force their way through (1). Others have wedge-shaped heads and bony plates with hard cutting edges to scrape at the soil (2). They squash the soil against the tunnel by moving their head up and down. A third group have tall, narrow heads and squash soil to the sides by swinging their head left and right (3).

to snatch their prey and drag it underground. The tunnel networks often connect to an ant or termite nest, which provides a rich source of food in the form of grubs. Scientists know little about the life cycle of amphisbaenians. Most lay eggs, with some species laying their eggs in ant or termite nests. When their young hatch out they feast on the insects. In some worm lizard species, the female carries the eggs inside her body and then gives birth to live young.

1

DID YOU KNOW? The largest amphisbaenian, the white worm lizard of South America, grows to 30 inches long. The Florida worm lizard measures up to 16 inches long. Worm lizards live in different parts of their burrows to control the temperature of their bodies. They rest in the cooler, deeper burrows to escape hot weather but live nearer the surface in cold weather.

2

3

405

XENOSAURS The word xenosaur means “strange lizard,” and these reptiles certainly live up to their name. Members of this small family all have flat heads and bumpy scales. Scientists find it difficult to classify the xenosaurs.

406

SnAkES AnD LIzARDS

X

enosaurs are odd-looking lizards with flattish bodies and large, knobbly scales on their backs. They range in size from 8 to 18 inches long. They have strong limbs and long, thin tails. Their bodies are covered with small scales mixed up with larger scales, forming a V-shaped pattern across the body. The ridged scales along the back and tail form a crest. These scales rise from bony plates called osteoderms, which are embedded in the skin. The flat head of the xenosaur is roughly triangular in shape. Their strong jaws contain many teeth. The short, broad tongue is slightly forked at the tip. Some species have a pair of ridges on their head, which run over the eyes to the back of the neck. Xenosaurs have fixed eyelids. Their ear openings are hidden by scales. The bodies of these reptiles are brown with pale V-shapes pointing toward the tail. Their front legs are often yellow. These subtle colors provide camouflage and help the xenosaur to blend in with the forested areas in which it lives.

Classifying Xenosaurs Scientists have had problems classifying xenosaurs and figuring out their relationship to other groups of lizards. Their small scales suggest they are related to beaded lizards. However, the bony plates beneath their scales suggest a link with the family of slender, snakelike lizards called anguids. Xenosaurs are now placed in a group of their own. The Chinese crocodile lizard is extremely rare in the wild. The survival of these xenosaurs depends on the

Fact File XeNOsAUrs Family: Xenosauridae contains six species, divided into two genera (subgroups): Xenosaurus (knobscaled lizards, five species) and Shinisaurus (one species, the Chinese crocodile lizard) Order: Squamata Where do they live?: Mexico and southwestern China Xenosaurs (xenosauridae)

Equator

Equator

Habitat: Mountain forests, usually near water Length: 8–18 in. (20–46 cm) Appearance: Flattish lizards with strong limbs and long tails. Larger scales form a crest running along the back and tail. Usually brown with pale, V-shaped markings pointing toward the tail Diet: Insects and plants; Chinese crocodile lizard eats fish and tadpoles Breeding: Females give birth to 2–10 live young Lifespan: At least 7 years status: Varies from endangered to data deficient

success of captive breeding programs by collectors.

407

XENOSAURS

DID YOU KNOW? Most xenosaurs have dark eyes, but one species has bright scarlet irises. This led people to believe it was a type of beaded lizard and therefore poisonous. Xenosaurs use scent to detect their prey. The forked tongue collects scents floating in the air. The lizard then “smells” the scent by touching the tongue on the Jacobson’s organ in the roof of the lizard’s mouth.

The Chinese crocodile lizard is often found resting on the branches above shallow ponds and streams.

408

The xenosaur family contains just six species, which are divided into two subgroups. One group, commonly called the knob-scaled lizards, contains five species. These xenosaurs live in the mountains of Mexico and Guatemala in Central America. The second group contains just one species, the crocodile lizard, which lives in southwestern China. The Chinese crocodile lizard was identified in 1928, but it was not classed as a xenosaur until the 1960s. The two groups of xenosaurs are thus found on different continents, thousands of miles apart, which is extremely unusual. So how could this widely scattered distribution of the xenosaurs have come about? Scientists explain the presence of the two groups on separate continents using the theory of tectonic drift. According to this theory, the continents sit atop

huge sections of Earth’s crust called tectonic plates. These plates are not fixed but slowly drift across the face of the planet, driven by churning currents in the hot, liquid rock in Earth’s center. Many millions of years ago, Earth’s continents were not in their present positions but linked as one huge landmass called Pangaea. Over time, the landmass gradually split apart. As the continents drifted apart, so the species that had once roamed freely across Pangaea became isolated. The discovery of xenosaur fossils in Europe, where there are no xenosaurs today, provides some support for this theory.

Breeding Habits Xenosaurs live alone for most of the year. If two lizards meet, a fight will often break out. Males in particular will bite one another ferociously. Scientists think that these lizards breed every other year. In all species, the female carries the eggs inside her body and gives birth to living young. Litters contain between two and ten offspring. Studies of one species suggest that mothers cooperate

Snakes and Lizards

Way of life Five species of knob-scaled lizards live in forests in the mountains of Mexico and Guatemala. These creatures are usually found near water. They dwell on the ground or under stones, but some species climb into shrubs in search of food. The Chinese crocodile lizard lives near water and is a semiaquatic species. Xenosaurs are active at dusk and at night. Knobscaled lizards feed on ants and winged termites, but the largest species also eat flowers and fruit and have been known

to care for their young, which is extremely unusual. Researchers report the babies are placed in a

to prey on small vertebrates. The Chinese crocodile lizard is a strong swimmer and often visits the water to catch fish, tadpoles, and other aquatic creatures. Xenosaurs show little fear of predators or people. If an intruder appears they freeze and rely on their camouflage to hide them. If the enemy approaches, they open their mouth wide to reveal a black membrane. If this warning display fails to scare off the intruder, their powerful jaws can deliver a painful bite.

“creche” or crib that is guarded by several females until the young are a few months old. 409

Glossary adaptation Any feature of

cannibalism The eating of the

conservation The act of

an animal’s body or behavior that makes it suited to live in a particular environment aggression Hostile, violent, or destructive behavior agile To be able to move quickly and easily algae Simple, plantlike living things that grow in water or wet places and make their own food ambush To lie in wait and make a surprise attack on a prey animal

flesh of an animal by another animal of the same species captivity When an animal is held in an enclosed space, such as a farm, wildlife park, or zoo carrion The decaying remains of dead animals classification The process by which all living things are grouped according to similarities and differences. Classification helps scientists to study living things and to suggest how they may have evolved over time claypan An Australian word used to describe a shallow, bowl-shaped dip in the ground where water collects after it has been raining climate The average weather conditions in a broad region over a long period of time clutch The group of eggs laid by a female at any one time cocoon A tough, protective covering for an animal’s body when it is developing

protecting the natural world and saving rare species courtship Any behavior that occurs between males and females before mating crustacean Water-living creatures, such as shrimp and water fleas, that form the main diet for the larval stages of many amphibians

annuli (singular annulus)

Ringlike structures on the body of a caecilian aquatic Living in the water arboreal Living fully or partly in trees Arctic The region around the North Pole bask To lie in the Sun to warm

up the body beak The narrow, protruding jaws of a tortoise or turtle biome A major zone of the living world, such as a desert or rain forest, and all the living things within it burrow A tunnel or series of tunnels in the ground made by an animal in which to live camouflage Patterns or colors that allow an animal to blend in with its surroundings to escape predators, or creep up on prey without being seen 410

desert A very dry region with

few plants and less than ten inches of rainfall each year dewlap A fold of loose skin that hangs from the throat of some animals

digestion The process of

breaking down food into small pieces so the body can absorb it direct development The process of development in which young amphibians hatch out of the eggs looking like adults instead of tadpoles diurnal Active during the day domesticated animals

Animals that are farmed or tamed by people

food web All the different food

family A group of related living

chains within a habitat fungi Living things that are neither plants nor animals. Fungi cannot make their own food and feed on living things or their dead remains gator A shortened name for an alligator, which is often used in the United States gestation period The time an animal spends developing inside its mother’s body gill A flaplike structure in aquatic animals through which the exchange of oxygen and waste gases takes place

things forming a classification category that ranks above a genus and below an order fang A long, pointed tooth that may be used to deliver venom fertilization When a female egg cell and a male sperm cell join to form a new living thing floodplain A wide, flat area near the mouth of a river, which is often flooded when the river spills over its banks food chain All the different feeding relationships between animals and plants

habitat The place in which an animal or plant lives hatching To break free from an egg into the outside world hatchling An animal that has just emerged from its egg heat pit A hole containing heat-sensitive cells that are on the side of the head, or along the lips, of some groups of snakes hibernate To spend the winter in an inactive sleeplike state to conserve energy

ecosystem A habitat such as a

patch of forest and all the living things found within it embryo The early stage in the development of a living thing estivation The sleeplike state some animals adopt in summer to avoid heat and drought evolution The gradual process of change in species that produces new species extinction The process by which a species dies out forever

home range The area that an animal uses during daily activities such as foraging hormone A chemical that is carried by the blood to other parts of the body where it causes a specific response humus A brown or black crumbly material in the soil, which consists of the remains of plants and animals immune The state of being resistant to poisons or disease introduced Describes an animal or plant brought by people to an region in which it is not naturally found invertebrate An animal without a backbone larva The early stage in the

development of an animal after hatching from an egg leaf litter A layer of leaves and other debris that collects on the surface of the soil in woodlands mammal An animal with

fur that maintains its own temperature and feeds its young on milk 411

metamorphosis The change

in body shape that takes place when some animals grow into their adult form molt Shedding the skin so that it can be replaced with new skin nocturnal Active at night nutrient Food that gives an

kills and eats other animals pregnant When a female is carrying one or more developing young inside her body prehensile A grasping structure, such as a tail, that gives an especially strong grip prey An animal that is caught and eaten by another animal

animal energy to grow rain forest A habitat that is omnivore An animal that eats

a wide range of foods, both animal and vegetable orbital gland A gland near a vertebrate’s eye that produces fluids that keep the eye moist order A classification group ranking above family and below class osteoderm A boney lump in a reptile’s skin that provides protection against predators placenta An organ that

develops inside the mother’s womb to help the embryo obtain nourishment from its mother during gestation pod A term used to describe a group of young alligators predator An animal that

hot and wet all year round and is dominated by tall trees that form an overhead canopy scale A thin, platelike structure

that forms part of the surface covering of various vertebrates, such as reptiles and fishes scrubland A dry habitat that is dominated by plants such as low-growing shrubs shrubland A biome that contains plants such as shrubs and short trees skull The boney framework that encases and protects a vertebrate’s brain species A scientific term that means a type of living thing that can breed with others of its own kind to produce offspring that can also interbreed successfully suffocation Killing an animal by stopping it breathing tadpole The earliest stage of

development of an amphibian

Antarctic Circle in the south tentacles Slender, flexible organs on an animal’s head, which are for feeling, exploring or grasping terrestrial Living wholly or partly on the ground territory A feeding or breeding area occupied by one animal or a group of animals of the same species transparent Something that is seethrough tropical grassland Hot grassland, with wet and dry seasons, which occurs both north and south of the equator venom A chemical produce by

some animals that can paralyze or kill prey or predators vertebrate An animal with a backbone. All amphibians and reptiles are vertebrates warning color The bright color on an animal’s body that warns it is poisonous or tastes bad and should be left alone webbed feet Having skin stretched between the toes, which helps the animal to swim wetland A habitat with a lot of water on the surface, ranging from marshes, swamps, and flooded forests to rivers, streams, and lakes

temperate zones Two broad

regions of the Earth between the Tropic of Cancer and the Arctic Circle in the north and the Tropic of Capricorn and the 412

yolk sac A large sac containing

stored nutrients, which is used to feed the embryos of reptiles and amphibians

FUrTHEr rEsoUrCEs BOOKS

Beltz, Ellin. Frogs: Inside Their Remarkable World. Firefly, 2005. Davies, Valerie. Incredible Reptiles (Wild Life!). School Specialty Publishing, 2007. Harrison, Paul. Reptiles (Up Close). PowerKids Press, 2007. Harrison, Paul. Snakes (Up Close). PowerKids Press, 2007. Huggins-Copper, Lynn. Ravenous Reptiles (Killer Nature!). Smart Apple Media, 2006. Huggins-Copper, Lynn. Revolting Reptiles and Awful Amphibians (Qeb Awesome Animals). Qeb Pub, 2008. Huggins-Copper, Lynn. Slithering Snakes (Killer Nature!). Smart Apple Media, 2006. Johnson, Sylvia A. Cobras (Nature Watch). Lerner Publications, 2007. Mattison, Chris, Val Davies, and David Alderton. Reptiles and Amphibians (Facts at Your Fingertips). Brown Bear Books, 2007.

Parket, Janice. Reptiles (Life Science). Weigl Publishers, 2007. Rebman, Renee. Turtles and Tortoises. Benchmark Books, 2007. Singer, Marilyn. Venom. Darby Creek Publishing, 2007. Sneddon, Robert. Amphibians (Living Things). Smart Apple Media, 2007. Sneddon, Robert. Reptiles (Living Things). Smart Apple Media, 2007. Solway, Andrew. Deadly Reptiles (Wild Predators). Heinemann, 2005. Somerville, Louisa. Snakes (World of Animals). Brown Bear Reference, 2008. Stone, Lynne M. Box Turtles (Nature Watch). Lerner Publications, 2007. Taylor, Barbara. Nature Watch: Snakes. Lorenz Books, 2008. Townsend, John. Incredible Reptiles. Raintree, 2005.

Miller, Ruth. Reptiles (Animal Kingdom). Raintree, 2005.

Williams, Brian. Amazing Reptiles and Amphibians (Amazing Life Cycles). Gareth Stevens Publishing, 2007.

Otfinoski, S. Alligators (Animals Animals). Benchmark Books, 2008.

Wilsdon, C. Snakes (Amazing Animals). Gareth Stevens Publishing, 2008.

INTERNET RESOURCES

All About Reptiles Detailed account of reptiles and amphibians, with some fantastic links to more information. www.livescience.com/ reptiles Amphibians and Reptiles of Europe Web site with lots of image and information about little-known amphibians and reptiles. www.herp.it Amphibians and Reptiles of North Carolina A comprehensive study of North Carolina’s coldblooded fauna. www.herpsofnc.org AmphibiaWeb Detailed Web site that lets you search amphibians by family and location. www.amphibiaweb.org California Reptiles and Amphibians A fascinating study of all the reptiles and amphibians in California in the United States. www.californiaherps. com Enchanted Learning Check out everything to do with reptiles. www.enchantedlearning. com/subjects/reptiles/ printouts.shtml Exploratorium: Frogs Another great exhibit from the Exploratorium includes cool information and activities. Check out the frog tracker for great frog sounds. www.exploratorium.edu/ frogs

Guide to Reptiles, Amphibians, and Herps Not-for-profit organization set up to help save animals and plants. www.reptilesweb.com Herper charity website Information about reptiles and amphibians and how to look after them. www.herper.com Iowa and Minnesota Field guides to the reptiles and amphibians of the two states. www.herpnet.net IUCN Red List of Threatened Species Worldwide assessment of the conservation status of species of living organisms. www.iucnredlist.org Reptile and Amphibian Resources for Kids Full of Web sites to visit to find out more about amphibians and reptiles. http://research. calacademy.org/ research/ library/biodiv/biblio/ zrepamph.htm Society for the Study of Amphibians and Reptiles Charity to promote the conservation and education of amphibians and reptiles worldwide. www.ssarherps.org World Wildlife Fund Find out more about wildlife conservation www.worldwildlife.org Yahooligans! An introduction to amphibians and reptiles. Click on the links to find out more information. www.kids.yahoo.com/ animals

413

Picture CREDITS Corbis: Michael & Patricia Fogden 60, Chris Mattison/ Frank Lane Picture Agency 42, David A. Northcott 64, Visuals Unlimited 18; Creatas: 24, 28, 79; Dreamstime: Mikhail Blajenov 30, Miroslava Kopecka 44, 45, Christopher Moncrieff 51, Paul Murphy 12, Photobunnyuk 49, Photointrigue 29, Egidijus Skiparis 13, 15, Wouter Van Der Wiel 55, Anke Van Wyk 34; FLPA: Piotr Naskrecki/Minden Pictures 2, 58; Fotolia: Outdoorsman 66, Prints2buy 48; Istockphoto: Patrick Gijsbers 68; Photographers Direct: Maik Dobiey Photography 46, Chris Mattison 38; Photolibrary: Oxford Scientific Films/Mills Tandy 56; Photoshot/NHPA: Anthony Bannister 16, Tony Crocetta 32, Ken Griffiths 38, 41, Daniel Heuclin 63, Kitchin & V Hurst 21, Chris Mattison 72; Shutterstock: Blewisphotography 25, Joel Bauchat Grant 69, David Hancock 71, Cathy Keifer 76, 77, Itinerant Lens 8, 67, Clara Natoli 27, Four Oaks 35, Dr. Morley Read 31, Natalia Sinjushina & Evgeniy Meyke 1, 52; Valuestock: 22, 78. Ardea: Pat Morris 80; Corbis: Winfred Wisniewski/Frank Lane Picture Agency 114; Creatas: 135, 137; Dreamstime: Mikhail Blajenov 104, 105, Karel Broz 113, Vinayak Chittar 139, Janpietruszka 128, Valery Kirsanov 122, 123, Kristina Mahlau 134; FLPA: Michael & Patricia Fogden/Minden Pictures 94, 102, 116; Fotolia: 120, Caleb Foster 130t; Istockphoto: Nancy Brammer 109, Joe Clemson 87, Phil Drinkwater 130b, Eric Isselée 81, Gabriela Schaufelberger 119; Photolibrary/Oxford Scientific Films: Satoshi Kuribayashi 126, John Mitchell 142; Photoshot/NHPA: Nick Garbutt 124, Chris Mattison 107, Karl Switak 90; Shutterstock: BZ Photos 111, Simon Catesby 106, Lucian Coman 84, Lyle E. Doberstein 141, Rusty Dodson 96, Susan Flashman 98, Steffen Foerster Photography 108, Darren Green 92, David Hancock 131, Lukás Hejtman 89, Iconex 82, Cathy Keifer 140, Abramova Kseniya 88, Larsek 110, 138, Steve McWilliam 86, Clara Natoli 136, Polushkin Ivan Nikolaevich 144, Carsten Reisinger 118, Ian Scott 101, Snowleopard1 93, Socrates 85, Michael Steden 112, Lorraine Swanson 143. Ardea: Greg Harold/Auscape 166; Corbis: Joe McDonald 164; Creatas: 194; Dreamstime: Jeremy Broad 178, Miroslav Hlavko 168, 169, Marek Kosmal 177, Liquidphoto 191, Paparico 149, Nico Smit 192, 193, Teddykebab 176; FLPA/ Minden Pictures: Claus Meyer 200, Michael & Patricia Fogden 188; Fotolia: Karl Keller 182, Getty Images: Visuals Unlimited/Dr. Nathan Cohen 161; Istockphoto: Alina Hart 196, Joe McDaniel 154, 155, Wolfgang Staib 171; Nature

414

Picture Library: Tim MacMillan/John Downer Pr 206, Barry Mansell 10, Peter Scoonies 156; NHPA: Mark Bowler 172, Robert Erwin 186, Karl Switak 159; Photographers Direct: Ottmar Bierwagen 152; Shutterstock: Ivan Cholakov 172, 175, Rusty Dodson 189, Rafal Dubiel 183, Karen Givens 204, Iconex 198, Eric Isselée 215, Boris Katsman 148, Cathy Keifer 214, Michael Ledray 181, Timothy Craig Lubcke 179, Dr. Morley Read 162, 208, 209, 211, Brad Phillips 188, S. Reynaud 212, Salamanderman 199, Snowleopard1 163, Specta 203, Frank B. Yuwono 202. Ardea: John Cancalosi 258, Karl Terblanche 256; Corbis: Frans Lanting 230, David A. Northcott 250; Creatas 218; Dreamstime: Mikhail Blajenov 277, Clearviewstock 246, Rusty Dodson 242, Steffen Foerster 216, 217, Tapio Salmela 247, Wong Chee Yen 249; FLPA: Chris Mattison 226, 253, Foto Natura/Duncan Usher 240; Fotolia: Robert Asento 245; Getty Images: Visuals Unlimited/Jack Dermid 254; Istockphoto: Chrisho 248, Martin Ruta 270, David Thyberg 235, Alan Tobey 224; Nature Picture Library: Dietmar Nill 266; NHPA: Daniel Heuclin 272, Karl Switak 238; Photolibrary: Olivier Grunewald 236; Science Photo Library: Suzanne L Collins 264; Shutterstock: John Arnold 279, Stephen Bonk 260, Norma Cornes 222, Rusty Dodson 223, 243, Cathy Keifer 221, Bruce MacQueen 268, 269, Dr. Morley Read 278, 282, Snowleopard1 228, 229, 283, David Thyberg 233, 234, Bill Wolfe 271, Michael Zysman 276; Value Stock Images 232. Ardea: John Cancalosi 336, Jean Paul Ferrero 289, Ken Lucas 330; Corbis: Michael & Patricia Fogden 290; Creatas: 302, 313; Dreamstime: Omar Ariff Kamarul Ariffin 304, Jeremy Broad 348, Andy Butkaj 338, 339, Rusty Dodson 329, Anthony Hall 307, Holger Leyrer 341, 342, Wouter Tolenaars 295; FLPA: Yossi Eshbol 318, Martin B Withers 326; Fotolia: Michel Bazin 311, Kasi Lodrigue 308; Istockphoto: Henry Chaplin 305, Karen H Johnson 303, John Pitcher 284, 285, Kevin Ross 351, Ashley Whitworth 350; NHPA: James Carmichael Jr 292; Photographers Direct: Zafer Kizilkaya/ Images&Stories 320, Thomas Mueller 323, Henk Wallays 306; Photos.com: 324, 328; Shutterstock: John Bell 296, 349, Piotr Bieniecki 316, 317, Troy Casswell 332, clearviewstock 335, Bobby Deal/ RealDealPhoto 299, Rusty Dodson 300, 346, Cathy Keifer 344, T. H. Klimmeck 288, Joyce Mar 314, 315, Steve McWilliam 340, Wouter Tolenaars 294; Valuestock: 298. Corbis: Frank Lane Picture Agency/Chris Mattison 364, 404, David A. Northcott 406; Creatas: 371, 374; Dreamstime: Roger Degen 362, Marianne Lachance 390, 391; FLPA: Foto Natura 352, Minden Pictures/Piotr

Naskrecki 402; Istockphoto: Nancy Nehring 399, 400, Phillip Stollery 378, 379, Alan Tobey 383; Photolibrary: Oxford Scientific Films/Olivier Grunewald 354; Photos. com 384; Photoshot/NHPA: Jordi Bas Casas 392, Andrea Bonetti 393, James Carmichael Jr 397, T. Kitchin & V. Hurst 409, Bill Love 358, Otto Pfiste 401; Science Photo Library: Bob Gibbons 360; Shutterstock: Lynsey Allan 356, Bruce

Amos 396, John Bell 357, 366, 367, Ryan M. Bolton 394, Joy Brown 368, 369, Efiplus 389, David Hamman 398, Innocent 382, Joern 363, Bruce MacQueen 395, William Attard McCarthy 386, Steve McWilliam 388, Stephen Meese 372, Snowleopard1 375, 377, Judy Worley 387. Artworks and maps © The Brown Reference Group plc

415

Exploring the World of Reptiles and Amphibians

Caribbean Amphibians and Reptiles

Reptiles and Amphibians of Minnesota

The Reptiles and Amphibians of Alabama

Herpetology: An Introductory Biology of Amphibians and Reptiles, 3rd Edition

Mammals, Amphibians, and Reptiles of Costa Rica: A Field Guide

Herpetology, Second Edition: An Introductory Biology of Amphibians and Reptiles

Herpetological Osteopathology. Annotated Bibliography of Amphibians and Reptiles

Herpetology, : An Introductory Biology of Amphibians and Reptiles

Herpetology, Third Edition: An Introductory Biology of Amphibians and Reptiles

A Guide to Amphibians and Reptiles (Stokes Nature Guides)

Their Blood Runs Cold: Adventures with Reptiles and Amphibians

Catalogue of New World Amphibians

Reptiles, Amphibians, and Invertebrates: An Identification and Care Guide

Instant Guide to Reptiles and Amphibians (Instant Guides (Random House))

Exploring the World of Mammals

Amphibians & Reptiles of Mount Kinabalu (North Borneo)

The Amphibians and Reptiles of Alberta: A Field Guide and Primer of Boreal Herpetology

Amphibians

The amphibians and reptiles of New York State: identification, natural history, and conservation

Reptiles

Clinical Anatomy and Physiology of Exotic Species: Structure and function of mammals, birds, reptiles and amphibians

Reptiles of the Northwest

Amphibians and Reptiles of Alberta: A Field Guide and Primer of Boreal Herpetology

Herpetological communities: a symposium of the Society for the Study of Amphibians and Reptiles and the Herpetologists' League, August 1977

Exploring the World of Lucid Dreaming

Exploring the World of Lucid Dreaming

The Ecology and Behavior of Amphibians

Exploring the World of Lucid Dreaming

Exploring the World of Lucid Dreaming

Amphibians and Reptiles of the Pacific Northwest (A Northwest naturalist book)

Exploring the World of Reptiles and Amphibians

Caribbean Amphibians and Reptiles

Reptiles and Amphibians of Minnesota

The Reptiles and Amphibians of Alabama

Herpetology: An Introductory Biology of Amphibians and Reptiles, 3rd Edition

Mammals, Amphibians, and Reptiles of Costa Rica: A Field Guide

Herpetology, Second Edition: An Introductory Biology of Amphibians and Reptiles

Herpetological Osteopathology. Annotated Bibliography of Amphibians and Reptiles

Herpetology, : An Introductory Biology of Amphibians and Reptiles

Herpetology, Third Edition: An Introductory Biology of Amphibians and Reptiles

A Guide to Amphibians and Reptiles (Stokes Nature Guides)

Their Blood Runs Cold: Adventures with Reptiles and Amphibians

Catalogue of New World Amphibians

Reptiles, Amphibians, and Invertebrates: An Identification and Care Guide

Instant Guide to Reptiles and Amphibians (Instant Guides (Random House))

Exploring the World of Mammals

Amphibians & Reptiles of Mount Kinabalu (North Borneo)

The Amphibians and Reptiles of Alberta: A Field Guide and Primer of Boreal Herpetology

Amphibians

The amphibians and reptiles of New York State: identification, natural history, and conservation

Reptiles

Clinical Anatomy and Physiology of Exotic Species: Structure and function of mammals, birds, reptiles and amphibians

Reptiles of the Northwest

Amphibians and Reptiles of Alberta: A Field Guide and Primer of Boreal Herpetology

Herpetological communities: a symposium of the Society for the Study of Amphibians and Reptiles and the Herpetologists' League, August 1977

Exploring the World of Lucid Dreaming

Exploring the World of Lucid Dreaming

The Ecology and Behavior of Amphibians

Exploring the World of Lucid Dreaming

Exploring the World of Lucid Dreaming

Amphibians and Reptiles of the Pacific Northwest (A Northwest naturalist book)

Recommend Documents