Our Living World: Earth's Biomes - Volume 5: Deserts

volume

5 Deserts

T R A D I T I O N A

N E W

Deserts

OUR LIVING WORLD: EARTH’S BIOMES B a r b a r a A . S o m e r v i l l

B O O K S

T R A D I T I O N

®

, I N

M A P L E

P L A I N ,

C H I L D R E N ’ S

M I N N E S O T A P U B L I S H I N G

TM



ABOUT THE AUTHOR

Barbara A. Somervill is the author of many books for children. She loves learning and sees every writing project as a chance to learn new information or gain a new understanding. Ms. Somervill grew up in New York State, but has also lived in Toronto, Canada; Canberra, Australia; California; and South Carolina. She currently lives with her husband in Simpsonville, South Carolina.

In gratitude to George R. Peterson Sr. for introducing me to the beauty of creation —George R. Peterson Jr., Publisher, Tradition Books® Published in the United States of America by Tradition Books® and distributed to the school and library market by The Child’s World® [ACKNOWLEDGMENTS] For Editorial Directions, Inc.: E. Russell Primm, Editorial Director; Dana Meachen Rau, Line Editor; Katie Marsico, Associate Editor; Judi Shiffer, Associate Editor and Library Media Specialist; Matthew Messbarger, Editorial Assistant; Susan Hindman, Copy Editor; Lucia Raatma, Proofreaders; Ann Grau Duvall, Peter Garnham, Deborah Grahame, Katie Marsico, Elizabeth K. Martin, and Kathy Stevenson, Fact Checkers; Tim Griffin/IndexServ, Indexer; Cian Loughlin O’Day, Photo Researcher; Linda S. Koutris, Photo Selector For The Design Lab: Kathleen Petelinsek, design, art direction, and cartography; Kari Thornborough, page production [PHOTOS] Cover/frontispiece: Jim Zuckerman/Corbis. Interior: John Alcock/Visuals Unlimited: 70; Animals Animals/Earth Scenes: 12 (J. & B. Photographers), 54 (Doug Wechsler), 58 (Mickey Gibson), 61 (Raymond A. Mendez), 64 (A. & M. Shah), 65 (Barbara von Hoffman); Getty Images/Brand X Pictures: 27; Corbis: 4 (Peter Johnson), 6 (Ludovic Maisant), 19 (Richard Cummins), 40 (Paul A. Souders), 41 (Theo Allofs), 43 (David Samuel Robbins), 45 (Michael & Patricia Fogden), 46 (Terry W. Eggers), 49 (Australian Picture Library), 50 (José Fuste Raga), 52 (Robert Garvey), 55 (Kennan Ward), 56 (David Muench), 57 (George H. H. Huey), 60 (Les Stone), 82 (Jamie Harron; Papilio), 85 (Annie Griffiths Belt), 91 (Ron Watts); E. R. Degginger/Color-Pic: 18, 71, 74, 80; Wendy Dennis/Dembinsky Photo Associates: 28, 84; Digital Vision: 17, 23, 29, 31, 35, 62, 68; Michael Fogden/Animals Animals/Earth Scenes: 44, 77; Owen Franken/Corbis: 81, 88; Eric and David Hosking/Corbis: 32, 67; Wolfgang Kaehler: 36; Steve Kaufman/Corbis: 25, 34, 78; Tom & Pat Leeson: 39; Joe & Mary Ann McDonald: 11; Photodisc: 8, 15, 37; James P. Rowan: 7; Scott T. Smith/Corbis: 21, 72. [ L I B R A RY O F C O N G R E S S C ATA L O G I N G - I N - P U B L I C AT I O N D ATA ] CIP data available



CONTENT ADVISER

Susan Woodward, Professor of Geography, Radford University, Radford, Virginia

4

Table of Contents

Table of Contents [Chapter One]

4 Defining Deserts [ C h a p t e r Tw o ]

18 Focus on Key Species [Chapter Three]

28 Predators [Chapter Four]

40 Prey [Chapter Five]

50 Flora [Chapter Six]

60 Herbivores [Chapter Seven]

70 A Cycle of Life [Chapter Eight]

78 The Sahara [Chapter Nine]

85 The Human Touch 92

[Chart of Species]

93

[Index]

4

1

[Chapter One]

Defining Deserts

Defining Deserts

area. They, too, will drink at this water hole. A lioness and her cubs lie in the shade of a tamarisk tree. They are hungry, but it is too hot

4Dainty springboks drink

to hunt. The temperature

from a muddy pool. Elephants

soars to 120˚ Fahrenheit

trumpet their arrival in the

(49˚ Celsius).

 Springboks drink at a water hole as the sun sets over the Kalahari Desert.

4

[Defining Deserts]

The water hole has nearly

about 18 inches (46

?

WORDS TO KNOW . . .

dried up. The water tastes of

centimeters) of rain

dormant (DOR-muhnt) sleep-

salt. Around the pool, cracked

each year. It lasts

ing or inactive

mud dries as hard as cement.

from November to

semiarid (SEM-i-A-rid)

It is November in the Kalahari

March. Rain brings

describes a climate with too

Desert. Summer is coming to

the desert to life.

little rain to support forests

southern Africa. And summer

Plant seeds that lie

but enough for desert plants

brings rain.

dormant through

to survive

The vast, semiarid

the dry season  READ IT!

Kalahari Desert has only two

sprout up overnight.

seasons—dry and wet. The dry

Fig, ebony, and

The Kalahari supports an

season is cloudless, sunny, and

baobab trees burst

astonishing range of wildlife in

hot. It lasts from April to Octo-

with bright green

a land that is dry eight months

ber. The wet season yields

leaves. Wildflowers

of the year. Read about this

sprinkle the land-

dramatic desert in Cry of the

scape with reds, yel-

Kalahari by Mark James Owens

lows, and purples.

(Mariner Books, 1992).

A

F

R

I

C

A

What Makes a Desert? Atlantic Ocean

0 0

1000 Miles

4Deserts are found on every

Kalahari Desert

1000 KM

Indian Ocean

continent except Europe. Generally, deserts receive less

 Africa’s Kalahari Desert

5

[Defining Deserts]

than 10 inches (25

For example, rainfall in the

evaporation (i-vap-uh-RAY-

cm) of precipitation

Atacama Desert evaporates

shuhn) the change from liquid

a year. Where more

200 times faster than rainfall

to gas

rain falls, deserts

in a milder climate. Even if

precipitation (pri-sip-i-TAY-

can be identified by

the Atacama got 60 inches

shuhn) all the rain, snow, sleet,

the rate of water

(150 cm) of rain (which never

hail, or other moisture falling

evaporation. In

happens), it would still be

on a region

most deserts, rain-

desert.

?

WORDS TO KNOW . . .

fall evaporates before the water can be used.

Most people think that deserts are hot, sandy, and dry. That is true for some, but not all, deserts. There are four different types of deserts, and only one type is hot and dry. The others are semiarid, cold, and coastal. The Sahara in Africa and the Sonoran Desert in the southwestern United States are hot, dry deserts. The Great Basin, a semiarid region, lies in the western United States. The Gobi and  The Atacama Desert gets its water from fog. Rain falls on the Atacama only once every 100 years.

 The Great Basin is typical “high” desert, with a semiarid (half-dry) climate.

Takla Makan deserts of Asia

mountains that rise more

are cold deserts. Coastal

than 10,000 feet (3,048

deserts include the Namib of

meters). Ancient rivers carved

southwestern Africa and the

deep canyons in the Great

Atacama of South America.

Basin. The deepest, biggest

Most deserts have a vari-

gorge of the desert region in

ety of landforms. Plains and

the United States is the Grand

plateaus are found in many

Canyon. Several deserts have

deserts. The Sahara has

huge, moving sand dunes. 7

 The flat-topped rocks of the Mojave Desert are called mesas, the Spanish word for “tables.”

Wind pushes against the

8

Deserts, like tundra,

dunes, creating ripples and

are not wastelands. Cactuses,

curves in the sand. Deserts

wildflowers, and scrub brush

change daily. Today’s land-

thrive in hot, dry lands.

mark may be covered with

Deserts have hundreds of

sand tomorrow. Or it may

animal species slithering,

stand as a marker for

skittering, and stalking day

1,000 years.

and night.

[Defining Deserts]

Desert animals’ lives dif-

leaves and their texture help

fer from those of wetland and

the plants hold water. Many

forest creatures. They live

types of cactuses bloat up with

with little water and often

water during the wet season.

intense heat. Finding food is

They hold the water for use

not simple. Few desert animals

during long, dry periods.

are fussy eaters. A hyena, for

Desert plants are usually

example, usually eats carrion.

perennials. They grow back or

It also eats birds, lizards, and

leaf out every year.

even berries when no carrion

Because the wet sea-

is available.

son is short, the

carrion (CAH-ree-uhn) dead or

time from sprout to

rotting flesh

flower to seed is

perennials (puh-REN-ee-uhlz)

4For desert plants, survival

also short. Animals,

plants that have lifespans of

means dealing with a harsh

heavy rains, and

longer than two years

climate. Some plants will only

wind carry seeds to

bloom at night. Bats, insects,

where they will sprout. Annual

and moths come out at night.

plants also exist in the desert.

They transfer pollen from

They live only one year and

flower to flower. Most desert

exist most of the time as

plants have small, thick leaves.

seeds. Seeds in the desert

The leaves may appear waxy

may lie dormant for months

or leathery. The shape of

or years until rain comes. It

Plants Adjust

?

WORDS TO KNOW . . .

9

[Defining Deserts]

is likely that only one seed

owls, snakes, or lizards move

from a flower or fruit will

in when a rat moves out.

become a full-grown plant.

Bats, geckos, and golden

For this reason, most desert

moles survive the heat by

plants produce many seeds.

hunting only at night. They

The fruit of the saguaro

are not the only nocturnal,

(suh-WAH-roh) cactus, for

or night, hunters. Coyotes,

example, contains thou-

Mexican gray wolves, and

sands of seeds.

foxes also hunt at night

Animals Adjust

when their favorite prey travel about.

4Animals also fight heat

Animals that cannot

and long droughts without

avoid the day’s heat deal with

rain. Most desert rodents,

it in different ways. Many ani-

snakes, and tortoises dig

mals keep water in their bod-

underground holes called

ies by not sweating. They

burrows. The tem-

have no sweat glands to

perature 1 foot

release body water. Others

urine (YOOR-uhn) liquid waste

(.3 m) underground

produce urine with very little

from an animal or human

is much cooler than

water. The urine is almost

on the desert’s sur-

solid. Camels and antelopes

?

WORDS TO KNOW . . .

10

face. Kangaroo rat burrows

pant. Panting allows the ani-

are so popular that burrowing

mals to breathe in and out

[Defining Deserts]

quickly and cool themselves. Some animals, such as beetles and scorpions, have hard shells that reflect light. This protects them from heat. Many desert animals do not need to drink water directly. They get water from their food. Kangaroo rats gain all the water they need from seeds. They never drink water—even if they are living in zoos. For animals that do

 A banner tail kangaroo rat like this one weighs from 1 to 6 ounces (28 to 168 grams).

drink, water can be scarce.  READ IT!

They must take advantage of

grouse in the

various water sources. Sand

Namib may fly

Discover how the seasons affect

vipers in the Namib Desert

more than 50 miles

animal and plant life in Carol

of Africa lie out in the morn-

(80 kilometers) to

Lerner’s A Desert Year (William

ing to collect dew on their

find a pool. The

Morrow, 1991).

skin. The vipers then lick

grouse have special

the water from their own

feathers on their chests that

bodies. Some kinds of sand-

hold water. A male grouse 11

 A sand grouse parent carries water under its chest feathers to give its nestlings a drink.

soaks his breast feathers,

sleeping. Sleeping through

then flies home.

the hot, dry summers is

Grouse hatchlings

called estivation. Spadefoot

estivation (ESS-tih-VAY-shuhn)

drink the water

toads practice estivation.

sleeping a long period to avoid

held in his feathers.

They sleep through the

?

WORDS TO KNOW . . .

summer heat and drought

When all else fails, desert animals

avoid hot, dry seasons by 12

driest weather. When the rains come, they awaken, mate, and produce young.

[Defining Deserts]

Deserts around the World

Sahara Desert

A

F

R

I

C

A

4The world’s largest desert is the Sahara. The

Atlantic Ocean

“desert.” It covers most of the

0 0

1000 Miles

t eser ib D Nam

name Sahara actually means

Kalahari Desert

1000 KM

Indian Ocean

northern part of Africa. In southern Africa, the Kalahari

 Africa’s Kalahari, Namib, and Sahara deserts

and Namib deserts support a strange, varied collection of

even fewer people live. The

creatures. Many are not found

largest deserts in Asia are the

anywhere else on earth.

Takla Makan and the Gobi.

Asia has many small

They are cold deserts where

deserts—small compared to

harsh winds blow and winter

the Sahara. People crossing

temperatures often drop

Asian deserts by camel would

below freezing.

not think they were so small.

Deserts cover more than

On the Arabian Peninsula lies

two-thirds of Australia and are

the Nafud Desert and the

semiarid. The Australian out-

Rub‘ al-Khali. Rub‘ al-Khali

back is both hot and dry. It

means the “empty quarter,” a

includes the Gibson, Simpson,

place where few animals and

Great Sandy, and Great 13

[Defining Deserts]

South America has two deserts: the Atacama and the Patagonia. The Atacama bears A

S

I

A Gobi Desert

Nafud Desert

Takla Makan Desert

Rub Al-Khali Desert

0 0

the title of “driest desert” in the world. Places in the Atacama may not see rainfall for many years. The Atacama

1000 Miles 1000 KM

lies mostly in Peru and Chile  Asia’s Gobi, Rub’ al-Khali, Nafud, and Takla Makan deserts

along the western side of the Andes Mountains. The moun-

 WATCH IT!

Victoria deserts.

tains block any rain coming

They leap across a land that few

Australia’s Sturt

from the east. The Atacama is

humans can tolerate. Meet the

Stony Desert is

not a “sand dune” desert. It

kangaroos and wallabies of the

unique among

has cliffs, mountain peaks,

Australian outback in the

deserts. While most

National Geographic video

deserts have a mix

Australia’s Kangaroos

of sand dunes,

[ASIN: 0792290623].

rocks, and hills,

Great Sandy Desert

Sturt Stony Desert

Gibson Desert

Indian Ocean A U S T R A L I A

Great Victoria Desert

is a mass of stones. Australian deserts support dragonlike lizards, huge snakes, and fast-

Simpson Desert Sturt Stony Desert

Indian Ocean 0 0

500 Miles 500 KM

moving kangaroos.  Australia’s Gibson, Great Sandy, Great Victoria, Simpson, and Sturt Stony deserts

14

[Defining Deserts]

and high plains, all dry as a bone. Patagonia, to the south, is a cold desert. Patagonia is closer to Antarctica than any other land area. North American deserts lie in the southwestern United States and northern Mexico. The region claims four deserts: the Chihuahuan, Great Basin, Sonoran, and Mojave. Smaller deserts, such as the Painted Desert, are really sections of the four larger deserts.

Pata gon ia

Pacific Ocean

S O U T H M E R I C A

Atacam a Desert

A

Atlantic Ocean

0 0

1000 Miles 1000 KM

 South America’s Atacama Desert and Patagonia

 Patagonia is a harsh, remote land at the southern tip of South America.

15

[Defining Deserts]

?

The largest

WORDS TO KNOW . . .

temperatures and more rain-

elevation (el-uh-VAY-shuhn)

North American

fall. Winters may see snow,

a place’s height above sea level

desert is the

which melts quickly.

Chihuahuan. It

The coolest, wettest North

covers parts of Mexico, Ari-

American desert is the Great

zona, New Mexico, and Texas.

Basin, a semiarid region. It

Cactuses, creosote bushes, and

covers parts of Nevada, Utah,

cottonwood trees grow in many

Wyoming, Idaho, Oregon, and

Chihuahuan Desert locations.

California. Precipitation in the

The desert has more plant

Great Basin usually falls as

cover than the Sonoran or

snow. Sagebrush covers Great

Mojave because it is at a

Basin plains where coyotes and

higher elevation. Chihuahuan

great horned owls hunt.

Desert summers have milder

The Sonoran Desert is what most people picture when they think of a desert. Cactuses grow in every imaginable shape and size. Rattle-

Great Basin Mojave

N O R T H A M E R I C A

Sonoran

an ahu ihu Ch

Pacific Ocean 0 0

Atlantic Ocean

500 Miles

snakes sun themselves on Sonoran rocks. The land is extremely dry, and summers are hot. The Sonoran Desert

500 KM

covers parts of Arizona,  North America’s Chihuahuan, Great Basin, Mojave, and Sonoran deserts

16

 Leopard tortoises like this one eat grasses, leafy plants, and toadstools. To add calcium to their diet, they gnaw on old bones.

California, and Mexico.

Sonoran Desert. Death Valley,

Mexico’s Baja California, a

the lowest and often hottest

peninsula south of California,

point in the United States, lies

is part of the Sonoran Desert.

in the Mojave. The region is

The Mojave is a small

home to slow-moving desert

desert, only half the size of the

tortoises and howling coyotes. 17

2

[ C h a p t e r Tw o ]

Focus on Key Species

Focus on Key Species

saguaro cactus. The woodpecker carves its nest in the side of the cactus. The cactus’s waxy skin will form a scar, coating the nest walls.

4About 30 feet (9 m) above

The woodpecker uses this

the desert floor, a Gila (HEE-

nest for one or more seasons.

luh) woodpecker rat-a-tat-tats

When a woodpecker finishes

against the thick skin of a

with its nest, a new tenant

 This Gila woodpecker is carving out a home in a cactus.

18

[Focus on Key Species]

N O R T H A M E R I C A

Atlantic Ocean

Sonoran Desert

Pacific Ocean 0 0

500 Miles 500 KM

 North America’s Sonoran Desert

moves in. Elf owls, the smallest North American owls, like empty woodpecker nests. Saguaro cactuses live only in the Sonoran Desert.

 Saguaro cactuses are found only in the Sonoran Desert.

They stretch their prickly limbs up to 50 feet (15 m)

saguaro for food,

into the sky. Needles 2 inches

housing, and shade.

(5 cm) long cover the cactus.

Saguaros are

!

WOULD YOU BELIEVE?

An adult saguaro cactus can take in 200 gallons (757 liters)

The needles provide protec-

slow growing and

of water in a day. The saguaro’s

tion from plant eaters and

long living. A

skin stretches like an accordion.

perches for cactus-loving

saguaro cactus

It will hold and use the water

birds. More than 35 bird

grows about

until the next big rainfall.

species depend on the

6 inches (15 cm) 19

[Focus on Key Species]

every nine years. It can live for up to 200 years, adding new ?

WORDS TO KNOW . . .

ecosystem (EE-koh-siss-tuhm) a community of plants and ani-

Keystone trees and cactuses perform many services for

arms when it is 50

desert ecosystems. Their root

or more years old.

systems reduce erosion.

Keystone Species

Tender leaves provide food and water for herbivores,

mals and their relationship with

4A keystone

which are animals that eat

the surrounding environment

species is an animal

only plants. Birds nest in their

erosion (i-ROH-zhuhn) the wast-

or plant that is cru-

limbs, while snakes and lizards

ing away or loss of soil or rock

cial for the survival

sun themselves on tree branch-

by wind, water, or chemicals

of an ecosystem.

es. Hot predators sleep in the

The species may

welcome shade provided by

change the land or create new habitats. Or the species may

20

desert trees. Small rodents, such as ger-

be the main food of predators

bils, jerboas, and kangaroo

in the area. Keystone species

rats, fulfill a keystone role in

of North American deserts

deserts around the world.

are saguaro cactuses, iron-

These rodents dig extensive

wood, cottonwood, and velvet

burrows underground. In

mesquite trees. Saksaul trees

doing so, they turn the soil

in Asia and tamarisk and

and help plants grow. Aban-

baobab trees in Africa are also

doned rodent burrows become

keystone species.

homes for snakes, burrowing

MEXICAN PRAIRIE DOGS IN THE NEWS Scientists studied prairie dog populations in northern Mexico. They found that the population dropped by half between 1995 and 2000. The species once dug burrows and built prairie dog towns over 580 square miles (1,500 square km). Today, the Mexican prairie dog’s range is less than 83 square miles (215 sq km). The habitat loss  Cottonwood trees send roots deep into the earth to find water.

owls, and other desert critters.

results from farmers using the land to grow crops. Prairie dogs are keystone species of

Small rodents feed dozens

the Chihuahuan Desert. Dozens of ani-

of different predators, from

mal species depend on Mexican prairie

lizards and snakes to kit

dogs for survival. Prairie dogs are food

foxes and sand lynxes. Kanga-

for Mexican gray wolves, owls, and

roo rats feed on seeds that

coyotes. Desert foxes, snakes, and

they hoard in their burrows.

burrowing owls live in their abandoned

They spread seeds through-

burrows. The loss of prairie dogs may

out their territory, extending

signal problems for other species in

plant growth.

the Chihuahuan Desert.

21

[Focus on Key Species]

Umbrella Species

need a large territory to find enough water and grazing

4An umbrella species is

plants for survival. The Gobi

an animal or plant with legal

is a unique blend of rocky

protection that spreads over

mountain peaks, stone-

other creatures.

covered flat land, tree-lined

Governments pass

borders, and oases. It is a

endangered (en-DAYN-jurd)

laws to protect

cold desert where winter tem-

on the edge of being complete-

endangered or

peratures can drop to –40˚F

ly wiped out; few members of

threatened species.

(–40˚C). Food and shelter are

a species still surviving

Hunting, drawing

scarce. Within the Bactrian

irrigate (IHR-uh-gate) to water

water to irrigate

camels’ range live Gobi bears,

crops on dry land by bringing in

crops, mining, and

Argali sheep, wild asses, and

water from another source

recreation put

black-tailed gazelles. These

oases (oh-AY-ses) natural water

desert plants and

holes in a desert

animals at risk.

threatened (THRET-uhnd) at risk

Laws protecting

of becoming endangered

animals or plants

?

WORDS TO KNOW . . .

A

tems protect all creatures that live there. 0 0

500 Miles 500 KM

roam the Gobi Desert. They  Asia’s Gobi Desert

22

I

A Gobi Desert

within these ecosys-

Wild Bactrian camels

S

 This cougar walks softly and silently as it hunts its prey.

are rare species of Asia. By

excellent umbrella species

protecting the full range of

for North American deserts.

Bactrian camels, other endan-

California cougars hunt on

gered species of the region

anywhere from 25 to 500

are also protected.

square miles (65 to 1,300 sq

The California cougar and bighorn sheep make

km). Bighorn sheep also graze over a large territory. Living 23

PRZEWALSKI HORSE

within their grazing territory

IN THE NEWS

are endangered kit foxes, kan-

The Przewalski horse, or takhi, is a flag-

garoo rats, and desert tortoises.

ship species of the Gobi Desert. They

Protection for either cougars

became extinct in the wild during the

or bighorn sheep spreads a

late 1900s. Bitter Mongolian winters

safety umbrella over all the

and loss of habitat to grazing camels

other animals in their region.

and sheep reduced the takhi population. Hunting destroyed the remaining horses until no more of them lived in the wild.

Flagship Species 4A flagship species draws public attention. Whether

This small,

beautiful, dramatic, or cuddly,

extinction (ek-STINGKT-shuhn)

rugged horse was

flagship species create interest

the state of having no more

saved from com-

and make news. Therefore, it

living members of a species

plete extinction by

is easier to get legal protection

zoos. Several zoos

for flagship species than for

?

WORDS TO KNOW . . .

ran breeding programs to build herds of Przewalski horses. During the 1990s,

24

many other animals. The Arabian oryx, a

small herds were reintroduced to the

desert antelope, has become

Hustain Nuruu Steppe Reserve of

the flagship species of the

Mongolia. The reserve provides

Arabian peninsula. For many

“wild living” under strict protection

years, hunters stalked herds

from hunters.

of oryx over the desert dunes.

 The Arabian oryx was hunted nearly to extinction once air-conditioned off-road vehicles became popular.

When desert hunters rode

ber of zoos around

camels, the oryx could still

the world saved the

poaching (POHCH-ing)

survive. Once air-conditioned

species. However,

hunting illegally

four-wheel-drive vehicles

poaching contin-

became popular, the oryx

ues because private collectors

didn’t stand a chance.

will pay thousands of dollars

Overhunting reduced this

for an Arabian oryx.

magnificent species to the

?

WORDS TO KNOW . . .

Zebras, wild asses, and

edge of extinction. A com-

wild horses are flagship

bined effort by the Kingdom

species. They live in desert

of Saudi Arabia and a num-

regions throughout the 25

[Focus on Key Species]

? WORDS TO KNOW . . .

world. In Australia,

make people aware of prob-

feral (FEH-ruhl) describes an ani-

feral burros and

lems in ecology. That aware-

mal living in the wild, although

brumbies (wild hors-

ness may become the key

its relatives were kept as pets

es) survive in the

to saving some less-popular

harsh landscape of

critters such as the barefoot

the outback. African Grevy’s zebras and Asian wild asses are threatened species. They need

Indicator Species

help to survive. These species

4Indicator species report

suffer from loss of habitat,

on an environment’s health.

drought, and grazing cattle or

When an indicator species

sheep. To preserve these

thrives, the ecosystem is

species, laws must protect the

healthy. If the species dies

animals and their territories

or moves away, the ecosystem

from hunters and farmers.

has problems.

People should be con-

26

banded gecko.

Often, indicator species

cerned with all endangered

are birds or insects, which are

or threatened species. Unfor-

more sensitive to environmen-

tunately, people choose sides.

tal problems. For example, the

The graceful Arabian oryx and

burrowing owl is an indicator

dynamic Australian brumby

of the general health of tree-

have more fans than ugly hye-

less prairies and semiarid

nas. But the flagship species

desert shrub lands. Burrowing

[Focus on Key Species]

owls live in prairie dog burrows and eat mice, rats, gophers, and ground squirrels. Birds are sensitive to loss of habitat, increases in chemical pest killers, and climate changes. If burrowing owls will not nest in a region, it is an indicator of ecological trouble. Failure to lay eggs or laying damaged eggs may show increased poison levels in the area. If there are only a few young owls, it can mean there is a limited food supply. Sagebrush lizards are also an indicator species. These

 Burrowing owls gladly move into empty prairie dog burrows. It saves them from having to dig their own homes.

lizards live where sagebrush covers the desert floor. Serious

many or too few, sagebrush

drought, pollution, or loss of

lizards give us clues about the

habitat reduces sagebrush

desert. When sagebrush lizard

lizard populations. Loss of

numbers change dramatically,

predators increases lizard

there is a serious environmen-

numbers greatly. Whether too

tal problem. 27

3

[Chapter Three]

Predators

Predators 4 Dawn breaks, and fog rolls over the Namib Desert. Most

ocean deposits droplets of water on leaves, branches, dunes, and animals lying in the right place. A sand viper lies along

mornings, Namib animals take

the ridge of a sand dune.

advantage of the Atlantic

Dew gathers on its scales,

Ocean’s gift. The fog from the

and the snake laps up the

 This fog-drinking beetle relies on morning fog for water in the Namib Desert of southern Africa.

28

[Predators]

water. A darkling beetle collects water drops on its back. Each precious drop drips along the beetle’s wing and into its mouth. Gemsbok browse on fog-dampened leaves. They can get a day’s worth of water from eating plants. For larger animals, morning is also time to drink. Collected dew is not enough water for most mammals. At a water hole, a lioness and her cubs slurp their fill. Skittish zebras

 Vultures raid ostrich nests while the parents drink at water holes.

and wildebeest dip their heads. They keep a sharp eye out for the lions. Nearby, a pair of vultures perch in a tamarisk tree.

A

F

R

I

C

A

They wait for local ostriches to come to the pool. Vultures feed

Atlantic Ocean

them when the parents aban-

0 0

1000 Miles 1000 KM

t eser ib D Nam

on ostrich eggs and will steal

Indian Ocean

don their nests to drink.  Africa’s Namib Desert

29

[Predators]

A caracal hides in desert

desert, there are few picky

grasses near the water hole.

eaters. Prey is hard to find,

It waits for a flock of sand-

hard to catch, and is never

grouse to arrive. When they

passed by. Because meat is

do, the caracal attacks. One

also a source of water, feed-

grouse provides a meal plus

ing is essential to survival.

all the liquid the caracal

Many animals that prefer

needs for the day.

fresh meat will also eat car-

 LOOK IT UP!

Food Supply

rion. Even rotting flesh provides water.

Tour the strange coastal

4Desert preda-

Namib Desert at http://www.

tors range from

of deserts in North and South

pbs.org/edens/namib/. Don’t

fierce spiders and

America, Africa, and Asia.

forget to take the Namib

burrowing moles to

These cats are lions, cheetahs,

trivia challenge!

birds of prey, rep-

cougars or pumas, caracals,

tiles, and mam-

and sand cats. Australia has

mals. The number

many feral cats in its deserts,

carnivores (KAR-nuh-vorz)

and variety of pred-

but these are house-pet rela-

animals that eat meat

ators depend on

tives gone wild. They do not

omnivores (OM-nuh-vorz)

the availability of

qualify as “big cats.”

animals that eat both plants

prey. Predators can

and meat

be carnivores or

do most of the hunting.

omnivores. In the

Lionesses hunt with other

? WORDS TO KNOW . . .

30

Big cats are top predators

Female cats generally

 Cheetahs slip silently through desert grasses when hunting antelopes.

females in their group, which

tahs are the fastest land ani-

is called a pride. They stalk

mals. They can run at speeds

prey, surround it, and bring

up to 70 miles (113 km) per

it down. Lionesses can bring

hour over short distances.

down elands, gemsbok, water

They hunt small antelopes in

buffalo, and wildebeest. When

a quick, deadly race. Big cats

running short distances, chee-

endure many hunting failures. 31

[Predators]

A cat that catches one in five

otes are the largest canines.

animals it chases is doing well.

They live and hunt in packs.

Canine relatives also hunt

They do not have claws like

in deserts. Desert

big cats to help them bring

“dogs” include small

down prey. They must rely

canine (KAY-nine) related

kit foxes and fennec

on sharp teeth and cunning

to dogs

foxes, rangy coyotes,

hunting skills.

? WORDS TO KNOW . . .

Mexican gray

Lone wolves and coyotes

wolves, African hunting dogs,

hunt smaller prey, such as

and dingoes. Wolves and coy-

rabbits and quail. Without

[Predators]

pack support, they cannot

insectivores thrive,

bring down pronghorns or

too. Common desert

Hyenas may look like dogs, but

mule deer. Lone canines are

insectivores include

they are distantly related to

usually young males. They

lizards, skinks,

cats. Hyenas, known for their

hope to find willing females so

birds, bats, and

laugh, feed on carrion. They

they can start their own packs.

rodents. Golden

often clean up the leftovers of

moles and lizards

lions. Hyenas will also hunt fresh

tiny compared to their wolf rel-

called legless skinks

meat, including young antelope,

atives. Fennec foxes live in the

swim through the

goats, lizards, and snakes.

Sahara. They have huge ears

sands of the Namib

that they use to hear their

Desert. They sneak

prey. They are night hunters,

up under their prey,

Most people think of coyotes as

so good vision and hearing

pop out of the

pests. Discover the fascinating

are essential. Small foxes

sand, and gobble

world of this predator in The

spend their days in burrows

their meals.

World of the Coyote by Wayne

Fennec and kit foxes are

to keep cool.

Insectivores

More than 18

!

WOULD YOU BELIEVE?

 READ IT!

Grady (Sierra Club Books, 1994).

different species of bats fly over North American

4Insect eaters—insectivores—

deserts at night. The largest

live in all deserts. Flies, spi-

is the big free-tailed bat, with

ders, beetles, roaches, and

a face that looks remarkably

crickets survive well in desert

like that of a dog. Some

environments. Therefore,

desert bats eat half their

 Dingoes—wild dogs—are the major predators of the Australian outback.

33

weight in insects nightly. This is equal to several thousand insects per bat. Three species of vampire bats also fly through the Chihuahuan Desert. They sip blood, usually from mammals. Families of meerkats live in the Kalahari Desert, where they find plenty of insects and spiders for food. PROFILE: HAIRY ARMADILLOS

Meerkats look like scrawny

The hairy armadillo of Patagonia (see

squirrels with skinny tails.

map at right) looks like a tank on legs.

They are quick, agile

It has armor shielding its head, back, and sides. The armor protects it from predators. A

These expert diggers tunnel under their prey. They feed on maggots,

S O U T H M E R I C A

Pacific Ocean

carrion, grubs, and insects. Surprisingly,

teeth, which are necessary equipment

Pata gon ia

hairy armadillos do not have sharp front

Atlantic Ocean

0 0

1000 Miles 1000 KM

for most predators.  South America’s Patagonia region

34

[Predators]

hunters. Meerkats hunt scorpions, spiders, and snakes

Desert Reptiles

? WORDS TO KNOW . . . tubers (TOO-buhrz) thick,

without fear. They are immune

4Desert reptiles

underground plant stems,

to poison from those creatures.

come in a variety

such as potatoes or turnips

Meerkats are opportunistic

of forms. There

feeders. They eat whatever is

are rattlesnakes,

available, including snails,

vipers, and side-

The Gila monster and the

ground-nesting birds, eggs,

winders. All are

Mexican beaded lizard are the

bulbs, roots, and tubers.

quite poisonous.

only two venomous lizards in

Monitor lizards

the world.

Australia’s echidna (ehKID-nuh) is a very particular predator. It specializes in eating ants and termites. Luckily, there are plenty of both in Australia’s deserts. The echidna has a tough snout and an extremely long tongue (7 inches, or 18 cm). The animal lies on an anthill, then sticks its tongue down the hole. An adult echidna can eat more than 2 pounds (900 g) of ants or termites in an hour. Meerkats stand at attention when watching  for enemies. If a predator approaches, they chatter and duck into their burrows.

look like miniature

!

WOULD YOU BELIEVE?

[Predators]

dinosaurs swaggering across

of their prey by tasting the

the sand. Gila monsters wear

air. Their forked tongues

beautiful colors, but carry

combine taste and smell.

dangerous venom.

A few flicks in the air,

Snakes prefer eating rodents, but they will also eat lizards and other snakes. Snakes can sense the location

and the snake knows what prey is available. All snakes eat their prey whole. Their jaws detach to

[Predators]

allow them to eat prey much larger than they are. Once fed, snakes retire to their burrows to digest their food. Eating large prey is a lot of work and can tire out even the largest snake. During digestion, snakes are open to attack by predators, such as meerkats and great horned owls. Gila monsters live in North American deserts. In summer months, Gila monsters sun themselves during the day. They absorb heat from the sun to keep warm. Gila monsters hunt at night, seeking rodents, lizards, birds,

 The great horned owl hunts its prey at night, which explains why it has such large eyes.

Birds on the Hunt

and eggs. During winter

4Birds of prey come in a

months, Gila monsters hiber-

variety of shapes and sizes.

nate, or sleep. To survive,

Tiny elf owls are barely the

their bodies feed off the fat

size of a sparrow. Great horned

in their tails.

owls, on the other hand, can

 Although monitor lizards look fearsome, they are basically cowards. They will run away, swim, or climb trees to avoid enemies.

37

[Predators]

weigh 4 pounds

other animals. They are

After a hawk or owl digests the

(1.8 kg) and stand

fearless hunters and often

meat of its prey, a pellet of fur,

2 feet (.61 m) tall.

attack rattlesnakes, lizards,

feathers, and bones forms in its

Elf owls usually

and other birds. Road-

stomach. The birds vomit these

inhabit empty Gila

runners have perfected

pellets. Studying pellet contents

woodpecker nests

the art of hunting poison-

tells scientists what the hawks

in cactuses. Bur-

ous snakes. They run around

and owls ate.

rowing owls nest

the snake until they can

underground.

dart forward without being

!

WOULD YOU BELIEVE?

Ferruginous hawks and great horned owls scour the

behind the head, then

desert floor for rodents.

pound the reptile’s head

Both birds feed on ground

against the ground.

squirrels, pocket gophers, prairie dogs, and kangaroo

Successful Predators

rats. They will also eat rab-

4Predators that eat a

bits, snakes, lizards, larks,

variety of different foods

and grasshoppers.

survive in harsh climates.

One of the most fascinat-

38

bitten. They grab the snake

Great horned owls and fer-

ing carnivorous birds is the

ruginous hawks do not limit

roadrunner. Roadrunners

their prey to rodents. They

run faster than any other

take advantage of opportuni-

bird and faster than most

ties to eat lizards, snakes,

A roadrunner is a small, but gifted, predator. It catches and kills snakes. 

[Predators]

frogs, and large insects. Food

vultures and buzzards,

is food, and no desert preda-

along with hyenas and

tor passes up a meal.

jackals, feast on the remains

Predators fulfill an

of animals. They remove

important role in nature.

rotting flesh from the eco-

They keep prey populations

system. Every predator has

from exploding. Without

its part to play in keeping

predators, insects would

nature’s balance—even in

take over deserts. Turkey

the desert.

Prey

4

[Chapter Four]

Prey

harmless. They thrive on a diet of ants. Molochs can eat up to

4A thorny devil, or

3,000 ants in one meal. The

moloch, is a strange-looking

moloch’s tongue flicks back

lizard. It is covered from

and forth, catching one ant

head to toe with thorns or

at a time. This is not a slow

spikes. Molochs look like

feeding process. Molochs

creatures from science-fiction

can eat at a rate of 45 ants

movies, but they are actually

per minute. A feral cat sneaks through the spiny-leafed spinifex grass. The cat hunts a moloch through the desert scrub. The thorny devil immediately freezes and changes its color to match the ground below it. The cat comes nearer. The moloch ducks its head. It reveals a false “head” or knob on its neck. The cat becomes confused as the lizard huffs and puffs to bloat its size.  Who can wonder why this lizard is called a thorny devil?

 A moloch (thorny devil) can change color to thwart its enemies.

This time, the moloch Indian Ocean

escapes. However, feral

Tanami Desert

cats are reducing moloch

Great Sandy Desert

numbers to dangerously

Gibson Desert

A U S T R A L I A

Great Victoria Desert

low levels. Unless feral cats are brought under control, Australia’s molochs

Indian Ocean 0 0

Simpson Desert Sturt Stony Desert

Little Desert

500 Miles 500 KM

face extinction.  Australia’s Gibson, Great Sandy, Great Victoria, Little, Simpson, Sturt Stony, and Tanami deserts

41

[Prey]

The Desert Supermarket

make up the first link in a meat-eater’s food chain. Each

4Deserts have

of these animal families feeds

many creatures that

on the others. They also

Learn more about desert insects

serve as prey for

provide water and nutrients

and invertebrates. Visit the

hungry animals.

needed by small creatures

Arizona Sonora Desert Museum

Common desert

to survive.

Web site at http://www.desert-

prey include insects,

museum.org/kids/funfacts.html.

reptiles, amphibians,

termite populations. These

rodents, and ground-

social creatures live in colonies

nesting birds. These

with populations in the thou-

biomes (BYE-ohmz) large

animal groups pro-

sands. As prey, they provide an

ecosystems in which the

vide the most prey

easy target. Termite mounds

plants and animals are adapted

in other land bi-

are highly visible in deserts.

to a particular climate or physi-

omes as well. One

They can rise more than 20

cal environment

difference, how-

feet (6 m) above the ground.

invertebrates (in-VUR-tuh-brits)

ever, is that desert

The mounds are as hard as

animals with no backbones

prey provide both

cement, which some people

nutrients (NOO-tree-uhnts)

food and water for

discover by crashing into them

substances needed by plants,

their predators.

with a jeep. The jeep suffers

 LOOK IT UP!

?

WORDS TO KNOW . . .

animals, or humans for growth; key elements of food

42

Large numbers

Deserts have huge ant and

serious damage, but the ter-

of insects, spiders,

mite mounds remain intact.

and invertebrates

Anteaters, echidnas, lizards,

!  Termites in the Kimberly region of Australia build mounds that are as hard as cement.

WOULD YOU BELIEVE?

Honey ants have specific workers that hold supplies of sweet

and birds feast on termites

tor becomes the

plant nectar in their bellies.

and ants.

prey. Thoroughly

The bellies are so swollen that

Termite mounds and

poisoned, an attack-

the ants cannot move. Worker

anthills have strong protection.

ing lizard or spider

ants must feed and groom

Soldier ants or termites attack

becomes a meal for

them. These ants are a favorite

predators. Soldier ants swarm

the ants.

prey of badgers, lizards, and

over a predator and sting it mercilessly. Often, the preda-

Amphibians are

native people.

animals that spend 43

PROFILE: SPADEFOOT TOADS The life of the spadefoot toad (right) is a constant race against time. These amphibians spend months in underground burrows, lying dormant. Somehow, they sense that the rainy season is about to begin. Rain pours across the desert, and spadefoot toads wake up. They immediately look for mates. In small pools, females lay their eggs, which the males fertilize. Now, the race is truly on. What will happen first? Will the eggs produce tadpoles that become toads before the water pool dries up? Will the hot desert sun evapo-

part of their lives in water.

rate the water quickly and kill the eggs

Toads mate in water and

and tadpoles?

lay their eggs there. It

The time from egg to tadpole to toad

44

would seem that few amphib-

is short. Egg to tadpole takes less than

ians would make their

two days. Tadpole to toad is nearly as

homes in deserts. But they

quick. Alive or dead, the eggs, tadpoles,

do. Deserts have a surpris-

and toads make good eating for reptiles,

ing number of frogs, toads,

birds, and meat-eating mammals.

and salamanders.

[Prey]

Reptiles thrive in hot

food. Snakes and

!

WOULD YOU BELIEVE?

desert ecosystems. The desert

lizards that feed on

Many lizards can “drop” their

sun warms their cold-blooded

gerbils are also noc-

tails when attacked by a preda-

bodies. Most people think

turnal and hunt

tor. The lost tail continues to

of reptiles as predators, such

their prey at night.

wiggle, which attracts the

as rattlesnakes and monitor

One odd

lizards. However, there are

rodent, called

fully escapes while its useless

hundreds of harmless lizards,

a gundi, looks a

tail becomes a meal. Most will

skinks, geckos, and snakes

bit like a gerbil.

probably even grow replace-

living in deserts. They, too,

It lives in the west-

ment tails.

prey on insects and rodents,

ern Sahara in rock

but they also serve as food

burrows. Gundis live in

for dozens of larger animals. Kangaroo rats, pocket mice, jerboas, and gerbils are common desert rodents. Carnivorous mammals, large reptiles, and birds of prey hunt rodents. Prey and their primary predators are active during the same period of the day. Gerbils roam the desert floor at night looking for Sand geckos in the Namib Desert hide under  the sand when an enemy approaches.

predator. The lizard then hope-

[Prey]

colonies. They must be careful

cats on the continent to bring

of snakes, feral cats, African

the multimillion rabbit popula-

hunting dogs, and birds of

tion under control. Similar

prey. To protect the colony,

problems happen

a guard keeps watch. When

whenever humans

danger lurks, the guard

ignore the natural

Prey in every biome need to

shrieks to warn the colony.

balance of the land.

hide from predators. Learn

Rabbits and hares also serve as prey in deserts. Jack-

The Best Defense

 READ IT!

more about natural camouflage by reading Anthony Frederick’s

rabbits are popular menu

4 Many desert

Clever Camouflages (Northward

items for coyotes, Mexican

critters survive

Press, 1997).

gray wolves, and great horned

because they have

owls. In North American

good camouflage.

deserts, predators control

Sandgrouse nest on

camouflage (KAM-uh-flahzh)

rabbit populations. The rabbit

the open desert.

coloring that blends in with

situation is a different story in

Their multicolored

the surroundings

Australia. Rabbits were origi-

feathers blend in

nally brought from England.

with local rocks, soils, and

They have no natural enemies

plants. Molochs and other

in Australia. As a result, the

lizards also use camouflage as

rabbit population did not

protection. Molochs change

expand—it exploded. There are

their skin colors to match the

not enough dingoes and wild

ground beneath them.

?

WORDS TO KNOW . . .

 The huge ears on black-tailed jackrabbits let them hear the faintest sounds, including approaching predators.

47

[Prey]

Several desert creatures find that being assertive

rely on their hopping ability

works well as a defense.

to escape predators.

Australia’s frilled lizard spreads its neck skin, called a ruff. The lizard appears to

Diner Today . . . Dinner Tomorrow

double in size, which scares

4Alive or dead, every

off many predators. North

desert animal feeds others.

American chuckwallas

Prey may be the eggs,

squeeze their bodies into

infants, or adults of a

cracks between rocks. They

species. Prey can also be

balloon up with air. It

the carrion left when ani-

becomes impossible for a

mals die. Nature does not

predator to pry a bloated

waste good food. If food is

chuckwalla out of its haven.

available, some animal will

Running away also works well for prey. Golden moles

48

to escape. Frogs and toads

gnaw, suck, or chomp it. The food cycle depends

are usually the hunters.

on prey and predators. An

When they become the

animal can be both predator

hunted, they dig through sand

to some and prey to others.

so fast that predators cannot

The food chain is not com-

catch them. Sand lizards sim-

posed of simple links. It is

ply swim through the dunes

an intricate web of creatures,

 The frilled dragon lizard spreads its ruff to scare away its enemies.

each playing several parts.

days without food, but they

The most important role

can’t live without water.

is providing water. Many

Thus, prey becomes a

desert animals can survive

crucial water source. 49

5

[Chapter Five]

Flora

Flora 4 Camels snort and bellow. They smell water on the air

the sugar-sweet scent of dates. An oasis lies nearby on the well-worn caravan path in the Rub‘ al-Khali. An oasis is a desert mira-

. . . and something more.

cle. It is water, life, rest, and

Their sensitive noses pick up

shade in an otherwise dry and

 Oases in the Sahara Desert provide freshwater, shade, and sweet dates.

50

[Flora]

bleak ecosystem. At this oasis,

Rodents, insects, and birds

date palms strain against the

feast on the sweet fruit.

weight of their fruit. There are

Humans have picked and

hundreds of types of date

dried dates for food for more

palms. Each produces fruit

than 5,000 years.

that is nearly 50 percent sugar

Desert Plants

when dried. Surprisingly, date palms

4Desert plants must be

need a tremendous amount of

strong, hardy, and

water to live. Date palms drink

durable. They are

? WORDS TO KNOW . . .

water equal to 120 inches

designed to retain

succulents (SUHK-yuh-luhntz)

(305 cm) of yearly rainfall.

water to survive.

plants whose leaves and stems

Their roots tap deep into the

Many desert plants

are full of sap or juice

sandy soil. The underground

are succulents,

water that feeds the oasis also feeds the date palms. The temperature climbs to 110˚F (43˚C). In that heat, the

A

S

[ M I D D L E

I

A E A S T ]

fruit dries on the tree. One bunch may bear 1,000 individ-

Arabian Desert

ual dates. One tree can produce more than 100 pounds

0 0

250 Miles 250 KM

(45 kg) of dates a year.  Asia’s Arabian Desert

51

[Flora]

which simply means “juicy.”

thickness allows the leaves to

Most desert plants have thick,

hold water. Leaf size keeps

small, pale-colored leaves. The

evaporation to a minimum.

[Flora]

 WATCH IT!

Pale color reflects heat. Each

before blooming.

aspect of the plant’s make-

Once the rains

After a rain, desert plants

up helps it survive the

come, the time

come to life. Watch the change

desert climate.

from sprout

from wasteland to wonderland

to flower to seed

in Desert Springs to Life:

is quick.

Treasures of the Wild

Few grasses survive in deserts. One exception is spiny-leafed spinifex grass,

Wildflowers

[ASIN: B00004YKMA].

found in Australian deserts.

bring color and

Most grasses do not have the

beauty to stark

natural design to survive

desert landscapes.

Have you ever thought about

desert climates. They cannot

The flowers come

planting a desert garden?

hold water for long periods.

in vivid colors that

Desert gardens do not contain

The leaves are too thin and

attract humming-

only cactuses. Many have

fragile to withstand months

birds, bees, and

beautiful wildflowers and

of draining heat. Semiarid

bats. Plants need

shrubs. If you are interested,

deserts tend to have more

them to carry

contact Native Seeds, 526

grasses and shrubs than hot

pollen from flower

North 4th Avenue, Tucson,

and dry or cold deserts.

to flower. Bright

Arizona 85705. The company

red-orange Cali-

sells seeds for growing Native

life after a desert rainstorm.

fornia poppies

American desert crops.

Flower seeds can survive long

thrive in hot desert

droughts. They can remain

winds. Pink and purple desert

dormant for several years

five-spots and bright blue

Wildflowers burst into

 Tufts of spinifex grass dot the red rocks of Australia’s deserts.

 DO IT!

53

PROFILE: WELWITSCHIA

desert lupines add to the

The Namib Desert is home to a rare,

wildflower rainbow.

enduring plant called the welwitschia.

Cactuses

The plant looks like a pile of brown leather strips lying in a heap on the

4Cactuses do not grow

desert floor. The leatherlike strips are

in every desert. They are

cast-off parts of the plant’s two main

not limited to deserts at

leaves. Welwitschias have long taproots,

all. Cactus plants also pros-

or main roots from which smaller roots

per in mountain, grassland,

often grow. The taproot swells to nearly

and beach environments.

3 feet (1 m) across. This remarkable

They are native to North

desert plant can live 2,000 years in a

and South America and

climate that proves challenging for most

are found as far north as

humans after only two days.

central Canada. !

WOULD YOU BELIEVE?

The night-blooming cereus produces creamy-white blossoms that bloom only one night a year. For this reason, the cereus is called the Queen of the Night.

 Organ pipe cactuses produce delicious fruit that can be made into a drink or jelly.

 When a saguaro cactus fills with water, it expands like an accordion.

Most desert cactuses have spines and thick, waxy skin. Cactus plants are succulents.

cut, the cactus oozes liquid to form a scab over the “wound.” All cactuses  READ IT!

They suck up water and use

bear flowers. Most

it during periods of drought.

cactus flowers are

Spiny cactuses paint the desert

Their skin is flexible and

white or varieties of

with beauty. Learn about the

expands for the plants to

pink and red. White

cactuses and their flowers in

hold water. Sharp spines pro-

cactus flowers are

George H. H. Huey’s Wild

tect the plants from animals.

easily seen at night.

Cactus (Artisan, 1996).

When the skin of the plant is

Pinks and reds can 55

[Flora]

? WORDS TO KNOW . . .

be seen over long

fruit produced from cactus

arroyo (ah-ROY-yoh) a deep,

distances. Cactuses

flowers feeds animals, birds,

dry streambed

need help to polli-

and humans.

feces (FEE-sees) solid waste of

nate. Flower colors

an animal or human

attract bees, bats,

thousands of seeds. A bat

pollinate (POL-uh-nate) to

birds, and other

or bird breaks open the fruit

transfer pollen and fertilize a

insects. Blossoms

and eats it. Some seeds drop

flower so it can reproduce

may appear over

to the ground. Others are

several weeks or

carried in the body of the

Cactus fruit contains

just one day. Some cactuses

diner and are eliminated as

bloom only at night. The

feces. The seeds must wait

many months for rain. Rain brings a flash flood, carrying the seeds down an arroyo. Only a handful of every thousand seeds takes root. Even fewer survive to grow into adult plants. Cactuses grow in many shapes and sizes. The gigantic saguaro stands high above every other cactus in the desert. Tiny cactuses look like  Cactuses may be prickly, but they are also beautiful. Just look at the blooms on this beavertail cactus.

 The spines on this fishhook cactus have curved hooks that protect it from birds and animals.

sea urchins—round and

barrel, beavertail, organ

covered with spines. Many

pipe, and bishop’s hat cactus-

cactuses have names based

es. Old man cactus is covered

on their appearance, such as

with white hair that looks 57

need plenty of water to survive, and deserts do not have water. Or, do they? Many deserts have rivers running through them. The Sahara has the Niger and the Nile rivers. The Sonoran and Chihuahuan deserts have the Rio Grande and the Colorado River. Desert rivers provide surface water. There is also water under desert land. That water flows  Bright blossoms cover ironwood trees each spring.

as underground streams or is held in aquifers. Deep roots

? WORDS TO KNOW . . .

like a beard. Fish-

tap underground water and

aquifers (AH-kwih-fuhrz)

hook cactus has

feed trees. Cabbage and desert

rocks that hold water

curved spines and

palms grow where their roots

bright yellow flowers,

can drink from underground

a rare color for cactus flowers.

Keystone Trees

58

water sources. Desert trees vary by location. California deserts support

4It seems odd that trees

fan and desert palms. Cotton-

grow in deserts. After all, trees

wood, ironwood, and mesquite

[Flora]

spread their branches in the

PROFILE: JOSHUA TREE

Sonoran and Chihuahuan

High in the Mojave Desert, Joshua trees

deserts. Baobab and tamarisk

spread their twisted branches. Joshua

trees grow in the Kalahari and

trees belong to the yucca family. They

the Namib. Acacia endures the

have developed an interesting relation-

hot winds of Australia’s Gibson

ship with the pronuba moth. Only the

and Simpson deserts.

female pronuba moth pollinates Joshua

Trees fill many functions

trees. She moves from flower to flower,

in desert biomes. They act as

collecting and depositing pollen. She lays

keystone species. Tree leaves

her eggs deep in the yellow-green flow-

and branches provide shelter

ers. As the moth larvae grow, they eat

for birds, bats, lizards, snakes,

yucca seeds. The relationship between

and big cats such as the chee-

tree and moth is

tah. Leaves feed giraffes, ante-

called symbiotic.

lopes, and elephants. Tree bark

Neither would

symbiotic (sihm-buy-AH-tik)

provides a scratching post for

survive without

concerning the close connection

itchy hides. Shade protects

the other.

and dependence on existence

animals from the heat. Insects

? WORDS TO KNOW . . .

between two living things

bore into the trunks to feed. Woodpeckers drill against the wood to find the insects. Tree roots hold soil in place, preventing erosion. 59

6

[Chapter Six]

Herbivores

Herbivores

lucky, the mole rat will run into food. This time, the naked

4A naked mole rat scurries

mole rat finds sweet potatoes,

along an underground bur-

a crop raised by local tribes-

row. It eats roots and tubers.

men. For the people of the

It uses a hit-or-miss method of

Ogaden Desert in Ethiopia

searching for food. The nearly

and Somalia, naked mole rats

blind mole rat digs shallow

are pests. They could eat an

burrows at the depth where

entire potato crop that the

tubers and roots grow. If it’s

people need to survive.

 Growing crops on such dry land creates a challenge for this Ethiopian farmer.

60

[Herbivores]

Weighing barely 2 ounces (57 grams), the naked mole rat may be the ugliest creature alive. Mole rats never leave their underground burrows. They have wrinkled, paperlike skin, beady eyes, and two large front teeth. Naked mole rats usually live in colonies of 30 to 80 animals, though there are sometimes hundreds in a colony. The colony closely resembles a beehive. Naked

 Naked mole rats live in colonies run by a queen.

mole rats have a queen. She is the only female in the colony that mates. The queen has up to three male mates and pro-

A

F

R

I

C

A Ogaden Desert

duces a new litter of pups every three months or so.

Atlantic Ocean

All other mole rats are workers. They dig burrows and

0 0

1000 Miles 1000 KM

Indian Ocean

tunnels in an underground  Africa’s Ogaden Desert in Ethiopia and Somalia

61

 Male gemsbok fight to see which one is the strongest. Only the strongest males get to mate with female gemsboks.

community that spans 1 square

wallabies. Asia has wild asses.

mile (2.6 sq km). A naked

Zebras, antelopes, and gazelles

mole rat colony has rest

roam African desert lands. In

areas, bathrooms, water-

North America, bighorn sheep

holding chambers, and

and mule deer are common

roadways for travel.

desert plant feeders. Camels are the best-

Large Plant Eaters

known desert mammals. They

in deserts. Learn more about

4Every desert has

pavements and changing sand

them by reading Endangered

its share of large

dunes. Camels store fat in

Desert Animals by Dave Taylor

herbivores, or plant

their humps. When several

(Crabtree, 1992).

eaters. Australia has

days pass without water,

red kangaroos and

camel bodies change the fat

 READ IT! Many endangered animals live

62

leisurely walk over stony desert

[Herbivores]

into usable water. Once they

WILD ASSES IN THE NEWS

reach a water hole, a camel can

Asian cultures have long praised

drink more than 20 gallons

wild asses for their strength. The

(76 L) in less than 10 minutes.

herds drift across the deserts of Iran.

There are two types of

Once, Persian wild asses numbered

desert camels: dromedaries

in the thousands. Today, only about

and Bactrians. Dromedaries

400 survive.

have one hump and live in

The wild ass is a flagship species in

Africa and on the Arabian

Iran. In the late 1990s, the Iranian

Peninsula. They are mostly

government launched a program to

tame and are owned by

save the Persian wild ass. Animals

nomads. Nomads are people

were captured and have been held

who roam about instead of liv-

in breeding areas. The plan is for

ing in one place. Dromedaries

the asses to form new herds. Small

eat dates, grain, grass, and

herds will be released into the high

leaves. Bactrian camels have

desert when there are enough wild

two humps and live in the

asses available.

Gobi Desert, the Takla Makan Desert, and regions of Afghanistan, Iran, and Turkey. Food is scarce in these areas. Bactrian camels have adjusted to eating any available plant 63

!

WOULD YOU BELIEVE?

Mother kangaroos are very busy creatures. A female kangaroo may have a one-year-old joey living outside her pouch, a much younger joey in the pouch, and

 Wild asses are a flagship species in Iran.

a fertilized egg in her body.

life. About 1,000

and antelopes need to drink

Females can adjust birthing

wild camels live

daily. They wander from one

times so that they have their

in the Gobi and

water hole to the next as water

babies when food is plentiful.

Takla Makan

sources dry up. They eat

deserts. They are

shrubs, bushes, trees, and

two different types of milk.

protected as endan-

grasses but cannot get enough

Joeys out of the pouch get milk

gered species.

water from plants to live.

Mother kangaroos produce

that is heavy in fat content.

Many large

Red kangaroos hop their

Joeys in the pouch drink milk

desert mammals

way across an extensive terri-

that is rich in carbohydrates to

cannot live far from

tory. They live in groups,

help them grow.

water holes. Zebras,

called mobs. Red kangaroos

wild asses, horses,

sleep most of the day and feed

64

[Herbivores]

 WATCH IT!

and travel at night. They stay

they need by eating

near water, where plants are

seeds, leaves, and

The Sonoran Desert has its share

more plentiful.

fruit.

of daily dramas. Discover them

Desert Rodents

Kangaroo rats

in National Geographic’s

never drink water,

Sonoran Desert: A Violent Eden

4 Many desert herbivores

even if it is right

[ASIN: 0792241509].

belong to the rodent family.

outside their bur-

They include furry chinchillas

row. They do not even eat

in South America’s Atacama

newly grown grasses. They eat

Desert and skittish kangaroo

only dry seeds. Their bodies

rats in the Mojave. Several of

have adjusted to a lack of

these species live “water-free”

drinking water. Even their

lives. They get all the moisture

urine has very little water.

 Chinchillas have been hunted nearly to extinction because of their prized fur.

65

PROFILE: THE DESERT TORTOISE The desert tortoise can be considered a

their relatives also live on

keystone, umbrella, flagship, and indica-

dry seeds and plants. They

tor species. The tortoise digs burrows

do not drink, either. These

that later house other animals. This

rodents have strong front

makes them a keystone species. Desert

teeth that continue to grow

tortoises cover fairly large ranges, which

throughout their lives. They

makes them an umbrella species. They

need to gnaw on tough,

cast a safety umbrella over other species

woody plants to keep their

living within their protected range.

teeth worn down.

Tortoises’ survival problems attract

66

Jerboas, gerbils, and

In the Atacama and

public interest, making them a flagship

Patagonia deserts of South

species. Finally, when desert environ-

America, the little chinchilla

ments suffer, so does the desert tortoise.

thrives in high desert ecosys-

Increased off-road vehicle use, pollution,

tems. They live at altitudes of

human activity, and loss of habitat affect

10,000 to 20,000 feet (3,000

desert tortoises. This makes the tortoise

to 6,000 m). Chinchillas eat

an indicator species.

grasses or seeds, except at

Desert tortoises live for about 100

dawn. Then, dew coats deli-

years. They eat herbs, wildflowers, and

cate plant leaves. The chin-

grasses. Adult tortoises can live a year or

chillas feed on dew-covered

more without direct access to water.

leaves and do not have to

They get liquid from the plants they eat.

search for water holes.

 The houbara bustard thrives on plants in the rugged deserts of the Arabian Peninsula.

Desert Birds

their eggs in burrows. There are neither enough seeds nor

4A large number of desert

enough insects to feed large

birds live unique lives.

flocks of birds. Most birds

Because there are few trees

eat some of each. Sand-

in deserts, many desert birds

grouse, desert larks, and

build ground nests or lay

houbara are among the main 67

[Herbivores]

 An ostrich can run at high speeds.

68

[Herbivores]

plant eaters. They eat seeds,

These huge birds usually

fruit, berries, and leaves.

eat grasses, seeds, leaves,

The houbara bustard of

and fruit. Ostriches also

North Africa and the Arab-

munch on grasshoppers and

ian Peninsula feeds on the

locusts, while emus will eat

artemisia plant. It gets all

mice and lizards.

its nutrition and water from

Desert herbivores pay

artemisia leaves, berries,

close attention to water sup-

and stems. It also eats wild

plies. Heavy rains fill water

onions on occasion.

holes and streams. Rainfall

Ostriches and emus are

also increases plant growth,

both large, flightless birds.

which supplies water to

Their bodies weigh far too

many creatures. Heavy rains

much for their wings to lift

can provide a large crop of

them off the ground. A full-

fruit and seeds. For animals

sized male ostrich can weigh

depending on plants for

more than 300 pounds (136

nutrition, even fog is a wel-

kg). Ostriches live in the

come water source.

southern Sahara, Kalahari,

Fog condenses into

and Namib deserts. Emus

dew on leaves and

condenses (kuhn-DENSS-ehzz)

live exclusively in Australia.

branches, refresh-

changes from a gaseous state

They weigh between 65 and

ing both the plant

to a liquid state

100 pounds (30 and 45 kg).

and the plant eater.

? WORDS TO KNOW . . .

69

7

[Chapter Seven]

A Cycle of Life

A Cycle of Life

70

is time to lay her eggs, and she needs the tarantula. She hunts the spider right into its burrow. She enters the den and attacks. The wasp stings

4A pepsis wasp is on the

the tarantula several times.

hunt. Her chosen prey is a

Her poison does not kill the

tarantula. Tarantulas are much

spider, just paralyzes it.

larger than pepsis wasps, but

Pepsis wasps are the

this female is determined. It

Hercules of wasps. This tiny

[A Cycle of Life]

female drags the tarantula to her nest. She lays her eggs on the paralyzed spider. As the larvae grow, they feed on the spider. And, yes, the spider is alive during most of the feast.

Poison Plants in the Desert 4Poison plays an essential role in the desert cycle of life. It protects some plants and animals from predators. Plants carry dangers as deadly as rattlesnake bites. Stinging nettles and poison ivy bear toxins, or poisonous substances, that are transferred by touch. Nettle

 Jimsonweed may look lovely with its delicate white blooms. Beware—this plant is poisonous!

stings burn and poison ivy

and dogbane, however, are

rashes itch, but their dan-

killers.

gers are only mild. Jimsonweed, poison milkweed,

Poison protects the plants from being eaten. Jimsonweed

 A pepsis wasp stings a tarantula and then lays its eggs on the spider’s paralyzed body.

71

[A Cycle of Life]

flowers stink. Dogbane is

poisonous plants in deserts.

nearly as bad. Most wild crea-

Milkweed sap is toxic to live-

tures recognize the odor of poi-

stock, yet the flowers attract

sonous plants and avoid them.

delicate butterflies. The butter-

Livestock are not quite as

flies pollinate the milkweed

smart. Many cows, sheep, and

and are not harmed by the

goats have died from eating

plant’s poison.

[A Cycle of Life]

 DO IT!

Poison Critters

sters pack a poisonous bite. Jewel

If you happen to tour a desert

4 Animals use poison to pro-

wasps, like pepsis

ecosystem, be careful. Stay on

tect themselves from predators.

wasps, paralyze their

marked paths. Do not turn over

For example, the Australian

prey and lay their

rocks or poke sticks under

water-holding frog sleeps

eggs on the live

shrubs. Never put your hand

through the dry season. It

body. Jewel wasps

into a burrow or a crack in the

survives by coating itself with

prefer to use cock-

rocks. If you see a poisonous

toxic mucus. The mucous

roaches as nurseries

critter, keep your distance.

coating repels animals inclined

for their young.

to eat the frog.

Surprisingly, the biggest

Poison also helps preda-

spiders don’t deliver the worst

tors catch their prey. Deserts

bite. Tarantulas look scary, but

are harsh ecosystems.

their bite is not much worse

Predators cannot afford to

than a bee sting. Small black

have prey escape. The next

widow spiders carry poison

meal may not come along for

that can kill a human. Their

several days. Predators with

venom is fifteen times more

poison make sure their prey

poisonous than prairie rattle-

does not run away.

snake venom. Recluse spiders

A host of poison-carrying

hide under rocks where it is

critters live in deserts. Wasps,

cool. Apache recluses, Arizona

spiders, toads, and Gila mon-

recluses, Baja recluses, and

 Dogbane carries a poison that causes skin to blister. Its poison discourages plant eaters from taking a bite.

73

 Poisonous cane toads have invaded nearly every region of Australia.

all feed on insects, the creaIndian Ocean

tures for whom their poison Queensland Desert

is intended.

A U S T R A L I A

Australian Desert

Indian Ocean 0 0

500 Miles

Super-sized cane toads live in Australia, but they do not belong there. They were brought to Australia to kill

500 KM

beetles that ate sugarcane  Australian and Queensland deserts

74

crops. Unfortunately, no

desert recluses are species com-

Australian predators hunt the

mon to North American

poison-carrying, 3-pound

deserts. They deliver a poison

(1.4-kg) cane toads. These

that kills flesh. These spiders

toads multiply at an alarming

[A Cycle of Life]

rate. A female lays about

PROFILE: SCORPIONS

35,000 eggs a year. The

Scorpions belong to the same animal

toad carries a poison that it

family as spiders and ticks. They thrive

squirts at any predator foolish

in desert climates but also live in grass-

enough to get close. As a

lands and forests. They carry their poi-

result, these amphibians have

son in the last of 12 sections of their

spread throughout Australia.

abdomen, or stomach. That section is

They threaten the existence of

not, as most people believe, a tail.

other reptiles and amphibians, even the desert death adder. Deserts even have danger-

Scorpions can grow up to 8 inches (20 cm) long. The largest is the “longtailed” South African scorpion. The

ous monsters—yes, monsters!

largest in North America are giant

Gila monsters are one of two

desert hairy scorpions that reach

venomous lizard species. They

5 inches (13 cm) in length.

live in North American des-

Scorpions use venom for protection

erts. Like snakes, Gila mon-

and hunting. Twenty scorpion species

sters use their poison to pre-

throughout the world deliver poison

vent prey from escaping. They

that can kill humans. Each species has

feed on rodents and birds.

its own particular poison recipe.

Unlike snakes, they do not have fangs. They bite hard and let their poison drip from mouth glands into their prey. 75

[A Cycle of Life]

bite. The most aggressive

S-s-s-s-snakes

rattler is the western diamond-

4When most people think of

back rattlesnake. This desert

poisonous creatures, they think

snake can reach 7 feet

of snakes. The most famous—

(2.1 m) long.

rattlesnakes—announce their presence before striking. Rattlesnakes  READ IT!

Diamondbacks feed on prairie dogs, rabbits, pocket gophers, ground squirrels,

belong to the pit

and kangaroo rats. They hunt

Here’s a book with a bite! Read

viper family.

at night, sensing their prey

Rattlesnake: Portrait of a

Different species of

by temperature. They can

Predator by Manny Rubio

rattlesnakes share

eat animals that weigh more

(Smithsonian, 1998).

certain characteris-

than themselves. Rattlers eat

tics. They have flat,

prey whole and can digest fur

almost triangular heads. Their tails end in rattles that they

76

and bones. A surprising number of

shake. They carry venom that

predators hunt rattlers. Eagles

they inject through their fangs.

and hawks attack from the sky.

They have heat-sensing organs

Spunky roadrunners never run

in pits in their skulls. These

from rattlesnakes—one of their

organs help them locate prey.

favorite foods. King snakes and

Smart people assume any

whipsnakes feed on rattlers, as

rattler they meet can and will

do coyotes, foxes, gray wolves,

 Australia’s desert death adder packs a nasty, toxin-filled bite.

and badgers. Snakes also

Poisonous creatures seem

get trampled by deer, ante-

to be more common in deserts

lopes, cows, horses, and

than in other biomes. This

bighorn sheep.

may be because of the amount

Rattlers are not the only

of prey available. Or it could

poisonous snakes in the

be that prey carries essential

world’s deserts. The Namib

water. Predators in most other

supports the sand viper.

biomes can afford to miss a

Australia has the desert death

meal or two. They get their

adder. Coral snakes, cobras,

water from rivers, lakes, ponds,

and black mambas slither

and puddles. For creatures that

through desert sands and sun

get water only from prey, loss

themselves on desert rocks.

of a meal can prove deadly. 77

8

[Chapter Eight]

The Sahara

The Sahara

There is little water in this most rugged of deserts. Addax eat tough grass,

4In the heart of the

go without water for long

Sahara, a newborn addax

periods of time, and bake

takes its first wobbly steps.

under the midday sun.

This desert-dwelling antelope

Luckily, the addax has

will face a harsh world.

adapted to this environment.

 The addax has been overhunted for its horns and skin. It is one of the few large animals that survives in the Sahara.

78

[The Sahara]

The addax is one of the world’s rarest animals. Fewer

Sahara Desert

than 500 of them are left on A

F

R

I

C

A

earth. Once, thousands of these magnificent antelope

Atlantic Ocean

roamed the Sahara. They were hunted for meat and

0 0

1000 Miles

Indian Ocean

1000 KM

leather, yet their numbers did not suffer. Politics and

 Africa’s Sahara Desert

modern hunting methods

vehicles chase addax

changed the fate of

herds across

the addax.

Saharan dunes.

 WATCH IT! Get a closer look at the

In the 1960s, the govern-

The addax situa-

ment of Sudan stated that all

tion is so dismal that

Sahara: A Place of Extremes

game animals should be con-

a nature park in the

[ASIN: B00004U2K8] by PBS

sidered food sources. They

Sahara in Tunisia

Home Video.

encouraged the killing and

had to obtain a

eating of several wild species.

small herd from Germany.

Since then, the addax popula-

Today, wild addax are limited

tion has become critically

to the most remote areas of

endangered. The population

the Sahara. If hunting contin-

continues to decrease as

ues, even those herds will

hunters in air-conditioned

not survive.

world’s largest desert. Watch

79

[The Sahara]

The Great Desert

(200,000 sq km), or 2 percent, is usable for growing

4The Sahara covers

crops. The Sahara is larger

3,500,000 square miles

than the continental United

(9,000,000 sq km) of north-

States. From east to west,

ern Africa. Of that land,

the Sahara stretches

only 80,000 square miles

3,000 miles (4,830 km)— from the Atlantic Ocean to the Red Sea. North to south, the desert measures about 1,200 miles (1,930 km)—from the Mediterranean Sea to the Sahel. The Sahel is a grassland region bordering the Sahara’s southern edge. Despite what Hollywood movies may show, the Sahara is not filled with sand dunes. Waving hills of sand cover only about 15 percent of the Sahara. The dunes (ergs) move with the constant desert wind. Ripples and  Sand dunes are what most people expect to see in the Sahara, but dunes make up only about 15 percent of the desert.

[The Sahara]

crests form on ergs, then disappear in the next sandstorm. More than two-thirds of the Sahara is covered with stark rock plateaus (hammadas) or gravel desert pavement (reg). The remaining land includes mountains, oases, and buffer zones that shift from one type of desert to another. The changes come from the endless, battering winds that sweep across the Sahara.

 Rock formations rise from desert sands in the Ahaggar region of southern Algeria.

The Sahara features three main mountain ranges: the Ahaggar, Aïr, and Tibesti. MAURITANIA

Mountain peaks jut up from

NIGER

ERRRITRREA ERITREA A

CHAD

SUDAN

BURKINA FASO

the desert floor. The tallest is

A

Emi Koussi (in the Tibesti

F

R

I

C

A

Atlantic Ocean

Range) at 11,204 feet (3,415 m). Saharan mountain ranges

0 0

1000 Miles 1000 KM

Indian Ocean

are not like the tree-covered  The countries of Burkina Faso, Chad, Eritrea, Mauritania, Niger, and Sudan in Africa

81

 This village lies in the Saharan mountains of Morocco.

Appalachians or Rockies. They

low rainfall and high rates of

are barren peaks with little or

evaporation. Even if the region

no plant life. They do, however,

gets heavy rain, water is lost in

get snow.

flash floods and intense heat.

Four thousand years ago,

82

There are few plants in

the Sahara was not the barren

the Sahara. Tough grasses, aca-

land it is today. A major cli-

cia trees, and date palms grow

mate-changing event took

around oases and underground

place. It changed the region

springs. The few plants that

from rain forests, grassy savan-

manage to thrive are eaten by

nas, and swamps to sand and

wild or grazing animals or are

stone. The Sahara suffers from

cut down for firewood.

[The Sahara]

Animals that live in the

THE SAHARA IN THE NEWS

Sahara must survive intense

Satellite pictures taken in 2002 show

heat, wind, sandstorms, and

an increase in plant growth along the

scarce water. As dawn breaks,

southern edges of the Sahara Desert.

addax, dorcas gazelles, and

For several decades, plants bordering

dama deer meet at a water

the desert had been dying. The plant

hole. They will look for shade

loss came from continued drought and

and rest during the worst heat.

poor farming methods. Because of this

A scarab beetle scurries behind the gazelles. It collects dung. Scarabs lay their eggs in

loss, the desert had been taking over more land. Recently, rainfall has increased. The

a ball of dung, or animal feces.

added water has supported increased

Their larvae feed on the dung

plant growth. Desert areas of Burkina

until they are ready to face the

Faso, Mauritania, Eritrea, Niger, Chad,

desert world.

and Sudan show an increase in shrubs

As dusk approaches, a fen-

and grasses. A very simple but effec-

nec fox peeks out of its burrow.

tive means of soil control has also

Its huge ears help the fox hear

helped plant growth. Farmers placed

prey at a distance. The fox

rows of rocks along slopes to hold

finds a desert mouse for din-

soil and water. The rock rows have

ner. Desert eagle owls float

greatly decreased erosion and pro-

high above the desert. Their

moted crop growth.

keen eyesight helps them pick 83

 Goats and cattle have over-grazed the land in the Sahara Desert and have therefore caused it to expand southward.

out jerboas and gerbils skitter-

too much desert plant life.

ing across the rocks. A houbara

Demands on water sources may

bustard has died. Its body pro-

become too great for oasis wells

vides food and water for a pair

to handle. Because many peo-

of spotted hyenas.

ple in the region still cook with

Much of the Sahara

84

firewood, few trees remain

remains natural and wild. It is

standing. And, wherever

too hot and barren to support

humans go, they leave trash

large human populations. The

behind. Abandoned vehicles,

desert heat and lack of water

tin cans, oil drips from cars,

do not encourage tourists.

and general rubbish do not

However, the Sahara still

decay in the desert. They cre-

suffers from human actions.

ate a lasting monument to the

Grazing cattle and goats eat

ignorance of humans.

9

[Chapter Nine]

4 Three off-road vehicles

across the desert, they crush

speed over the sand dunes of

burrows and kill the inhabi-

Mexico’s Baja California. It’s

tants. The vehicles squash

The Human Touch

The Human Touch

just a bit of harmless fun. There’s no one around for miles. How could this everyday event cause a problem? Most desert creatures live in burrows or under rocks. When off-road vehicles zoom

 This car may win its race in Baja California, but it may also kill desert tortoises and other underground desert dwellers.

85

[ T h e H u m a n To u c h ]

 LOOK IT UP!

lizards, snakes,

gered desert tortoises make

If you still want to know more

insects, and

their homes.

about deserts, check out this

spiders beneath

Web site filled with helpful links:

their wheels.

http://www.desertusa.com/.

Thoughtless

4Desertification is the

drivers ride over

process of turning fertile

shrubs, wildflowers, and

land into desert. The world’s

desert grass. Alive, these

deserts spread over more

plants provide food and

land every day. In some cases,

water for dozens of animal

deserts creep along inches at

species. Their roots hold soil

a time. In other cases, they

and reduce erosion. Dead,

spread into land that once sup-

the plants are worthless.

ported crops, farms, and cattle.

Half an hour of off-

86

Desertification

Consider the area that is

road fun tips the balance

called the Sahel. It is a band

of nature in the fragile

of land along the southern

desert ecosystem. For endan-

border of the Sahara Desert.

gered species, the imbalance

This land once supported

may signal the difference

farms where goats were raised

between survival and extinc-

and grains and vegetables

tion. For this reason, off-road

were grown. In the past

vehicles are not allowed in

50 years, the Sahara has

territories where the endan-

taken more than 160,615,000

[ T h e H u m a n To u c h ]

acres (65,000,000 hectares) of

decades, countries lying just

this farmland.

south of the Sahara have

The Sahara’s advance

suffered serious drought.

comes from both natural and

The limited rain that did

human activities. For several

fall came at odd times. When

30˚N

Sahara Desert 20˚N

10˚N

A

F

R

I

C

A

0˚

Atlantic Ocean 10˚S

N

Sahara Desert 50 years ago

20˚S

Sahara Desert today 0 0

500 Miles

Indian Ocean

500 KM

30˚S

10˚W

0˚

10˚E

20˚E

30˚E

40˚E

50˚E

 The Sahara Desert borders 50 years ago and today

87

[ T h e H u m a n To u c h ]

a region has no rain for

floods. It washes away top-

months, getting 2 inches

soil needed for crops.

(5 cm) in one day does not

Human actions made

help. That rain pours off

drought conditions worse.

overly dry land in flash

Farmers moved their herds

 Saharan people burn firewood for cooking. They cut down trees that protect the soil from erosion.

88

[ T h e H u m a n To u c h ]

 WATCH IT!

to graze on shrubs at the

the ever-growing

desert’s edge. Overgrazing

Gobi Desert. After

Dorling Kindersley brings

reduced plant cover to zero.

10 years, the forest

the desert biome to life

People also cut down trees or

buffer covered about

in Eyewitness Desert

shrubs to use as firewood.

19,748,000 acres

[ASIN: 6304165234].

Without plant cover, farmland

(8,000,000 hec-

became instant desert.

tares). Farmers have had suc-

The situation in the Sahel

cess in growing wheat in the

is slowly improving. Increased

protected area. The cost of

rainfall for the last several

planting the forest buffer

years has encouraged plant

was small compared to other

growth. Education has taught

attempts to turn back desert

farmers not to overgraze live-

advances. The Chinese spent

stock. Planting perennials,

only $600,000 to create the

which will last many years,

forest buffer. Other efforts to

helps to slow desertification.

stop deserts have cost billions

Using rocks to hold down soil

and have been less effective.

instead of dumping them is a cheap, effective means of soil conservation. The Chinese began a pro-

Beneath the Surface 4The earth under many deserts holds hidden treasures.

gram to build a buffer zone of

Human efforts to tap those

trees and shrubs along

treasures damage delicate 89

[ T h e H u m a n To u c h ]

desert ecosystems. The

Irrigation has turned desert

two biggest problems come

lands of Iran, Libya, and

from drilling water wells

Israel into farms.

and mining.

Desert irrigation has

Many deserts have large

been a science success story.

aquifers under their land.

However, aquifer water is

The Great Basin is basically

valuable and cannot be

semiarid sagebrush plain.

wasted. New methods of

Tapping underground water

watering crops had to be

allowed people to clear some

developed to save water.

of this land and irrigate crops.

Drip irrigation allows water

About 15 percent of the

to soak into the soil instead

world’s farmland is usable

of being sprayed over crops.

only because of irrigation.

Improved seeds and fertilizers produce more crops without

E

U

R

O

P

increasing water use. Special

E

Casp

Aral Sea

Black Sea

ian Sea

Mediterranean Sea

oped to hold water around plant roots.

IRAN ISRAEL

LIBYA

Desert mining has not

A S I A Red

been quite as positive. Desert

Sea

A 0 0

F

R

I

500 Miles

C

types of mulch were devel-

A

Indian Ocean

rocks hold copper, iron, gold,

500 KM

uranium, and borax. Mining  Iran, Israel, and Libya in Asia and North Africa

90

[ T h e H u m a n To u c h ]

efforts take these riches from the ground. They also pollute the air and water. Mines use tremendous amounts of water in an area where water is scarce. Excess water released from mines contains polluting chemicals. The area around the mine suffers from poor quality water, water and plant loss, and loss of animal habitats. On one hand, people are trying to save deserts from pollution, overuse, and poaching or overhunting animals. On the other hand, people are also trying to stop the advance of deserts onto farmland. We

 Some places in Egypt get freshwater by tapping underground springs.

must save desert lands for the

ing crops and grazing lands.

animals and plants that belong

In doing so, we’ll achieve

there. And we must stop the

what is already nature’s plan—

invading deserts from destroy-

a balanced desert biome. 91

Chart of Species

[Deserts]

KEYSTONE SPECIES

FLAGSHIP SPECIES

UMBRELLA SPECIES

INDICATOR SPECIES

AFRICA

tamarisk trees, baobab trees, acacias, date palms, SaheloSaharan antelopes

Grevy’s zebras, Barbary lions, Arabian oryxes, Scimitar-horned oryxes

Sahelo-Saharan antelopes, Barbary lions, Arabian oryxes, Scimitarhorned oryxes

emperor dragonflies, red admiral butterflies

ASIA

saksaul trees, plateau pikas, jerboas

Przewalski horses, Arabian oryxes, wild asses

wild Bactrian camels, Gobi bears, Argali sheep, wild asses, black-tailed gazelles

ladybugs

AUSTRALIA

acacias

feral burros, brumbies

kangaroos, wallabies

moths, butterflies

NORTH AMERICA

saguaro cactuses, velvet mesquite trees, prairie dogs, kangaroo rats

desert tortoises, rattlesnakes, burrowing owls

California cougars, bighorn sheep, desert tortoises

tarbush, sagebrush, sagebrush lizards, desert tortoises, butterflies, burrowing owls

SOUTH AMERICA

voles, prosopis trees, tegu lizards

guanacos, greater rheas, king vultures

sea lions, crowned eagles

butterflies, moths, bees, ladybugs

CONTINENT

 The above chart gives a starting point for identifying key species. Each desert environment has its own key species. The above chart lists some of those species. [Bold-faced entries are the ones discussed in the text.]

92