Horns, Tusks, and Flippers: The Evolution of Hoofed Mammals

Horns, Tusks, and Flippers

HORNS, TUSKS, AND FLIPPERS: THE EVOLUTION OF HOOFED MAMMALS

Donald R. Prothero Occidental College Los Angeles, California and

Robert M. Schoch Boston University Boston, Massachusetts

The Johns Hopkins University Press Baltimore and London

© 2002 The Johns Hopkins University Press All rights reserved. Published 2002 Printed in the United States of America on acid-free paper. 9876543 2

The Johns HopkinsUniversity Press 2715 North Charles Street Baltimore, Maryland 21218-4363 www.press.jhu.edu

Library of Congress Cataloging-in-Publication Data Prothero, Donald R. Horns, tusks, and flippers: the evolution of hoofed mammals / Donald R. Prothero and. Robert M. Schoch. p. cm. Includes bibliographical references (p. ) and index. ISBN 0-8018-7135-2 (alk. paper) 1. Ungulates-Evolution. 2. Ungulates, Fossil. 3. Elephants-Evolution. 4. Cetacea-Evolution. I. Schoch, Robert M. II. Title. QL737.U4 P76 2002 599.6138-dc21

2002069394

A catalog record for this book is available from the British Library.

Dedicated to our wives and sons Teresa LeVelIe and Erik Prothero Cynthia, Nicholas and Edward Schoch

and to the future of the animals described herein

Contents

Preface and Acknowledgments

Xl

1. Introduction American savanna . Names and dates Hoofed mammals Uinta beasts and the Cope-Marsh wars The lost world

1 2 6 9 13

2. Cloven hooves The kingdom of cloven hooves . Gut reactions "Bunny deer" Phosphate and fossils Pseudopigs Sui generis . "Nebraska man" and javelinas The "river horse"

19 19 19 23 25 26 27 35 39

3. Tylopods Camels without humps Ships of the desert "Mountain tooth"

45 45 53 56

4. Where the deer and the antelope play Graveyard of the Amazons Horns and antlers "Mouse deer" The "forest donkey" .. The camelopard Deer perfume AII-American-but not an antelope Deer to us all Abbe David and his deer

61 61 63 65 66 67 72 74 76 84

5. Hollow horns A world of bovids .. Bovines Aurochs and wisent Where the buffalo roam Cattle call Diving bucks "Bright eyes" Mountain monarchs

1

87 87 90 92 94 97 99 100 107

viii

6. A whale's tale Dr. Koch's "sea serpent" Walking whales? Andrews' giant "bear" The pedigree of Leviathan Life of a Leviathan "So long, and thanks for all the fish" Moby Dick, Flipper, and their kin Filter-feeding monsters Save the whales!

~................................................................................................

115 115 117 118 120 121 124 127 133 135

7. Out of Africa The tethytheres Mermaids The "feeble folk"

141 141 143 149

8. The origin of Jumbo Giants in the earth Early tuskers The "Great Missoul-ium" Shovel-tuskers and gomphotheres Elephant grinders Woolly wanderers The mystery of the missing mammoths

157 157 159 163 166 169 170 176

9. Kingdom of ivory Behold the behemoth Behemoth biology..... The sisterhood God and slave Blood and ivory

179 179 182 185 190 191

10. A horse of a different color (and shape) The origin of perissodactyIs The "hyrax beast" Cuvier's "ancient beast" Halfway horses Browsing anchitheres Grazing horses The hipparion controversy .

197 197 198 203 204 205 207 209

~.........................................................................................

11. Equus One-toed horses Stripes do not a zebra make Wild asses Wild and domesticated horses

213 216 221 223

12. Thunder beasts The legend of the Thunder Beasts Bone rush Osborn, Asia, and orthogenesis The biology of brontotheres

229 229 230 233 235

213

IX

13. Proboscises and claws Dragons' teeth Hall of the mountain cow.... Chalicotheres don't obey Cuvier's Law Just what are chalicotheres? Moropomorphs .

241 241 242 247 250 252

14. Rhinoceroses without horns "Ancient Dacians" and Siberian mummies . American rhinos The amphibious amynodonts Running rhinos and rhino ·giants True rhinoceroses Miocene invasions Rhinoceros Pompeii Hairy rhinos and giant "unicorns"

255 255 256 257 258 262 264 268 271

15. Thundering to extinction Unicorn, monoceros, and rhinoceros Black and white One-homed rhinos Horns of doom

277 277 280 284 287

Epilogue

293

References

297

Index

~.......................................................................................................

309

Preface and Acknowledgments

During the period 1983-1985 Schoch set about organizing a gathering of scientists that specialize in the evolution of perissodactyls (horses, rhinos, tapirs and their close living and extinct relatives). This culminated in a workshop on the evolution of perissodactyls (organized by Schoch and Jens Lorenz Franzen of the Forschunginstitut Senckenberg, Germany) which was held as part of the Fourth International Theriological Congress in Edmonton, Canada, in August 1985. Both of us played major roles in this workshop, and we found that so many new discoveries and ideas were presented at the workshop that it would be a shame to have no permanent record of its proceedings. Consequently, we invited the contributors to the workshop, plus other selected scientists who were not able to attend the meeting, to write updated articles on their work. These technical articles were then collected in a volume entitled The Evolution of Perissodactyls (edited by D. R. Prothero and R. M. Schoch, Oxford University Press, New York, 1989, 537 pages). After The Evolution of Perissodactyls was published we felt that the new ideas expressed in it should be made more readily accessible to a general audience. The evolution of horses in particular, as well as the evolution of other types of perissodactyls (such as brontotheres, see chapter 12 of this book) and their close relatives, the elephants, continue-to provide classic examples of evolution in both textbooks and popular books on evolution and prehistoric life. Yet much of what is put forth in these popular books is badly outdated, or simply wrong. We find this appalling, yet it is understandable in that many authors of popular books are not scientific experts in all of the fields they address. Out of enthusiasm for our subj'ect-we want scientifically up-to-date ideas about hoofed mammal evolution disseminated to the public-we decided to write this book. Initially we focused on the perissodactyls, but as the work progressed, the need for a book on all hoofed mammals and their close relatives (including whales and dolphins) became apparent. Eventually the book expanded to the present document. S·uch a book is timely, not only because of all the updated information, but also because most living hoofed mammals are now threatened by extinction. We find these animals to be intrinsically fascinating, and we hope that the reader will too. If more people come to appreciate these wonders of nature, perhaps their doom can be averted. Although no one is an expert on all the hoofed mammals, we have taken on this project because we have learned from the best. We thank Earl Manning for his many insights about ungulates, especially rhinos, Rich Cifelli for his ideas on ungulate relationships, Jens Franzen for his work on the Perissodactyl Workshop, Spencer Lucas and Margery Coombs for their enthusiasm for large mammals, Bruce MacFadden for his untiring work on horses, and Christine Janis and Elisabeth Vrba for their insights on ruminants. We thank our graduate advisers, Malcolm McKenna and John Ostrom, for their guidance and inspiration over the years. The entire book was reviewed by the late Herb Brauer, Colin Groves, Teresa LeVelIe, and the late Bob Savage. Individual chapters were reviewed by Larry Barnes, Rich Cifelli, Margery Coombs, Daryl Domning, Ewan Fordyce, William Franklin, John Harris, Christine Janis, Spencer Lucas, Tab Rasmussen, Hezy Shoshani, Lisa Spoon, Pascal Tassy, and Elisabeth Vrba. We are grateful to them all, and take complete responsibility, of course, for any errors of fact or interpretation. This book would never have been completed without the patience and understanding of our families, Teresa LeVelIe and Erik Prothero, and Cynthia, Nicholas, and Edward Schoch. Much of Prothero's portions of the book were written during a sabbatical in 1991, supported by grant EAR91-17819 from the National Science Foundation. The entire book was prepared by Prothero as camera-ready copy on a Macintosh PowerMac G4 computer, using Microsoft Word 8.0 and QuarkXpress 4.1 to layout the book for the printer. We thank Edward Tenner of Princeton University Press for originally suggesting this book, and Trevor Lipscombe of the Johns Hopkins University Press for handling the final editorial details.

Horns, Tusks, and Flippers

Figure 1.1. Artist's conception of the American savanna of the Great Plains during the late Miocene (about 710 million years ago). A great variety of hoofed mammals lived in the region then, and many resembled their counterparts in the modern East African savanna-except that they were the ecological equivalents of those living in Africa today, not closely related to them. For example, in Africa there is a great diversity of antelopes (members of the cattle family Bovidae). In the North American Miocene, there were three-toed horses (center right background), protoceratids (with "slingshot" horns on noses, left center), dromomerycids (with three horns, extreme left), and pronghorns (kneeling lower left). Instead of elephants, North America had mastodonts (left background). Instead of giraffes, North America had giraffe-like camels (extreme right). Instead of warthogs and other true pigs, North America had peccaries (center foreground). Instead of hippos, North America had hippo-like rhinos (center and left background), as well as more normally proportioned rhinos like the aceratherine Aphelops (center background) instead of black rhinos found in Africa today. (Painting by J. Matternes, courtesy Smithsonian Institution).

1. Introduction

AMERICAN SAVANNA If you took a time machine back to Nebraska or Kansas or South Dakota seven million years ago, at first you might not notice a remarkable difference. Everywhere you looked, there would be grass as far as the eye could see. However, there would be numerous stands of trees, much denser than you'd find in the Great Plains of North America today. As you gazed around, the landscape would begin to remind you not of the modern Plains, but the African savanna, so familiar from countless nature documentaries (Fig. 1.1). Dense stands of trees, and areas of deep underbrush punctuate the mostly grassy landscape. Looking again, the similarity to the modern African savanna would be fUlther reinforced by the cast of characters that lived on the landscape. Tall giraffe-like animals stretched their necks to reach leaves in the high tree canopy. Elephant-like beasts push aside the undergrowth to strip leaves away from the greenest branches. Large herds of striped horses resembling zebras and hundreds of antelopelike animals move slowly along, grazing the tender green shoots in the open grasslands. Pig-like beasts scuttle out of the dense brush, and occasionally you catch a glimpse of impala-like creatures which live in the dense undergrowth as well. In the nearby waterhole, huge barrel-chested animals wallow in the deep end, much like living hippos. Lurking nearby are the predators and scavengers, including packs of wild dogs, cat-like beasts with saber teeth, and even skulking hyaena-like animals with bone-crushing teeth, waiting to move in on a carcass once the predators have finished. But a closer look at these animals (especially if you could study their skeletons and teeth) would reveal that this similarity to animals of the modern African savanna is only superficial. Everyone of the beasts we've just noticed is in reality unrelated to its modern counterpart in Africa. Take, for example, the hippo-like beasts wallowing in the water hole. They may have the barrel chest and short legs of a hippo, and live in the same habitat, but on the tip of their nose is a small horn-they are the hippo-like rhinoceros known as Teleoceras, not actual hippos. Further inspection would show that they have the three-toed feet of rhinos, not the four-toed feet of hippos, and details of their skull, teeth, skeleton, muscles, and other soft tissues would further confirm that their similarities to hippos are strictly convergence:

an unrelated group of animals evol ves into a similar body form to occupy a specific niche. True hippos never came to North America, so a group of rhinos developed the same body form and ecological habitats to exploit this important niche of a semi-aquatic grazer. Indeed, if you were to watch Teleoceras feed, you would see even more similarities. Like hippos, Teleoceras did not eat water plants, but strolled around on the grassy meadows near their water holes (probably at night) eating grasses. Today, African rhinos are strictly land-dwelling, largebodied creatures who feed on either grasses (the white rhino) or green shoots and leaves in the bushes (the black rhino). North America also had a more normally proportioned rhinoceros known as Aphelops, which lived side-byside with the hippo-like Teleoceras. Like the living black rhino, it probably spent most of its time browsing leaves in the undergrowth. What about the giraffe-like beast browsing leaves from the tops of the trees? A closer inspection would show that the head lacks the two knob-like horns, and is all wrong for a giraffe. Instead, it has the distinctive face, eyes, and nostrils of a camel. Unlike any camel in the Old World, however, it lacks a hump (but so do the living South American camels, the llama, alpaca, guanaco, and vicuna), and it has an incredibly long neck (reaching over 22 feet, or 7 m, above the ground) and legs (some over 6 feet, or 2 m, in length). Once again, the niche for a long-necked treetop browser in North America had no occupant (since giraffes never reached this continent), so a native group (the camels) evolved a form to occupy it. As you gaze at the herds of animals on the plains, you find more examples of this trend. The delicate, gazelle-like creatures with extremely long, thin legs can run as fast as any living antelope, but they're not antelopes. Not only do they lack horns that almost all antelopes have-but once again, you realize that you're looking at another kind of camel. In fact, looking around, you would find over a dozen different species of camels, some adapted for giraffe-like or gazelle-like existences, but others of the size and proportions of the South American camels. And none had humps. The rest of the herd is also composed of mimics. Those horned beasts that resemble African antelopes? They're actually related to the American pronghorn, which is mis-

2

HORNS, TUSKS, AND FLIPPERS

takenly called "antelope" but is unrelated to the true antelopes of Africa and Eurasia. In North America seven million years ago, there were over a dozen species of pronghorns in over eight genera, all with distinctively different horns (see Fig. 4.12). And those zebra-like beasts are indeed related to zebras and other horses-but most of them are far more primitive than the Ii ving zebra. Most are rnuch smaller, with simpler teeth, and they almost all have three toes on their feet. In some places, there are as many as a dozen different species of horses living side-by-side. Some hide in the underbrush, using their robust side toes on marshy ground~ their simple, low-crowned teeth are only suited for soft leafy vegetation. Others are clearly plains dwellers, with greatly reduced side toes, longer more slender limbs, and ever-growing cheek teeth that allow them to eat gritty grasses without wearing their teeth down to the gums and starving to death. What about the elephant-like animal breaking off branches from the trees? It does have a trunk and simple tusks, but it is smaller than any living elephant, with a long jaw and flat forehead~and it has four straight tusks, not the two long curved upper tusks of a living elephant. Instead, it's a primitive mastodont, from which the living elephants and mammoths would one day evolve. Like the three-toed horses and zebras, this animal is indeed related to its living counterpart, but it is a much more primitive relative than the beast that lives in Africa today. Here we have a partial substitution of a remote ancestor in the role of its descendant, rather than the complete replacement of rhinos for hippos, camels for giraffes and antelopes, and pronghorns for antelopes that we saw earlier. And the impala-like beast hiding in the bushes near the water? In Africa, we'd expect a true antelope like the impala or bushbuck, but in ancient North America that role is occupied by Synthetoceras, a member of an extinct group known as the protoceratids. Instead of paired spiral horns on their heads like impala, Synthetoceras has a slingshot-like hom on its nose, and a pair of unbranched horns curving upward and inward from above its ears. Synthetoceras has no living descendants, but is distantly related to the camels. Nearby is another extinct beast, Cranioceras, with short straight horns pointing straight up above its eyes, and a thick blunt hom curving up and forward from the back of its head. This animal also has no close living relatives, since it is a member of the extinct family, the dromomerycids, which are only distantly related to deer. Scuttling in and out of the underbrush are pig-like beasts that might remind you of African hogs like the warthog or forest hog. But they are not true pigs at all, but peccaries, which live today in Central and South America, and even in the southwestern deserts of the United States. Peccaries resemble pigs in many superficial ways, but they are an entirely different family, restricted to North America, while true pigs and hippos were restricted to the Old World. But these extinct peccaries are much larger than the living javelinas of Mexico. They had longer snouts and flatter

heads, and much more prominent, dangerous-looking tusks. This list of similarities could go on and on. The hyaena-like animals feeding on carcasses are not true hyaenas, but bone-crushing borophagine dogs. Some of the "sabertooth cats" are not true members of the cat family, but an extinct group known as nimravids, which were related to dogs but had extremely cat-like bodies and teeth. Even the "bear" role is performed not by a bear, but by an extinct group of "beardogs," or amphicyonids. And this story is not restricted to the American savanna of seven million years ago. In Eurasia, there were similar savannas with ecological counterparts of the modern African savanna fauna, but with many substitutions. Indeed, this is a typical occurrence in the evolution of life: ecological niches are often occupied by unrelated groups of animals when the opportunity arrives, and the modern group was not present to occupy the niche. Throughout this book, this will be a common theme. Hoofed mammals have dominated the large bodied herbivorous niches on this planet for the past 65 million years, but many different, unrelated groups of hoofed mammals have evolved on many different continents. Frequently they develop body forms that converge on living animals when the same niche is available. And more often, they develop body forms which have no n\odern analog, making it very hard for the paleontologist to describe their lifestyle and ecology in terms of anything we're familiar with in the living world. NAMES AND DATES Paleontologists work in a world with a time frame completely different from ordinary human life. From various methods, we now know that Earth is about 4.5 billion years old. That's 4,500 million years, a number that is staggering in human terms. It is such an immense amount of time that some sort of analogy is necessary to make it comprehensible. Suppose we were to compress all 4.5 billion years of Earth history into a single calendar year. On this scale, each of the 365 "calendar days" equals twelve million years, and each minute of the "calendar" is 8561 years long! The formation of Earth would then take place on New Year's Day in this "calendar." The first recognizable life would not appear until February 21, and it would consist of tiny, single-celled blue-green bacteria. Complex, multicellular life, such as jellyfish, trilobites, and corals do not appear until November 12. The first amphibians crawled out on land on November 28. The first tiny mammals, and the first bird Archaeopteryx, appear during the peak of the age of dinosaurs, on December 17. The final extinction of the dinosaurs and the beginning of the age of mammals occur on the day after Christmas. The first ape-like primates that are members of our own family, the hominids, do not appear until eight hours before New Year's Eve. Neanderthal man, the classic Stone Age "cave man," appears ten minutes before New Year's Eve, as the countdown begins in parties everywhere. Recorded history began less than one minute before New Year's Eve, as the conductor raises his baton to

3

INTRODUCTION

Ma

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PERIOD

PleIstocene

( )119t

2

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Pliocene

Q

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34

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55

BARSTOVIAN HEMINGFORDIAN

ARIKAREEAN

-= = ~

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CLARENDONlM'

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ORELLAN CHADRONIAN DUCHESNEAN

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UINTAN BRIDGERIAN

~

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WmTNEYAN

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Figure 1.2. Cenozoic time scale. "Quat." = Quaternary; "IRV./RLB" = Irvingtonian/Rancholabrean land mammal ages; "Ma" = million years before present; "NALMA" = North American land mammal ages.

start Auld Lang Syne. Within a second before midnight, Charles Darwin's On the Origin of Species was published, and the American Civil War was fought. Virtually all of human history, especially the last few millennia, is drowned out by the drunks who blew their noisemakers a fraction of a second too early! On the scale of geologic time, human affairs appear pretty insignificant. The geologist is accustomed to dealing with such large amounts of time, and routinely deals with thousands and millions of years. For most geologic problems, events of less than thousands of years in duration cannot even be distinguished in the layers of sedimentary rocks. When dealing with events that occurred hundreds of millions or billions of years ago, even a million years here or there is negligible. A sense of "deep time" (as John McPhee labeled it) is very important to all of us, and not just to the geologists. Most geologists, however, find it practical to

deal with time not in absolute millions of years, but in relative time terms. Just as historians use "Elizabethan" or "Edwardian" to refer to periods in English history, so geologists use "Cambrian" and "Cretaceous" to refer to distinct episodes in Earth history. For the purposes of this book, most of these time terms will not be necessary. The evolution of rhinos, horses, elephants and their relatives has taken place in the last 65 million years, known as the Cenozoic Era (Fig. 1.2). The Cenozoic is divided into a number of epochs, which began with the Paleocene approximately 65 million years ago and run to the present. The Paleocene, which lasted from 65 to 54 million years ago, is followed by the Eocene (54-34 million years ago), the Oligocene (34-24 million years ago), the Miocene (24-5 million years ago), the Pliocene (5-1.8 million years ago), and the Pleistocene or Ice Ages (1.8 million years ago to 10,000 years ago). The period since the last

HORNS, TUSKS, AND FLIPPERS

4

retreat of the glaciers and present interglacial warming is called the Holocene, or Recent (10,000 years ago to present). Although these terms may seem intimidating at first, they are much easier to use than trying to estimate the age of an event in millions of years. Paleontologists and biologists must also use different names for the animals, as well as for their ages. Most living mammals today have common names which are widely understood, so that we know a white rhino from a black rhino from an Indian rhino. Yet in many parts of the Englishspeaking world, the same common name can have different meanings. In most of the United States, for example, a "gopher" is a digging rodent. In the southeastern states, a "gopher" can be a tortoise. Many animals have different common names in different parts of the country. In countries which do not speak English, the animals have names in the local language. To get around this problem, biologists have long ago adopted a series of scientific names which is universal, regardless of region or native language. In 1758 when the system was ~irst widely adopted, Latin was the universal language of scholars, so all scientific names are Latin in form, or Latinized words from Greek or some other language. A scientist will always understand Geomys to mean the rodent gopher, and Gopherus to mean the gopher tortoise. By convention, each species name is a compound of two words, always found together. These names are always italicized in print or underlined elsewhere. The first word is the genus name (plural: genera), which is always capitalized. The second word is the trivial name for the species, which is never capitalized. Four example, the correct scientific name of our species is Homo (genus) sapiens (species), which means "thinking man." Another related species in our genus is Homo erectus ("erect man"), our probable ancestor. Similarly, the Indian and Javan rhinoceros are in the same genus (Rhinoceros), but in different species. The Indian rhino is Rhinoceros unicornis, and the Javan rhino is Rhinoceros sondaicus. The black rhino is in a different genus Diceros, which has only one living species, Diceros bicornis. An example of the hierarchical classification of humans and Indian rhinos is shown below:

KINGDOM PHYLUM CLASS ORDER FAMILY SUBFAMILY TRIBE GENUS SPECIES

For most fossil mammals discussed in this book there are no popular names. The fossils are known only by their scientific names, and are always italicized in this book. At first, these long scientific names may seem hard to pronounce and remember. If you break them down syllable by syllable, however, they are not so intimidating. Generic and specific (species) names are not the only names used to identify and classify an organism. Every genus belongs to a larger subdivision of life called a family. For example, humans belong in the Family Hominidae, and true rhinos in the Family Rhinocerotidae. All zoological family names can be recognized by the "-idae" ending. All the families, in turn, can be included in orders. Thus, the Hominidae can be grouped with the other families of apes, monkeys, lemurs, and tarsiers in the Order Primates. Rhinos belong with the tapirs, horses, and various extinct groups in the Order Perissodactyla, or the odd-toed hoofed mammals. Orders are subdivisions of a larger group, the class. Both perissodactyls and primates are mammals, or members of Class Mammalia. Classes are grouped into even larger groups, the phylum. For example, mammals, birds, amphibians, reptiles, and fishes are all members of the Phylum Chordata, which includes all animals with a spinal cord. Finally, the major phyla are grouped into the great k%jngdoms of life: the Kingdom Animalia, the Kingdom Plantae, the Kingdom Fungi, and so on. This hierarchical arrangement of classification not only serves as a useful tool, but also indicates closeness of evolutionary relationship. Animals in the same genus are more closely related to each other than they are to animals in any other genus, and so on. The division of kingdoms into phyla, and phyla into classes, and so on, is actually a reflection of the branching tree of life. Of the mammals living today, most can be clustered into distinct, well defined groups that even a child can recognize. In most classifications of the mammals, these groups are ranked as orders. Many of the orders are obvious to the average zoo visitor. The bats comprise one order, the rodents another, the primates a third, and so on. Most of these orders have been recognized since the formalization of modern classification in 1758. Yet until recently, little was known about how these orders were related to one another, or from

Animalia Chordata Mammalia Primates Hominidae Homininae Hominini Homo sapiens

C

Animalia Chordata Mammalia Perissodactyla Rhinocerotidae Rhinocerotinae Rhinocerotini Rhinoceros unicornis

INTRODUCTION what kind of mammal they evolved. For over a century paleontologists tried to trace the ancestry of the major orders of mammals back to a common ancestor, but the quality of the fossil record was not good enough to do this. Most of the mammals of the late Cretaceous and Paleocene, when most of the orders must have differentiated, are not members of Ii ving orders, nor ancestral to them. Thus, mammal classifications have treated all orders as if they were independent and unrelated, when we know that there must be some orders which are close relatives of one another. In the last decade, however, new approaches have made major advances in deciphering mammal relationships. Scientists have begun to look at the complete anatomy of the animal, not just the teeth (the most commonly preserved part for most fossil mammals). They looked in detail at other parts of the skeleton, particularly the details of the bones and canals in the skull and ear region. They also looked at the muscles and other soft tissues of the living mammals. Finally, they began to look at the various molecules found in mammal tissues, and discovered that the similarity of molecules can also give clues to relationships. All of this emphasis on complete anatomical analysis is not completely new. In fact, most of it was first done by German anatomists in the late nineteenth century, and much recent work has begun to rediscover how careful and perceptive those early German anatomists were. However, the method of analyzing the data has changed. The traditional methods concentrated primarily on teeth and tried to find progressively more primitive teeth in older rock units. The new methods instead concentrate on shared specializations, or evolutionary novelties, that indicate close relationship. For example, there were many evolutionary novelties that appeared when mammals evolved. Some of these include the presence of hair (instead of scales or· feathers), and mammary glands to nurse their young. These features are called shared derived characters, and are among those used to define the Class Mammalia. Other shared specializations can be used to define orders within the Mammalia. For example, the bats can be defined by their complex wing .structure, formed by highly modified hands and fingers. The primates can be defined by a number of features, including their grasping hands and feet with opposable thumbs, nails instead of claws, or their forward-facing eyes with binocular color vision. Within the Order Primates, still smaller groups can be defined by their own evolutionary novelties. For example, the great apes (orangutan, gorilla, chimpanzee) and humans share a number of specializations, including the loss ofa tail, complex nasal sinuses, five or six vertebrae in the hip, an elongated middle finger, and over two dozen other features in the skeleton alone. Thus, the emphasis has shifted from seeking ancestral forms with their shared primitive similarity (which does nothing to indicate relationships-animals which share primitive characteristics mayor may not be closely related) to seeking out only shared derived similarity. For example, hair and mammary glands are good indicators distinguish-

5

ing mammals from other animals, but are of no use in determining relationships within mammals (since all mammals have them, they are primitive characters within the mammals). In traditional mammal classifications, some orders were based on nothing but these shared primitive similarities. For example, the old definition of the order Insectivora (which properly includes moles, shrews, and hedgehogs) was broadened to include a wide variety of primitive insecteating mammals unrelated to moles, shrews, or hedgehogs. To expand the meaning of "insectivore," the group was defined on characters such as having five toes on hand and foot (primitive not only for mammals, but even for their reptilian ancestors) or having 42 teeth, which is also primitive for all placental mammals. By doing this, the Insectivora became a "wastebasket" group. All primitive placental mammals that retained the ancestral insectivorous ecology were thrown into this "wastebasket," even though they were not closely related. Usually, this was done because there was no better place for these problematic animals, and people like to have their classifications tidy. Everything in its place, and every mammal in its proper order! Unfortunately, these wastebasket groups had a negative effect as well. For those not familiar with the animals, it created the impression that all the problems were solved (which they were not), and that these problematic animals were closely related to moles, shrews, and hedgehogs (which they were not). In many cases, scientists could not find a particular fossil that was the perfect ancestor for later animals, and would construct a "hypothetical ancestor" based on a wastebasket assemblage of animals. In doing this, they would ignore the fact that each of the members of the wastebasket group had its own anatomical specializations that prevented it from being the actual ancestor. In short, the use of these "wastebasket" groups created concepts in people's minds of animals that never really existed. Insectivores were not the only group to be made into a wastebasket. One of the worst wastebaskets was the archaic animals related to the hoofed mammals, or ungulates. Today, the living ungulates (Fig. 1.3) can be divided into at least six major groups of mammals, including the even-toed artiodactyIs (pigs, camels, sheep, deer, antelope, cattle), the odd-toed perissodactyls (horses, rhinos, tapirs), the elephants, and three other groups (hyraxes, whales, and sea cows) we will discuss later. However, there are a number of extinct animals which have hooves and all the other hallmarks of ungulates. These could not be assigned to any of the living orders, mostly because their bodies were built on a very archaic plan. They shared no specializations with any living order, and so they were placed in the ultimate "wastebasket" group, the order "Condylarthra." The only thing that "condylarths" had in common was that they were archaic hoofed mammals that didn't belong somewhere else. As in the case of other wastebasket groups, the "Condylarthra" made the classification appear neat and tidy, but it obscured all the problems and areas needing work.

HORNS, TUSKS, AND FLIPPERS

w z w

o

o

w

55

zw o

o

...w

6& a. 4(

Protungulatum

Figure 1.3. Relationships of the living and extinct ungulates. PLI Prothero, based on Prothero, Manning, and Fischer, 1988). Scientists would suggest that one or more of the Ii ving ungulate orders evolved from a "condyla11h ancestor," a hypothetical creature with no basis in reality. Others would generalize about the ecology, or behavior, or extinction of "condylarths," when in fact each of the "condylarth" groups had completely different ecologies and probably different behavioral patterns as well. Even worse, it misled anyone who did not know the fossils and got the mistaken impression that "Condylarthra" was as real a group as the order of bats or of whales. These people would make comparisons between "condylarths" and real groups, and the features they analyzed in the "condylarths" would not be true of most of its members. The "Order Condylarthra" obstructed the understanding of mammalian relationships for over a century, and finally it is being abandoned. Indeed, once the living and extinct ungulate groups were analyzed, using only shared specializations to cluster groups together, it became apparent that the ungulates have a very rich, interesting history. This story, however, remained unknown for over a century because of the

= Pliocene; Q = Quaternary.

(Drawn by C.R.

"condylarth" veil. In this book, we will present the new ideas about hoofed mammals. HOOFED MAMMALS The hoofed mammals, or ungulates, are the largest, most anatomically diverse, and ecologically dominant group of mammals alive today. One need only to look at the huge variety of elephants, rhinos, hippos, antelopes, wildebeest, zebras, giraffes, and buffalo on the African savannah to realize that all of the large plant-eating mammals are ungulates. Ungulates make up about a third of the genera and families of living mammals, outnumbering even the abundant and diverse rodents. Since many ungulates feed on large quantities of low-quality vegetation, they can get big. Indeed, the largest mammals (both on land or sea) that ever Ii ved, or are alive today, are all ungulates. Even when housecat-sized ungulates first appeared at the end of the reign of the dinosaurs, they were larger than most of their rat-sized contemporaries among the mammals. The earliest ungulates are a group of extremely primitive

INTRODUCTION

7

Figure 1.4. Restoration of the archaic ungulate Chriacus, an arctocyonid, emphasizing its superficial resemblance to the living coatimundis or raccoons. (Drawn by E. Kasmer, courtesy K. Rose). forms known as the zhelestids, recently described by David Archibald and the late Lev Nessov from Late Cretaceous rocks almost 90 million years old from Uzbekistan, central Asia. Although these animals are known only from a few jaws, they already show that the hallmarks of ungulate teeth were well established at an extremely ancient time-about as far back as any of the recognized orders of placental mammals is known to have lived. Clearly, the ungulate branch of the Mammalia is one that goes back to the very beginning of the radiation of the placental mammals, some 30 million years earlier than they were once thought to have originated. By the latest Cretaceous and earliest Paleocene, the zhelestids were replaced by the arctocyonids. The most complete skeletons known of these archaic ungulates (once called "condylarths") from the Paleocene reveal an animal that had a body much like a raccoon or coatimundi (Fig. 1.4). The skeleton was not specialized for running, like most Ii ving ungulates. Instead, it is a very generalized mammal body, with flexible limbs and long fingers, suitable for both climbing and walking. The tail is also quite long, probably

for balance. The head had a long snout, much like a raccoon. In most cases, the teeth were unspecialized, suitable for an omnivorous diet. However, there are a few features that tell us this animal is not related to raccoons. First, the relatively unspecialized teeth have a few advanced ungulate features compared to the other primitive mammals of the time. The cusps of the teeth are more bulbous than those of its insectivorous contemporaries, with low relief between cusps. These teeth were suited for a more grinding type of chewing, appropriate to an omnivorous diet of plants, seeds, and tubers, with some meat, eggs, fish or carrion. By contrast, most early mammals were insectivorous, with sharp, slicing crests on their teeth and very high relief between cusps. This kind of tooth pattern is suitable for chopping up the tough skins of insects, and shredding small prey animals. In addition to the teeth, there are several specializations of the skull openings for the arteries in the head, and in the bones that make up the ear region, which show that these arctocyonids are indeed ungulates. Finally, the ankle bones in even the most archaic ungulates are already adapted for

8

HORNS, TUSKS, AND FLIPPERS

Figure 1.5. A. Restoration of the Paleocene periptychid Ectoconus (painting by R. Bruce Horsfall, from Scott, 1913). B. Reconstruction of dachshundlike Eocene archaic ungulate Hyopsodus (After Gazin, 1968).

B

walking and bearing greater weight. Although the ankle is flexible, it is not as adapted for tree climbing as the ankle of primates or primitive carnivores. Hooves, the feature most characteristic of ungulates, have not yet appeared. The most primitive ungulates still had claws, although they were relatively short and blunt. When hooves finally develop, they do so independently in several different groups. This can be seen by looking at the details of the anatomy of the hoof. It is constructed very differently in horses than in deer, for example. There must be a great evolutionary advantage to developing hooves in large animals which are adapted for running (as most living ungulates are). Clearly, hooves are valuable protection for running across hard ground without cutting the foot and bleeding profusely (as can happen to cats or dogs when they run, and certainly to humans!). Recent research suggests that the first group to branch off from these earliest ungulates were the artiodactyIs, or the even-toed hoofed mammals (Fig. 1.3). Today, the artiodactyls are the most abundant ungulates, with over 190 living species. They include pigs, peccaries, hippos, camels and llamas, deer, pronghorns, giraffes, sheep, goats, and dozens of species of antelopes and cattle. We will discuss the artiodactyls in greater detail in the next four chapters.

After the artiodactyIs branched off from the ungulate common ancestor, the next groups were certain archaic ungulates (once called "condylarths") such as the extinct hyopsodonts and periptychids (Fig. 1.5). Periptychids became big, almost bear-like forms, with few anatomical specializations except in their teeth, which have highly wrinkled enamel surfaces. Hyopsodonts, on the other hand, developed a body form much like a weasel or dachshund. Although their skulls and teeth were primitive, they had very short limbs and a long trunk and tail. Many people have speculated about how hyopsodonts lived. Some think they may have burrowed, since they have strong digging limbs with claws. Others suggest that they were slinking along in the lower vegetation. Whatever they were doing, they were very successful archaic ungulates. While most archaic ungulates were dominant in the Paleocene and declined by the Eocene, hyopsodonts were some of the most common animals in the Eocene. They were also among the last archaic ungulates to die out at the end of the Eocene, long after all the others had gone extinct. In the older books, some scientists speculated that hyopsodonts were ancestral to artiodactyls. There are no shared specializations to support this idea, however, so it is no longer believed by paleontologists. After the divergence of artiodactyls, and of the peripty-

INTRODUCTION

9

Figure 1.6. Restoration of the archaic Eocene ungulate Phenacodus, once thought to be related to . .: perissodactyls (painting by R. Bruce Horsfall, from Scott, 1913).

chid-hyopsodont group, the next step is a surprising one. A wide variety of evidence, both from fossils, and from anatomy and molecular biology, clearly indicates that whales are also ungulates (Fig. 1.3). "What?" you say, "whales don't have hooves!" This is true, but remember that hooves are not the most important character that defines ungulates. When we trace whales back into the fossil record, we find progressively less specialized forms that look less like whales and more like other archaic ungulates. We will discuss the evidence for this surprising conclusion in Chapter 6. Once the whale lineage had split off in the Paleocene, the next groups to diverge are archaic ungulates formerly lumped with the periptychids and hyopsodonts in the "condylarth" wastebasket. The best known of these are the phenacodonts (Fig. 1.6). Phenacodonts evolved into sheepsized animals, with long faces and tails. However, their limbs are still unspecialized, along with the rest of their skull and skeleton. In the past, several scientists tried to show that phenacodonts were directly ancestral to the perissodactyls (horses, rhinos, and their relatives). However, as we shall see in Chapter 10, new discoveries suggest that phenacodonts are only distantly related to perissodactyls. Finally, we come to the last major grouping of ungulates, the higher ungulates (the Altungulata). This includes not only the traditional perissodactyls (horses, rhinos, tapirs, and their relatives), but also the hyraxes (or conies), and the tethytheres (elephants, manatees, and their relatives), as well as a number of extinct forms. These animals are the subject of the latter half of the book. UINTA BEASTS AND THE COPE-MARSH WARS One group often considered to be related to ungulates includes the bizarre animals known as the uintatheres (Fig. 1.7). Their name comes from the middle Eocene beds of the Uinta Basin of Utah, where they were first discovered. These animals reached elephantine size, yet they are not elephants. Their most distinctive features are the six knob-like

horns on the top of the head, and the huge protruding canine teeth protected by a flange on the lower jaw. It was a face only a mother could love! During the middle Eocene, they were the largest land mammals in both Asia and North America. By the late Eocene, they were extinct. T~eir role as a large, heavy-limbed herbivore was then taken over in North America by a succession of mammals: brontotheres in the late Eocene, rhinos in the Oligocene, and mastodonts in the middle Miocene. Some of the Mongolian uintatheres lack the knobs and canines; instead, Gobiatherium had a huge inflated bulb on its nose. What this structure was used for is anyone's guess. Some have suggested that it was functionally similar to the bulbous nose of the saiga antelope, which uses it for warming cold air as it inhales. However, uintatheres were found mostly during the tropical climates of the Eocene, which rules out any need for warming inhaled air. Uintatheres were large-bodied beasts that seem to have many specialized similarities to ungulates. For this reason, they have long been placed in ungulates, or in their own special order. In 1977, Earl Manning and Malcolm McKenna argued that uintatheres were ungulates related to the higher ungulate group, which incl udes perissodacty Is and tethytheres. However, in 1982 Tong Yongsheng and Spencer Lucas proposed that uintatheres were related to a bizarre group of Chinese Paleocene mammals known as anagalids, which are distantly related to rodents and rabbits. This suggestion is rather startling, since uintatheres are rhino-sized, and anagalids are much like rabbits in size and skeleton. Most of this argument is based on uintathere teeth, which are abnormally small for the size of the beast, and have a peculiar V-shaped crest pattern seen in a lot of primitive mammals. We are not convinced that uintatheres are "giant bunnies," but we admit that the evidence for their relationships to ungulates is also slim. Whatever uintatheres are related to, they are certainly among the most spectacular mammals in the middle Eocene of North America and Asia.

10

HORNS, TUSKS, AND FLIPPERS

B

Figure 1.7. A. The rhino-sized uintatheres had six knobby horns on top of their skulls, and huge tusks. Whether or not they were truly ungulates, they were the largest land mammals during the middle Eocene in North America and Asia (painting by R. Bruce Horsfall, from Scott, 1913). B. Cope's reconstruction of uintatheres with elephant ears and trunks. (From Penn Monthly, August, 1873).

INTRODUCTION

11

Figure 1.8. A. A typically pugnacious photograph of Edward Drinker Cope, the most brilliant paleontologist and herpetologist of his time. (Courtesy Academy of Natural Sciences, Philadelphia). B. Othniel Charles Marsh (back row, center) and the Yale field party of 1872, posing for a rough season in the Bridger Basin of Wyoming. The guns were no props, since the area was stil' controlled by hostile tribes. (Courtesy Yale Peabody Museum). Uintatheres were such spectacular fossils that they became the focus of a major war between America's dominant late nineteenth-century paleontologists, Edward Drinker Cope and Othniel Charles Marsh (Fig. 1.8). Cope (1840-1897) was a brilliant, intense academic and political outsider of Pennsylvania Quaker heritage who never had a steady, respectable position until late in his life (from 1889 until his death he was a professor at the University of Pennsylvania). Often in need of money, Cope either lived off money he inherited or raised funds for his paleontological work as opportunity arose. In spite of these limitations, he had true paleontological genius, and managed to publish some 1,400 scientific papers during the course of his life. Cope married and had a single daughter. His personality was complex and often difficult. In particular, he held and expressed his opinions very adamantly and did not take orders from anyone, be it a college administrator, the council of a learned society, or an army officer or government official on a geological survey. Although his immediate family was of a relatively humble New England background, Marsh (1831-1899) had the good fortune to be a nephew of the wealthy philanthropist George Peabody. Through his uncle's generosity (later inheritance), Marsh attended Yale University both as an undergraduate and graduate student, saw money donated to Yale for the Peabody Museum of Natural History, and from 1866 until his death was professor of paleontology at Yale. For most of his tenure he received no salary from Yale, but only an allowance from his uncle. Marsh remained a bachelor all of his life. He was alternately amicable and sociable,

or formal and aloof (more often the latter). He also had a secretive and suspicious nature, and could suffer from bouts of jealousy (such as when Cope beat him to the naming of new fossil species). Marsh was in no way as prolific as Cope; he published only 270 scientific papers in his lifetime. Unlike Cope, however, he was part of the establishment. Besides his position at Yale, Marsh often served as an officer of learned societies, such as holding the presidency of the National Academy of Sciences for a number of years. In the late 1860s Cope and Marsh each decided separately to aspire to the position of being the foremost vertebrate paleontologist in America. Until then, this title was held by Joseph Leidy, whom we will discuss more in the next chapter. Initially on friendly terms, Cope and Marsh began to compete with each other for specimens and information as the vast fossil beds of the American West were opened up. Each wanted the best specimens for his own collection, and the recognition that came with being the first to describe and name the fantastic extinct animals that were being newly discovered by science. To these ends, both men organized and unde1100k personal expeditions to the West. At various times they associated themselves with various official government geological and paleontological surveys, and bought (and some say stole) fossil specimens, the rights to collect on certain lands, and the services of local collectors (the alliances of collectors often changed quickly as the rivals outbid each other). The feud began in the summer of 1872 when Leidy, Cope, and Marsh were independently collecting fossils in the Bridger Basin and Washakie Basin of Wyoming. The

12

HORNS, TUSKS, AND FLIPPERS

largest and most spectacular specimens they found were skulls of the bizarre uintatheres, which impressed all three scientists with their weird horns and tusks. Naturally, they rushed to describe their new finds before they left the field. Since all three men were in remote parts of the country, with limited access to civilization, they had to leave camp to send news east by way of telegraph. In those days, it was common practice to publish a short note of only a few paragraphs naming a new animal, so that one could get credit for being its discoverer and namer. Today, such slapdash methods are frowned upon, but they were common in 1872especially when trying to beat a rival to press. Leidy was the first to publish, when a short note he had sent east, dated August 1, 1872, described Uintatherium robustum (this is now the correct name for most of the spec~ imens). On August 17 Cope sent a telegram from the Black Buttes in the Washakie Basin of Wyoming which was badly garbled when it was published two days later. His intended name for the beast, Loxolophodon, was misspelled Lefalaphodon. The nexr day, another notice that had actually been sent before the first telegram was published for Cope, naming the same beast Eobasileus cornutus. Today, this is the valid name for the largest of the uintatheres. On August 22 he corrected the garbled name back to Loxolophodon, although it was not available since he had already recklessly used it for another animal. Meanwhile, Marsh sent a note on August 20 naming his specimens Dinoceras and Tinoceras (they are now considered the same thing as Leidy's Uintatherium). All three were aware of the others nearby, and disputed their rivals' right to collect in "their" fossil field. Soon, this bitter rivalry drove Leidy into retirement from vertebrate paleontology as a field no longer fit for gentlemen. When Cope and Marsh returned east and began to publish longer descriptions, they became convinced that they both had the same animal and that their own name for it was correct. Actually, Cope had an Eobasileus, and Marsh had a specimen of Leidy's Uintatherium, but at the time they considered the differences slight, or the result of their rivals' mistakes. In 1873, Cope compounded his errors by suggesting that uintatheres were related to elephants, even putting elephant ears and trunk on them (Fig. 1.7). Marsh disputed this, and instead placed them in their own order, the Dinocerata (a name still used today, even if his name of Dinoceras was invalid). Between August 1872 and June 1873 Cope and Marsh each published 16 articles on uintatheres, each ignoring his rival's names, and both ignoring Leidy's work. As a result, uintathere names reached a state of chaos, with multiple names for the same species. Marsh grew so bitter at Cope's actions that he lashed out in print: "Cope has endeavored to secure priority by sharp practice, and failed. For this kind of sharp practice in science, Prof. Cope is almost as well known as he is for the number and magnitude of his blunders ... Prof. Cope's errors will continue to invite correction, but these, like his blunders, are hydra-headed, and life is really too short to spend valuable

time in such an ungracious task, especially as in the present case Prof. Cope has not even returned thanks for the correction of nearly half a hundred errors ... he repeats his statements, as though the Uintatherium were a Rosinante, and the ninth commandment a windmill" (Marsh 1873). Eventually, the uintathere wars died down as the rivals moved into conflicts over the naming of other beasts, such as the brontotheres discussed in Chapter 12. Fourteen years later, in 1884 Marsh finally published his huge scientific monograph on uintatheres, a 237-page volume entitled Dinocerata: a monograph of an extinct order of gigantic mammals, with giant folio pages and lavish plates. Meanwhile, Cope was losing ground politically. In the 1870s he had served under Ferdinand Hayden (see Chapter 12) on the U.S. Geological and Geographical Survey of the Territories, and from his collections made on those surveys, he had written a giant 1,009-page, 134-plate monograph for the Survey, now known as "Cope's Bible." However, in 1879 the Hayden Survey was merged with several other government surveys to form the present U.S. Geological Survey. The first directors were Clarence King and John Wesley Powell, both good friends of Marsh, and Cope found himself out in the cold. On December 16, 1889, Cope was ordered to turn his collections over to the Smithsonian, even though he had made most of them from private expenditures, not on government surveys. Cope was so outraged that he lashed out and called a reporter, William Hosea Ballou of The New York Herald, and filled his ear with grievances against Marsh and his cronies King and Powell. He charged that they were "partners in incompetence, ignorance, and plagiarism," and that the Survey was a "gigantic politico-scientific monopoly next in importance to Tammany Hall." He leveled charges of every kind at Marsh, including scientific blunders, keeping the salaries of his employees, and that most of his work (especially the Dinocerata monograph) was actually the work of assistants. This accusation was later supported by some of Marsh's former assistants, including the famous paleontologist Samuel Wendell Williston. Marsh defended himself by taking the train to Philadelphia and visiting the president and trustees of the University of Pennsylvania. He consoled them about "the shame that has befallen you," suggesting that "poor Cope" had cracked up and that Marsh would help locate "a more substantial scientist" to replace him. In the January 19, 1890 issue of the Herald, Marsh replied to Cope's accusations, charging that Cope had stolen his specimens, and that he had spied on Marsh's work when he was visiting Yale, and tried to publish it later. Ballou continued to play the feud out for several more columns, quoting and misquoting a number of paleontologists about the scientific competence and personal character of the two rivals. Eventually, this particular battle died down, leaving Cope and Marsh with egg on their faces. Cope retained his position and his fossils, as did Marsh and Powell.

INTRODUCTION Eventually, though, public scandals did hurt Marsh. When the budget of the U.S. Geological Survey came up before a House committee in 1892, fundamentalist congressman Hilary Herbert of Alabama discovered Marsh's recently published monograph, entitled Odontornithes, on toothed birds from the Cretaceous seas of Kansas. Waving it on the House floor, he shouted, "Birds with teeth! That's where your hard-earned money goes, folks-on some professor's silly birds with teeth." In terms similar to the recent science-bashing of William Proxmire and John Dingell, he stampeded Congress into cutting off funds from such "Godless" activities as monographs about impossibilities such as birds with teeth, and other creatures not mentioned in the Bible. Powell was finally forced to send Marsh a telegram: "Appropriations cut off. Please send your resignation at once." By this point both Cope and Marsh were broken men, and the field soon moved on to a new generation: Osborn, Scott, Hatcher, and others discussed elsewhere in this book. Cope continued to teach at the University of Pennsylvania for five more years, visiting the Dakota badlands in 1892 and 1893, and died on a cot in his study amidst all his unfinished projects and unpublished specimens on April 12, 1897. Marsh had spent all Uncle George Peabody's legacy on his expeditions and lavish publications, so he was forced to live on a modest salary from Yale in a brownstone near the Peabody Museum. In 1896 he published his greatest work, The Dinosaurs of North America. Early in 1899, he caught pneumonia, and died on March 18, with less than $100 to his name. Although the Cope-Marsh feud generated a lot of bad blood, it catalyzed the collection of literally tens of thousands of vertebrate fossils and inspired a number of younger geologists and biologists to pursue this field. Even if done in a sometimes less than gentlemanly fashion (Cope and Marsh criticized and insulted each other in otherwise "objective" scientific papers), an amazing amount of research was accomplished during these years. Modem American vertebrate paleotonlogy grew out of their work. THE LOST WORLD In his novel The Lost World, Sir Arthur Conan Doyle (creator of Sherlock Holmes) describes a plateau in the Amazon jungle which was a haven for dinosaurs still survi ving today. Although this is science fiction, South America was a "lost world" in a very different sense. It was isolated from all the other continents during most of the Age of Dinosaurs, and during the first sixty million years of the Age of Malumals. Almost no mammals or birds from the Old World managed to penetrate this island continent during this entire time. Consequently, the few mammals and birds that originally colonized it had the entire continent to themselves for millions of years. As we saw at the beginning of this chapter, ecological niches occupied by typical Old World or North American animals on other continents had to be filled by South American substitutes. There were no cats,

13

dogs, or bears, so carnivorous marsupials and gigantic, flightless, predatory birds were the main flesh eaters. In some cases this led to remarkable cases of evolutionary convergence. One South American marsupial, Thylacosmilus, had the same saber-like canines as the saber-toothed cat, even though it was a pouched mammal like a kangaroo. Others, known as borhyaenids, did a remarkable job of mimicking the wolves, bears, and hyaenas we have today, even though they too were pouched mammals. South America had three "old timer" groups inherited from the age of dinosaurs. The first include the marsupials, or pouched mammals, mentioned above. The second was the xenarthrans, or edentates (including the living tree sloths, armadillos, and anteaters), which eventually led to the giant ground sloths, and huge armadillo-:-like glyptodonts that were so characteristic of the Ice Ages. The third was hoofed mammals unique to South America, which evolved into the most amazing creatures of all. These South American experiments in evolution demonstrate just how stereotyped certain ecological niches are. For example, native South American ungulates evolved into beasts which converged on the body shape of horses, hippos, camels, elephants, and many other familiar beasts (Fig. 1.9). Yet none of these were related to their ecological counterparts-the resemblances are strictly due to evolutionary convergence, just as fish and dolphins have the same streamlined body shape even though they are unrelated in an evolutionary sense. The origin of these South American ungulate groups is still controversial. Only a few scraps of mammals are known from the age of dinosaurs in South America, and they include no hoofed mammals. The earliest Paleocene Tiupampa fauna includes a diverse assemblage of extremely primitive ungulates. The most familiar of these is called Perutherium. It is difficult to say what this animal is, other than that the teeth look much like those of typical archaic ungulates from other continents. We next pick up the South American record in the late Paleocene, but by then mammal diversity had blossomed. There are a great variety of bizalTe and unique forms whose relationships to mammals from the rest of the world are controversial. One group, the didolodonts, has long been placed in the "condylarth" wastebasket, but appears to be related to North American hyopsodonts. If so, then there was some sort of communication between North and South America during the Paleocene after all. Didolodonts flourished in the Eocene, but are not definitely known thereafter. Another group which appear to be related to hyopsodonts were the litopterns. They evolved into a variety of body forms throughout the Cenozoic, with their greatest diversity during the Miocene, when South America had savannas similar to the rest of the world at that time. Some litopterns were truly amazing. The proterotheriids, for example, paralleled the trend toward limb elongation and side-toe reduction that we see in horses on other continents at the same time. Diadaphorus, from the early Miocene, had

14

HORNS, TUSKS, AND FLIPPERS

D

Figure 1.9. Reconstructions of typical South American ungulates. A. The camel-like litoptern Macrauchenia. B. The hippo-like notoungulate Toxodon. C. The tapir-like Astrapotherium. D. The mastodont-like Pyrotherium. (Paintings by R. Bruce Horsfall, from Scott, 1913). a very horse-like build, but still retained three toes on each foot. Thoatherium, however, outdid even true horses-it had a single toe on each foot, with no vestiges of side toes like modern horses (Fig. 11.3)! As horse-like as their limbs and skeletons were, these animals were truly litopterns and not horses. Their teeth and skulls are completely unlike any mammal, horse or otherwise, from North America or the Old World. One of the most unusual of the litopterns was a beast known as Macrauchenia (Fig. 1.9A). Darwin first discovered it during the voyage of the Beagle, and wrote of it: "At Port St. Julian, in some red mud capping the gravel on the ninety-feet plain, I found half the skeleton of the Macrauchenia Patachonica, a remarkable quadruped, fully as large as a camel. It belongs to the same division of the Pachydermata with the rhinoceros, tapir, and

palaeotherium; but in structure of the bones of its long neck it shows a clear relation to the camel, or rather to the guanaco and llama" (Darwin 1839: 173).

Macrauchenia indeed had a camel-like neck, and primitive, heavy, rhinoceros-like feet, but its weirdest feature is the head. Unlike most advanced hoofed mammals, it still had all 44 teeth, with no gap between the front nipping teeth and the grinders, like horses and cattle have. To top it off, the nasal opening is up over the forehead, indicating that Macrauchenia had a long proboscis like a tapir or elephant. A "camel" with the feet of a rhino and the trunk of an elephant sounds like something out of Dr. Doolittle, but it was real and thrived during the Ice Ages in South America! The dominant group of hoofed mammals was the notoungulates, literally "southern hoofed mammals." They were by far the most diverse, with at least thirteen families

INTRODUCTION and well over 100 genera represented over their sixty million year history. They include peculiar beasts such as typotheres, which culminated in the beaver-like Mesotherium during the Pleistocene, and the hegetotheres, which converged on rabbits. The archaeohyracids, as their name implies, closely resembled the living hyraxes (which we will discuss in Chapter 7). The most diverse of notoungulates, however, were the toxodonts. Some toxodonts, like Thomashuxleya, looked much like warthogs; others, like Rhynchippus, converged on horses; still others resembled the primitive·homless rhinoceroses discussed in Chapter 14. Homalodotherium had robust limbs with claws on the toes, much like the chalicotheres we will discuss in Chapter 13. One of the most remarkable was Toxodon itself (Fig. 1.9B), which was also found by Darwin during the Beagle voyage: "Toxodon [is] perhaps one of the strangest animals ever discovered. In size it equalled an elephant or megatherium; but the structure of the teeth, as Mr. Owen states, proves indisputably that it was intimately related to the Gnawers, the order which at the present day includes most of the smaller quadrupeds. In many details it is allied to the Pachydermata. Judging from the position of its eyes, ears, and nostrils, it was probably aquatic, like the dugong and manatee, to which it is also allied. How wonderfully are the different orders, at the present time so well separated, blended together in different points of the structure of the toxodon!" (Darwin 1839: 83). Although Darwin was puzzled, we now know that Toxodon was not related to rodents, "pachyderms," manatees, or anything else outside South America; it is a native notoungulate. Its body form most closely converges on a hippopotamus, although its front teeth are chisels like those of gnawing rodents. Other toxodonts, such as Trigodon, had a single small horn in the center of the forehead, like one of the extinct rhinos; the sheep-sized Adinotherium also had a small hom on the forehead. Despite their great diversity and abundance of excellent fossils, the affinities of notoungulates are still a mystery. In 1913 William Stein was collecting Paleocene mammals for the American Museum of Natural History in the Bighorn Basin of Wyoming. When his collections were sent to New York for study, the great paleontologist William Diller Matthew was startled to find a primitive notoungulate he named Arctostylops. At first, he thought there had been a mistake. Stein had recently been collecting in Patagoniahad the specimen gotten trapped in a pant cuff and then accidentally added to the Wyoming collections? Stein assured him that it was from Wyoming, and in subsequent years, more Arctostylops fossils have been found in· the Bighorn Basin. Did the presence of a primitive notoungulate from the Paleocene of Wyoming indicate that these beasts had

15

escaped South America, or that they originated in North America and then spread south? The discovery of more arctostylopids from the Paleocene of China further complicated the story. Did they originate in Asia, pass through Wyoming, and then reach South America? Or was it the other way around? Philip Gingerich argues for the latter. The appearance of arctostylopids, along with edentate-like epoicotheres and the uintathere-like forms (discussed below) is clear evidence to him of a migration from South America through Wyoming to China in the late Paleocene. More recently, Richard Cifelli, an expert on notoungulates, has become less convinced that arctostylopids are notoungulates. He suggests that the Wyoming arctostylopids may be immigrants from China, but he sees no concrete evidence that either is truly part of the great South American notoungulate radiation. Besides the didolodont-litoptern-hyopsodont group, and the notoungulates, there were two other important kinds of native South American hoofed mammals. One of the most puzzling are the "lightning beasts," or astrapotheres (Fig. 19.C), typical of the Miocene, and their primitive Eocene relatives, the trigonostylopids. Astrapotherium itself was rhino-sized, but had short feeble legs and small feet for so large an animal. It had large flaring tusks in both the upper and lower jaws, which closely mimic those seen in living hippopotamuses. The forehead was domed and full of air sinuses. Its most outlandish feature was a deep retraction of the nasal notch in the skull, indicating that it also had a tapirlike or elephantine trunk or proboscis (even more developed than the one seen in Macrauchenia). A weak-footed hippo with a trunk? The animals most similar to astrapotheres were the hippo-like amynodont rhinoceroses discussed in Chapter 14, which had stout aquatic bodies and well developed tusks, and heavy molar teeth. The relationships of astrapotheres and trigonostylopids are still a mystery. Their teeth bear some resemblance to those of notoungulates, but recent work by Richard Cifelli has shown that there are no true shared specializations. The fourth odd South American ungulate group was the "fire beasts," or pyrotheres and their relatives (Fig. 1.9D). Pyrotherium itself comes from the late Oligocene of Patagonia and Bolivia, and is a truly amazing animal. The size of a small elephant, it had short upper and lower tusks and simple cheek teeth with cross-crests like primitive mastodonts. Like astrapotheres, its nasal bones are deeply notched to receive the muscles of a well-developed trunk. This animal is one of the best imaginable examples of convergence with mastodonts, since there is no question that it is not actually related to elephants or mastodonts. For a long time, it was said to have specializations of notoungulates, but recently this has been discounted. Although its teeth are highly specialized and stereotyped into tapir-like leaf-eating cross-crests, there is some evidence from more primitive beasts. Weird Eocene animals known as Carolozittelia, Proticia and Columbitherium have last molars like Pyrotherium, but their other teeth resemble the curious ani-

16

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HORNS, TUSKS, AND FLIPPERS

B

IS

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.

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Figure 1.10. Although not related to ungulates, the pantodonts were the largest herbivores of the Paleocene and early Eocene. A. Barylambda, a sheep-sized beast of the late Paleocene. B. Coryphodon, one of the last of the pantodonts, and the largest beast of the northern continents in the early Eocene (From Fenton and Fenton, 1958). mal called Carodnia, from the Paleocene of Brazil. ing discovery of all. In 1992, Henk Godthelp, Mike Archer, Carodnia was a mystery for so long that it was placed in its and others reported an early Eocene fauna from Australia. own order, the Xenungulata ("strange ungulates"). However, Prior to this report, there were no fossil mammals known a number of scientists have recently argued that Carodnia is from Australia earlier than the early Miocene (about 23 milvery similar to primitive uintatheres, implying that the lion years ago), and they were all pouched marsupials (like pyrothere-Carodnia group is part of the Dinocerata. If this is the kangaroo and koala), or egg-laying monotremes (like the the case, then once again the question arises: did a uin- platypus). For years, scientists have used this fact to argue tathere-pyrothere group arise in Asia and spread to South that Australia was isolated from the rest of the wofId back in America (passing through North America in the late the Cretaceous, when marsupials and placental mammals Paleocene), or vice versa? As in the case of arctostylopids were just differentiating. According to this hypothesis, plaand epoicotheres discussed above, some would argue that all centals never reached Australia (until the Ice Ages), allowthree groups originated in South America and ultimately ing the "island continent" to evolve marsupials in great reached China. However, if uintatheres are related to the abundance without placental competition for most of the higher ungulates (which began in Asia in the late Paleocene, Cenozoic. But this dogma came crashing down, since the as we shall see in Chapter 7), or to rabbits (as Tong and early Eocene Tinga Marra fauna included not only primitive Lucas argue), then perhaps it was the other way around. marsupials, but also a tooth of what appeared to be an archaic ungulate! Clearly, we need more fossils to test these hypotheses. It now appears that in the late Cretaceous (about 70 milRecently, another group of animals has been found in South America that suggest a northern connection. They are lion years ago), very archaic ungulates were present not only known as pantodonts, big galumphing mammals common in in North America and Asia, but also in South America and the Paleocene of Asia and North America (Fig. 1.10). Australia (and probably in Europe and Africa, if we had fosAlthough they were primitive in most skeletal features, they sils of the right age). For reasons not yet understood, they had very distinctive teeth, with molars which had distinctive did not persist in Australia, ceding the dominance to marsu"V"-shaped crests on the crowns. The last and largest of the pials. Ungulates flourished in the Northern Hemisphere, as pantodonts occurred in the Eocene, where the sheep-sized detailed in the rest of the book. As we have seen, in South Coryphodon is the largest mammal in the early Eocene beds America they evolved in isolation to produce extraordinary of North America and Europe (Fig. 1.10B), and the cow- ecological parallels with Northern Hemisphere ecological sized Hypercoryphodon lived on until the middle Eocene of equivalents. Returning to South America, these four bizarre groups China. Pantodonts were long thought to be a strictly Northern of endemic hoofed mammals remain a great puzzle. Two Hemisphere group, until 1987, when Christian de Muizon groups seem traceable to animals found outside South and Larry Marshall reported an extremely primitive America: didolodonts-litopterns to hyopsodonts, and pantodont they named Alcidedorbignya from the early pyrotheres-Carodnia to uintatheres. Arctostylopids may be Paleocene of Bolivia. Although it is the earliest pantodont notoungulates, giving us a third instance of exchange known, it is less primitive than some later Paleocene between South American ungulates and the rest of the world. pantodonts from China. Once again, this discovery poses a However, all of these possible cases are restricted to the puzzle. Did pantodonts originate in China (where the most Paleocene. By the Eocene, there is no further evidence that primitive species are found), then migrate through North South America's native ungulates ever traveled to other conAmerica to South America, or vice versa? tinents, and they continued to flourish for almost 50 million This puzzle is further complicated by the most surpris- years unmolested by outsiders. Secure on their island conti-

INTRODUCTION nent, they evolved startling examples of parallelism with horses, camels, rhinos, hippos, and elephants. Sometime in the late Oligocene, between 30 and 24 million years ago, rodents and primates arrived, possibly on rafts of floating vegetation or by island hopping. The rodents soon diversified into the great South American caviomorph radiation, producing everything from giant capybaras to agoutis to chinchillas and Guinea pigs. The primates became the prehensile-tailed New World monkeys, including the spider monkeys, howler monkeys and their kin. Raccoons and their relatives arrived sometime in the late Miocene, between 6 and 9 million years ago. However, none of these later arrivals seriously impacted the large ungulates, which continued to dominate the forests and grasslands. The isolation of South America was finally broken in the Pliocene, about 3.5 million years ago. Continental collisions lifted up sea floor and triggered volcanic eruptions,

17

building the Central American land bridge. As it did so, nature began one of its greatest experiments, the "Great American Interchange." Waves of invaders swept down from the north and competed for the first time with their southern equivalents. These included horses, sabertooth cats, pumas and jaguars, wolves and dogs, bears, mastodonts and mammoths, camels, tapirs, and deer. Some of these northern predators were undoubtedly more efficient than the native marsupial predators and giant predatory birds that had been there for millions of years. The native South American fauna was overwhelmed not only by the new predators, but also by competition from their ecological equivalents from the north. Most went extinct in a few thousand years, although some managed to survive well into the Ice Ages before finally disappearing, possibly due to hunting by the first humans to reach South America.

Figure 2.1. Two bull hippos battling for dominance with their sharp tusks. (Photo from IMSI Master Photo Collection).

2. Cloven Hooves

THE KINGDOM OF CLOVEN HOOVES When you hear "hoofed mammals," the animals that immediately come to mind are artiodactyls. Most domesticated ungulates, including cows, water buffalo, yaks, sheep, goats, camels, llamas, and even pigs, are artiodactyIs. Virtually all meat (whether beef, pork, or more exotic fare such as goat or venison) comes from artiodactyls. In addition, artiodactyls produce all our milk (whether from a cow, goat, or camel), and all of our wool. In the natural world, artiodactyls are equally dominant. Just think of the common large mammals found in North America. Deer, moose, elk, bison, bighorn sheep, mountain goats, peccaries, pronghorns-they are all artiodactyls. But North America is now depleted in large mammals-during the Ice Ages, there were camels, tapirs, horses, mammoths, and mastodonts here as well. A more typical natural setting is the East African savanna. On your average safari, every large herbivorous mammal you would encounter (except the zebra, rhino, and elephant) would be an artiodactyl. These include the treetopbrowsing giraffes, the huge hippos in the river (Fig. 2.1), the ugly warthogs, the dangerous Cape buffalo, and a tremendous diversity of antelopes-wildebeest (or gnus), impalas, gazelles, bushbucks, elands, sable antelopes, hartebeests, kudus, gerenuks, and even tiny klipspringers and dik diks. Today, the artiodactyls are the most abundant ungulates, with over 190 living species. They include pigs, peccaries, hippos, camels and llamas, deer, pronghorns, giraffes, sheep, goats, and dozens of species of antelopes and cattle (Fig. 2.2). Artiodactyls share many specializations, but the most obvious one is in their feet (Fig. 2.3). All artiodactyls are "cloven hoofed" in the Biblical sense. Their feet are di vided into an even number of toes (usually two or four), since the axis of the foot runs between the third and fourth fingers and toes (equivalent to your big finger and ring finger). The first digit (thumb or big toe equivalent) is lost completely. As they become more specialized for running, the finger and toe bones lengthen, giving their limbs an extra segment. The side toes (digits 2 and 5, equivalent to your index finger and pinky) become shorter than digits 3 and 4, and in many specialized artiodactyls, the side toes nearly disappear. The most specialized artiodactyIs run on two elongate toes, digits 3 and 4, as you can see by examining any camel, deer, antelope, or cow. These two toe bones

are usually fused together into a single bone, the "cannon bone," which makes them less likely to break while running. Along with toes developed for running, artiodactyls develop other limb specializations. The upper limb segments (upper arm and thigh) become short relative to the middle leg segment (lower arm and shin). With the addition of elongated toes, this lengthens the total stride and greatly increases running efficiency. The most diagnostic feature of artiodactyIs is in the ankle. The main pivot bone of the ankle, the astragalus, is highly specialized (Fig. 2.3). It has well-developed hinges on both the shin side and toe side, so that the limb can move rapidly back and forth in a front-to-back plane. This makes running more efficient, but it prevents other kinds of motion. Unlike you (or cats, opossums, rodents or many other mammals),artiodactyls cannot rotate their feet out of the front-to-back plane. This prevents grasping, or climbing, or other motions that such rotations allow. Another feature characteristic of many artiodactyls is antlers and horns. Antlers are found mainly in deer and elk, and are formed and shed once each year by the males. Horns, on the other hand, have a permanent bony core that is capped by a horny sheath. This is rarely shed, and the bony core is not lost at all. True horns are found on antelopes, goats, and cattle. (Rhino horns are made of matted hair-like fibers with no bony core.) These horns and antlers are very important, not only as defense against predators, but also in combat between males for females and territory, and for recognition of species. GUT REACTIONS Artiodactyls develop other specializations that are related to feeding. Their teeth become more and more specialized for grinding, and the front teeth that were once specialized for biting or stabbing are lost, or reduced to simple nippers. Many have taken to eating grass, which is an abundant but poor-quality source of food. To do so, their teeth have to develop very tall crowns that grow almost continuously because grass is full of gritty material that grinds teeth down very fast. All mammals have some kind of gut bacteria to handle the digestion since they do not have the necessary enzymes for most food. Humans have the all-purpose digestive bacterium, Escherischia coli, which breaks down food not pre-

HORNS, TUSKS, AND FLIPPERS

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= Quaternary (drawn by C.R. Prothero; from

ChevrOlai n (even· toed)

Figure 2.3. The contrast between even-toed ungulates (artiodactyls) and odd-toed ungulates (perissodactyls). Although the number of toes is important, the primary distinction is the axis of symmetry of the foot. In artiodactyl feet, the axis of the foot runs between the third and fourth digits. In perissodactyl feet, the axis runs through the central (third) digit; side toes (the second and fourth digits) are present in most perissodactyls except forthe one-toed horses. (After Colbert 1991).

,...

Rhinoceros (odd-toed)

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CLOVEN HOOVES

Esophagus

21

Small intestine

Omasum

Figure 2.4. The ungulates employ different digestive strategies. Most mammals (including perissodactyls, elephants, and primitive artiodactyls on the left) are hindgut fermenters. Bacterial breakdown of the food takes place in the cecum and colon, which decreases the efficiency of digestion, but allows the food to move through the gut faster. Ruminant artiodactyls (right), however, are foregut fermenters, with a four-chambered stomach, which allows immediate fermentation of the cellulose. In addition, the food can be regurgitated from the rumen and chewed again ("chewing the cud"), allowing further digestion. By the time the food has reached the digestive surfaces of the intestines and cecum, it has been broken down by gut bacteria, so it is more efficiently used. It also passes through the gut much more slowly. (After Pough et aI., 2002) viously digested and renders it digestible in our large intestines. Indeed, over 80% of our feces are actually coliform bacteria. In essence, we get many of our nutrients indirectly by digesting the byproducts of bacterial metabolism. This works pretty well for most proteins and carbohydrates in our diet, or the diets of most omnivores and carnivores. However, the hardest material to digest is cellulose, which is a complex carbohydrate that takes much longer to break down into soluble sugars. Since it is one of the major parts of most plant matter, we digest this inefficiently, adding to the fiber or "roughage" in our diet. In a microscope slide of a human stool most of the undigested material is cellulose fibers. Herbivorous animals, which must get all their proteins and carbohydrates from plants, have a more difficult problem. Termites have solved it by having a large colony of cellulose-digesting bacteria in their gut so they can digest raw wood. Most herbivorous mammals minimize the problem by eating the greenest and newest vegetation, which has not yet developed too much woody cellulose fiber. This "high-qual-

ity" vegetation is relatively rare and requires much selective feeding to obtain enough nutrition. Another strategy is to substitute quantity for quality. Most grazers (grass-eaters) eat large quantities of high-fiber, low-quality grass in an effort to get enough nutrition; most of the cellulose is left undigested and then excreted. In either case, a herbivore must have a chamber in its gastrointestinal tract where the digestive bacteria can operate. Most mammals have such a bacterial flora in their intestines, and a blind pouch between the large and small intestines, called the cecum, for fermentation by gut bacteria (Fig. 2.4). The cecum of some herbivores, such as the rabbit, is immense. Longer than the rest of the digestive tract, it winds around the abdominal cavity. However, since the cecum opens after the digestive area in the small intestine, most of the material that was broken down in the cecum is not digested, but simply passes out as feces. To compensate, rabbits are well known for eating their own feces to digest the material broken down during the first pass through their gut.

22

HORNS, TUSKS, AND FLIPPERS

Most herbivorous ungulates use a similar system of fermentation in the cecum. Because their bacterial breakdown takes place after the stomach and small intestine, this is known as "hindgut fermentation." Hindgut fermenters include perissodactyIs, elephants, and other non-ruminating ungulates. By contrast, some artiodactyls have "foregut fermentation" in their stomach. Camels, deer, pronghorns, giraffes, goats, sheep, antelopes and cattle have a stomach with multiple chambers. This allows them to crop their food quickly and swallow it immediately without chewing. The undigested food is stored in the first chamber of the stomach, called the rumen. Although only partly chewed, the bacteria in the rumen begin to ferment the food. Then, when the animal is resting, it regurgitates the food to its mouth and chews at its leisure. We call this rumination, or "chewing the cud." After this chewing, the food passes through the rest of the digestive tract, where further bacterial fermentation occurs. These bacteria are essential to breaking down the indigestible cellulose, which is the bulk of the material in their low-quality food., In addition to the ability to crop food quickly, the ruminating stomach gives its owner several other advantages. By having bacteria in their stomach to aid digestion, they are much more efficient at using all the nutrients in their food. In contrast to the foregut-fermenting ruminants, most herbivorous mammals must ferment their food in the cecum and colon of their intestinal tract. Since the tough cellulose is only partially digested by the cecum or colon of a hindgut fermenter, much of the nutrient value is excreted without being digested. A typical hindgut fermenter utilizes only 450/0 of the cellulose in its food, while a ruminating foregut fermenter typically digests 60%. The tradeoff, however, is digestion speed. A ruminant takes much longer (typically 80 hours) to digest the same amount of food that a horse would take (typically 48 hours). This difference between hindgut and foregut fermentation makes a big difference in ecology. Living hindgut fermenters, such as horses, rhinos, elephants, and hippos, must eat large quantities of low-quality vegetation in order to compensate for their low digestion efficiency. This works well for large-bodied animals, such as elephants, rhinos, and hippos, but not as well for smaller herbivores. By contrast, ruminants are so much more efficient in digestion that they must be selective about what they eat, and concentrate on smaller amounts of higher-quality vegetation (such as tender green leaves and shoots, with relatively little cellulose). In Africa, for example, the great diversity of savanna antelopes is ecologically stable because they do not compete directly; each feeds on a different type of vegetation, or at a different level in the vegetation. For example, giraffes feed on the tops of trees, gerenuks and impalas on the tops of bushes-, and other smaller antelopes feed on the middle or lower level bushes, or on grasses. In summary, hindgut fermenters (especially perissodactyls and elephants) have an advantage where there are large quantities of low-quality, high-fiber foods, such as

grass. Ruminants, on the other hand, can cope with almost any kind of food, even in limited quantities. In fact, ruminants do well even in deserts or tundra where the food is scarce. Where hindgut and foregut fermenters compete directly, they specialize on different parts of the plant. In the East African savanna, for example, hindgut-fermenting zebras eat the poor quality dry grass tops, while ruminating gazelles and wildebeest eat the higher-quality young green grass uncovered by zebras. Ruminants have other advantages as well. Unlike hindgut fermenters, ruminants do not have to excrete urea, which is normally eliminated through the urine. Instead, this nitrogenous waste product goes to feed the microorganisms, which the ruminant later digests. For desert artiodactyls, this means that they need to drink less water to balance the urea in their urine. A wild ass in the desert must drink daily, while the camel or oryx can go days without drinking. The ability to digest the protein-rich microorganisms efficiently means that ruminants get all the essential amino acids in their diets, and can eat a much narrower range of plant materials than can hindgut fermenters. There are a few disadvantages to ruminating stomachs. Foods with high caloric value and little fiber, such as fruits or extremely rich fodder, are too easy to digest. If a cow eats vegetation that is too rich, for example, it can become bloated with a huge gas-filled rumen. The gut bacteria are working so fast that they produce more carbon dioxide and methane than the cow can get rid of. If the cow cannot belch, it may die. The rancher may have to slash the rumen of the cow, or punch a hole in it and place a tube through the hole, to relieve the pressure. Although a slimy green mass of partially digested fodder pours out, the cow may have a chance of surviving. Hindgut fermenters, on the other hand, don't have that problem, since fruits are absorbed in the small intestine before the region of fermentation is reached. Another problem with the fermentation process is that it generates a lot of heat. Anyone who has ever had a compost heap in their garden knows that the fermentation process is very rapid, and can generate temperatures of over 160°F (70°C). The blood vessels that drain the gut region are not suited to dumping heat through the blood circulation. Instead, ruminants have arranged their stomach (particularly the rumen, where the fermentation takes place) into a wide, flattened external chamber which lies just under their skin along the left side and belly of the animal. It spreads out over 70% of the body wall! In hindgut fermenters, such as horses, where fermentation takes place in the cecum and large intestine, these organs are arranged around the entire surface of the abdominal cavity. In both cases, the heat-generating organs are located so they have maximum surface area to disperse the heat, and they are near the surface where the heat can diffuse out through the skin. As an animal gets larger, its body mass increases at a power of three (volume = length 3 ), as does the volume of its stomach, but its surface area for losing heat only increases by a power of two (area = length2). Jim Mellett suggests that

CLOVEN HOOVES the main reason herbivorous mammals don't get any larger is this problem of heat loss. Foregut fermenters, such as ruminants, seldom get larger than a giraffe (4200 pounds, or 1900 kg in body weight). Hindgut fermenters pass the food through much quicker with less heat generation, so they can be larger. The largest living hindgut fermenter, the elephant, reaches about 16,500 pounds (7500 kg). Paraceratherium, the gigantic hornless rhino, was the largest land herbivore, and must certainly have been a hindgut fermenter at 40,00060,000 pounds (20,000-30,000 kg) body weight. Mellett suggests that this is the upper limit for herbivorous land mammals. If so, then what about herbivorous dinosaurs, which were even larger? Mellett points out that those dinosaurs with complex shearing teeth for chopping food finely (such as duckbills and ceratopsians) did not exceed the elephant in size. Only the sauropod dinosaurs, with their simple peg-like teeth, were larger, and they must have passed their vast volumes of food through their guts quickly to prevent too much heat. The evolution of the ruminating stomach was a great advance in the evolution of herbivorous mammals. During the middle and late Eocene both perissodactyls and artiodactyls roamed the forests, browsing on large quantities of different kinds of leaves. When the world became drier and grassier in the Oligocene, however, specialized hindgut-fermenting browsers (including the great variety of tapirs, rhinos, and brontotheres discussed later in this book) were at a disadvantage. In North America, ruminating camels, pronghorns, and a variety of deer-like forms eventually came to dominate the Miocene grasslands of the midcontinent, pushing the perissodactyls into high-volume grazing (especially among the horses and rhinos). In Eurasia and Africa, ruminants were even more dominant, and today these continents have a great variety of deer, antelope, and cattle, but only a few horses or rhinos. Clearly, artiodactyls have come a long way from relatively unimportant animals to the dominant group of land herbivores. But where did they come from? To understand their story, we must look at some of their earliest fossils.

23

"BUNNY DEER" At the end of the Paleocene and beginning of the Eocene, the world was a very different place from what it is today. The climate was temperate to subtropical, with no polar ice caps or cold oceans. It was so warm and unseasonal that even the regions above the Arctic Circle were warm enough for alligators and a broadleaf, warm-climate vegetation. The thick, forest vegetation was found from pole to equator, and most of the animals were small and adapted to browsing on leaves or fruits in forests. There were no significant grasslands; indeed, modem grasses had not yet evolved. The tree cover was so thick that the most common animals were lemur-like primates, and a tree-dwelling extinct group of mammals called multituberculates. The largest mammal was about the size of a sheep, and most were much smaller. The main ground dwellers were small archaic ungulates, and the main predator was a large flightless carnivorous bird almost 7 feet (2 m) tall! In fact, very few of the mammals belonged to groups alive today, and those that did (like horses) looked nothing like their descendants. The beginning of the Eocene was unusual in another way. There were great migrations of mammals between Europe, eastern Asia, and North America. Malcolm McKenna has shown that many of these migrations took place across the connection between Greenland and northern Europe, since the Atlantic Ocean had still not opened very wide. There are great similarities between the archaic ungulates, the carnivorous mammals, the primates, and many other typical animals inhabiting Europe and those living in North America. This immigration event represents not only the first appearance in North America of even-toed artiodactyIs, but also the first appearance of the odd-toed perissodactyls, and the rodents. Since the closest relatives of all three of these are known from the Paleocene of Asia, they were probably all migrating across the precursor of the Bering land bridge. The early Eocene was one of the greatest periods of migration in the last 65 million years. Not until the Ice Age opening of the Bering land bridge and the Isthmus of Panama did so much exchange take place

Figure 2.5. Restoration of the archaic early Eocene artiodactyl Oiacodexis. (Courtesy K. Rose).

24

HORNS, TUSKS, AND FLIPPERS

between the animals of different continents. By the middle Eocene, however, this great exchange was nearly over. Asia and North America continued to exchange some kinds of mammals, but to a lesser degree than previously. The connection across Greenland and Scandinavia was severed as the Atlantic Ocean began to spread even further. Since Europe was separated from Asia by a shallow inland sea running along the present Ural Mountains, and from Africa by the Tethys seaway, it was truly isolated. In addition, high sea levels meant that much of Europe was under water, forming an archipelago of small islands. At different times, these islands were either connected or separated, allowing their mammals to evolve in small populations and produce unique species at some times, and allowing intermingling at other times. The earliest and most primitive known artiodactyls are found around the world in the early Eocene. These animals, known as dichobunids, had very simple low-cusped teeth without the curved crests so typical of most artiodactyls. The best known of the dichobunids was first described in North America and named lJiacodexis (Fig. 2.5). It is often considered the ancestor of the artiodactyIs. Diacodexis was a tiny, rabbit-sized animal with very few specializations in its teeth to tell us that it was an artiodactyl. Unlike most later artiodactyls, it still had all five fingers, and four toes on the hind foot. It even retains the collarbone, which is lost in almost all ungulates (including more advanced artiodactyls). However, in the details of the skull, and especially in the ankle region, it was clearly already specialized. Diacodexis was very abundant in North America. Contrary to expectations, the skeleton of these animals does not have simple, primitive limb proportions. Instead, North American Diacodexis has relatively long, slender limbs, suitable for very fast running and even jumping; its proportions were very much like some of the tiny deer we will discuss in Chapter 4. This is also true of the dichobunid relatives of Diacodexis, such as Bunophorus, Antiacodon, and Pentacemylus. Although these long limbs seem specialized, they are actually scaled appropriately for such a small, lightweight deer-like mammal. As body size increased in their later descendants, such as pigs and hippos, the limbs became less adapted for running and leaping. In fact, not all Diacodexis were as delicate as the North American species. Specimens of Diacodexis from the early Eocene of Pakistan are not only smaller and more primitive than those from North America, but they also have shorter limbs with no obvious specializations for running or leaping. Thus, the shorter-limbed artiodactyls could be descended from Asian Diacodexis, rather than from the highly specialized species found in North America. This leads to the most puzzling question of all: where did the artiodactyls come from? When Diacodexis appears worldwide at the beginning of the Eocene it already has a fully developed artiodacty1 limb with the specialized ankle bones. In the past most paleontologists have looked at relatively well known and complete specimens from North

America in seeking the artiodacty1 ancestor. Almost all of them have derived artiodactyls from one of the groups of archaic ungulates found in North America in the late Paleocene, such as the arctocyonids or the hyopsodonts. Certainly, the teeth of some of these animals are very similar to those of Diacodexis. But, as Ken Rose has shown, the rest of the skeletons of these "candidates for ancestry" have their own specializations, and do not show much affinity with Diacodexis. In addition, Earl Manning has shown that the most primitive artiodactyls are even more primitive than most of the known arctocyonids or hyopsodonts, and must have branched off first before these other groups evolved. The discovery of the primitive Diacodexis from Pakistan suggests that our North American bias was a mistake. As we get better and better fossils from poorly explored places such as Asia and Africa, we are finding many specimens that shatter old notions of deriving everything from well-known North American fossils. Later in this book, we will discuss the new evidence that shows the elephants and the perissodactyls probably originated in the late Paleocene of Asia or Africa. The Pakistani Diacodexis suggests the same thing. Several scientists, including Malcolm McKenna, David Krause, and Mary Maas, have pointed out that India was an island continent at the beginnin~of the age of mammals. After breaking off from Africa in the late Cretaceous, it traveled northward through the Indian Ocean, lying just off the eastern coast of Africa (Fig. 2.6). These scientists have suggested that the ancestors of several groups of mammals, including artiodactyls (and possibly lemur-like primates and perissodactyIs) island-hopped from Africa to Madagascar to India during the late Cretaceous and early Paleocene. Then India moved further north, and through the rest of the Paleocene it was isolated from the world. In this isolation lab, ancestral populations could evolve into specialized groups such as artiodactyIs, perissodactyIs, and lemur-like primates without competing with animals found around the rest of the world in the Paleocene. Then, when India collided with Asia at the beginning of the Eocene, they hopped off their floating "Noah's ark" and spread around the world. For these scientists, this explains why Diacodexis, Hyracotherium and certain primates appeared suddenly at the beginning of the Eocene in Europe and North America with no obvious local ancestors in the late Paleocene. This idea certainly seems to fit the available facts, so far as they are known. Unfortunately, no Paleocene mammals have yet been found from the Indian subcontinent to test this hypothesis. The oldest mammals come from early Eocene beds in both India and Pakistan and they contain animals that are known worldwide (although some, such as Diacodexis, are the most primitive known). However, the evidence from the recently discovered relatives of elephants and perissodactyIs discussed later in this book clearly shows that most of the dominant groups of Iiving ungulates must have originated in this region of continents bordering the ancient Tethys seaway, including Africa, India, and southern Asia. We may never be able to pinpoint their exact time and place

CLOVEN HOOVES

25

for many years before its true scientific value was realized. Much of the phosphate in the Quercy mines was in the form of actual vertebrate bones, and some were remarkably well preserved. Each pocket of phosphate occurred in a cavern or fissure dissolved in the ancient limestones which formed the bedrock. However, these pockets and fissures began to fill with fossils in the Eocene and Oligocene, so they preserved ancient bones that had washed or fallen into them 40 million years ago. The quality of the fossils rivaled the great finds of Cope, Leidy, and Marsh in North America. In the introduction to his 1876 monograph on the Quercy mammals, the French paleontologist Henri Filhol enthused, "The localities of Quercy must be considered as having yielded the most interesting evidence hitherto discovered in Europe for the study of fossil mammals, and the animal forms which they reveal are no less valuable than those which have been brought to light in America in recent years."

Figure 2.6. Hypothesis of origin of artiodactyls, perissodactyls, and several other mammalian groups from isolation on the "Noah's ark" of the Indian microcontinent during the Cretaceous and Paleocene. When India collided with Asia in the early Eocene, its natives may have escaped, explaining their sudden appearance in Eocene rocks around the world. (From Krause and Maas 1990). of origin, but it was certainly not North America. The appearance of artiodactyls, perissodactyls, lemur-like primates, hyaena-like creodonts, and even rodents in Europe and North America during the Paleocene-Eocene transition was clearly due to immigration, not evolution from native animals. PHOSPHATE AND FOSSILS One of the most important chemicals used in fertilizers and gunpowder is phosphate. Mineral deposits of phosphate are quite rare in most regions of the world, so when an abundant source of phosphate is discovered, it is quickly exploited. Much of the world's phosphate comes from animal sources. Bird droppings and other fecal matter are rich in phosphate, and in some places the abundant droppings of fish-eating seabirds (known as guano) is so encrusted on sea cliffs and islands that it can be mined commercially. Bat guano at the bottoms of heavily used caves has also been mined. Vertebrate bone is made mostly of phosphate, so abundant sources of bone can serve as fertilizer. In areas with abundant fishing, ground-up fish meal is used. In other parts of the world phosphate occurs in pockets of ancient limestone. One such deposit is located in the Quercy region of south-central France. First discovered in 1865, it was mined

Unfortunately, fissures opened at different times, so they were all of different geologic ages. At first this jumble of fossils confused the scientists, who assumed that everything found in the Quercy pockets was the same age. After 1890 the commercial value of the French phosphate plummeted, since much cheaper phosphates (also a source of vertebrate bones) were found in North Africa. The phosphate mines were abandoned. In the 1960s scientists from the uni versities of Montpellier and Paris began to systematically reopen the old mines. Since nobody knew what pocket (and therefore what age) the fossils in the old collections had come from, it was necessary to re-excavate them and sort out their complex sequence of ages. Over the last few decades they have now worked out the sequence of more than 100 localities, and determined which level each fossil comes from. They have also found many more fossils (especially of small mammals) that were undiscovered, or neglected, by the nineteenth-century scientists. The Quercy deposits contain a staggering array of opossums, carnivores and hyaena-like creodonts, bats, rodents, lemur-like primates, and primitive hoofed mammals. Among the most common elements, however, were extremely primitive artiodactyls. Their feet had not yet lost the side toes, although they clearly were cloven hoofed. Some of the artiodactyls were more specialized, including European relatives of the camels, and others distantly related to the pig-hippo family. Most, however, were members of groups unique to Europe in the Eocene, and not found elsewhere. Except for paleontologists, few people have heard of choeropotamids, cebochoeres, mixtotheres, cainotheres, dacrytheres, haplobunodonts, xiphodonts, and amphimerycids. All of these evolved in isolation in Europe in the Eocene, and with few exceptions were only distantly related to artiodactyls of other continents. Since Europe was an archipelago in the Eocene, it had many unique endemic

26

HORNS, TUSKS, AND FLIPPERS

Figure 2.7. The big entelodont Archaeotherium, common in the upper Eocene-Oligocene beds of the Big Badlands of South Dakota. (Painting by R. B. Horsfall, from Scott 1913). mammals, including such bizarre perissodactyls as palaeotheres and lophiodonts. Like these other endemic forms, the majority of these unique artiodactyls became extinct in the late Eocene as the climate deteriorated. When the island isolation ended in the early Oligocene artiodactyls from the outside world replaced them. PSEUDOPIGS North America and Asia, which were not isolated, also had a great radiation of artiodactyIs in the middle and late Eocene. The descendants of the dichobunids began to specialize in a number of different ways. Some remained primitive forms with simple, low-crowned cusps on their teeth, and ShOlt limbs. One such group, the leptochoerids, survived in North America well into the Oligocene. Most developed longer limbs with reduced side toes, and eventually highercrowned teeth with sharp curved crests for eating tougher vegetation. These groups evolved into the oreodonts and camels, which dominated in North America, and the earliest relati ves of ruminants, which were found in both Asia and North America. We will discuss these animals in greater detail later. A third line of specialization is represented by the pigs and peccaries today (Fig. 2.2). These animals are mainly

omnivorous, eating a wide variety of foods, including fruits, roots and tubers, fungi, ferns, grasses, and even insects, earthworms, and occasional carrion and small vertebrates (such as frogs and mice, if they can catch them). This generalized, omnivorous diet means that their teeth cannot become too specialized for meat slicing or plant grinding. Instead, all of these animals have low, rounded cusps on their teeth, which are suitable for many purposes. This kind of tooth structure is known as bunodont, and it is also found in other omnivorous animals, including bears and most primates (even humans !). Because they eat just about anything they can find on the forest floor, omni vorous artiodactyIs do not need large home ranges to supply their food, which are inhabited by large herds of fast running ungulates. Instead, omnivores rely on concealment in the underbrush, and retain the primitive shorter limb proportions of a generalized walker. Of course, as artiodactyls, they still have cloven hooves and the specialized ankle joint. However, they usually retain four toes on both their front and hind feet, so that they can get good traction on marshy soil. This pig-like mode of life evolved several times in the artiodactyIs during the Eocene. In the European archipelago there were animals such as cebochoerids and choeropotamids which had bunodont teeth and four-toed feet, but

CLOVEN HOOVES were extinct side branches unrelated to pigs. In Asia similar animals known as helohyids, entelodonts, and anthracotheres performed this role. North America also had helohyids and a bizarre hippo-sized animal known as Achaenodon. Most of these groups did not survive into the Oligocene. However, the entelodonts and anthracotheres were very successful "pseudopigs" and "pseudohippos," dominating North America and Asia through much of the Oligocene and Miocene. The most spectacular of these groups was the entelodonts. They first appeared in the middle Eocene of China with an animal known as Eoentelodon. By the late Eocene, they had reached North America, represented by a peculiar animal known as Brachyhyops ("short pig face"). In the late Eocene and Oligocene deposits of the Big Badlands of South Dakota one of the most common large mammals is the ugly entelodont Archaeotherium (Fig. 2.7). This animal was the size of a large hog,. and very pig-like in most of its features. Undoubtedly, it also had a very pig-like diet, feeding on roots, fungi, carrion, and occasional meat. Its face was truly grotesque. The huge, heavy head had broad flaring cheekbones, and there were weird bony protuberances sticking out of the bottom of the jaw. Each male had a very impressive set of canines, which were probably not used so much for catching prey as for fighting and intimidating rivals and predators. Indeed, several specimens have been found which have deep "battle scars"-healed wounds in the bone around the eye that could only have been formed from the canines of a rival male. The "warts" on warthogs have a similar function-they pad the blows during head-tohead wrestling matches between adult males. Although entelodonts have bunodont teeth, they have a very bizarre pattern of wear. In many mammals it is typical for the grinding molars and premolars to be worn down from the top of their crowns. But the biting incisors ("eye teeth") and stabbing canines usually keep their sharp points. Entelodonts, however, have conical premolars much like their canines and incisors, and all of these teeth are worn flat on the tips. Apparently, they were using all their front teeth for crushing, rather than the usual stabbing and cutting. Matt Joeckel has studied the jaw mechanics of entelodonts, and concludes that they probably ate a great deal of bone and carrion, since this same wear pattern is seen in scavengers like bears and hyaenas. In addition, he found that they were capable of tremendous side-to-side movement of their lower jaw as they ground up the food with their simple bunodont teeth. Although this is also seen to some degree in pigs, no animal ever ate quite like an entelodont! Entelodonts migrated to Europe in the early Oligocene, replacing the cebochoerids and choeropotamids that had occupied the piglike ecological niche in the Eocene. They are also found in the youngest of the Quercy deposits, although they were never as important as they were in North America. By the late Oligocene and early Miocene, entelodonts reached the culmination of their evol ution. The last and most spectacular of these was Daeodon (formerly

27

known as Dinohyus) from the famous early Miocene locality at Agate Springs, Nebraska. (We will discuss this place further in Chapter 14). This animal was truly hippo-sized, reaching almost 8 feet (2.4 m) at the shoulder, and 11 feet (3.4 m) long, and with a skull over five feet (1.5 m) long! Its weight is estimated around 2000 pounds (900 kg), although it was not fat and short-limbed like a hippo. Instead, it has fairly long, robust limbs, and most of its weight was in the pig-like body and huge head. Daeodon was like Archaeotherium in having the broad, flaring cheekbones and bony protuberances on the base of the jaw, but they were even more extreme. The cheekbones of Daeodon even had a thick bony flange that stuck out from the side of the face like a set of wings. No one knows what all this bone was for. Some have suggested that it served as an attachment point for complicated jaw muscles. However, it is hard to imagine that their diet was so different from smaller pig-like forms that it required such unusual bony growths. Their presence around the eyes suggests another hypothesis-they were used for threat and display rituals~ Most artiodactyls today used their horns or antlers to signal their position in the herd, and threaten rivals with a display of their size. Since the piglike artiodactyIs never developed either horns or antlers, they must have used their huge canines and their weird bony cheekbones for the same purpose. Daeodon was the last of the entelodonts found anywhere in the world. Why the group died out is a mystery since no large pig-like form appeared in North America in the early Miocene to replace them. Indeed, the pig-like niche on this continent was not filled by anything that large until late in the Miocene, when peccaries reached the peak of their evolution. SUI GENERIS Everyone is familiar with the pig family, the Suidae, and many of the typical members, such as the domestic pig, the wild boar, and the warthog. Few people distinguish between the Old World Suidae, and their New World counterparts, the peccaries or Tayassuidae. Superficially, pigs and peccaries look very similar. Most people have trouble telling them apart, and they occupy virtually the same ecological niche. In evolutionary terms, however, they have been distinct since the late Eocene, over 35 million years ago. Pigs have longer skulls than peccaries, with wide flaring tusks, whereas peccaries have a relatively short head with downward-pointing tusks (Fig. 2.8). This is particularly apparent in a side view of the skull. In pigs, the jaw joint is high on the side of their head, rather than just above the plane of the teeth, as itis in peccaries and most other mammals. The rear of a pig's lower jaw has extended flanges in the back to support this high jaw joint and anchor the long jaw muscles. Pig molars often develop very wrinkled, complex surfaces, and pigs have diversified into many more ecological niches than have peccaries. Unlike peccaries, however, they have never become long-limbed, efficient runners.

28

HORNS, TUSKS, AND FLIPPERS

Figure 2.8. Comparison of the skulls of a living warthog (right) with a large extinct peccary Macrogenis (left). Although both have large flaring ridges below their eyes, the tusks of pigs flare outward, whereas the tusks of peccaries point straight up and down. (Photo courtesy C. Janis). Another difference is their biogeography. Although both groups apparently originated in Asia in the late Eocene and spread widely across Eurasia in the early Oligocene, wild pigs never left the Old World. Peccaries, on the other hand, were rare visitors to the Old World, but had no pig competition in the New World until Europeans brought domesticated pigs to this continent for the first time. The earliest known pig, Propalaeochoerus, is found in the early Oligocene of China. At about this time it immigrated to Europe after the late Eocene extinctions discussed in other chapters. Pigs are rare in the Oligocene of Eurasia compared to the competing anthracotheres. By the early Miocene, however, they began to flourish all over the Old World. Hyotherium, the typical early Miocene pig of Europe, also managed to hop across the narrowing Tethys seaway and invade the island continent of Africa. Another early Miocene pig from Africa, Xenochoerus, is part of a specialized side-branch, the sanitherines, leading to pigs like Sanitherium, Hyosus and Hippohyus, which flourished in Pakistan in the middle and late Miocene before becoming extinct. These pigs were among the first to adopt a grazing mode of life, with complexly folded enamel on their highcrowned teeth. Another extinct side branch are the tetraconodontine pigs. Early Miocene forms like Conohyus from Asia differ

very little from Hyotherium except that they have enlarged premolars. Their evolution culminated in the late Miocene of the Siwalik Hills of Pakistan with forms known as Tetraconodon and Sivachoerus. Tetraconodon had huge crushing premolars and gigantic tusks; its teeth converge on those of a hyaena, suggesting that it was a bone-crushing scavenger. During the Pliocene the tetraconodontine lineage underwent a great evolutionary radiation in Africa. Pigs such as Nyanzachoerus and Notochoerus developed wide flaring cheekbones similar to those we have already seen in entelodonts and peccaries. One peculiar tetraconodontine pig from the early-middle Miocene of North Africa was Kubanochoerus. This pig was truly bizarre in that the males had a small bony horn above the forehead (Fig. 2.9). Since horns are rare in other primitive artiodactyl families, and common in ruminants, this pig is a true exception to the rule. A third lineage of middle Miocene pigs did not go extinct, but is related to the living suines. Although many of these animals, such as Bunolistriodon, retained primitive pig features, there are specialized beasts such as Listriodon, from the middle-late Miocene of Pakistan. Its molars have transverse cross-crests which closely resemble those found in a tapir, or many mastodonts. This suggests that it was a specialized leaf-eater, abandoning the typical pig omnivorous habitat. The main line of pig evolution can be seen in

CLOVEN HOOVES

Figure 2.9. The Miocene horned pig Kubanochoe-rus. (From Agusti and Anton 2002).

forms like Propotamochoerus and Dicoryphochoerus of the middle-late Miocene of Pakistan. By the late Miocene, fossils that are put in the living pig genus Sus are known from Europe and Pakistan. Sus falconeri from the late Miocene of Pakistan has many features that place it near the living warthog, including a long snout and skull, with the eyes placed far back on the skull. In the Pliocene, several modern lineages of pigs replaced the tetraconodontines in Africa. The bush pigs (Potamochoerus) and forest hogs (Kolpochoerus, Hylochoerus) replaced Nyanza-

29

choerus, and the warthogs (Metridiochoerus, Phacochoerus) replaced Notochoerus. One warthog, Metridiochoerus compactus, from the Pleistocene of Tanzania was a true giant. It stood over a meter high at the shoulder, and had long curved upper and lower tusks, and a single elongate, high-crowned molar in each jaw that had complexly folded enamel. This condition parallels the pattern evol ved independently in the elephants. At the end of the Pleistocene, this variety of warthogs went extinct, leaving only the living warthog, Phacochoerus aethiopicus. The face of the warthog is so grotesque that its name has become synonymous with "ugly" in our language (Fig. 2.10). Its bony protuberances in front of the eye and along the upper jaw are coupled with huge, flaring canine tusks that are reminiscent of the extinct entelodonts. Warthog boars have more elaborate "warts," and their primary function is protection during head-to-head wrestling and butting with other males. Although their large upper tusks are more impressive, the smaller, sharper lower tusks are their primary weapons, not only against other males of their own species, but especially against predators. Even lions do not want to be slashed by their fearsome tusks. As I.-P. Hallet described it, "Every family of warthogs has its own aardvark hole where the wary pigs sleep, hide out, bear babies and raise them. Senge, as he is called in Swahili, is a good natured but rather timid fellow, much less apt to stand and fight than the Indian wild boar. When disturbed, whole families or solitary males literally hightail it to the burrow,

Figure 2.10. The warthog, Phacochoerus aethiopicus, wallowing in the mud. (Photo courtesy A. Walker).

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HORNS, TUSKS, AND FLIPPERS fleeing to safety with their tufted tails stiffly erect. They enter hindfirst so that they can use their huge tusks to stave off enemy pursuit, and leopards rarely push the issue: full-grown male warthogs may weigh as much as 200 pounds and the leopard prefers, as with all sizable prey, to attack them from the rear. Lions may claw at the burrows like a pack of excited dogs, trying to dig out the holed-up pigs. If they succeed they have a fine pork dinner, but the dinner fights back, often inflicting serious wounds before the lions seize and snap the neck. At waterholes the warthog also approaches hindfirst, kicking at the edge with his back feet before turning to drink. He is stamping some salty crust into his drinking water-he doesn't like to take his salt straight-but Azande tribesmen say, observing that strange little ritual, that Senge has another reason. According to their legend, the first-created walthog saw a savage-looking creature lurking in a pool of still water. Appalled, timid Senge ran away to hide in his burrow. But he never forgot, warning all of his descendants to stir the water well before they faced it (so that they wouldn't have to see their own reflections). Big-headed, broad-snouted, maned on the neck and back with bristling brownish hair, Senge has a pair of huge warty protuberances just below his eyes and another pair flanking his massive ivory tusks. Unlike those of true pigs, his tusks are upper canines, not lower ones; the paired warts protect his small, rather dim-sighted eyes as he plows up wild roots and tubers for a living" (Hallet, 1968: 251-252).

Although they are omnivores like other pigs, warthogs are the most specialized for grazing. They drop to their knees and pluck the tender growing tips of grasses with their lips, and grind them with their enlarged last molars. At the end of the rainy season, they take grass seeds, and during the dry season, they use the tough upper edge of their noses to scoop grass rhizomes out of the dry, sun-baked savanna soils. Contrary to popular accounts, they seldom use their tusks to dig up food. Warthogs are not strictly territorial, but divide the grasslands into home ranges that vary from 60 to 370 hectares. They share water holes and aardvark burrows when necessary, although their grazing areas may be marked with saliva and secretions from glands around the eyes. They can have a population density as great as ten individuals per square kilometer, although typically there are fewer than, two. The abundance of available aardvark burrows largely determines their population density. The population is divided into clans, each composed of several bands, or "sounders," plus associated loners. Most sounders contain 46 warthogs, although some are as large as 40. The sounders

consist mostly of females and their young, plus immature males that have not yet gone off on their own. Adult boars only join the sounders during mating, at which time they undergo a complex ritual of display and head wrestling for dominance. Once the dominant boar has been established, he sniffs the sow's urine to determine if she is in estrus. Then there is a long, drawn-out courtship ritual. A boar may squirt urine where the sow has urinated, and then pursue her, raising his mane, champing his jaws, and salivating as he mumbles deep in his throat. Eventually the sow gives up and the boar places his head across her back, and massages her rump. This induces her to stand still, and he mounts her for as long as ten minutes, jerking his head along with his thrusts. His spiral penis fits into her grooved cervix, and after copulation, a plug forms to prevent further mating. Mating occurs in May and June, and births in October and November, about 170-175 days later. Although the sow has only four teats, she may have as many as eight young, but one to three is more typical. The piglets hide in the grass-lined burrow for a long time, since they are especially sensitive to the temperature fluctuations outside. After about 50 days, they leave the burrow and accompany their mother, and they are weaned by 21 weeks. They start eating grass early, as well as their motheE's dung, so they can pick up her gut bacteria. The young are driven away when the sow is about to bear a new litter, although they may return later. After 15 months, the male young leave for good, but the females may stay indefinitely. They become sexually mature at 18 to 20 months, but males may not be strong enough to win sows until they are four years old. Young warthogs are extremely vulnerable to predation by lions, leopards, and cheetahs, and less than half Iive past the first year. Although they have lived as long as seventeen years in zoos, they seldom live that long in the wild, and their high reproductive rate must compensate for this. Besides the diversity of warthogs in the PlioPleistocene, there is a second major lineage of forest pigs in Africa. Kolpochoerus (formerly called Mesochoerus) was one of the most characteristic pigs of the cradle of humankind. In fact, Kolpochoerus figured prominently in the dating of early hominid fossils. Don Johanson, in his book Lucy, describes a controversy between Richard Leakey and other scientists regarding the dating of the oldest Homo habilis specimens from Lake Turkana. Leakey and his group insisted on a date of 2.9 million years, based on the controversial KBS Tuff. Mammalian paleontologists said that the pig and elephant fossils were comparable to those found in beds about 2 million years ago in the Omo Valley of Ethiopia and elsewhere in East Africa. The foremost pig expert, Basil Cooke, had found that Kolpochoerus limnetes was especially characteristic of the interval around 2 million years everywhere except East Turkana, where Leakey insisted that it was three million years old. At a 1975 conference in London the conflict c:ame to a head. One of Leakey's group came wearing a "pig-proof helmet." Cooke came wearing a tie embroidered with the initials "MCP," which

CLOVEN HOOVES

Figure 2.11. The bushpig, Potamochoerus porcus (Photo by D.R. Prothero). were widely available for "Male Chauvinist Pigs." When asked about the tie, Cooke said that the initials stood for "Mesochoerus Correlates Properly." Eventually, the problematic KBS Tuff date was redated and the results supported the pigs. From Kolpochoerus, two major lineages evolved. One became the giant forest hog, Hylochoerus meinertzhageni. The second is now represented by the bushpig or red river hog, Potamochoerus porcus (Fig. 2.11). Both pigs are found in dense forests, primarily in the Congo Basin and other parts of central and eastern Africa. Bushpigs are able to plow up soil and tum over heavy logs in search of a varied diet of roots, fruits, cultivated plants, fungi, beetle larvae, giant snails, small amphibians, reptiles, and mammals, as well as eggs and bird nestlings. They will also eat carrion when it is available. Forest hogs eat a diet of grasses and shrubs, and are particularly characteristic of the forest margin, where there is a mixed habitat of trees and grasslands. The bush pig is spectacularly marked. It has long russet-red hair with a white mane on the head and a crest along the back, white spectacles around the eyes, white ear tufts and white side whiskers. Ivan Sanderson vividly describes his encounter with them in Animal Treasure: "Abruptly I came upon them, a veritable herd of the weirdest animals I have ever seen. Rich orange in color, with monstrous heads, they formed a vivid contrast to the sombre greens of the water weeds. It seemed, in fact, as if they were more than half head, since their short legs were sunk deep in the morass that they were busily creating in the soft earth. On their heads they bore tall crests of spotless white which passed backward into a long white mane falling this way or that over their shoulders. Their ears were long and pointed, terminated by a long white plume, which they constantly flicked and

twitched as they ploughed up the ground in long, even furrows. All the while they grunted and grumbled contentedly. A herd of river hogs (Potamochoerus porcus) is an unusual sight. They seem as contented and lazy as ordinary farmyard pigs, yet their vivid coloration and grotesque form make one pause to consider whether one's sight is playing a trick. In the wilds they don't look like pigs at all. They are, in fact, unlike any other animal with their big heads, long tapering plumed ears, and tall narrow bodies ... They are indeed peculiar hunters. I had always supposed them to be herbivorous, yet I saw one large sow unearth a cluster of huge snails and set to work cracking the shells and munching up the juicy contents. In this she was assisted by three small hogs who tussled and bit each other in an effort to get at the morsels. The tactics consisted of flying tackles in which they threw their whole weight into their shoulders and banged their opponents, one of whom was sent sprawling into a muddy bog. The sight of a wild animal floundering on its back was really most remarkable and gave me the impression of watching a group of school children at play. One old hog who kept looking at me as if realizing that I might be potentially dangerous made a most comical misjudgment. He was rooting along the edge of the marsh, stopping now and then with his long snout several inches in the mud to crunch up some hidden root, when he inadvertently pushed under a particularly tough root extending from a large tree on the solid ground nearby. It appeared that he had small tusks (as I saw later) and these must have got locked under a root, for he suddenly set up the most terrific racket, dancing about with his back legs and giving little hops like a ballet dancer, heaving, pulling and squealing as if caught by the nose. At first I thought he was fighting something on the ground, since his nose was out of view behind a small plant, and I stupidly moved to see what it was all about. This worried the others, who began to move off hun~iedly, but I got a good view of the hog as he writhed in fury, tugging at the root. Then my attention was drawn to one of the loveliest sights I have ever seen. As the herd moved past me with increasing speed, out trotted some indi viduals I had not seen before. Among them was a swarm of tiny piglets, each immaculately striped with gold on its little, otherwise unmarked body. They trotted along in a line uttering high-pitched grunts and herded from behind by an agitated mother who kept prodding their delicate little

31

32

HORNS, TUSKS, AND FLIPPERS

Figure 2.12. A family group of giant forest hogs, Hylochoerus meinertzhageni. (Photo courtesy A. Walker). hind legs as if to say: 'Go on, hurry up, or the bogeyman will get you.' The whole scene was so perfect that I stood spellbound at the sight of it" (Sanderson, 1937: 75-78). Unlike the warthog, the upper tusks of female bushpigs point downward and wear against their lower tusks. The boar has walts in front of his eyes, which are usually covered by the long hair; these serve as protection during head wrestling with other boars. The white facial markings are particularly important in face-to-face displays, since they accentuate the facial expressions and ear position, and signal the intentions of rivals. Like the warthog, their sounders are composed mostly of sows and their offspring, with or without a dominant boar. Most sounders consist of only 4-6 pigs, but occasionally they form groups as large as 40. They mark their home ranges with secretions from glands found at the nape of the neck, the front comer of the eye, and the wart in front of the eye. Relatively little is known about their reproductive behavior since it is hard to follow them in the dense forests. The sow builds a nest in a deep thicket or hollow tree, lining it with reeds, grasses, and branches. She excavates the cen-

ter into a shallow dish, where she gives birth during midsummer to as many as ten piglets (although she has only six teats). The tiny piglets are marked with white or yellow spots on a black or brown background, which fade after six months. These markings conceal the young in the mottled forest light, and they freeze when they hear mother's alarm grunt and stay crouched until she returns. The young are vulnerable to many predators, including smaller cats and eagles, and the adults are also threatened by leopards and pythons. However, they are so aggressive that they have been seen to drive a leopard away from its kill and eat it themselves. Because of human hunting of leopards, the bushpig population of southern Africa has actually expanded, and they are now a serious threat to crops in many parts of the continent. They have been known to wipe out an entire peanut crop. Since they are so versatile, they have adapted to the loss of their forest habitat by raiding the spreading agricultural areas, making them very unpopular with the natives. The giant forest hog (Fig. 2.12) is the largest of all living wild pigs, reaching over a meter in height, two meters in length, and weighing up to 600 pounds (275 kg). After the discovery of the okapi in 1900 (see Chapter 4), it was

CLOVEN HOOVES thought that there were no more large mammals left undiscovered in the wild. Nevertheless, African tribes and early travelers (including Henry Morton Stanley) had long reported a "giant black hog" that had never been captured or described. Then in 1904 a Captain Meinertzhagen of the British East African Rifles in Kenya received the severely damaged skin of a large black pig from villagers near Mount Kenya. Later he received a huge skull and partial skin from near Lake Victoria. He sent these to the British Museum in London where the zoologist Oldfield Thomas recognized it as a new species and named it Hylochoerus meinertzhageni, or "Meinertzhagen's forest hog." Because of its size, the giant forest hog is not afraid to turn and fight off leopards or humans, and boars are known to charge without warning or provocation. With its huge head, broad flat bony ridges beneath the eyes, flaring tusks, and long coarse black hair, it can be a terrifying sight, and most natives fear it. Its forehead and snout form a broad, flat surface, which it uses in pushing contests with other boars. There is a concavity on the roof of the skull that can hold a cup of water. Like other wild pigs, the skull above the brain is protected by bony sinuses which act as a shock absorbers during impact (similar to that seen in the extinct brontotheres, who also may have head-wrestled). It is found in scattered local populations in tropical Africa, hiding wherever there is dense evergreen cover and fodder. It is known from subalpine areas and bamboo groves to lowland swamps, but prefers savanna-margin mosaics and wooded savannas. It frequently shares its habitat with Cape buffalo, rhinos, and others, helping to maintain the "buffalo glade" by their feeding. Like the warthog, it uses its lips to bite off grasses where they are dominant, but in other areas it eats herbaceous shrubs, lianas, bamboo, and some carrion; it rarely roots like bushpigs or other typical pigs. However, it does excavate soft earth to pick up salt and other minerals. Forest hog sounders may contain as many as 20 pigs, composed mostly of the mother and as many as three generations of her offspring, along with a dominant boar. These sounders may cover home ranges as large as 10 square kilometers. These social units are very loosely established, amalgamating and then breaking up into a new sounder. After a rough, noisy courtship, forest hogs breed nearly year round. Little is known about their reproductive biology, since they are so secreti vee Gestation is thought to be about 125 days, after which the sow bears 2-6 piglets in a protected dry spot under a fallen tree. They soon accompany their mother, and when they hear the sow's alarm grunt, they freeze flat against the ground. Nevertheless, they are apparently very vulnerable to predators. Population studies have shown that piglets have a high mortality rate, in spite of the fiercely protective adults. The biology of Asian wild pigs is less well studied than their African counterparts. Perhaps the most grotesque is the fabulous babirusa (Babyrousa babyrussa), found only on the Celebes and nearby islands in the Malay archipelago. It is one of the strangest beasts ever conceived (Fig. 2.13). Its

33

upper tusks actually pierce the roof of the snout and curl upward and backward, reaching lengths of seventeen inches. The lower tusks also protrude upward outside the mouth, giving it the weird combination of four upward and backward curling tusks in front of its eyes. Neither set of tusks occlude, so the uppers grow continuously and curl around until they eventually touch the roof of the snout again. The lowers must be sharpened against trees to keep them from becoming useless. Many explanations have been suggested for the function of these curled tusks. Native legends say that the babirusa hooks its head to a tree limb at night to rest. However, the extreme tusks occur only in boars, and are probably used mostly for sexual competition. The wear on them suggests that the boars spar and wrestle with them, with the upper tusks locking in the opponent's sharp lower tusks. In this sense they are very similar to deer antlers, whose primary function is display and combat between

Figure 2.13. The bizarre curve-tusked Asian pig known as the babirusa, Babyrousa babyrussa (Photo by D.R. Prothero).

34

HORNS, TUSKS, AND FLIPPERS

Figure 2.14. The bearded pig (Sus barbafus) , a unique wild pig found only in Malaysia and the Philippines (Photo by D.R. Prothero).

bucks. Indeed, "babirusa" means "pig deer" in the native tongue. The babirusa lives in moist forests, canebrakes, and the shores of ri vers and lakes. It is a swift runner, and a good swimmer, often swimming out to nearby islands to seek food. Its naked body is well suited for its swimming, wallowing habits. Its senses of hearing and smell are acute, and it is mainly nocturnal. Consequently, little is known about its biology. Babirusas travel in small sounders, making continuous low grunting moans as they move. They do not root with their snouts, but instead browse on leaves and fallen fruit. Offspring are borne in the early months of the year after a five-month gestation, and are not striped like other piglets. Only two piglets are born, both identical twins of the same sex. Their wild lifespan is unknown, although most captives live about 10 years, and the maximum in a zoo was 24 years. Native Malayans frequently capture young babirusas and tame them. They are also hunted regularly for food on Celebes. Because of this, and the destruction of their habitat on their only island home, they are now considered endangered in the wild. Recently, the New York Post reported that the babirusa is a "kosher pig," and could be bred to be eaten by Jews and Muslims. This is because babirusas are chiefly leaf eaters, and have a multi-chambered stomach like ruminants to aid in bacterial fermentation. However, they do not chew their cud like ruminants, so rabbinical authorities have rejected the notion of a "kosher pig." All remaining wild pigs are members of the genus Sus, which includes Sus serofa, the domesticated pig. Three rare species live in the Malay archipelago along with the babirusa. The most spectacular is the bearded pig, Sus barbatus (Fig. 2.14) found on the Malay Peninsula, Sumatra and Borneo. Its long white side whiskers flare out from the

cheeks, reminiscent of the red river hog. Bearded pigs live mainly in tropical rain forests and mangrove jungles, where they feed on a typical rooting pig diet of fruits, insect larvae, roots and shoots, and carrion. They especially favor the roots of cycads ("sago palms"), and occasionally raid cultivated yam and manioc fields. Bearded pigs often follow the sounds of monkeys or gibbons to collect the fruit that they drop. On Borneo they are noted for their long migrations; herds of hundreds of bearded pigs were easy prey for native hunters. These pigs permit the crowned wood partridge to pick worms right before their nose, and ticks from their skin. When the bird gives an alarm call, the pigs also flee. On Borneo they have no predators except the rare clouded leopard, and most of the Muslim population does not eat pork, so only the native tribes of the interior hunt them. Much less is known about the rare Javan warty pig, Sus verrueosus. Found only in Javan forests, it has three huge bony warts on the side of its head: one above and one below the eye, and a third on the far corner of the lower jaw, which may grow very large and look like a big, slack blister dangling from the jaw. Its biology, so far as it is known, is much like that of the wild boar. Even less common is the Celebes pig, Sus eelebensis, which is sometimes considered a subspecies of the Javan warty pig. Almost nothing is~known of its biology. The rarest of all wild pigs, however, is the pygmy hog, Sus salvanius. Found only in the Himalayan foothills, it is so small (less than 20 pounds, or 9 kg) that it looks like a toy pig. They live in small herds in dense brush, coming out mainly at night. It is now restricted to northwestern Assam, where only 100-150 individuals are thought to survive. Almost nothing is known of its biology, and very few sightings have been reported in recent years. Finally, the familiar domestic pig is a descendant of the wild boar, Sus serofa. Even before domestication and dispersal by humans, wild boars were long widespread in the Old World, occurring all over Europe, North Africa, and temperate and tropical Asia; they have been secondarily introduced to North and South America. Wild boars are extremely versatile in diet and habitat, as the large geographic range suggests. They are found in plains and mountains up to 13,000 feet (4000 m) in elevation, in swamps and dry steppes, and even close to civilization. They can live in cold regions with heavy snow cover, trekking single-file through their paths in the snow when it becomes too deep. In central Europe they eat not only grasses, but the full spectrum of pig foods found by rooting (such as fungi, roots, tubers, bulbs, nuts), as well as carrion, wounded animals, rodents and other small mammals, reptiles and amphibians, eggs and young ground-nesting birds, insects and their larvae (especially grasshoppers), crabs, clams, worms, and just about anything else they can catch or dig up. Wild boars have similar social habits to most of the other suids we have just discussed. Sounders consist of about 20 individuals, mostly sows and their offspring, with occasional dominant boars accompanying them, as well as

CLOVEN HOOVES peripheral bachelor herds of submature males. Their large home ranges (typically about 200 hectares) encompass a central den or sleeping area constructed of grass mats with a roof held up by grass, and several wallows. From these centers, they spend much of the evening foraging over a large area in search of anything edible. They mark their home ranges with cut marks from their canines on "marking trees," as well as scent from lip glands. Their eyesight is poor, since they live. in dense cover, and hunters have long known that hiding quietly in ambush is the best way to catch them. Their sense of smell, however, is acute, since they must find food underground; domestic pigs are used to hunt for truffles for this very reason. Their hearing is also excellent, and like domestic pigs, they are among the most intelligent of hoofed mammals. They quickly learn how to avoid danger and outwit hunters routinely. Males wage violent battles for estrus females, pushing and shoving shoulder to shoulder as they try to slash with their sharp tusks. During rutting season adult boars develop a thick, loose layer of connective tissue on their shoulders and on their face that helps protect them from bleeding to death of tusk wounds. By the end of mating season the older boars are covered with serious wounds and severely emaciated, losing up to 20% of their original weight. They then retreat to their solitary lives to recover their strength. In tropical climates mating occurs year round, but in more temperate regions the mating season is November to January. After a gestation of about 115-140 days, the piglets are born in late March and April in a quiet place with dense plant cover. They build large nests of branches, which protect the naked piglets from the cold. The sow has six pairs of mammae and the piglets squeal and push and shove to compete for a position at a teat. This "suckling order" often means that the smallest "runt" is starved to death, and piglets often injure each other with their emerging tusks. By two weeks they are rooting and eating solid food. Piglets are weaned after three or four months, but they do not become sexually mature until 12-18 months. Infant mortality is extremely high, and only one or two piglets make it to adulthood. Their lifespan in the wild is about fifteen years. Their major predator in most of Eurasia is the wolf. In other areas they may be hunted by lynx, leopards, or tigers. They were hunted by humans for a long time, and many ancient civilizations and Germanic tribes gloried in boar hunts. Because of their gregariousness and adaptability to any diet, pigs were remarkably easy to domesticate. The earliest certain record of domestic pigs is from 6500 B.C. in Mesopotamia, near the town of Jarmo, Iraq. Domestication is documented from China around 4900 B.C., and possibly as early as 10,000 B.C. in Thailand. They have apparently been domesticated in many different places over the centuries, although all domesticated pigs are descended from the Eurasian wild boar. Domestic pigs are found in cultures that are sedentary and usually agrarian, not in nomadic cultures. This is because pigs cannot be driven over long distances like cattle, sheep, or goats. On the other hand, they

35

are valuable to agricultural economies, since they are easily kept in a confined pigpen, mature sooner than other ungulates, have larger litters, and consume human refuse. In many cultures the pigs wander around the village, performing the task of garbage collector. Pigs are so versatile that a number of domestic stocks have been reintroduced to the wild, and become feral pigs. Many were released for sport hunting, or escaped from human settlements. Feral pigs are widespread from the Carolinas to California, on eight of the Hawaiian Islands, Puerto Rico and the Virgin Islands, and many other islands where Europeans have brought livestock. Under these conditions the domestic features tend to disappear after generations of wild breeding, and some begin to resemble the ancestral wild boars again. Feral pigs, along with goats, are the bane of the conservationist. Their rooting is far more destructive than the grazing of goats, and they easily destroy habitat for vulnerable native species that once lived in isolation. "NEBRASKA MAN" AND JAVELINAS Although we think of the "Roaring Twenties" as an age of bootleg liquor, flappers, and jazz, it was also an age of conservative backlash. After the stresses of the First World War, America yearned to return to "normalcy," as' Warren Harding promised when he was elected President. Businesses were allowed to make money without regulation, eventually leading to the stock market crash of 1929 and the Great Depression. The Ku Klux Klan returned to the South in force with lynchings and cross-burnings. During such conservative periods in American history it is common for religious conservatism to stage a comeback as well. Evangelists such as Billy Sunday were at the peak of their popularity. Tent revival meetings were so widespread that they became moneymakers for corrupt preachers so vividly described by Sinclair Lewis in Elmer Gantry. Amongst all this religious fervor, fundamentalist attacks on evolution returned. The battle between science and religion has a peculiar history in N011h America. In Europe, the religious objections to Darwin's book had virtually vanished by his death in 1882. Few educated people disputed the fact of evolution, although among scientists there was still disagreement as to whether Darwin's mechanism of natural selection was sufficient. In the United States, Cornell University President and historian Andrew Dickson White wrote A History of the Waifare of Science with Theology in Christendom in 1896 on the assumption that the war was over, and that religion had ceased interfering in scientific matters. Yet at the same time, religious conservatives who were upset at scholarly findings about the origin of the Bible founded the Fundamentalist movement in 1895 in Buffalo, New York. Their major tenet was the belief in the literal truth of the Bible. Long after the educated world had thought the issue settled, a handful of reactionaries tried to go back to the world before 1859.

HORNS, TUSKS, AND FLIPPERS

36

A

H_s,o.rt}~(-th.cu,s

~~t.~&""

:....r-·

.... .-,

1-· ....

('J~,.

On-t:.,.';'"

".",..

Lb~ (J

HtDnD

~4pi"'$

(N.a·,".~)

Figure 2.15. A. The teeth of "Nebraska man," which Osborn and many others mistakenly identified as a North American "anthropoid." They were eventually shown to be peccary teeth. (From Osborn, 1922). B. Reconstruction of "Nebraska man" (from the Illustrated London News, 1922). Fundamentalism virtually disappeared during the first two decades of the twentieth century, but its revival in the Twenties was paI1icularly strong. Many states in the "Bible Belt" passed laws prohibiting the teaching of evolution, which eventually led to the famous "Scopes Monkey Trial" of 1925. The famous populist orator (and three-time Democratic presidential candidate) William Jennings Bryan spent much of his time attacking evolution. This led Henry Fairfield Osborn, President of the American Museum of Natural History in New York, and one of the foremost paleontologists in the country, to answer Bryan's attacks. In a series of articles beginning in 1922, and culminating in the 1925 book, The Earth Speaks to Bryan, Osborn brought the strong case for evolution to the public eye. But his favorite piece ofevidence was a small, worn tooth that had been discovered by Harold Cook in Nebraska in 1917. The tooth appeared to be a tiny, square-shaped molar of an anthropoid ape or human (Fig. 2.15A). It was from a very old individual, so virtually all the crown surface had been

worn off, and furthermore it was very abraded before it was buried. Coming at a time when evolution was under attack and few fossil humans were known, Osborn was overjoyed. He received it in March, 1922, and a month later announced it to the world as Hesperopithecus haroldcooki, "Harold Cook's western ape." The scientific world was very skeptical. Not only was the specimen too poor to be sure it was an ape, but there was no evidence that apes had ever lived outside the Old World. This specimen, from the supposed Pliocene (now known to be late Miocene) Snake Creek beds just south of the famous Agate Springs Quarry in western Nebraska, would be the only primate in North America since their disappearance from this continent in the late Eocene. However, the specimen convinced the British anatomist Grafton Eliot Smith (one of the proponents of Piltdown Man, also recently discovered), who commissioned an overly imaginative "complete reconstruction" of the ancient ape (Fig. 2.15B). This illustration made the Illustrated London News, a classic example of the overzealousness of the scientists and the public to flesh out details about our ancestry. One of the strengths of science is that it is self-coITecting. Osborn's colleague, William King Gregory, was an expert on primate anatomy, and he had doubts about the specimen as well. While Bryan and Osborn were battling it out in print, more field work was being conducted in the Snake Creek beds. Additional specimens showed that among the Snake Creek fossils was an extinct peccary, Prosthennops crassigenus, which had remarkably humanlike teeth. By 1928 Gregory was convinced that the Hesperopithecus tooth was not anthropoid at all, but simply a very worn peccary tooth. His announcement was actually a relief for most scientists, who had doubts from the beginning, but it was seized upon with SCOIll by the fundamentalists and the newspaper editorials. How were Osborn and Smith so easily fooled? First of all, it was a very easy mistake to make. As we have already seen, both primate and pig teeth look very similar because they are square, bunodont teeth adapted for omnivorous diets. Most people would not be able to tell them apaI1. In addition, the specimen was highly worn and abraded, so any characteristics of peccaries had been lost. Even more misleading was the wear on the tooth. Apparently, it had rotated in its socket while the animal was alive, and had wear patterns that were more characteristic of primates than of peccaries. Osborn was also influenced by the fact that the Snake Creek beds contained immigrant Eurasian antelopes, so why not apes? He also saw many bone splinters which appeared to have been worked by humans. (We now know that they were fractured by an extinct family of bone-crushing dogs). Finally, there is the drive to discover our own ancestry. Osborn and Smith were not the first to misinterpret a fossil attempting to find a link to our past. As Piltdown and many other examples (detailed by Roger Lewin in his book Bones of Contention) have shown, there is tremendous pressure on paleoanthropologists to make the most of every find.

CLOVEN HOOVES

37

Figure 2.16. Restoration of the extinct long-nosed peccary, Mylohyus nasutus (right) and the flat-headed peccary, Platygonus compressus (left). (Drawn by C. L. Ripper, courtesy Carnegie Museum of Natural History). The demotion of Hesperopithecus from a primate to a peccary may have been a disappointment for some, but it actually highlights the fact that peccaries are an important part of North American mammal history. The oldest known peccary specimens occur in the late Eocene of China, and they quickly migrated around the world during the late Eocene. Among the best known of these early forms was Perchoerus, which occurs in the Big Badlands of South Dakota. It was about the size of a dog, with a relatively unspecialized skeleton. In these features, it resembles the first true pigs, which diverged from peccaries in the late Eocene. Peccaries specialized in a different direction from pigs, however. Unlike the long skulls of pigs, peccary skulls are usually shorter and deeper. Their long, slashing canines occlude only in the vertical plane, unlike the widely flaring canines of pigs. Peccary molars remain fairly simple, while those of pigs often develop very wrinkled, complex surfaces. The most significant difference is that peccaries develop significantly longer, more slender limbs with more reduced side toes than do pigs. Peccaries are much better at running from predators. From Perchoerus, several different groups of peccaries developed during the Miocene in North America. One group retained the typical short, deep skull, and was probably related to all the living species. Another group developed very long faces with broadly expanded cheek regions. In the late Miocene-Pleistocene, animals such as Prosthennops (the correct identification for the Hesperopithecus specimen), the flat-headed peccary Platygonus, and the longnosed peccary Mylohyus had wide flaring cheekbones that made their faces look very similar to the entelodonts (Fig. 2.16). Perhaps it also served to improve their threat displays and show dominance in the herd. Mylohyus was one of the most extreme of these animals, with a body almost the size of a deer, and long slender limbs suitable for running. Platygonus was the size of a very large hog, with a dis-

tinctive flat forehead. Unlike the solitary Mylohyus, Platygonus lived in large herds across the Great Plains. It was so well adapted for running on hard ground that it had lost its side toes, and was down to just two toes. Large numbers of these peccaries fell into sinkholes and collected in caves. Bat Cave in Pulaski County, Missouri, contains at least 96 individuals, and Zoo Cave in Taney County, Missouri, contains 81 (most of which are young individuals with baby teeth). Near Hickman, Kentucky, five individuals of Platygonus were found in a row, buried in a sand dune deposit, with their heads all oriented in the same direction and their backs turned toward the windstorm. One of the most famous finds was made in 1946. The owner of a brewery in St. Louis found some peculiar bones in his basement. They were sent to New York, where the famous paleontologist George Gaylord Simpson identified them as Platygonus. When he and George Whitaker went out there to investigate, they found that the "brewery" was a natural cave under an historic mansion; it had been used as a brewery in the nineteenth century because the cool cave provided an ideal place for storing kegs of lager. The cave had also served as an Ice Age trap, and had filled with clay that was studded with peccary bones "like raisins in a cake." Simpson and Whitaker camped out in the dilapidated mansion and began excavating the bones. They were perfectly preserved and easily dug out of the clay, but had to be immediately coated in preservative because they were drying out for the first time in 10,000 years. Simpson recounts a story of the time when the excavation was a big tourist attraction. While they were working, one of them let loose with an expletive, only to be reprimanded by a visiting clergyman, "Profanity will get you nowhere in this cave, young man." Despite their great success during the Ice Ages, Platygonus and Mylohyus went extinct at the end of the Ice Ages, probably due to a loss of habitat when the climate changed. Today only a remnant of the long, proud history of

38

HORNS, TUSKS, AND FLIPPERS

Figure 2.17. The collared peccary, Tayassu tajacu, has short bristly hair and a distinct collar of light fur around its neck. (Photo by D. R. Prothero).

Figure 2.18. The "extinct" Chacoan peccary, Catagonus wagneri, originally described from fossils and then discovered living in the Gran Chaco of Paraguay in 1972. (Photo by D.R. Prothero).

North American peccaries remains. The best known species are the collared peccary, Tayassu tajacu (also known as the javelina in Mexico) and the white-lipped peccary, Tayassu pecari. Both species are a little over a meter long and weigh about 70-90 pounds (30-40 kg) full grown (Fig. 2.17). They have gray-black to dark brown hair with long white bristles on the lips, chin, throat and rump; the collared peccary has a whitish band from the middle of the back to the chest that is responsible for its name. Both occupy a wide range of habitats, from dry chapparal to tropical forests. They range from Mexico to Argentina, although the collared peccary ranges as far north as Texas, New Mexico, and Arizona. As might be expected from their wide range of habitats, peccaries are omnivorous, although they prefer roots, seeds, and fruits, along with occasional insects or other invertebrates. Although they are not ruminants, they do have a three-chambered stomach with some microbial fermentation helping their digestion of cellulose. Their sharp tusks are palticular- . ly adept at digging out and cutting roots, which they love. They have strong jaw muscles, so they can crush tough seeds as well. Unlike pigs, which live in small sounders, collared peccaries live in herds of 14-50 individuals, and white-lipped peccary herds may include 100 animals. The herds are subdivided into family groups of females and their offspring, which are remarkably stable over the lives of the individuals. In the dry season, the herds tend to split up into subgroups and forage over a wide area, keeping in contact with a wide variety of barks, grunts, and nasal noises. The herd occupies a stable territory, which is defended from intruders' and marked by secretions from a scent gland in the rump. The core area of their territory is marked by dung piles. They also reinforce herd cohesion by standing side-to-side and rubbing each other's facial glands (located below the eye), which aids in scent recognition. There is also much

mutual grooming and scratching with snouts before they go off to feed in the morning. Adult males guard the periphery of the group: and battle with other males to defend the territory and prevent them from mating. Although the dominant male tries to prevent it, the females may mate with several different males. Because most males are excluded by the dominant male, there is typically a 3: 1 ratio of females to males in the herd. There is no courtship ritual, and copulation lasts only a few seconds. Gestation lasts 142 to 158 days, after which a single precocious young is born. It is weaned after 6-8 weeks, although it remains dependent upon its mother for 24 weeks. It is also protected by other family members, and if danger threatens, all will come to its defense, sheltering the young under their hind legs while they present a threat display. When threatened, they produce a remarkable rasping sound that is caused by the chattering of their teeth. Their natural predators are mountain lions or jaguars. Other than their sharp canines and speed, peccaries have few natural defenses. If the predator surprises the herd, they scatter while emitting alarm calls to confuse the big cat. If young are present and there is dense habitat to hide them, one peccary (usually a subadult) may stand up to the predator to allow the others to escape, at considerable risk to itself. This kind of fatal altruism is rare among mammals, and could only be evolutionarily successful in an animal with a highly developed herd structure and close familial bonds. When the Panamanian land bridge reconnected South America to the rest of the world about 3 million years ago, peccaries migrated southward. One of the first to do so was the flat-nosed peccary, Platygonus. In 1904 the great Argentinian paleontologist Florentino Ameghino described a fossil of one of its descendants as Catagonus. This animal was thought to have become extinct at the end of the last ice age. Since no more large mammals had been found any-

CLOVEN HOOVES where in the world after the discoveries of the okapi in 1901 and the giant forest hog in 1904, there was no reason to think that any more big unknown beasts had been missed by zoologists. When a group of zoologists, led by Ralph Wetzel, began to explore the Gran Chaco in 1972, they found a region full of a diversity of mammals that had never been studied. The Gran Chaco is a broad flat region about the size of California that covers 60% of Paraguay and parts of northern Argentina, yet only 5% of Paraguayans live there. It is covered with a thick thorny scrub with isolated islands of palms and grasses, with great extremes of both rainfall and temperature during the year. Imagine the shock and surprise of the zoological world when, in 1972, the supposedly extinct Catagonus wagneri was discovered alive and well and living in Paraguay (Fig. 2.18)! Although the local people knew it well and hunted it for its meat, they considered all peccaries to be alike. This animal was marked like the collared peccary, only it was much larger, weighing up to 95 pounds (43 kg). It had white jowls and a black stripe along the middle of its back, and more importantly, it had a long snout with eyes high in the back of its head like Platygonus. It was also a long-limbed runner like Platygonus, although it still had four toes on its front feet. Only limited zoological studies have been done on the Chacoan peccary to date, but in most features its biology is similar to the other two species. However, it has herds of only five individuals, and is known to be much more waterloving than the other two species which live with it. The Chacoan peccary is more of a browser and less omnivorous than other species, feeding mostly on legume seeds, roots, and cacti; it munches down the spiny pads without flinching! It has a more complicated system of nasal sinuses than other peccaries, giving it an advantage when breathing the dry, dusty air of the Gran Chaco. All of the evidence indicates that this species is a remnant of a much larger animal found widely over South America during the Ice Age. Its teeth are large for its body size, and they are crowded together, indicating that they have undergone some kind of postglacial dwarfing. The remaining populations in the Gran Chaco are probably a relict which survived in the thorny scrub, where it is difficult for jaguars or cougars to find them, and there are few people to hunt them. Zoologists confidently assert that most large mammals around the world have been found, and therefore no such things as unicorns could exist. As the Chacoan peccary shows, however, not everything has been discovered. THE "RIVER HORSE" When most people hear the word "hippopotamus," they think of a fat, jolly, droll, slow-moving, lazy, roly-poly beast that eats water plants. Hippos from the Nile were familiar to the Egyptians, and thus to the Greeks and especially Romans, who put them in the arena to fight to the death. In medieval legends, there were many myths about the strange beast the Romans called hippopotamus (from the Greek hip-

39

grazing in the savannas near their river homes. (From the IMSI Master Photo Collection) pos, "horse", and potamos, "river"). Hippos were frequently portrayed as biting other animals or humans in half, or breathing fire from their gaping mouths. In actuality, hippos are very different from the popular perception. Although they are indeed fat, they are well adapted to their aquatic lifestyle, and can swim very quickly and gracefully under water. Even on land, they can move remarkably well, and a charging hippo can outrun a human over short distances! More importantly, they rarely eat water plants. Instead, they sleep in the water during the day and come out at night to graze along the riverbank, sometimes wandering miles from their homes (Fig. 2.19). In his book Animal Kitabu, Jean-Pierre Hallet writes: "Hippopotamuses, or 'river horses' as the Greeks called them, love to horse around in rivers, lakes, shallow pools, and evil-smelling mudholesgrunting, rumbling, snorting, blowing, bellowing, and burping, or sleeping in the shallows with their heads pillowed on each other's backs. They can swim at more than ten knots per hour and stay beneath the surface for as long as five to ten minutes, but when darknrss falls, they· march inland to conduct the second and nocturnal phase of their amphibious operations. [At the] Jinja Golf Course in Uganda ... they trek from green to green during the night, happily mowing the grass while leaving sets of parallel tracks that look like ruts impressed by broad-tired cart wheels. Golfers raved and cursed until Jinja club officials made a new ground-rule: if your ball lands in a hippo's footprint, you may remove it and drop it on the adjacent turf without being penalized. At the Rwindi Camp in Congo's Albert National Park, the hippos sometimes used to come out on moonlit nights, walking a full mile from the Rwindi River, just to stand outside the restaurant and watch the tourists eating, drinking,

40

HORNS, TUSKS, AND FLIPPERS chattering, and playing cards. During the day, the tourists went to the river and watched the hippos. Zoo-going citizens of the Western world ... visit the hippo pool and peer at a vast shadowy form lurking on the bottom. After a few minutes, it surfaces. They catch a glimpse of turreted eyes and slit-like nostrils on a bulging snout. It submerges. Then they leave the hippo pool, convinced that the fat, stodgy-looking animal spends his entire lifetime in the water. At best, they feel, he may creep along the shore. The mere thought of hippos ambling through a golf course or a churchyard strikes them as a Disney-style cartoon or an LSD-inspired hallucination. Kiboko [Swahili for hippo] may be fat, but he is far from stodgy. Aside from his proficiency in water sports, he is surprisingly agile on land, where he roams from dusk to dawn and even ventures forth on cloudy days. On longer treks, when his skin begins to) grow too dry, subcutaneous glands secrete a sort of 'suntan lotion,' a reddish oily liquid that soothes and lubricates his skin, and has led men to believe ever since Biblical times that hippos 'sweat blood.' [Switching the tail back and forth to break up their dung] is the hippo's homely method of staking out territory; and he stakes it out so thoroughly, switching his tail like a frantic pendulum, that zoo hippo pools must be drained and refilled every day. Odder still, if one hippo dares to invade another's territory, the rivals stage a weird duel: they 'shoot' each other, not with guns but with bowels, whisking their tails to send the dung flying. The intruder then retreats, but for some obscure reason both parties feel that honor has been satisfied. If a younger bull is, however, bent on issuing a serious challenge to an older one's established territorial rights-especially in overcrowded areas-the two of them will really fight, booming and splashing half the night while they gash each other's hides with their tusks and sharp incisor teeth. It is an epic battle, for mature hippos may reach twelve or fourteen feet in length, measuring five feet tall at the shoulder and weighing over three tons. Some bulls may even exceed eight thousand pounds ... Kiboko looks like an up-ended barrel covered with slate-colored, nearly hairless skin. His girth is nearly equal to his length, so his pinkish belly barely clears the ground while he goes galumphing forward on his stubby little legs. Port and starboard sides move independently in a rather sprightly pacing gait, preceded by his huge boxshaped head and followed by his foolish eighteeninch tail. His rounded ears, placed at· the very summit of his head, are equally minute but never

stop twitching. His eyes, close beneath them, are set in periscopic turrets like the eyes of crocodiles or frogs, so that he can watch the passing scene while the rest of him is underneath the water. His squared off muzzle, two feet broad, is tipped with bristling hairs and crowned at its highest point by two slit-like nostrils; like his ears, they seal completely at will, enabling him to dive swim, walk, or even sleep beneath the surface. To submerge, he has two separate and distinctive styles: if he decides to dive while already in the water, he lets his rear end sink slowly while his front end follows after; but if startled while he is standing on a high bank, he launches himself headlong, landing among the fish with a gargantuan belly-whopping splash. When he surfaces he spouts a column of water, blowing air through his nostrils with a loud snorting noise ... When [his mouth] is opened to the widest, whether he is merely yawning or challenging an enemy in water or on land, his entire head appears to split apart. His gaping mouth, some three feet from jaw to jaw, looks like a huge red cavern edged with ivory '4 stalactites and stalagmites. He has fourteen pairs of molars and premolars, all of them grinding away daily at some two to four hundred pounds of grass and ground forage plus the few water plants he eats as tidbits, mostly lotuses and water lilies ... Tusks and incisors, all composed of fine-quality, extremely hard ivory, are not used in feeding. Hippos clip grass with their heavy lips, trimming it as closely as a flock of sheep. The front teeth are employed for fighting among themselves, since no animal predator will attack a full-grown hippo, not even twenty-foot Nile crocodiles who may weigh a ton." (Hallet, 1968: 132-138). By most animal standards, hippos have enormous appetites. A typical 5-6 hours of feeding each night will yield 80-100 pounds (35-45 kg) of short grasses. As much as this sounds, it is actually only about 1-1.5% of their body weight, compared to 2-3% for most hoofed mammals. Like peccaries, hippos have two extra compartments in their stomach, but it is not as efficient as a fully ruminating stomach. Instead, hippos get by on proportionately less food by conserving energy better. The short active feeding period is balanced by almost 18 hours of sleeping nearly motionless in warm, buoyant water. This minimizes the energy expended holding their bodies up, moving for protection or feeding, or keeping themselves warm. The drawback of this lifestyle is their dependence upon water. When there are severe African droughts, hippos often have to fight for the few remaining mud holes. Many die from heat prostration because they have few mechanisms to dump heat from their well insulated bodies other than immersion in water.

CLOVEN HOOVES

41

Figure 2.20. The pygmy hippopotamus, Choeropsis liberiensis. (Photo by D.R. Prothero). Mating season occurs at the peak of the dry season, when hippo populations are concentrated in the rivers and larger waterholes. As described above, bull hippos go through noisy, violent combat rituals to establish dominance in their pool (Fig. 2.1). Hippos mate in the water, with the female submerging for some length of time, lifting only her head to breathe. In dry years only 6% of females will be pregnant, but in wet years as many as 37% will be carrying calves. After about 240 days of gestation the cow leaves the group and seeks out a secluded pool where she gives birth underwater, or sometimes bears the calf on land. The calf knows how to swim as soon as it is born, since at birth it may have to paddle to the surface to breathe. After 10-14 days of seclusion, the mother returns to the main herd, and the calf frequently rides on her back with his head above water. Although the cow is fiercely protective, and can attack any predator (she can even kill a lion or bite a crocodile in half), calves are very vulnerable to lions, leopards, hyaenas and crocodiles. Only half survive the first year, 150/0 are lost in the second year, and 40/0 each year thereafter until they reach maturity at about 7-9 years of age. Although hippos have a high infant mortality rate, their populations are actually expanding. They are the only megaherbivores thriving in Africa at present, since they do not have the ivory or horn that leads to the poaching of elephants and rhinos. In some areas hippo densities have become so great that they are overgrazing their habitat. Culling has been allowed to reduce numbers, and the hunted animals are prized by the natives for their meat. In addition to the familiar species, Hippopotamus

amphibius, there is another, less familiar animal, the pygmy hippo, Choeropsis (sometimes called Hexaprotodon) liberiensis (Fig. 2.20). This beast is less than five feet (1.5 m) long, only about a meter at the shoulder, and weighs 400600 pounds (180-275 kg). It is found only in tropical west Africa, primarily in Liberia, the Ivory Coast, Sierra Leone, and Guinea. Unlike the larger hippo, the pygmy hippo is more adapted for browsing in the dense forest on leaves, shoots, and fallen fruit. Its head is much more streamlined, without the eyes and nostrils set high on the skull for seeing and breathing submerged. Its feet are less webbed, and the toes spread out more broadly for better traction on land. Pygmy hippos hide in forests and swamps, tunneling through the bushes in the dense jungles. They do take to water to hide, but spend most of their time on land. Their prolonged exposure to air means that they secrete more of the red exudate ("blood") to protect their skins, and they typically have a sleeker appearance. Since they are rarely seen, however, very little is known of their biology. Sadly, most of their forest habitat in western Africa has disappeared, and they are now very seriously endangered in the wild. Africans have also hunted them for meat, since they are considered as tasty as pigs. Indeed, it appears that pygmy hippos have always been rare. Rumors of a "large black pig" were common in the nineteenth century, but most of these referred to the giant forest hog. Zoologists did not see bones of the pygmy hippo until the 1840s, when it was formally described and given a name. Not until 1870 did a live specimen come into scientific hands, where it was kept in the Dublin Zoo. Subsequent

42

HORNS, TUSKS, AND FLIPPERS

Figure 2.21. The piglike artiodactyls known as anthracotheres were found in Eocene and Oligocene riverbed deposits all over the world. This restoration of Bothriodon from the Big Badlands of South Dakota is not nearly as hippo-like as later descendants. (Painting by R. B. Horsfall, from Scott 1913).

expeditions to Liberia allow the observation of this strange beast in its natural habitat. The living pygmy hippo is not the only example of dwarfing in this family. Indeed, hippo dwarfing has happened often in the geologic past. Most of these dwarfs have occurred on islands, where there are no large grassy savannas, so they must take up a forest-browsing, pig-like habit. During the Ice Ages there were different species of dwarfed hippos on Cyprus (Hippopotamus minor), Crete, Sicily and Malta (Hippopotamus pentlandi), and Madagascar (Hippopotamus lemerlei). The dwarf hippo from Cyprus was only the size of a small pig! This pattern of large grazer and small (or dwarf) browser is actually quite common in hoofed mammals. As we shall see in later chapters, the forest species of African buffalo and elephant are small versions of their plains counterparts. There were also dwarfed species of rhinos in the Miocene of Texas which were apparently more adapted to the coastal forests than their High Plains relatives. Where do hippos come from? They have an excellent fossil record in Africa over the last seven million years, and they were widespread over Europe during the Pleistocene interglacials. Indeed, hippo fossils have been found even in the London suburbs! Hippo fossils are known from the Pliocene of the Siwalik Hills in Pakistan, and even from Burma and Java, so they once spread across the Old World tropics. In East Africa their evolution can be traced from Olduvai Bed I (1.8 million years old) with relatively small, short-snouted forms to Olduvai Bed IV (300,000 years), where we encounter Hippopotamus gorgops. This beast had truly periscopic eyes elevated well above its head, so it could see when submerged even better than the living hippos.

Prior to seven million years, however, the hippo fossil record is very poor. Until recently, only a few scraps of teeth were known from lower Miocene beds that suggested an earlier history. The same ecological niche suitable for hippos was occupied by an ancient group of artiodacyls known as anthracotheres (Fig. 2.21). These beasts are known as early as the late Eocene in Burma, China, and North America, and were very successfully performing the role of aquatic grazerlbrowser all over the world during the Oligocene and Miocene. Indeed, their name means "coal beasts" because their fossils were first found in coal seams that were remnants of ancient swamps. In the Big Badlands of South Dakota, anthracotheres such as Heptacodon, Bothriodon, Elomeryx, Arretotherium, and Kukusepasatanka are rare, but typically found' in the river channel deposits. Anthracotheres were even more diverse in the Oligocene and Miocene of Eurasia. In the early Miocene Dera Bugti locality in Pakistan, for example, there are dozens of species and genera of anthracotheres, whereas there were only four species of pig and one of peccary, and only a few species of deer, antelope, horse, tapir, rhino, and mastodont. (This locality is also unusual in that the last survivors of the amynodont and indricotherine rhinocerotoids, discussed in Chapter 14, peristed here almost 10 million years after they had become extinct elsewhere in the world). Anthracotheres were also one of the first groups to successfully invade the island continent of Africa and compete with the native endemic species. The last of the anthracotheres, Merycopotamus, persisted until the middle Miocene in Africa, and the early Pleistocene in Asia (especially Pakistan and China). It was by far the most hippo-like of anthracotheres, with a broad flaring snout, prominent tusks, and a lower jaw whose shape

CLOVEN HOOVES is extremely hippo-like. Most paleontologists such as Edwin Colbert and Shirley Coryndon had used this similarity to suggest that hippos were descended from anthracotheres. In 1983 Martin Pickford described the oldest known hippo fossils from the middle Miocene, about 15 million years ago, in Kenya. Called Kenyapotamus, these fossils led Pickford to suggest that hippos were not related to anthracotheres, but to peccaries. Like peccaries, hippos have extra stomach compartments, distinctive features of the jaw, a buried groove in the palate, and vertically pointing canines which do not show sexual differences (unlike pigs). Since there were peccaries in many parts of the Old World before Kenyapotamus, there is no problem with their closer relationship to the typically New World peccaries than the typically Old World pigs and anthracotheres. According to Pickford, most of the features which are similar in Merycopotamus and hippos are due to evolutionary convergence. Anthracotheres disappeared from the aquatic grazer niche in Africa about 15 million years ago, but not until about 7 million years ago did hippos evolve to fill it again. A remarkable beast, the hippo. What better way to conclude our discussion than with a poem?

Much more an enormous pig than a sort of horse, Hippo lives, as a matter of course, Both in water-still or running, fresh or saltAnd on adjacent land, where its Gestalt Takes fifty poonds (dry weight) of grass per night. In human cropland, which it freely samples, Much of what it doesn't eat it tramples, And signs point to a final interspecies fight. The losing bull in an intraspecific bout Hides wounded skin and pride in water, where, With only eyes and nostrils out, He surveys the scene and takes the air. To save its skin from air as well as flood, Hippo "sweats" thick, oily "blood." (Burns, 1975)

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Figure 3.1. A guanaco male group at Torres del Paine National Park, Chile. (Photo courtesy W.R. Franklin.)

3. Tylopods

CAMELS WITHOUT HUMPS When we hear the word "camel," our minds make many associations: "ship of the desert," a brand of cigarettes we'd walk a mile for, an animal designed by a committee, a haughty foul-tempered scowling beast that spits on people. As children,· we heard the Rudyard Kipling "Just So Story" about how the camel got its hump from saying "harrumph" too often. From our earliest trips to the zoo, we learned to associate the word "camel" with humps and the Arabian desert. Contrary to expectations, most of these features are late developments in camel evolution; they are not typical of most of their 45 million year history. Camels evolved in North America in the middle Eocene, and remained restricted to this continent for about 40 million years. The latest research recognizes over 90 species and 35 genera in North America alone. They have a longer history on this continent than any other group except horses and rhinos, but they did not travel to other continents (as horses and rhinos did) during much of the Tertiary. For most of their history camels were not desert beasts with humps. On the contrary, camels had diverse ecologies, and acted as surrogates for African antelopes and giraffes in the North American savanna grasslands. Then, about 6 million years ago, they began to spread to other continents and establish the living species. Some went south along the new Panamanian land bridge and invaded South America about 3.5 million years ago, where they became the llama, alpaca, vicuna, and guanaco (Fig. 3.1). Others crossed the Bering land bridge and spread to Asia and Africa about 6 million years ago, eventually evolving into the dromedary and Bactrian camel. Finally, at the end of the last Ice Age, camels and llamas went extinct in their North American homeland. The earliest camels are represented by Poebrodon, which comes from the middle Eocene of Utah and California (Fig. 3.2). As we have seen, the middle Eocene was the time of greatest diversification of artiodactyls, but Poebrodon stands out. Many of the middle Eocene artiodactyls were changing their simple round-cusped cheek teeth (like those of pigs and peccaries) into specialized teeth with four high crescent-shaped crests (selenodont teeth) for shredding fibrous vegetation. But the rabbit-sized Poebrodon was the most selenodont animal of the time, with

the highest-crowned teeth by far, apparently adapted for the coarsest vegetation available. Since that time, camels have retained a stereotyped, high-crowned selenodont dentition, long before the rest of their skeleton evolved into its present form. Alongside the earliest camels in the middle and late Eocene was a group of close relatives, the oromerycids. For a long time, the oromerycids were mistakenly placed with the camels. The best known oromerycid, Proty[opus, is commonly portrayed in popular books as the ancestor of the camels. However, recent research has shown that oromerycids split off from camels early in the middle Eocene, and late in their history evolved high-crowned teeth like those of true camels. One of us (Prothero) described Montanaty[opus, the most camel-like of oromerycids, from the late Eocene of Montana. For 40 years after the specimens were discovered, they were misidentified as a camel. Oromerycids died out at the end of the Eocene, along with brontotheres and many other beasts we shall discuss later in this book. In addition to the diversification of camels and oromerycids during the middle Eocene in North America, there was a third group of strange-looking tylopods (camel relatives) on this continent. Known as the protoceratids (Fig. 3.3), they were long associated with the hypertragulids, one of the primitive hornless "deer" we will discuss later. However, recent research has shown that they are in fact the closest relatives of camels, and belong in the Tylopoda. The earliest protoceratids (from the middle and late Eocene) were hornless, but may have had a prehensile lip for browsing. The most distinctive feature of advanced protoceratids is the horn-like appendages on their heads. In the Oligocene deposits of the Big Badlands we find a striking animal known as Protoceras. Males (but not females) had a series of odd-looking short horns on their snout, over their eyes, and on top of their heads. The early Miocene Syndyoceras had a branched hom on its nose, and backwardpointing curved horns above its eyes. By the late Miocene its descendant, Synthetoceras, had a slingshot on its nose and the same curved horns above its eyes. Paratoceras, a middle Miocene beast from the Gulf Coast of Texas, had curved horns over its eyes, and a Y-shaped hom on the top of its head that vaguely resembles a propeller on a beanie.

HORNS, TUSKS, AND FLIPPERS

46

'lEIS.

OXydllCtylua

I Kyptoceras, the last of the family, was recently described from the late Miocene of Florida by Dave Webb. It had paired horns coming from its snout, and forward-pointing' horns arising from the top of the head. Although their horns seem grotesque, they are no weirder than the amazing suite of horns we will see in deer and antelopes. Dave Webb has argued that their horns were used for both combat between males, and for display to

Figure 3.2. Phylogeny of the tylopods, showing the major features of camel evolution. PLIO = Pliocene; PLEIS = Pleistocene (drawn by C. R. Prothero).

frighten rivals and attract females. This is the way that most horned ruminants use their horns, so it is reasonable to infer the same behavior for the horned tylopods. Kyptoceras, in particular, was well suited for display, and for neckwrestling and pushing, since the angle of attack of the horns would force males to interlock without seriously injuring their opponent. Protoceratids were always rare, and they probably lived

PLEIS

Synthetoceras

PLIO

W

Z

W

0

0-

~

W

Z

W

0

0
Syndyoceras

w

z

w

o

Protoceras

o

w

Figure 3.3. Phylogeny of the protoceratid tylopods. PLIO Prothero).

= Pliocene; PLEIS = Pleistocene

(drawn by C. R.

48

HORNS, TUSKS, AND FLIPPERS

in habitats that are not often fossilized. During the Miocene virtually all known protoceratids come from the swampy, forested Gulf Coast region. According to Christine Janis, their molars and broad, moose-like snout indicate a diet of swampy vegetation with little fibrous cellulose. They also have relatively short limbs, and do not fuse their toes up like camels or ruminants. This suggests that they were not open plains runners, but preferred more brushy or swampy terrain. The only protoceratid from the High Plains, Lambdoceras, has a narrower snout suitable for tree browsing. Like many other characteristic Miocene mammals in North America, protoceratids became extinct at the end of the Miocene. As we shall see for camels, horses, rhinos, and many other mammals, this was a time of climatic change, cooling and drying, with a destruction of much of the Miocene habitat-including, apparently, the swampy Gulf Coastal plain on which protoceratids depended. By the late Eocene and Oligocene true camels (Family Camelidae) had become well established in North America. Next to leptomerycids and oreodonts (discussed below), they are the most common artiodactyls in the deposits of the Big Badlands of South Dakota. They are most common in the more southern part of the continent (from Colorado and southern California to Texas), but rare in North Dakota or Canada, so they must have been sensitive to temperature. The typical Badlands camel, Poebrotherium, was the size of a goat, and built much like one. Unlike any other contemporary hoofed mammal, it had already evolved a relatively long slender neck and limbs. The central digits of its feet had already become elongated for running, and nearly fused together into a "cannon bone." A distinctive feature of camel cannon bones is that they fork at the far end, allowing the toe bones to splay out and giving camels their characteristic broad feet. The side toes were completely lost, so camels were the earliest two-toed artiodactyIs. The gap (or "diastema") between its nipping front teeth and the cheek

teeth was enlarging as the snout became longer, and the cheek teeth became even more specialized for grinding. Another characteristic camel feature is the spongy bone filling the chamber which surrounds the middle ear. All of these features were even further developed through the evolution of camels, but they were already well established in Poebrotherium of the late Eocene. In the late Oligocene and early Miocene, camels diversified in North America. Conservative, poebrothere-like camels such as Paratylopus lived alongside a more highcrowned group, the pseudolabines, including Pseudolabis and Miotylopus. The most specialized descendant of these pseudolabine camels were the stenomylines, whose long, narrow molar teeth were rooted deep in the jaw and skull (Fig. 3.4). Stenomylines were extremely graceful and gazelle-like in proportions, and have been found in large grazing herds much like gazelles. A third group was the bizarre floridatragulines, whose long snout is like that of a fish-eating crocodile! Found only in Texas and Florida, they probably lived in the subtropical forests of the Gulf Coast, but the purpose of their unusually long thin snout is unknown. There were also the long-necked, long-limbed oxydactylines, which eventually evolved into the g~raffe-like Aepycamelus (formerly Alticamelus). Oxydactylus may have been the ecological equivalent of the gerenuk antelope (Fig. 5.16B), which stands on its hind legs to reach bush tops and trees. Eventually aepycamelines became extremely longnecked and long-legged, with a neck capable of reaching leaves 18 feet (5.5 m) above the ground! These animals functioned as the ecological equivalent of the giraffe in North America, even though they are descended from camels (Fig. 3.5). By the middle Miocene there were at least 9 genera and 17 species of camel in North America, especially in the hilly country of Nevada, California, and New Mexico, and in the

A

B

Figure 3.4. A. Side view of the skull of the gazelle-camel Stenomylus. Some of the bone has been removed to show the extremely high-crowned, deep-rooted teeth adapted for eating grasses. (From Frick and Taylor 1968). B. Restoration of Stenomylus, showing its gazelle-like proportions. (Painting by R. B. Horsfall, from Scott 1913).

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Figure 3.5. The antelope-camel Oxydactylus and the giraffe-camel Aepycamelus, both common in the middle and late Miocene savannas of North America. Primitive gomphothere mastodonts and horses are shown in the ba~kground. (From a mural by R. Zallinger, courtesy Yale Peabody Museum). swampy Gulf Coast forests of Texas and Florida. They performed virtually all the roles that antelopes and giraffes do in the East African savanna today. Along with the gazellelike stenomylines and the giraffe-like aepycamelines, there were two other major groups. Both the miolabines (including Miolabis, Homocamelus, and Nothotylopus) and the protolabines (including Tanymykter, Protolabis, and Michenia) became more short-legged and stockier than their oxydactyline relatives. The teeth of miolabines eventually became relati vely low-crowned again, whereas protolabines are distinctive in having a long, narrow snout. Both groups have strong ecological similarities with a number of African antelopes which specialize in browsing certain low-level bushes and grasses. Fossil footprints show that camels had acquired their distinctive walk by the Miocene. When camels move, they pace, moving both legs on the same side of the body together. Most other hoofed mammals trot (the foreleg on one side moves at the same time as the diagonally opposite hind leg).

Pacing is particularly useful for long-legged animals, since legs on the same side of the body never end up hitting each other (as they can when trotting). The disadvantage of pacing is that they lift both feet on the same side, so they are less maneuverable and stable, and can fall over. (This is why camel riders sway so much and feel seasick riding the "ship of the desert"). Camels have compensated by developing widely splay-toed feet, strong ligaments supporting the feet, and placing their limbs near the midline of the body. Dave Webb has shown that the low forward placement of the head also helps to counterbalance the body sway during pacing. Pacing is very well suited for animals which run across open plains, and requires fewer steps and less energy than trotting to cover the same distance. This is one of the many tricks that gives camels an advantage over other hoofed mammals when crossing the desert. At the end of the Miocene the great camel radiation was decimated. Miolabines, protolabines, and aepycamelines all disappeared, along with many other mammals characteristic

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HORNS, TUSKS, AND FLIPPERS

of the North American Miocene savanna. Climates were again changing around the world. Many mammals which had been abundant in the middle and late Miocene savannahs of North America were severely reduced in numbers. Horses, which had been so diverse in the late Miocene, are represented by only a few genera. Oreodonts were extinct, as were several other types of artiodactyIs, such as the protoceratids. Rhinos (discussed in Chapter 14) also went extinct in North America. The great profusion of deer-like animals and pronghorns was diminished. Several genera of mastodonts also disappear. Small mammals show less of an effect, although several archaic rodent families (the mylagaulids, or "horned gophers" and the eomyids) die out, as do a number of other rodents, rabbits, shrews and moles. What caused these late Miocene changes in North American land mammals? The end of the Miocene experienced a worldwide climatic event whose effects can be seen in Europe and Asia, and especially in the microfossils of the deep sea. This event, known as the "Messinian crisis," has recently been explained. During the late Miocene the northward drift of Africa toward Europe had been steadily closing off the Mediterranean and raising the Alps. The Mediterranean was already closed off at its eastern end in the Middle East, and water flowed only through the western opening. About 5.5 million years ago a major expansion of the Antarctic glaciers caused a large drop in sea level. When this happened there was no further oceanic flow across the present-day Straits of Gibraltar. The Mediterranean, without its oceanic flow, became first a gigantic stagnant sea, like the Black Sea, and then an evaporating lake, like the Great Salt Lake. Finally it completely evaporated away, leaving a giant basin 10,000 feet deep covered with a mile-thick deposit of salt and gypsum. For thousands of years this basin remained cut off and empty, until sea level rose again as the ice caps melted. When the Gibraltar barrier was finally breached it formed a gigantic waterfall with a flow of 10,000 cubic miles of water per year. This is a thousand times the flow of Niagara Falls. The water rushed into this gigantic salty basin and filled it up again, producing the modern Mediterranean. Naturally such a dramatic event had worldwide consequences. All of the world's oceans are closely linked in a global system of circulation and chemical balances which are the main force controlling climate. When such a large body as the Mediterranean is first isolated and then catastrophically reunited with the world's oceans, it has major effects. Global oceanic circulation changed, and the withdrawal and sudden reintroduction of all that salt caused severe salinity imbalances. For this reason the terminal Miocene is often called the "Messinian salinity crisis." These oceanic changes, combined with the Antarctic glaciation, meant a drastic change in worldwide climate. Naturally, the vegetation on land responded to this climatic change. The land mammals were not far behind. This time, however, many did not adapt, but instead were driven to extinction. By the Pliocene the mammal fauna of North America has a very modern look, and many beasts of the Ice

Ages had already appeared. The habitat had changed from the savannas so typical of the Miocene to a steppe vegeta.. tion. Most of North America's native groups which had dominated so long, such as rhinos, oreodonts, protoceratids, camels, horses, and others, would never again be so abundant. The first three were gone from North America for good. Only the two modem groups of camels, the lamines (now represented by the llama and its relatives) and camelines (now represented by the Old World camels) survived. According to Jim Honey, lamines are derived from more primitive aepycamelines, but the camelines are related to Procamelus, a more advanced aepycameline characteristic of the late Miocene. Lamines are distinctive in having a larger, more domed skull than camelines, since they have larger brains, and in their distinctive "llama buttress," a pillar-like feature on their molars. The most successful and long-lived of the North American lamines was Hemiauchenia, which persisted for 11 million years from the middle Miocene until late in the Ice Ages. Long-limbed and fast running, it was found all over North America in the Pliocene and Pleistocene. In Florida it lived alongside its short-limbed relative, Palaeolama, whose stout legs suggest that it originated in the Andes and then migrated back, over the Panamanian land bridge to North America. The last and best known of the lamines was Camelops, found everywhere in western North America from Saskatchewan to Mexico (but not in the southeast, where other llamas dominated). Camelops was about 20% larger than the living dromedary, with a longer neck and legs, a long slender face and large, deeply split, mobile upper lips which were prehensile for grasping food. The high arch on its backbone suggests that it had a hump, unlike any other lamine. Camelops is known from many deposits characteristic of the end of the Ice Ages, such as the famous La Brea tar pits. Mummified remains of Camelops have been found in the arid Southwest, radiocarbon dated as young as 10,000 years ago, so it survived until the present interglacial. Although there are no clear kill sites, its extinction may have been caused by overhunting by humans, since it has been found in association with Clovis arrowheads. In the mid-Pliocene (about 3.5 million years ago) the Panamanian land bridge rose up and reconnected South to North America after tens of millions of years of isolation. In the early Pleistocene (about 1.5 million years ago), one of the northern invaders were lamines such as Hemiauchenia, which quickly became established all over South America. From these ancestors arose the modern species of South American lamines: the wild vicuna and guanaco, and their domestic derivatives, the llama and alpaca. The vicuna and guanaco are humpless camels that give us a glimpse of what prehistoric camels must have looked and behaved like (Fig. 3.6). The vicuna (Vicugna vicugna) live almost exclusively in the alpine puna grassland in the Andean foothills of Peru, Bolivia, Chile, and Argentina at elevations of 12,000-16,000 feet (3500-4900 m). It is the

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Figure 3.6. An adult territorial male vicuna in the Pampa Galeras National Vicuna Reserve in Peru. Note the large bib of white hair in the chest region of this Peruvian subspecies (not found in the Argentinian subspecies). (Photo courtesy W.R. Franklin.) smallest of the wild camels, weighing about 100 pounds (45 kg), and reaching three feet (1 m) at the shoulder. It is covered with long, soft cinnamon-colored fleece, with white undersides. The males may have a white bib. The vicuna is very graceful, and very adept at running over rocky terrain at high altitudes. It can run 30 mph (5 km/hour) at elevations of 15,000 feet (4500 m), which leaves most humans gasping for breath. Since it lives in open terrain, it has excellent vision for spotting predators at a distance, but does not need as good a sense of smell or hearing. It spends much of its time grazing low .perennial grasses of the Andean tundra. This harsh environment is characterized by extremes of heat, cold, wind, and aridity. A mild rainy growing season from December to April alternates with a cold, dry season from May to November when temperatures and wind chills are below freezing and little plant life can grow. William Franklin has shown that vicunas are one of the few ungulates to defend a year-round feeding territory and separate sleeping territory. A feeding territory of approximately 45-acres is connected to a 6-acre sleeping territory

51

by an undefended corridor. Territories are marked by numerous communal dung piles. Family groups consist of a dominant male, several females, and associated young-up to 5-10 individuals. The male warns the others of dangers with a loud alarm trill. He leads the group in its daily rounds, and defends it against other males. Lone males and bachelor herds of 15-25 individuals constantly provide challenges to the dominant male in each family group, resulting in occasional vicious· fights. Like other camels, vicunas have sharp canine teeth in males that can be used to slash a rival. The males typically fight by biting at the front legs and hind quarters or crossing their necks to force their rival to his knees. Like other camels, vicunas mate with the female lying down on her chest, and the male mounting her from behind. Copulation lasts 10-20 minutes, and is accompanied by many grunts and squeals. Mating occurs during the end of the rainy growing season in March and April, and births take place 11 months later at the middle of the next growing season. The single young vicuna can stand and walk 15 minutes after it is born. It runs and sleeps alongside its mother until about 10 months of age, when it is weaned. Young males and females are driven away by the dominant male before they reach one year old, when they join another group. Females mate at about 2 years of age, and can reproduce until 10-12 years of age. The maximum captive longevity is 24 years and 9 months. The Incas routinely rounded up wild vicunas and sheared them of their wool. The Andes may have supported as many as 1.5 million vicunas before the arrival of the Spaniards. The slaughter of the Incas also led to the slaughter 'of vicunas, mostly for their wool and meat. By the 1950s there were fewer than 400,000, and intensified hunting diminished that number to 10,000 by 1967. Since that time, they have been classified as an endangered species, and there are believed to be about 80,000 today. The guanaco (Lama guanicoe) is similar in many ways to the vicuna, but larger, weighing 220-265 pounds (100120 kg) and reaching 4 feet (1.2 m) at the shoulder (Fig. 3.1). It has a cinnamon brown color with white undersides, but it may also have blackish fleece on its face. The guanaco lives not only in barren grasslands, but also in lower-elevation pampas and desert scrubs of Peru, Chile, and especially Argentina. Since it lives in the dry pampas, it must be able to go a long time without drinking, unlike the vicuna, which must drink daily. It can run 35 mph (55 km/hour) across the plains, and swims well, too. Depending upon its habitat, it can be both a grazer and/or a browser, and populations are either migratory or sedentary. Family groups consist of 4-10 females and a single dominant male. Like vicunas, guanacos use communal dung piles of small, dry pellets, which reach 8 feet (2.4 m) in diameter and a foot (31 cm) in height. Females mate and give birth every other year after an II-month gestation. Unlike the vicuna, the guanaco mating season is in August and September, at the beginning of the pampean spring. The

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famous paleontologist George Gaylord Simpson, while collecting fossils in Patagonia, wrote a memorable description of guanaco behavior: "The favorite child of Patagonia is surely the guanaco. A guanaco looks like a small, humpless camel, which it is, and it also looks like a careless mixture of parts intended for other beasts and turned down as below standard, or like the result of a long period of miscegenation. It has a head something like that of a hornless deer, long ears like a mule, a neck that tries but fails to reach the giraffe standard, a scrawny, shapeless body, and gangling legs like those of a young colt. To top off the joke, it has a stubby little brush of a tail, only a few inches long, which it carries crooked, the base vertical and the tip curved back and down, so that it looks very much like the handle of a jug. Unlovely and miscellaneous as is his exterior, it is less erratic than a guanaco's mental processes. If actions are a fair guide, his mind is often vacant, sometimes hysterical, and always stupid. It would be charitable to suppose that some of the guanacos I have seen were insane, and that all suffered from a sort of animal arrested development of the intellect and emotions. Their psychology, if such apparently vague and disordered thoughts can be dignified by such a term, seems primarily to involve a lifelong conflict between curiosity and timidity. Among the first guanacos I saw, and the one that I came to know best of all, was a solitary animal that used to watch me work on the barranca south of Colhue-Huapf. Safely separated from me by an impassable gorge, he would appear every afternoon and curse at me for intruding in his realm, yammering by the hour. Imagine a tin horse that has been left out in the rain until thoroughly rusty, and then imagine that the tin horse has colic and is trying to whinny, and you will have a faint conception of a guanaco's yammer. The only other sound I heard them utter was an expression of fright and sounded like the first notes of a coloratura donkey, also rusty. Yammering expresses all at once, 'I see you, ' 'What the hell are you doing on my property?' 'Look out, boys, here's something queer!' and 'Oh, dear, oh, dear, oh, dear, what shall I do about this?' A full translation would aso have to include some obscenity, for there is something distinctly indecent about the noise as it issues from the beast's protrusile and derisive lips. Any unusual thing, such as a man, is sure to attract the attention of every guanaco in the vicinity, and a chorus of yammers results. A gua-

naco is an artist who simply must express himself. Not for him to take in a situation and then silently slip away. He must get close enough for a good look, and then must express his disgust with the whole arrangement in a full and decisive way. Here is the conflict in guanaco psychology again: when he is afraid of anything he proceeds to call attention to it himself. Often we should have been quite unaware that there were any guanacos around if they had not insisted upon telling us so. When we heard a yammer, we could be sure that the beast was in plain sight, perhaps half a mile away, but surely somewhere where he had a good, clear view of us. This is also demonstrated by the guanaco strategy of retreat. They never hide. When startled, their primary idea is always to keep their presumed enemy in sight. They make for the nearest good lookout point, and if they decide on flight, they run along ridges and in exposed places as much as possible. Perhaps this is not quite so dumb as most of their doings, since it might well be an ideal system against their primeval enemy, the puma, but it is worse than useless against their present archenemy, man. Still, they have only known man for a few generations and their learning ability is practically zero. What was good enough for their ancestors in the Pliocene Epoch is good enough for them. Climbing seems to have an irresistible fascination for them and they spend hours running up and down barrancas. There is no food for them there, or any other apparent legitimate business, and they seem to climb for fun and because they do not have anything better to do. All the cliffs are covered with their trails, often the most practicable routes for human climbers to follow, and they go almost anywhere that a man can and many places that he should not. Often we have cursed at them as we toiled slowly up an almost vertical trail behind a guanaco who went bounding lightly along, having the time of his life. One of the most curious and inexplicable of all the habits of these curious and inexplicable beasts is their way of depositing their dung in certain fixed places. The dung, which resembles that of a sheep but is larger, is always deposited on an old pile, and some of these piles still in use must be many years old. How they get started and whether the piles are individual, communal, or used by all comers we were unable to learn" (Simpson, 1934: 189-195). Although Simpson was a colorful writer, he was a poor observer. William Franklin and others have shown that guanacos are actually quite intelligent, adaptable and handsome

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Figure 3.7. A. The two-humped Bactrian camel of Asia. (From the IMSI Master Photo Collection). B. The onehumped dromedary camel of Africa. (Photo courtesy A. Walker). animals, expert at coping with the harsh conditions in Patagonia. Simpson may have insulted the guanaco for the sake of humor, but it is not a modem view of their intelligence or behavior. When settlers brought their sheep to Patagonia, the puma began to hunt the slower, stupider sheep in preference to its usual prey, the guanaco. This drove the humans to kill the pumas, which led to a population explosion in guanacos. Then people were angry that guanacos were eating all the grass for their sheep, and began a senseless slaughter of guanacos. Adult guanacos were hard to catch, but the gauchos had no trouble catching their young, the chulengos, with their bolas. Soft chulengo hide was worth several pesos, and nearly all the young guanacos were destroyed, resulting in a severe population crash when the adults began dying off without replacement. From an original population of millions, they were driven to near extinction, and are now endangered in Peru and Bolivia. However, the Argentinian government stepped in and declared them protected, so now there are about half a million in Patagonia. Llamas and alpacas are believed to be domesticated descendants of the guanaco, although some argue that they may be partly bred from vicunas, or descended from some other extinct lamine. Domesticated by pre-Incas, llamas and alpacas numbered in the tens of millions before the Spanish conquest. Like the Plains Indians with the bison, Incas made good use of their llamas: as a beast of burden, the meat used as food, the wool for clothing, the hide for sandals, the fat for candles, its hair· for rope, and its dried dung as fuel. Llamas were the prime source of wealth of the Incan civilization, carrying their loads, helping build their cities, packing out the ore in their gold and silver mines, and moving their armies. Incan royalty was always accompanied by a napa, a white llama dressed in a scarlet shirt, gold earrings, and a necklace of red shells. During religious ceremonies, thousands of llamas and alpacas were sacrified to the gods. The Incan civilization was essentially bounded by the range and ecological limits of the llama. Today, llamas are used primarily as pack animals, but their numbers are declining

because they are being replaced by trucks and trains. The Incas concentrated on breeding the alpaca for its long, fine wool. Today, alpacas are replacing llamas in terms of numbers and importance, since their wool is so valuable. Each alpaca produces 3-5 pounds (1.7-2.3 kg) of wool a year, so that Peru alone exports over 6 million pounds (3 million kg) of wool valued at about $24 million a year. SHIPS OF THE DESERT In contrast to the lamines, the camelines have had a slightly different history. After evolving from Procamelus in the late Miocene, most Pliocene camelines went in for huge size. As their names testify, they were giants: Megatylopus, Megacamelus, Titanotylopus, and Gigantocamelus are typical late Miocene and Pliocene camelines, and some reached 11 feet (3.4 m) at the shoulder. Their limbs were massive, and the skulls of some were almost 3 feet (1 m) in length! Apparently, most of them had humps, as do all living camelines. Like Camelops, the camelines were restricted to western North America, and were not found in the llama haven in Florida. However, camelines died out in North America at the end of the Pliocene, and only lamines persisted on this continent until the end of the Ice Ages. The earliest record of camels in the Old World is from the late Miocene (about 6-7 million years ago) of Venta del Moro, Spain. They are proof that North American camels had migrated across the Bering land bridge by this time, and immigration continued sporadically through the Pliocene. The genus Camelus quickly became established all over the Eurasian desert region. There are sparse fossils that indicate camels were in northern and eastern Africa in the Pliocene. By the Pleistocene, species of extinct camels resembling the two-humped Bactrian were known from southern Russia and Romania to India, and ancestors of the one-humped dromedary were known from the Middle East and North Africa (Fig. 3.7). Today, the Bactrian and dromedary maintain the same separation, with the long-haired, cold-adapted Bactrian found in the mountainous regions of central Asia, and the dromedary in the deserts of the Middle East and

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North Africa. The two species coexist in Turkey, Afghanistan, and Turkmenistan, where they may interbreed. They are not very different genetically, and as embryos, dromedaries have two humps that merge into one as they develop. Research indicates that the Bactrian was domesticated before 2500 B.C. in the plateaus of northern Iran and southwestern Turkmenistan. The origin of the domestic dromedary is more controversial; some say that it happened as early as 12,000 B.C. in southern Arabia, while others argue that there is no good evidence of domestic dromedaries before the 4th century B.C. Camels are legendary for their strength and endurance, especially in the harsh deserts and steppes of Africa and Asia. Caravans of dromedaries have crossed 375 miles (600 km) of the Sahara Desert in three weeks with little water and with scant feed. In winter, camels can graze for two months without water. In summer camels endure desert heat for eight days without water, and may lose up to 40% of their body weight. By contrast, a man is dehydrated when he loses only 5% of his water, delirious at 10% loss, and dead at 12%. A donkey can lose no more than 25% of its body weight before dropping dead. Camels have been clocked at 40 mph (65 kmlhour), and are good swimmers. Normally they walk about 20 miles (32 km) per day, carrying loads of 220 pounds apiece. Over a four-day period, camels have been known to carry 600 pounds (275 kg) at a rate of 30 miles (50 km) per day and 3 mph (5 km/hour). How do they manage these feats of endurance? Camels have a wide variety of physiological and anatomical features that are uniquely suited to harsh conditions. We have already seen how the pacing walk of camels is more efficient than the trot of most other herbivores. In addition, all camels have unique crescentic red blood cells. This enables the high-altitude South American camels to retain oxygen better. The red blood cells of Camelus hold onto water longer than any other mammal, and can reabsorb large amounts of water without exploding, as human red blood cells would after a long dry spell. Camel blood retains water in the bloodstream longer than other mammals, so when the camel is dehydrated, its blood doesn't become too thick (as human blood does). Camels also allow their urine to become very concentrated, so they do not need to excrete water as often. Many people think that camels store water in their humps, but this is not exactly true. The hump is made entirely of fatty tissue, which serves mostly as a food reserve. When the camel has gone a long time without food or water, its hump becomes flaccid, and its ribs show. Water is also stored in the rumen of their stomach. Once they have fed and watered, the hump fills up again, and they plump out. Camels are capable of prodigious drinking bouts after a long period without water. In hot weather, thirsty camels can guzzle down 35 gallons (132 liters) of water in about 6 minutes, and under extreme conditions, a really thirsty camel can drink 50 gallons (190 liters) in a day! When necessary, camels can drink brackish and even salty water. They eat virtually any vegetation found in their desert habitat, includ-

ing salty plants that are rejected by other mammals, and even flesh, fish, bones and skin in a pinch. Besides their blood, camels have many other anatomical specializations. Chief among these is their method of temperature regulation. Camels have very few sweat glands, so they cannot dump heat quickly as most mammals. Instead, camels do not try to regulate their body temperature as closely as we do. Their large body mass takes a long time to heat up or cool down, and they can allow their temperature to rise as much as 1OaF (6°C) without ill effects, retaining much of this body heat in the cold nights. (By contrast, humans only tolerate about 2°F, or 1°C, in temperature fluctuation before they have a fever or chills). Camels turn broadside to the sun when they are trying to warm up, and face their narrow profiles into the sun at midday when they want to minimize heat gain. The rest of their anatomy is ideally suited for desert conditions. They have a bony "visor" in the skull to shield the eyes, and long eyelashes to catch the sand. If these fail, they have a "third eyelid" which sweeps the sand from their eyes. In sandstorms, they can see through this "third eyelid" and continue walking with their eyes protected. Their nostrils are slit-like, so they can close them and keep out the sand as well. The groove in their cleft upper lip helps direct moisture from the nose into the mouth. Finally, their widesplayed toes give them broad feet like snowshoes, giving excellent traction and are less likely to sink into loose sand. Camels are indispensable to many nomadic cultures of the arid regions of Africa and Asia. The Bedouins of the Sahara use them not only for riding and carrying loads, but also to pull plows, provide milk, meat, wool for clothes and tents, and leather for water bags. They use dried camel dung as fuel, and the urine is used as an antiseptic, as a baby bath, a cure for acne, a mouthwash, and an aphrodisiac. Women use camel urine as a henna rinse for their hair, and men for reddening their beards. Camels are also the prime source of wealth and currency in much of the Sahara and Arabian peninsula. Naturally, the Bedouin consider them "the gift of Allah." However, to others they are very difficult, temperamental beasts. The camel has terribly bad breath, strays away unless watched constantly, and it is legendary for spitting on people. All camelids are capable of drawing foulsmelling gastric juices up the length of their throats and spitting them with great precision. When a camel is really angry at its master, it can bite with its sharp teeth. At these times, camel owners have learned to give the camel the coat off their back. The angry camel will bite it to shreds, but its anger will be displaced from its owner. Since camels now depend on humans for their water, a sudden rainstorm in the desert can cause a stampede of camels who don't need peopIe any more. A particularly vivid description of life with a camel was provided by Arthur Weigall: "All camels are discontented. They hate being camels, but they would hate being anything else,

TYLOPODS because in their opinion all other living creatures are beneath contempt, especially human beings. The expression upon their faces when they pass you on the road indicates that they regard you as a bad smell. They nurse a perpetual grievance against mankind and ruminate upon their wrongs until they groan aloud. When you go to them to find out what is. the matter they give you no hint of any specific trouble, but merely look at you with sad, reproachful eyes and groan more loudly. In certain cases when their sense of unbearable insult is overwhelming, they try rather halfheartedly to bite you. The fact that a camel has yellow teeth, a harelip, a hump, corns and halitosis places the poor creature beyond the range of ordinary sympathy. People never put their arms around camels or stroke or kiss them, and yet their sorrowful eyes, fringed with long, languishing lashes, are beautiful, and their whimpering is heartbreaking. But camels do not ask for love or pity. They make no response whatsoever to overtures of that sort. They have no hope, and they make no friends. When they are being ridden, they do not attempt to cooperate with their riders, and when they are being used as beasts of burden they try their best to make you feel like a cad ... Like all camels, Laura was extremely stupid. For instance, she could never be taught that she must remain crouched until her rider was in the saddle, and must not scramble to her feet just at the moment when he was mounting... Laura always watched me out of the comer of her eye until she caught me at a disadvantage. When I swore at her she only gazed at me sorrowfully and uttered her inconsolable grumbles. A camel, by the way, can do more than look at you out of the corner of an eye. It can turn its head completely round and stare at you full in the face with both eyes. I know of nothing more disconcerting ... It is not customary to allow a riding-camel to walk, because the motion is rolling and you lurch from side to side in a sickly manner which suggests a reason for calling the camel the "ship of the desert." A quick jog trot is the usual gait; you simply bump up and down in the saddle like a cavalry trooper, the bumps becoming bigger and better as the pace increases to a gallop. Laura used to add to the fun by occasionally jumping over low rocks, but she never fell. In fact, I have never heard of a camel falling. Laura became a mother when she was about ten. In the spring the male camels attract the attention of the females by making gurgling noises, like water running out of the bath, and inflating their tongues until they hang out of their mouths like

55

pink balloons. Laura could not resist the blandishments of a magnificently disdainful he-camel who hailed from down Suez way and was in the transport business. As she appeared to be all wrought up in her own melancholy fashion, we arranged a rendezvous. Although Laura was not a large animal as camels go, the resulting foal stood three feet high when it was a week old ... Laura's various expressions of loathing, together with endless groans and complaining, made you think she could not possibly be in good health. I used to watch her teaching her foal· to grumble. When she saw me coming she would start bleating and bubbling, putting her head close to her infant's as she did so, in order that the sounds might be imitated" (Weigall, 1933). The success of camels in Old World deserts eventually inspired people to bring them back to their original homeland in the New World, where Camelops had roamed just 10,000 years before. In 1836 a young Army major named George Crossman suggested that camels be used for western exploration, but .nothing came of it for 15 years until Crossman became deputy quartermaster general. His subordinate, Major Henry C. Wayne, investigated the idea and supported it enthusiastically, and eventually they prevailed on Secretary of War Jefferson Davis to get $30,000 from Congress to fund the project. In 1855 Wayne went to Syria, Egypt, and Tunisia on a camel-buying trip, eventually obtaining 20 dromedaries and 13 Bactrians. He also hired six Levantine Arabs and a Turk to accompany the animals back to the United States on the corvette ship U.S.S. Supply. Quartered in wooden stalls on the deck, all but one survi ved the three-month journey, and two more were born on the trip, in spite of the rough seas. The Turk, acting as veterinarian, had no medications, so when a camel became ill, he tickled its nose with a lizard's tail. The camels landed on May 14, 1856, near Galveston, Texas, but most of their Arab attendants deserted when they reached America. The two remaining Arabs had to instruct American cavalrymen on the feeding and watering of this strange animal that did not behave like a horse. Naturally, their instructions were hampered by the language barrier. In those days Army rations included a daily amount of beer, but the Arabs, as strict Muslims, could not drink theirs. Instead, they poured it into the camel's water, since they knew camels would drink anything, and water was scarce. The troopers assumed that beer was an essential part of camel's diet, and this practice continued until the commander halted the issue of beer when he saw drunken camels lurching around the compound. When the camels sobered up, they were tested, and the War Department report concluded that they could carry 1000-pound (450-kg) loads for 30-40 miles (50-65 km) a day, and would not require water for 6-10 days. This was the necessary impetus for further camel imports. In February 1857 the Army brought 44 more

56

HORNS, TUSKS, AND FLIPPERS

camels to Texas, and they soon became a familiar sight, plodding along between San Antonio and the Gulf Coast ports. Along with the second shipment was an Arab named Hadji Ali, who was known to Americans as "Hi Jolly." He soon became the primary defender of camels in America, helping the Army understand their psychology and trying to overcome the resistance of lifetime cavalrymen. The major problem was that the troopers had not been raised around camels as the Arabs had, and had little patience or understanding for their idiosyncrasies. Time and again, they got angry when camels wouldn't do things that horses do, and they never did learn to appreciate what camels were best at. The other problem was the strong scent of camels always frightened horses, and frequently caused a stampede. The city of Brownsville, Texas, even passed an ordinance banning camels from the city streets. Again, this was a problem of unfamiliarity, because Arab horses raised around camels are not bothered by their smell. In 1858 a British company landed two more cargoes of camels in Texas for the Watson Ranch near Houston. A San Francisco company brought in 20 Bactrians to haul s~lt over a 200-mile (320-km) trek in Nevada. These camels so frightened horses that Nevada passed a Camel Traffic Law in 1857, barring camels from public highways. The largest experiment used camels to haul supplies between Fort Tejon, just north of Los Angeles, and Fort Defiance, New Mexico. This was so successful that they had a camel corral in downtown Los Angeles, where the Los Angeles Times building now stands. By this point, camels were breeding successfully in their long-lost homeland, so that over 100 were found across the country. The Great Camel Experiment seemed destined to make camels a common feature of the western landscape, along with mustangs and longhorns. Our western movies might have shown Tom Mix or Roy Rogers on his faithful camel, Trigger. Unfortunately, the Civil War broke out, and the Army lost interest in the camels, or the West in general-it had more pressing matters to deal with in the East. Hi Jolly struggled to keep the camels ali ve during the 1860s after the Army abandoned them, but it was a futile effort. By the late 1860s he had to turn the rest of them loose to forage for themselves. Hi Jolly eventually died in Arizona, broken and disappointed; his grave is marked by a statue of a camel. Feral camels continued to wander around the American desert for the rest of the century, but they were hunted viciously by cattle ranchers who did not want them grazing on their lands. The last one supposedly died in 1900, although the Paiute Indians claim to have seen three wild camels in the Mojave Desert near Victorville, California, as late as 1928. Another historian insists that the last U.S. Cavalry camel died as late as the 1930s. The camel could have become well established in the land of its origin, but it never caught on due to intolerance, not to its own inability to adapt. Camels became very successful when introduced to the Great Australian Outback, and are still found there. Ironically, these camels were mostly derived from American zoo-bred stock!

Figure 3.8. Joseph Leidy, the founder of vertebrate paleontology in North America. This photo was taken in 1853, at the height of his career describing fossils. (Photo courtesy Academy of Natural Sciences, Philadelphia).

"MOUNTAIN TOOTH" After the expeditions of Lewis and Clark in 1803-1805 there were few scientific ventures into the Great West fo; over 40 years. Most of the exploration was carried out by fur traders and mountain men, who were interested primarily in beaver furs and routes through the mountain passes. In 1846 a fur trader brought a fossilized jawbone down to the Missouri River to St. Louis, and showed it to Dr. Hiram Prout. It had come from the forbidden region known to the French fur traders as the Mauvaises Terres, or "bad lands," because they were bad lands to travel across or find water in. As described in Chapter 12, Prout recognized it as the remains of a gigantic extinct beast he called Palaeotherium although today we call it a brontothere. ' News of this discovery prompted others to leave the Oregon Trail or the Missouri River route in search of more fossils. In 1849 David Dale Owen, U.S. Geologist, sent John Evans nOlth of the overland trail up the Platte Valley, and he managed to pacify the Sioux long enough to make a short visit to the "bad lands." Evans came back with many specimens of fossilized teeth and jaws. In 1850 the Smithsonian Institution sent Thaddeus Culbertson to the "bad lands," and

TYLOPODS he came back with an even larger collection. Almost all of these specimens ended up with Dr. Joseph Leidy of Philadelphia, one of the few men in the country who was interested in them (Fig. 3.8). Joseph Leidy was then a 25-year-old professor of anatomy at the University of Pennsylvania, and a gifted naturalist. Abandoning his medical practice, he concentrated on the many natural objects that excited his curiosity. It was an age when almost all scientists were true amateurs (since no one made their living from science), and few were specialists. A good natural historian had state-of-the-art expertise in virtually any animal or plant that came his· way, since very little was known about the great fauna and flora of America at the time. Leidy published short one-page papers in the Proceedings of the Philadelphia Academy of Natural Sciences almost weekly, describing the many interesting finds he had displayed at their meetings. His publications ranged over many subjects, from the wings of locusts, to the anatomy of the sloth, the red snow of the Arctic, and the parasites of fishes. Collectors were happy to send him their finds, because he always gave them credit (often naming a new animal after them), and published it promptly. When Joseph Leidy began to receive these fossils, he realized that they represented extinct animals never seen on this continent, or among any fossils previously described. In 1847 he described the first American camel, Poebrotherium, which we discussed earlier. In 1850 he described the first American rhinoceros (as we shall see in Chapter 14), and in 1853 he described a little deer-like beast he named Leptomeryx evansi (after the collector, John Evans); we shall discuss leptomerycids in the next chapter. By this time, he was specializing in fossil vertebrates from North America, and he became the father of vertebrate paleontology in this country. He published several large monographs on the fossils he had received, including two on the fossils of the "bad lands." He remained one of the few men studying vertebrate fossils in this country until he retired in 1870, tired of competition from Edward Drinker Cope and Othniel C. Marsh (see Chapter 1). Although he acquired and named the camel Poebrotherium first, the commonest animal in the collections was a strange beast with primitive pig-like limbs, but selenodont teeth like those of a ruminant (Fig. 3.9). In 1848 he described this animal and called it Merycoidodon culbertsonii from the Big Badlands. (Merycoidodon means "ruminant-like tooth," and the species name honors the collector, Thaddeus Culbertson) . Later, Leidy used the name "Oreodon," which means "mountain tooth," since it was based on teeth found in the Rocky Mountains. Since Leidy had first called it Merycoidodon, this is the proper name of the beast so common in the Badlands that hundreds of thousands of specimens are known. They occur in virtually every rock shop around the country, and if you collect fossils in the Badlands, the odds are very good that the first fossil you pick up will be an oreodont. But what is an oreodont? In most features, it is not too

57

Figure 3.9. The typical Badlands oreodont Merycoidodon culbertsoni, a sheep-sized beast that is the most common fossils in the Badlands. It was relatively primitive compared to later oreodonts. (Painting by R. B. Horsfall, from Scott 1913).

different from other primitive Eocene artiodactyls. It still has relatively short toes, with all five digits on the front foot, characters shared by all primitive hoofed mammals. Oreodonts never became long-limbed or specialized for running. Early oreodonts also had relatively unspecialized heads-no long snouts, or horns, or bizarre changes in their front teeth as we shall see so often in artiodactyIs. However, they are more advanced than pigs in that their grinding teeth have crescent-shaped crests, or selenodonty, as we saw in camels, and in all ruminants as well. Their selenodont teeth, however, rarely get as high-crowned for gritty grasses as in camels or ruminants. According to Jeremy Hooker, oreodonts have specializations that place them as distant relatives of the camel/oromerycid/protoceratid group, and so they are now classified as tylopods. Oreodonts, like most of the artiodactyls we have seen so far, originated in the middle Eocene in North America. But unlike the others, they became one of the most common mammals in this continent, and never migrated elsewhere. Protoreodon is the fossil most often found in the middle Eocene deposits of the Uinta Basin, and this abundance prevails throughout their history. Given that they were such an unspecialized herbivore, it is not clear why oreodonts were so abundant. Perhaps they weren't fussy, eating a wide mix of vegetation, which was important during the climatic and vegetational changes that marked the end of the Eocene jungles and the gradual change to open savannas by the middle Miocene. If oreodonts were like "ruminating swine," they could have lived in large numbers in a variety of habitats, which might be why we find so many of them in the floodplain deposits of the later Eocene and Oligocene. By the late Oligocene, however, more specialized oreodonts appeared on the scene (Fig. 3.10). One Oligocene lineage descended from the sheep-sized Merycoidodon was

HORNS, TUSKS, AND FLIPPERS

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TYLOPODS

59

Figure 3.11. The late Oligocene oreodont Leptauchenia, with its high-set eyes and deep jaws. In this reconstruction by Bruce Horsfall, it is shown as an aquatic beast, although most specimens apparently lived in desert habitats. (Painting by R. B. Horsfall, from Scott 1913).

the much larger Mesoreodon. A second group 'was the dwarfed oreodont, Miniochoerus, which shows progressive dwarfing during the climatic stresses at the EoceneOligocene boundary. One of the most common and characteristic beasts of the middle Oligocene is known as Leptauchenia. It was a small oreodont with high-crowned teeth, and eyes, ears, and nostrils on the top of its head (Fig. 3.11). Some have suggested that this is an aquatic adaptation, but this is difficult to reconcile with the fact that they are found in large numbers in the arid dunes of volcanic dust that dominated the High Plains in the late Oligocene. The high-crowned teeth suggest a much grittier, coarser diet, and there are living desert animals with high-placed nostrils and eyes, and openings on the snout like Leptauchenia for the filters which keep dust out of the lungs. In the early Miocene oreodonts had reached their peak in diversity. Although the leptachenids were gone, there were small, slender forms known as Merychyus which were the swiftest oreodonts ever. The most peculiar, however, were the amphibious oreodonts, such as Promerycochoerus, Merycochoerus, and Brachycrus. These animals were shortlimbed and heavy bodied, like pygmy hippos or pigs, with wide flaring cheekbones and broad snouts (Fig. 3.12). Through the early and middle Miocene, the skulls of Merycochoerus and Brachycrus show a progressively more retracted nasal opening. This suggests that they developed a short trunk or proboscis like a tapir. Clearly, these oreodonts were more specialized for living in rivers and marshy habitats, browsing on leaves which they pulled down with their proboscis. By the middle Miocene, however, oreodonts were on the decline. The last of their line, Ustatochoerus, was a pigsized beast which also had a tapir-like proboscis, although

Figure 3.12. A. The hippo-like or pig-like oreodont Promerycochoerus, from the early Miocene. B. The middle Miocene oreodont Brachycrus, which had a distinct tapir-like proboscis. (Paintings by R. B. Horsfall, from Scott 1913). not as large as that of Brachycrus. Oreodonts were extinct by the end of the middle Miocene (listed as Pliocene in older, outdated books). The cause of their extinction is unknown. It is interesting, though, that they were most prolific and di verse during the gradual transition from forests to grasslands from the middle Eocene to early Miocene. The last of the oreodonts were almost all amphibious beasts with a proboscis or prehensile lip, suggesting that they were specialized leaf-eating browsers who lived mostly in riverine forests. With the exception of Leptauchenia, few oreodonts even developed high-crowned teeth for grazing. When fullfledged open savanna grasslands (which favored fast runner grazers such as horses, camels and ruminants) finally developed and the forests retreated in the middle Miocene, the slow, primitive oreodonts disappeared.

Figure 4.1. The giraffe truly towers above the plains, and is able to see for miles. (Photo courtesy A. Walker).

4. Where the Deer and the Antelope Play

GRAVEYARD OF THE AMAZONS "It was a bright November morning. A tang of fall was in the air. The underbrush was aglow with the rosy-pink of cyclamen ... fields were gay with yellow whins, and heather was coming on the hills. There was no indication whatever of the great moment that was about to break-no trumpets blaring-no angels singing. Barnum [Brown] had gone to the quarry as usual, and I was giving Pups a bath, when I heard loud talking down the trail. Looking up, I saw Niko and Pan in feverish conversation. Then they both came running toward me, shouting in Greek. 'Calm down,' I pleaded. 'What gives? I can't understand a word you're saying.' Niko gulped for breath. 'Dr. Brown... ' he panted. 'Dr. Brown wants you at the quarry quick.' 'Barnum isn't hurt?' Niko laughed. 'Right now he's the happiest man in the world. He's ... ' 'I know! I know!' I shouted. 'He's found the Samotherium! ' I raced to the qualTY. A cloud of dust rose from one corner. It was coming from Barnum's pick. He was digging furiously, around him the crew. Pushing through, I knelt beside him and touched his arm. He was trembling. Before him, where the clay had been dug away, lay a small skull with sharp pointed horns. Twisting away from it into the bank was a long line of neck bones. It was some minutes before he spoke. When he did, his voice was shaking with excitement. 'This is it! This is what we've been waiting for, Pixie. I believe the entire beast is in here-a SAMOTHERIUM! Do you know what this means? The expedition's a success!' With a whack of the pick he cut still further into the bank, exposing another vertebra. 'I can see them back at the Museum when they get my wire,' he chortled. 'President Osborn will be shouting hallelujahs all over the place. And dear Charlie Lang ... he's so excitable anyway.' Barnum was laughing-a little hysterically, I

thought. It made me happy to see him this way. He had been hoping so long for this moment ... and now it was like a dam breaking. 'This will mean a lot to us, Pixie, when we get back to New York,' he was saying. 'It's a big thing to make a discovery like this. Look at those neck bones .. how solid and graceful, like an antelope's. And that skull-how finely formed the eye sockets! The teeth are perfectly preserved!' 'And that jaw!' he exclaimed. 'That jaw did plenty of chewing in its day. See how powerful the ascending ramus is? And to think this fellow has been lying here five or more million years-waiting for me. That's why I am a paleontologist, Pixiejust for moments like this." (Brown, 1951: 201203). So wrote Lilian Brown, the wife of Barnum Brown, one of the most celebrated fossil collectors of this century. These events took place in 1924, his last year of excavations on the Greek island of Samos, off the coast of Turkey. Samoshas proven to be a treasure trove of fossil bones-over 30,000 were collected there between 1850 and 1963. Even the Greeks had myths about Samos to explain all the bones found there. According to Aelianus, they were the bones of huge beasts, the Neades, which could fracture the earth with their voices and scare off travellers. Plutarch wrote that they were the bones of Amazons, killed by Dionysus, and the ground was so covered by their blood that it is now called Panhaema ("blood covered"). From these myths, the expatriate Englishman Charles Forsyth Major decided that there must be fossil bones on Samos, and he made large collections between 1885 and 1887. Between 1890 and 1920 Samos was collected by Germans. The last and biggest excavations were made by Barnum Brown for the American Museum of Natural History in New York between 1921 and 1924, removing some 56 crates of bones in 1924 alone. In recent years, the entire area has been recollected and sorted out by Nikos Solounias. It has proven to be one of the richest and most important late Miocene (around 8.5 to 9 million years old) localities in the world. Samos contains over 100 species at latest count, including bears, weasels, badgers, skunks, otters, hyaenas, cats,

HORNS, TUSKS, AND FLIPPERS

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Figure 4.2. Phylogeny of the tylopods and ruminants, showing the different types of cranial appendages in each group. (From Janis and Scott 1987). sabertooths,· aardvarks, three kinds of mastodonts, hyraxes, three-toed horses, clawed chalicotheres, and five species of rhinoceros. More than half of the mammals, however, are artiodactyls, and most of these are ruminants: muntjacs, deer, giraffes and sivatheres (Samotherium was a primitive giraffe, discussed further below), a huge variety of antelopes, including gazelles and many extinct forms, and extinct relatives of the musk ox and nyala, chamois and mountain goat. This diversity of a11iodactyls is repeated at localities such as Pikermi, near Athens, which was first discovered in 1838, and Maragheh in Iran, and the Siwalik Hills of Pakistan. These bonebeds show that most of Eurasia and Africa was a vast savanna grassland in the late Miocene, dominated by dozens of species of ruminants. If you take the diversity of antelopes, giraffes (Fig. 4.1), and cattle in the modern East African savanna and double it, you can get some sense of what immense numbers of game roamed all over Eurasia back then. Since they first arose in the Oligocene, the dominant group of large mammals throughout the Old World has been ruminants, just as hornless artiodactyls (especially camels and oreodonts) and horses dominated in North America. Along with the suines (pigs, peccaries, and hippos) and tylopods (camels, oromerycids, protoceratids, and oreodonts), the ruminants represent one of three great divisions of the living artiodactyls. Unlike the other two groups, however, ruminants far outnumber all other artiodactyIs: there

are over 164 species living today, compared to the six species of tylopod, and fourteen suines. In fact, ruminants outnumber all other living terrestrial hoofed mammals combined (since there are only 16 living species of non-hyracoid perissodactyls and two elephants, plus the 11 species of hyrax). As we saw in Chapter 2, this advantage is probably due to their specializations of digestion. Foregut-fermenting herbivores, such as the ruminants, have a great advantage in efficiency of digestion, and thus can specialize into many different feeding niches. Not all cud-chewing artiodactyls are classified as members of the Ruminantia, however. As we saw already, some pigs and hippos have a form of foregut fermentation, even though they do· not have a fully four-chambered stomach. Camel stomachs are three-chambered in that they do not separate the last two stomach chambers, the abomasum and the omasum. The Ruminantia are distinguished by having a fully four-chambered stomach, as well as specializations of the teeth and of the ankle joint. The first chamber, or rumen, is the big fermentation vat. After the fermented food is regurgitated and chewed in the mouth as cud, it bypasses the rumen and goes to the second chamber, the reticulum, for continued fermentation. The food then passes through two more stomach chambers, the abomasum and the omasum. In the latter chamber, it is treated with gastric juices before moving on to the small intestine and caecum for digestion.

WHERE THE DEER AND THE ANTELOPE PLAY HORNS AND ANTLERS The most striking features of ruminants are their cranial appendages, whether they are horns or antlers. In Africa, the horns are the easiest method to recognize antelopes, from the graceful curves of the sable antelope to the spirals of the eland to the straight shafts of the oryx. The broad horns of Cape buffalo and water buffalo are their most prominent and dangerous feature. Hunters try to shoot the deer with the most impressive racks. Both humans and the ruminants themsel ves use horns or antlers to recognize species, their age, size, sexual maturity, and their status in their herd. In addition, these appendages are essential in sparring with other males for dominance, and in defense against natural predators-even if they are a handicap when they attract human hunters. It is not surprising that such a useful feature has evolved several times in the ruminants (Fig. 4.2). Horns are formed from a solid bony core that is covered by a sheath of the protein keratin, the same protein found in your hair or fingernails. The bony part of the hom grows only once and is permanent; it is never shed like an antler. True horns of this type are found only in the cattle and antelopes and a number of their extinct relatives. Giraffes have short bony knobs (called "ossicones") capped with keratinous sheaths on their heads which have been called horns, but their structure is fundamentally different. In giraffe development, the bony core is preceded by cartilage, while the true horns of cattle and antelopes have no cartilage precursor, but arise directly from the skull and skin. Thus, giraffe ossicones are a distinct structure from true horns. Pronghorns (which are not closely related to true Old World antelopes) also have a bony core in their horns, but the keratinous sheath is shed each year. Thus, their "horns" are anatomically distinct from cattleantelope horns. Antlers are a completely different structure entirely. They form as direct outgrowths of the skull roof, growing very rapidly with a blood-filled layer of "velvet" covering them during growth. Antlers are pure bone, and never have a keratinous sheath, but shed their velvet when growth stops and the breeding male is ready to use them for combat and defense. Then, the antler is shed after the breeding season, only to grow back next year. True antlers are found only in the deer family, including the moose, elk and caribou. Hornlike appendages occur elsewhere in the hoofed mammals. Rhinos have a horn-like structure formed of cemented hair fibers, not bone. The extinct brontotheres had huge paired bony knobs on the tips of their noses. The extinct pig Kubanochoerus had a small median unicorn-like hom on its skull, and the leptauchenine oreodonts had tiny paired horns on their noses. The extinct protoceratids had a variety of curved and slingshot-like horns, which were apparently made of bone covered with skin. This was also true of a number of extinct deerlike forms we will review in this chapter, including the dromomerycids, the merycodonts, and the climacoceratids. Surprisingly, horns are not universal among hoofed mammals. Camels never developed

63

them, nor did most pigs, peccaries or entelodonts. No horse has ever had horns, despite the myths of unicorns. Even among the higher ruminants, a variety of small deer have large canine teeth instead of horns. The mystery of horns has been extensively studied by Peter Jarman. He has shown that hom types are correlated with ecology (Fig. 4.3). Tiny ruminants (Jarman's Category A), for example, live as solitary individuals or pairs in thick forests, browsing selectively on low-fiber shoots and berries. Since they have an efficient ruminating stomach, they cannot eat too much fibrous vegetation, and must restrict themselves to small amounts of more nutritous vegetation; this restricts their maximum size as well as their habitat. Consequently, they must forage far and wide for succulent vegetation, and cannot defend a· single territory. Tiny ruminants do not show much difference between the sexes in size, and consequently have no need for complex cranial appendages. In fact, such structures might hinder their movements in the thick brush. Instead, males of mouse deer, musk deer, water deer and muntjacs have long saberlike upper canine teeth, mostly for displaying and driving off other males. Above a body weight of 33 pounds (15 kg), ruminants have more choices in diet and habitat. Most of these animals live in moderately wooded habitats, eating leaves of all types. In more open country with less restricted diets, it is practical for a male to defend a territory of palatable bushes. These antelopes (Category B, such as the bushbuck and reedbuck) tend to have the greatest difference between sexes: larger males with spectacular horns and smaller females that are hornless. Some examples, such as the kudu, differ not only in size and horns, but even in coloration. Their dietary versatility also allows the females and young to forage together in small herds, and there is less direct competition for the food among individuals. Once ruminants reach an even larger size, their diets cannot be so selective. They must eat a larger percentage of less nutritious grasses in their diet, which requires a much larger foraging range. Male antelopes or deer can no longer maintain a boundary patrol of a small territory, but instead concentrate on defending a roaming herd of females. Category D includes large antelope such as wildebeest, which have males and females that are equal in size and have horns. These animals roam over the grassland, and males defend a small area of turf against other males only during the breeding season. In Category C (including the impala and gazelle), males hold territories for part of the year, but form mixed herds with females during the rest of the year. Males may be slightly larger than females, and have more elaborate horns. The largest horned ruminants, such as the buffalo (Category E), have no territories. In these animals, the male and females both have horns, but the males are much larger, and fight among each other to establish dominance in the herd. According to Christine Janis, this ecological segregation explains the development of horns in ungulates. At the

64

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Figure 4.3. Jarman's feeding categories of ungulates as modified by Christine Janis. The top fauna is the living East African savanna fauna; the middle one is from the early Miocene of North America; the bottom one is from the late Miocene of North America. Letters identify animals in each of Jarman's feeding categories. Numbers identifying each of the silhouetted animals are given by Janis (1981). (From Janis 1981). beginning of the Oligocene the continents of the Northern Hemisphere were covered by a subtropical woodland, inhabited by hornless artiodactyls. The subtropical woodland was gradually replaced by a grassland in Eurasia in the late early Miocene (about 18-20 million years ago), and large horned ruminants appear there for the first time. These animals must have developed a strongly territorial phase in their habitat, where horns became essential; sexual differences and large, single-male herds became the rule. And so we see that the history of the Old World is dominated by horned ruminants, with little competition from camels or horses. Why, then, didn't the New World ungulates also develop horns? As we have seen, one group (the protoceratids) did so, in the late Oligocene in North America. According to Janis, this was the time of the transition to more open, grassy habitats, but it was much more abrupt than in Eurasia. Consequently, the protoceratids became the equivalent of small antelopes (Category B), with sexual differences in horns and body size, and a diet of leaves. Camels, on the other hand, moved straight from the forest (Category A) to the open grassland (Category C or D), bypassing the need to develop a territorial strategy and the requirement for horns. According to Janis, horses bypassed the threshold for hom development for a different reason. Since they are hindgut

fermenters, they always need to forage wider and eat more low-quality vegetation than ruminants of comparable size. As horses got larger during the Oligocene and began to rely more on grasses, they were already ranging over much larger territories; they could not pass through the Category B stage of browsing on leaves, and defending small territories. The key concept is the idea of a threshold for size and diet; only lineages which gradually move from non-territorial forest browsers (Category A) into territorial mixed woodland browsers (Category B) before reaching large body size and grazing can develop horns. Janis' hypothesis fits most of the available evidence quite well, although it is difficult to find a critical test, since these events happened long ago and are no longer being repeated. Horns and antlers have long been used to unite the five living families of ruminants: the giraffids (Giraffidae), the Iiving cattle-buffalo-antelope-goat-sheep family (Bovidae), the musk deer (Moschidae), the American pronghorn (Antilocapridae), and the deer family (Cervidae). Together these five families compose the Pecora and are all closely related. The pecorans apparently originated during the Oligocene in the group of primitive Eurasian fossil ruminants known as the gelocids. However, the relationships of these five families to each other has long been controversial. Until recently, the prevailing idea was that giraffes, prong-

WHERE THE DEER AND THE ANTELOPE PLAY horns, and bovids (with their bony horns or ossicones) formed one group, and deer (with antlers) and musk-deer formed the other. However, W.R. Hamilton, and later Christine Janis and Kathleen Scott argued that the embryonic development and anatomical details of deer antlers, giraffe ossicones, and bovid and pronghorn horns are very different (Fig. 4.2). Giraffe ossicones are covered only by skin, whereas both bovids and pronghorns have bony horn cores covered by hard horny keratin sheaths-but pronghorns shed theirs and bovids don't. Janis and Scott argue that the four different kinds of cranial appendages evolved independently and cannot be used to group various pecorans. When other features of the anatomy are considered, Janis and Scott find that pronghorns, deer, and musk-deer form one group (the cervoids), bovids another, and that giraffes are more primitive than any of them. Although their ideas have not yet been accepted by all ruminant specialists, we find them convincing and adopt their classification here. In recent years, most of the new evidence from molecular similarities seem to support their hypotheses. However, even more recent molecular data dispute their conclusions. For the moment, we find the molecular arguments inconclusive. "MOUSE DEER" The earliest and most primitive ruminants are hornless rabbit-sized animals from the middle and late Eocene known as leptomerycids. Leptomeryx evansi, mentioned in the last chapter, is particularly characteristic of the Big Badlands; it "is the most common artiodactyl after oreodonts. Along with the very similar hypertragulids, leptomerycids are very closely related to a living fossil, the chevrotains, or "mouse deer" (Fig. 4.4). These tiny hornless "deer" are not actually deer at all, but relicts of the origin of ruminants over 40 million years ago, and give us a good idea of the transition between ruminants and more primitive artiodactyls. As might be expected from these primitive, transitional ruminants, they lack many of the specializations in the skeleton seen in all deer, pronghorns, giraffes, antelopes, sheep, and cattle. They still have all four front toes, which have not yet fused into a cannon bone, and they have tough skin on their rumps like pigs to protect against the canines of ri val males. Chevrotains, or the tragulids (Family Tragulidae), are ruminants in the sense that they have the four-chambered stomach, but the separation between the reticulum and the abomasum is so weakly developed that they have a functionally three-chambered stomach. In the past the tragulids have been considered to be either somewhat intermediate between pigs and camels, closely related to camels, intermediate between camels (Tylopoda) and the true Ruminantia, or essentially a type of primiti ve deer. Today the living tragulids are best regarded as true members of the Ruminantia, but also the most primitive living members of this group. In some respects they appear to be living fossils, closely resembling the ancestral forms that inhabit-

65

Figure 4.4. The lesser mouse deer, Tragulus javaniGUS, showing the distinctive backward-pointing tusks. (Photo courtesy C. Janis). ed the globe in Oligocene times and subsequently gave rise to the living higher ruminants. They have successfully persisted in their ancient tropical forest habitat, while most other ruminants evolved into other niches offered by the spread of grasses and other vegetation. Christine Janis suggests that this might explain why the Old World has always been the center of ruminant evolution, since there is a land connection between the tropical forest refuges and more temperate latitudes. In the Americas, by contrast, the isolation of the Amazonian tropics from North America prevented many archaic animals from surviving in this potential refuge. It is not surprising that fossil tragulids and tragulid-like animals, classified into various extinct families and genera (such as the Hypertragulidae and the Leptomerycidae), are known from the Oligocene through Pleistocene of Eurasia, Africa, and North America. These were all small, hornless, primitive ruminants that have persisted until the present in the form of the two survi ving genera of tragulids, the water chevrotains (Hyemoschus aquaticus) of tropical central and west Africa, and the three species of mouse deer (genus Tragulus) of India, Sri Lanka, and Southeast Asia. Living tragulids are diminutive creatures (hence the name "mouse deer") that range in head and body length from about 20-36 inches (0.5 to 1 m), have a shoulder height of about 8-14 inches (20-36 cm), and weigh from 5-11 pounds (2-5 kg) as adults; the males tend to be somewhat smaller than the females. They have small heads, pointed snouts, long, thin, delicate legs, and short tails. The coat is brown to red-brown and decorated with horizontal white stripes and spots, and the belly is lighter in color than the back and sides. Relatively little is known about the detailed behavior and biology of tragulids. They inhabit exclusively equatorial tropical forests, jungles, and mangrove thickets where they feed on fallen fruit, various aquatic plants, and some foliage. They are shy, primarily nocturnal, solitary animals

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that communicate among themselves via scents and vocalizations, including a shrill, birdlike call. Their nocturnal lifestyle is particularly evident in their huge, dark-adapted eyes, which give them a timid, vulnerable look. Chevrotains have home ranges that they mark with urine and feces containing secretions from anal glands. These territories are criss-crossed with tunnel-like trails through the vegetation. The African water chevrotain is a good swimmer, and when threatened it will dive into the water and hide under a floating log or mat of vegetation with just its nose out to breathe. The three Asian species of Tragulus prefer rocky habitats. Chevrotains have chin glands that in the males of some species produce secretions which are used to mark the back of a mate or an antagonist. The males have long dagger-like canine teeth, which seem incongruous on a fruit eater, until you realize they do not have horns or antlers for display and combat between males. Instead, the males duel with a short, sharp rush, each antagonist biting his opponent all over the body with stabbing canines. As we shall see, other tiny deerlike animals have sub~tituted long canines for horns or antlers. Various large snakes, eagles, crocodiles, cats, and other forest carnivores prey on tragulids, but their most immediate long-term threat is caused by humans. Along with small hornless antelopes, such as duikers, they were one of the main prey of the Mbuti pygmies of the Ituri Forest in the Congo Basin of the Congo (described in Colin Turnbull's famous study, Forest People). The pygmies, however, never overhunted these beasts, since they also prayed to them, and depended on the forest animals for their survival. The wholesale destruction of African and Asian rainforests will probably do more than anything to drive chevrotains to extinction. The African water chevrotain is already on the endangered species list; too little is known of the Asian mouse deer species to determine if they are endangered or not. THE "FOREST DONKEY" Despite the fact that it stands five to six feet (1.5 to 1.7 m) tall and can weigh as much as 550 pounds (250 kg), the elusive okapi (Fig. 4.5) was unknown to western science until it was "discovered" by the British explorer Sir Harry Johnston in 1900. Of course, the pygmies that lived in the forests of the Congo had known and hunted the okapi for centuries and the animal was also familiar to the Belgian officials of the area. Yet the okapi was unknown in professional zoological circles. Who would expect that an animal the size of a horse remained incognito at such a late date? Sir Harry Johnston thought this might be the case, however. Sir Henry Stanley, the newspaper reporter turned explorer who rescued the missionary and explorer David Li vingstone on Lake Tanganyika in 1871, had reported tales of an otherwise unknown beast in his book In Darkest Africa (1890). An informant of one of the pygmy tribes of the Congo region stated that in their forests lived a creature that greatly resembled an ass in appearance that they occasional-

ly trapped in pits (the meat being highly prized). Based on this report, Johnston thought that there might be an unknown horse or zebra in the forests, and resolved to search for it if he ever had the opportunity. In late 1899 Johnston found himself on official business in Uganda and in the process of liberating some captured pygmies chanced upon the opportunity to learn more about the beast that Stanley's informant had mentioned. Several years later Johnston recounted that "I came in contact with a large party of dwarfs [pygmies] who had been kidnapped by a too enterprising German impresario, who had decided to show them at the Paris Exhibition. As the Belgians objected to this procedure, I released the dwarfs from their kidnapper, and retained them with me for some months in Uganda, until I was able personally to escort them back to their homes in the Congo Forest. . . . As soon as I could make the dwarfs understand me by means of an interpreter, I questioned them regarding the existence of this horse-like creature in their forests. They at once understood what I meant; and pointing to a zebra-skin and a live mule, they informed me that the creature in question, which was called OKAPI, was like a mule with zebra stripes on it" (Johnston, 1909: 268). On reaching Fort Mbeni, Congo Free State, 10hnston questioned the Belgian officers concerning the okapi. They were familiar with the animal for the native soldiers were in the habit of hunting it and returning with the skins and flesh for use at the f011. In fact, the officers thought there was a fresh skin lying about the fort that Johnston could have. Upon finding the skin,· however, they discovered that most of it had already been thrown away-only a bit of the gaudier portions (with fancy zebra-like stripes) had been saved and already cut up into thin strips to be used as belts and bandoliers. These strips of hide were given to Johnston, and he forwarded them to the Zoological Society of London in August of 1900. On the basis of these sparse remains Dr. P. L. Sclater tentatively named a presumed new species of zebra after Johnston, Equus? johnstoni. Johnston was determined to obtain a complete okapi. He entered the Congo forest and remained there for some days searching for the beast, but to no avail. Thinking that he was looking for a zebra or horse, Johnston expected the okapi to have typical horse-like hooves. Therefore when the natives pointed out the tracks of a cloven-footed animal and claimed they were the tracks of the okapi, he did not believe them. Sickness and time constraints forced Johnston to give . up his search, but his Belgian officer hosts promised to work on obtaining an okapi skin for him. After Johnston returned to Uganda, an okapi skin and two skulls were forwarded to him. Upon inspecting these specimens he realized that the okapi was not a horse at all, but a very primitive relict of the ancestors of the giraffe family. Indeed, the okapi struck Johnston as being a "living fossil," very similar to both the ancient Samotherium from the Samos fauna and the ancient Helladotherium found in the Pikermi fauna of Greece. The skin and skulls were sent to

WHERE THE DEER AND THE ANTELOPE PLAY

Figure 4.5. The okapi, Okapia johnstoni, the only living relative of the giraffe. (Photo by D. R. Prothero). London, and arrived in June of 1901. After studying them Professor E. Ray Lankester declared that they represented a previously unknown genus of giraffid which he formally named Okapia, thus giving the okapi its full modem scientific name: Okapia johnstoni. The okapi remained a recluse to western scientists for many decades. It was not until the mid-1930s that an okapi was captured alive and kept for any substantial length of time in a zoological park (there were a few earlier captures of live okapis, but they all died within a short period of time). Indeed, the official seal of the International Society of Cryptozoology, an organization dedicated to finding beasts such as the Sasquatch, the Loch Ness monster, unicorns, and the Congo brontosaur, features the okapi. Even today little is known about the behavior of the okapi in the wild. Adult okapis do indeed resemble horses in a vague way. They have long heads and drawn-out muzzles, large dark eyes, relatively large ears and a long neck, long limbs, a long black tongue (so long that they can reach their eyes with their tongue), and the males have small giraffe-like skin-covered horns. Most distinctive is the okapi's markings. The body is covered with short, sleek hair that varies in overall appearance from deep reddish-brown to purplish to not quite black. The face is lighter in color with a dark muzzle. The haunches and upper portions of both the front and back limbs have zebra-like horizontal black and white stripes, and the shanks of the limbs are lighter colored and

67

unstriped. Okapis inhabit the dense equatorial rain forest of northern Congo, particularly the riverside woodlands of the area. They are apparently active at daytime, relatively solitary, and spend much of their time wandering around singly or occasionally in pairs or small family groups. They beat tracks through the forest to their favorite feeding areas, and have glands on their feet which they may use, along with urine marking, to stake out territories. In the forests the okapis feed on various leaves, fruits, and seeds. They are reportedly very timid, running at any sign of danger-their principal enemies are leopards, snakes, and man. Their hearing is very acute. The female okapi stays in heat for up to a month at a time, advertising her condition by urine marking and vocalizations. Courtship encounters between male and female are marked by female aggression and male dominance displays, including lip-curling, displaying of a white throat patch, head tossing, and leg kicking. In the presence of a female in heat, male to male encounters may involve ritualized neck fighting, butting, and charging. Calves are born during the period of maximum rainfall, from about August to October after a gestation period of approximately 430-460 days. Babies are born with a small head, short neck, and a conspicuous mane which is essentially lost in adults. It has been suggested that stripes on the legs and flanks of the adult okapi may be important for calf imprinting. Female okapis will defend their young by kicking potential predators. The longevity of okapis is unknown, but they are reported to have lived for over 15 years in captivity. The okapi keeps to fairly localized areas, and is reported to remain relatively common in some parts of the Congo. It has fallen under government protection since 1933, yet it is difficult to prevent poaching in dense and remote forests. Even though the okapi is not at present officially an endangered species, invariably increased human pressures could unfortunately always change this for the worse. THE CAMELOPARD Arab poets and prophets considered the giraffe the queen of beasts, with enchantingly long eyelashes, delicate features, and fragile form. The Koran referred to her as the serafe, roughly translated "the lovely one." Eastern sultans prized them as very special pets. Yet Westerners since the time of the ancient Greeks tended to view these beasts at best as strange marvels, but more often as peculiar monstrosities-hybrid forms that mixed the parts of known creatures and did not quite fit into God's natural order. Just imagine a beast with a long neck, long legs, and even a hump on its back like a camel, spotted like a leopard or panther, with a tail like a pard (as panthers and leopards were once known), and horny bumps on its head that resembled those of a stag after sheddings its antlers. The camelopard (as the giraffe was called) was an odd beast indeed, thought to be the product of miscegenation between a male camel and a female leopard. Even today the giraffe (scientifically

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known as Giraffa camelopardalis) is often referred to as "the animal built by a committee," presumably assembled from left-over parts of animals at the end of creation. Giraffes were known to the ancients of the Mediterranean region. Pompey, for instance, is said to have exhibited ten of them at his theatre in Rome. During the Middle Ages giraffes seem to have been nearly forgotten, except in legends and embellished tales from Arab travelers. When they were mentioned at all they might be confused with large, bizarre antelopes. In the mid-fifteenth century Europeans had the opportunity to see a giraffe in the flesh for the first time in many centuries when Cosimo de Medici acquired one for his zoological park in Florence. According to the story, Cosimo could not decide whether the camelopard was more of a camel or more of a pard. To help him make up his mind, when honored by a visit from Pope Pius II, he set up a little experiment for his and the Pope's amusement. Cosimo had the giraffe placed in an enclosure along with a few lions, some blood-hounds, and a few fighting bulls--then he aI1d the Pope eagerly awaited the outcome. Presumably if the giraffe was more of a leopard it should put up a good fight, but if it was more of a camel it would quickly succumb to the lions and dogs. Fortunately for the poor giraffe, the lions, blood-hounds, and bulls all ignored the giraffe and only gave the gentle vegetarian a good fright. For centuries after Cosimo's display and experiment the giraffe remained relatively unknown to Europeans. In the late sixteenth century one Melchior Lorch of Flensburg (northern Germany) considered a giraffe the greatest wonder he had seen during his travels to Constantinople and back. Likewise, France (and probably much of Europe) was suitably impressed when, in 1783 while on a trip to what is now South Africa, the adventurer Francois Levaillant became the first modern European to shoot a giraffe. The specimen was shipped to the Jardin du Roi (reorganized during the French Revolution as the Musee National d'Histoire Naturelle in 1793) and a couple of decades later was used by Jean Baptiste Lamarck as an example of his newly proposed evolutionary mechanism. Today, many associate the introduction of modem evolutionary theory with the name of Charles Darwin and his publication of On the Origin ofSpecies in 1859. But Darwin did not invent evolution; rather, he convinced the scientific community that evolution had occurred and proposed a mechanism of evolution, namely evolution by means of natural selection. Proposed simultaneously by Alfred Russel Wallace, it is also commonly known as "the survival of the fittest." Within each species or population, during each generation of organisms more offsping are born than mature and reproduce. Furthermore, not all offspring are identical; there is variation in every trait to a greater or lesser extent. The driving force of evolution, according to Darwin, is that certain individuals that by chance have certain variant traits may be more successful in surviving and reproducing than other members of their generation, and thus pass their use-

ful variant traits on to the next generation. By analogy to artificial selection, in which a breeder picks certain animals and plants with desirable traits and allows them to propagate, Darwin termed this weeding out and choosing of individuals during each generation "natural selection." According to Darwin, just as selective artificial breeding over the centuries could produce new varieties of plants and animals, so too natural selection working over millions and millions of years could produce whole new species and kinds of organisms. Darwin was not the first scientist to espouse evolution. Jean Baptiste Lamarck, the French soldier turned botanist turned zoologist, actively espoused a theory of evolution from the year 1800 until his death in 1829. Among his many ideas, Lamarck followed the widespread notion that evolution occurred due to the inheritance of acquired characteristics. By the "habit" or "striving" of organisms in a certain direction from generation to generation evolutionary changes might actually be effected. Under this idea, the strong muscles of the blacksmith would be passed on to his sons. Although only briefly mentioned in the large corpus of Lamarck's work, the notion that the giraffe acquired a long neck by continually stretching it to reach high leaves, generation after generation, soon became the classic textbook example of Lamarckian evolution (and remains so to this day). Lamarck's own ideas along these lines are as follows: "It is interesting to observe the result of the habit in the peculiar shape and size of the giraffe (Camelopardalis): this animal, the largest of the mammals, is known to live in the interior of Africa in places where the soil is nearly always arid and barren, so that it is obliged to browse on the leaves of trees and to make constant efforts to reach them. From this habit long maintained in all its race, it has resulted that the animal's fore-legs have become longer than its hind legs, and that its neck is lengthened to such a degree that the giraffe, without standing up on its hind legs, attains a height of six metres (nearly 20 feet)." (Lamarck, 1809: 122). Unfortunately for Lamarck, he found few supporters of his evolutionary theory during his lifetime, largely due to his battles with the politically more astute Baron Georges Cuvier. The puzzle of inheritance was such a problem for evolutionists that even Darwin continued to believe in the inheritance of acquired characters until the end of his life. A number of prominent scientists of the second half of the nineteenth century, including paleontologists such as Edward Drinker Cope, accepted the inheritance of acquired characters. By the turn of the century, however, the experiments of August Weissman demonstrated that features acquired during one's lifetime never made it into the next generation. In 1900, long after Darwin and Lamarck, modern genetics was born with the rediscovery of Mendel's

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20

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Figure 4.6. Phylogeny of the giraffes, modified from W. D. Hamilton (1973). (Drawn by C.R. Prothero). work. Weismann and the neo-Mendelian geneticists destroyed the credibility of acquired characters in evolution. To give this concept a label, they called this notion "Lamarckism." Thus, the wide-ranging work of one of the eighteenth century's greatest naturalists was reduced to a single idea. Ironically, acquired inheritance was a notion that all Lamarck's contemporaries believed in, and was peripheral to most of his main ideas. Nevertheless, we still refer to any idea about inheritance of acquired characters as "Lamarckism." Today, we believe that the great neck of the giraffe can be explained much more cogently as the result of Darwinian natural selection. Short-necked giraffe ancestors evolved into present-day long-necked giraffes because over a number of generations offspring that developed (by a combination of inheriting genes for long necks from long-necked parents and random favorable variation) slightly longer necks would be at a competitive advantage. On average, they would out-reproduce their shorter-necked contemporaries. In each generation, the longer-necked giraffes would pass on their genes for long necks in disproportionate numbers and cause the giraffe population to evolve toward having long necks.

But what of these evolutionary scenarios? Whether you believed Darwin or Lamarck, the presupposition was that modern giraffes had evolved from short-necked ancestors. Was this really the case? The answer was forthcoming from the rocks. UntiI the. very end of the nineteenth century only the single species of giraffe was known among living animals. No other living animals appeared to be closely related to giraffes, and zoologists argued whether giraffes were closely related to deer, pronghorns, bovids, or perhaps to none of these artiodactyls. Beginning in the 1830s, however, close relatives of giraffes were found-but from Miocene, Pliocene, and Pleistocene rocks. In such late Miocene deposits as those at Samos and Pikermi in Greece, from the Siwalik Hills of Pakistan, and from numerous other Miocene to Pleistocene deposits of eastern Europe, Africa, and Asia, numerous giraffe-relatives were discovered (Fig. 4.6). According to Janis and Scott, the most primitive giraffoid is Propalaeoryx from the early Miocene of Africa. By the middle Miocene, there were several giraffe lineages coexisting in Africa. Climacoceras, for instance, has long, thin, branched, antler-like ossicones. Canthumeryx (also called Zarafa) had two long pointed ossicones directed side-

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Figure 4.7. The moose-like giraffid Sivatherium, with its palmate horns, was common in the PlioPleistocene of Asia and Africa, and may be represented in cave paintings. (Neg. no. 327253, courtesy Department of Library Services, American Museum of Natural History). ways away from the top of its eyes. The okapi is a living relict of these middle Miocene giraffoids, even though its fossils are known only from the Pleistocene. According to W.R. Hamilton, the next more advanced group· of giraffids are the sivatheres, which roamed Africa and Asia from the early Miocene until the end of the Pleistocene, and may even have co-existed with man but a mere handful of millennia ago. Giraffokeryx, from the middle Miocene of India, had two sets of V-shaped ossicones over its eyes and its ears. Brahmatherium (including Helladotherium) , a late Miocene sivathere from Eurasia, had thick conical ossicones on its head. Sivatherium (from the Plio-Pleistocene of Asia and Africa), was a huge, burly, short-necked giraffid that had gigantic palmate and branching ossicones resembling the horns of a moose (Fig. 4.7). There are petroglyphs, perhaps dating to 8000 years ago, of possible moose-like sivatheres known from a rock shelter in the central Sahara. An ancient Sumerian bronze figurine, possibly representing a sivathere, has also been reported. Following the sivatheres was another sidebranch, the samotheres. Derived from "Palaeotragus" eminens of the middle Miocene, Samotherium was widespread over Africa and Europe in the late Miocene and Pliocene. As the anecdote at the beginning of this chapter describes, little was known of it until Barnum Brown found a nearly complete skeleton on the Greek island of Samos, from which it took its name. Samotherium had two long, curved ossicones on its head that looked like a pair of bananas pointed upward and outward. These animals were distinctly members of the giraffe family, yet they had short necks and in other features were very different from the known living giraffes. The speculations of the early evolutionists were in principle correctthe modern long-necked giraffes had short-necked fore-

bears. But the fossil record did not answer the question of how the giraffes evolved their long necks, either by Lamarckian "stretching" or by Darwinian natural selection. The lineage leading to modern giraffes began with "Palaeotragus" tungurensis from the middle Miocene of Mongolia, Hunanotherium from the late Miocene of China, and Bohlinia from the middle Miocene of Greece. None of the extinct genera have the long neck or legs, although most are known only from teeth and skulls. The earliest known species of Giraffa, G. jumae, from the late Miocene of eastern and southern Africa, apparently already had long legs, and presumably also a long neck. For decades, zoologists pointed to the giraffe neck as an example of the flexibility of the mammalian body plan. Like almost all other mammals, giraffes appeared to have only seven vertebrae in their neck, despite the fact that it is much , longer. Instead of adding additional short vertebrae as it lengthened, they lengthened each vertebra itself, making them long and spindly. However, Nikos Solounias has shown that this is not true. Giraffes have actually added an additional vertebra between the second and sixth vertebrae of the neck. But the last neck vertebra (the seventh cervical in anatomical terms) has been shifted to the thoracic region, where it supports a rib like the rest of the thoracic 'Vertebrae. Consequently, the giraffe's neck begins slightly behind its forelimbs, and this gives the giraffe its unusual appearance of a neck located further back on the torso and the forelimbs protruding. Solounias interprets this unusual addition as a functional shift in vertebrae to balance the long neck on such a slender body-if the neck were hinged too far forward on the body, it would be unbalanced and prone to topple forward. Living giraffes inhabit much of the open woodland and wooded grassland of Africa south of the Sahara desert. They all belong to a single species (Giraffa camelopardalis), but within this species there is much variability and some nine different subspecies are generally recognized: West African giraffes, Kordofan giraffes, Nubian giraffes, Reticulated giraffes, Rothschild giraffes, Masai giraffes, Thornicroft giraffes, Angolan giraffes, and South African giraffes. Giraffes are large mammals. The head and body length of an adult male can range from 12-15 feet (3.8-4.7 m), the shoulder height can be 8-12 feet (2.5-3.7 m), and the height to the horn tips can be 15-17 feet (4.705.3 m). Females tend to be somewhat smaller, the height to the horn tips for females generally ranging from 13-15 feet (3.9-4.5 m). Giraffes have tails that range in length from about 31-39 inches (80-100 cm), not including the terminal tuft or tassel of black hairs that may be up to a meter in length. Adult giraffes can weigh from 1200 to over 4200 pounds (5501900 kg), the lighter weights being among females. Of course, giraffes are known for their extremely elongated necks, but their odd appearance is further accentuated by the fact that their bodies are relatively foreshortened from front to back, and the fore-legs are slightly longer than the hind-legs. The giraffe's skin is very thick and tough-it

WHERE THE DEER AND THE ANTELOPE PLAY is reported to be up to an inch thick in some old males. It is so tough that it is commonly used for sandals in Africa. The coat pattern is extremely variable in different populations of giraffes, giving rise to the number of subspecies that have been named. All giraffes are covered by dark, more or less polygonal patches separated by a network of lighter (creamy, yellowish-white, or white) lines, but the network of lighter lines may be more or less thick and is better defined in some varieties than others. The dark patches can vary from pale orange through a number of shades of brown and red-chestnut to almost black. Apparently specific variants on patterns of coat markings are unique to individuals, and such patterns remain constant from birth to death (although the color of the patches and network may change during the life of the individual, growing darker with age). On this basis individual giraffes may be able to recognize each other. The basic giraffe skull has two short horns, called ossicones, on top of the head. These are formed of bone and covered with skin and terminal tufts of black hair (which may be lost, especially in males). In males the ossicones tend to be thicker, heavier, and may fuse together at the base. At birth the ossicones are present as flat-lying cartilaginous cores that during the first week after birth take an upright position and subsequently ossify and fuse with the skull. Giraffe skulls are also characterized by their increase in bone deposition throughout life, especially in males. Bony lumps and concretions are often deposited on the skull, especially on the back of the nasal bones and also above each eye socket, and sometimes at the back of the skull. Due to these bony growths giraffes are seen with from three to five "horns." The eyes are large, dark brown, and protected by long lashes. The lower canine teeth are splayed out, lobed, and used to "comb" leaves off tender shoots. Giraffes also have long black tongues that are useful in gathering food into the mouth, and tough, hairy, prehensile lips. Giraffes have extremely acute sight, probably the best sight of any large mammal, and this combined with their high heads allows them to survey the area for many miles. They also have well-developed senses of hearing and smell. It is a common misconception that giraffes are completely mute; although they seldom vocalize, they can produce various moans, grunts, snorts, and bleats. Confined to open woodlands and wooded grasslands of sub-Saharan Africa, giraffe populations are most often associated with acacia plants upon which they frequently feed. In the wild giraffes are highly selective browsers, feeding on leaves, shoots, fruits, and seeds. Giraffes may be able to go for weeks or months without water, but they do make regular visits to water supplies when such are available. When watching giraffes feed from a distance, one can distinguish males from females; adult males typically fully stretch the neck and head vertically so as to feed on high vegetation, whereas females tend to feed with the neck curled down thus reaching vegetation which is at body or even knee

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height. Giraffes spend about half of each twenty-four hour day feeding (a bit more for females, and a bit less time for males). Feeding occurs primarily in the mornings and evenings, and during bright, moonlit nights. During the heat of midday giraffes rest and chew their cud. In order to drink or reach food on the ground, giraffes can spread their forelegs widely to the sides and slightly in front of them, and bend their knees. Giraffes band together in loose herds (whose composition changes daily), ranging in size from less than a dozen individuals up to 70, presumably simply because they are social animals and also for protection from predators such as lions, man, and to a lesser degree leopards. Because of their excellent eyesight, giraffe herds may be able to communicate visually over many miles. Giraffes have large home ranges (on the order of 120 square km), but they are not territorial. Instead, there is a distinct dominance hierarchy among adults where their ranges overlap, especially among the bulls. Young males in particular undergo ritualized fighting in order to determine and secure their position in the hierarchy. They typically intertwine their necks ("necking") and push from one side to another. Occasionally heavy blows will be exchanged using the sides of the bony head and horns. Dominant bulls spend much of their time searching for females in heat with which to mate. On sighting and joining a herd of giraffes (usually composed of cows, calves, young males, and perhaps an older male leader), a dominant bull will sample each female's urine using the flehmen, or lip-curl, response to determine if she is in heat. The bull lays his head on the flanks of the cow and while she urinates collects the urine in his mouth. He then curls his lips and spits out the urine in a thin stream; this probably forces molecules of scent to Jacobson's organ (located above the palate) and in this manner the male can determine the female's condition. If a cow is in heat a dominant bull will displace any subordinate bull that may be with the herd and consort and copulate with the cow, only to leave later and search for more cows in heat. Giraffes can breed year round. The gestation period is approximately 450 days, and the young stand 5.5-6.5 feet (1.7-2 m) tall shortly after birth. Cows give birth standing up, so the newborn drops several feet to the ground. A newborn giraffe will often join a group of calves when only one or two weeks old. The female giraffes are reported to be excellent mothers, and will defend their offspring from lions, leopards, hyenas, African wild dogs, and other predators by kicking with their feet; a single well-placed blow can kill a lion. Normally only a single calf is born at a time, and the mortality rate is approximately 50% in the first six months. Giraffes reach maturity at five to eight years, and have a usual life span in the wild of 15 to 25 years (in captivity one giraffe lived to be 28 years old). Other than intraspecific dominance rituals and fights, giraffes are naturally quiet, shy, and inoffensive animals. When around man, however, they will quickly get used to his presence. Giraffes have an interesting and unusual form of loco-

HORNS, TUSKS, AND FLIPPERS

Figure 4.8. Giraffes must spread their forelegs to drink. This posture also diminishes the dangers of the sudden changes in blood pressure to their head. (Photo courtesy A. Walker). motion. At slower speeds they pace, or raise and swing the two legs on one side of the body at almost the same time. When galloping, however, the two hind legs are brought forward almost simultaneously and land outside of the front legs, which are then moved forward. Giraffes rest or sleep standing up or lying down with their legs folded beneath them. The head may be rested on the rump, the neck forming an arch, for very short periods (on the order of five minutes at a time) of sleep. Otherwise the neck remains vertical, with the eyes only half-closed and the ears alert. The fact that their heads are about ten feet (3 meters) higher than their hearts creates unusual physiological problems. Not surprisingly, they have a huge heart about 2 feet (60 cm) long, weighing about 25 pounds (11 kg), with muscular walls up to three inches (7.5 cm) thick. Their hearts must pump about twice as hard as a human's for blood to reach their heads and permeate their brains. Such high blood pressure would probably rupture the blood vessels of any other animal, but giraffes have unusually toughwalled blood vessels, and they maintain fluid pressure within the tissues of their body with their tightly stretched thick skin, which functions like an anti-gravity suit. The tight skin also prevents the blood from pooling down in the legs. When you stand up too quickly after lying down, you feel faint because blood pressure to your brain drops suddenly. Giraffes have the same problem, only more extreme. When they get up, they must do so slowly and in stages to allow their blood pressure to stabilize gradually, or they will pass out. When a giraffe is drinking, its head is lower than the heart, which creates too much blood pressure (Fig. 4.8). Giraffes have a series of one-way valves in their jugular vein that prevents the venous blood headed back to the body from flowing back to the brain when the head is down. For the arterial blood to the head, giraffes have a rete mirabile, or "wonderful net," sponge-like network of vessels in the

arteries leading into the brain, which buffers the pressure before it causes brain capillaries to burst. By spreading its front legs to drink, the giraffe not only brings the head down, but also lowers the heart, so the gradient isn't as steep and the pressure difference is less. Another problem with having a long neck is the enormous volume of dead air in the windpipe. As the giraffe breathes, it must expel all 5 pints of dead air in its neck with each breath, and then inhale enough air to refill its lungs and its windpipe. Since this reduces the total air flow, the giraffe has to breathe much faster-20 breaths per minute, compared to 12 for us and 10 for an elephant-to get enough oxygen into its blood supply. Yet breathing faster is more difficult, since it requires moving all that dead air up and down a long pipe. It is not surprising that they move much slower, run more efficiently, and cannot run with much endurance. Giraffes and humans have had a long relationship. North African Stone Age men produced rock drawings of modem giraffes. Certain tribes of the Sudan, Chad, and Ethiopia have traditionally hunted giraffe on horseback, eating the meat with reverence. The thick hides of giraffes have been used to make shields, whips, and other objects. Although giraffes have been reported to reach speeds upwards of 30 mph (50 km per hour), David Livingston stated that at times a rider on a good horse could chase a giraffe only a few hundred yards before it might drop dead from exhaustion. Writing in the early twentieth century the hunter H. A. Bryden stated that to chase a troop of giraffes on horseback and place a bullet through the root of the tail from behind (which would then penetrate the length of the body and surely kill the exhausted giraffe) "is one of the most thrilling and exciting of all human experiences." One hopes that tastes in recreation have changed over the years. To Bryden's credit, however, he did advise that for the sake of the giraffes, the "humane hunter" not partake of this pleasure more than a few times. At present giraffes are still relatively common in East and South Africa, although they are always subject to the threat of poaching. Giraffe-hair bracelets, made from the tail tufts, are particularly popular with tourists and have encouraged some poachers to slaughter animals, removing only the tails, and leaving the carcasses. Giraffe meat has been eaten for centuries and is said to have a good flavor (like gamey veal), and the roasted marrow of the long bones is considered by some to be a delicacy. It has been suggested that giraffes, properly managed and cropped, could become an important source of animal protein for human consumption in parts of Africa, especially since they feed on vegetation that is unused by domesticated animals and therefore would not compete with other livestock. DEER PERFUME The deer superfamily, the Cervoidea, forms another large group of artiodactyls. Among living ungulates, the cervoids include the musk deer, the American pronghorn "ante-

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Figure 4.10. Extinct relatives of the musk deer, the blastomerycids, were common in the early and middle Miocene in North America. (Painting by R. B. Horsfall, from Scott 1913).

Figure 4.9. The living musk deer, Moschus, has long protruding canines instead of antlers. (From Whitehead, 1972). lope," and approximately three dozen species of true deer (family Cervidae). Of these three living groups of cervoids, the musk deer (Fig. 4.9) are generally considered the most primitive (perhaps reminiscent of the ancestors of the true deer) and are placed in their own family, the Moschidae. Musk deer are comparatively small, deer-like animals with an adult head and body length of about a meter, and a weight of about 15-38 pounds (7-17 kg). They lack horns or antlers, but the male musk deer have long upper canines that project down from the lips as long tusks similar to the familiar canines of an extinct saber-tooth cat. Musk deer inhabit the high, mountainous forests of Asia, especially China, Manchuria, Korea, Siberia, Mongolia, Tibet, Kashmir, and Nepal. To this day relatively little is known about their biology and habits. Not long ago it was the opinion of most mammalogists that all musk deer belonged to a single species, known as Moschus moschiferus, which was divided into a number of subspecies. It is now believed that there are at least three, and maybe four, distinct species of musk deer. Musk deer tend to be solitary (except during the rutting season) and extremely territorial; the males mark their turf by rubbing scent glands against stones, trees, and other vegetation. In the presence of man they are shy and timid, quickly fleeing if disturbed. Moschids feed on a variety of plant matter, including young shoots, leaves, flowers, grasses, twigs, buds, and mosses and lichens. Moschids are the source of natural musk, an ingredient

that has been used in perfumes and expensive soaps for centuries, and in the Far East is also traditionally used for all sorts of medicinal purposes, such as a treatment for fevers, sore throats, and rheumatism. The highly prized musk is carried only by males; at sexual maturity a musk sac develops in front of the genital area, and glands within the sac secrete the brownish, wax-like musk. No one is exactly sure why the males produce musk, but most likely it is used for signalling and attracting females, or repelling other males. When filled, the musk sac may contain about an ounce of musk. Because of the high human demand for musk, resulting in very high prices for the substance, musk deer are probably slaughtered by the hundreds of thousands annually. Many of the musk deer are captured by traps that do not discriminate between musk-bearing males, and the worthless females and young; as a result these animals are becoming increasingly rare and endangered. However, there is actually no need to kill musk deer in order to obtain musk, as was demonstrated by an experimental program in Sichuan, China. Musk deer can be caught alive and bred in huge, enclosed parks. Periodically the adult males can be captured by hand and while they are restrained the musk can be spooned out of the musk sac (which contains a natural opening), then the musk deer can be released and will secrete more musk. Still, the raising of musk deer and the extracting of the musk is a time-consuming and laborious process. Furthermore, the musk deer have not proven to breed well, or live a long time, in captivity. The earliest known moschid is Dremotherium, from the late Oligocene of Europe. By the early Miocene, fossil moschids were spread all over the Northern Hemisphere. Early Miocene deposits in Nebraska produce the first American moschid, Blastomeryx (Fig. 4.10), as well as the earliest pronghorn and the earliest dromomerycid (an extinct family related to true deer, which we discuss below). Blastomerycid musk deer persisted until the late Miocene in North America, but they were never particularly numerous.

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Figure 4.11. Male prongbucks have an impressive set of horns, which are shed annually. (Photo courtesy B. O'Gara.) ALL-AMERICAN-BUT NOT AN ANTELOPE "Hurra for the prairies and the swift antelope," wrote the pioneering naturalist John James Audubon on an expedition up the Missouri River in 1843, "they fleet by the hunter like flashes or meteors . . . they pass along, up or down hills, or along the level plain with the same apparent ease, while so rapidly do their legs perform their graceful movements ... that like the spokes of a fast-turning wheel we can hardly see them, but instead, observe a gauzy or film-like appearance..." (Audubon, 1851). Prior to the middle of the nineteenth century the pronghorn (Antilocapra americana) and the American bison were the dominant ungulates of the western plains, roaming the grasslands and deserts from northern Mexico, through the western United States, and into southwestern Canada. It has been estimated that some forty to fifty million pronghorns roamed the land before 1850, but just as the bison was brought close to extermination, so too the pronghorn population was decimated by man. The pronghorn did not come as near to total extinction as did the bison, however. An estimated 13,000 remained in 1920, and today there are perhaps half a million pronghorns. Pronghorns are unique among the living ungulates. On their heads they bear horns composed of a solid and perma-

nent bony core (as in giraffes, cattle, and antelopes) covered with a sheath of fused hairs (keratin) that is shed yearly (Fig. 4.11). In contrast, the keratin covering the horns of cattle and true antelopes is never shed during the lifetime of the individual. True deer (discussed below) have antlers that are composed of bone and shed annually as are the hom sheaths of the pronghorns. But deer cranial appendages are very different in structure from those of pronghorns. In deer, the mature antler is not covered with any type of sheath, but is composed of solid deciduous bone that is completely shed each winter and subsequently regrown in its entirety. Although everyone calls them "antelopes," it is clear that they are not related to the true antelopes of Africa, which are bovids. Taking the horns and other characteristics into account, the pronghorn does not neatly fit into either the Bovidae or the deer family (Cervidae). In the past they were placed with the bovids, or simply given the distinct family Antilocapridae without specifying whether they are more closely related to cattle or deer. Recent work on the phylogenetic relationships of the ruminants, notably by J.J.M. Leinders, Christine Janis and Kathleen Scott, suggests that the pronghorns are most closely related to the true deer, and belong in the Cervoidea along with moschids and true deer. The pronghorns are true native Americans. They are the sole living survivors of the family Antilocapridae, an American group of cervoids that was once much more diverse than it is currently-just one or two million years ago there were over a dozen species of antilocaprids roaming the plains of North America (Fig. 4.12). In recognition of this true American origin, the American Society of Mammalogists uses the pronghorn as its official symbol on their journals and emblems. Originating from some late Oligocene Eurasian cervoid, pronghorns reached North America in the earliest Miocene and became established as the antelope surrogate for this continent. Like African antelopes, they diversified into a tremendous variety characterized by different horn shapes. The earliest form, Paracosoryx, had long straight horns with forked tips. Other members of this group, the merycodonts, had long gazellelike horns, deer-like horns with multiple tines, or flat bladed horns with comb-like edges. Merycodonts had very highcrowned cheek teeth, and were small gazelle-sized creatures. According to Christine Janis, they lived in more open grasslands, and may have competed with and displaced the stenomyline camels mentioned in Chapter 3. From the merycodonts evolved the more advanced antilocaprids of the later Miocene and Plio-Pleistocene. Some, such as Hexameryx and Hexobelomeryx, had six horns. llingoceros had long straight horns twisted into a spiral. Stockoceros was a third larger than the living pronghorn, and had four horns arranged in simple V-shaped prongs. Hayoceros had four horns arranged with a typical short pronghorn in front, and a long straight horn in back. In merycodonts, only the males had horns, but all more advanced antilocaprids (including the living species) have horns in females as well.

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Tht prt'prun,i!horn, P/ioctros

Ramoenes, from New MIX;C()

ParfUOSflryX.

ftom N,brtUU

Figure 4.12. The variety of horns in the extinct pronghorns of North America was truly impressive. (From Scheele, 1955). Except for the Ii ving species, all pronghorns went extinct at the end of the last Ice Age, along with many other large mammals discussed elsewhere. Several have been found in association with kill sites, so there is a good chance that they were overhunted by the first humans on this continent. Pronghorns are well known for their speed. They are the fastest mammal in the Americas, capable of reaching speeds of 55 miles per hour (86 kmlh) in short bursts. They can maintain a speed of 45 miles per hour (70 km/h) for approximately four miles (6.4 km), outrunning horses and most vehicles in rough terrain. They have enormous windpipes for efficient breathing, and a heart twice the size of a sheep's (which has a similar body size). They are extremely agile, and can make horizontal leaps over 20 feet (6 m). However, they do not like to jump vertically. They have a habit of leaping between the wires of a barbed wire fence, rather than over it, as deer will. One of us (Prothero) witnessed a pronghorn that jumped between the wires and then became snagged. It tore itself free before anyone could approach. Adult pronghorns stand about just over one meter at the shoulder, typically have a head and body length of 3-5 feet (1-1.5 m), and weigh about 80-130 pounds (36-60 kg). The

horns have tips that point backwards and a short prong midway up the horn that points forward. Although found in both sexes, the horns are considerably larger in the males. The coat is reddish brown to tan, with a white belly, rump, neck, and head markings. A short black mane runs down the back of the neck, and males have black patches on their faces. Pronghorns have excellent eyesight (useful on the open plains) and are naturally inquisitive and curious. Their curiosity will even induce them to approach unknown objects, sometimes to their detriment. It is reported that early settlers would attract the otherwise fleetfooted pronghorns within shooting distance by waving flags and handkerchiefs tied to poles, thus sparking the pronghorns' interest and attracting them closer to humans. Their eyes are large and set on the extreme sides of the skull, which allows a nearly 360 0 field of view. Their eyesight is so acute that one old hunter commented, "What a live antelope don't see between dawn and dark isn't visible from his standpoint; and while you're a gawkin' at him thro' that 'ere glass to make out whether he's a rock or a goat, he's a countin' your cartridges and fixin's, and makin' up his mind which way he'll scoot when you disappear in the draw to sneak on 'im-and don't you ferget it."

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Figure 4.13. A small herd of pronghorns does and fawns feeding in Wyoming. Their white rump patches produce a "signal flash" when they start to run. (Photo courtesy B. O'Gara.) Highly territorial, dominant prongbucks defend their territories and the forage they contain. Pronghorns also congregate in bands, or small herds (containing up to about a hundred individuals), especially during the winter (Fig. 4.13). After a summer of feeding, the prongbucks become restless, jumping sideways from a standing position and fighting among themselves. They gather harems of as many as fifteen does during the rut, marking their territories with their many scent glands. After mating, up to four fertilized eggs implant, and several embryos grow in the compartmentalized womb. After eight months of gestation, twin fawns are born in late May and June. They lie quietly where they are dropped for two or three days, with their lack of scent and mottled brown color concealing them from coyotes. The mother moves cautiously between the two hidden fawns to nurse them one at a time. She will distract predators away from her hidden fawns, or attack wolves and coyotes with her horns and sharp front hooves if necessary. After two days, the fawn can run faster than a horse for short distances, but stays hidden for almost a month since it lacks the stamina to outrun a predator over distance. The naturalist George Bird Grinnell witnessed several occasions where the doe led her fawns into a cactus patch, knowing that the coyotes could not walk there without getting their feet full of thorns. The coyotes tried rushing at the fawns to get them to panic and run out the other side, but the predators would not enter the cactus. At three weeks the fawn begins eating green vegetation, and by three months it acquires its adult coat coloration. The fawns are weaned by 4-5 months, and are sexually mature by 16 months. Pronghorns signal each other with the white hairs on their rump, which flash in the sunlight when they take off. This alerts the rest of their herd much quicker than sound,

and can be seen from two miles away. At the same time, the rump flash also releases a musk from their rump gland which further alerts any pronghorns downwind. Their main enemies are now humans and their sheep, who destroy their range. Coyotes and wolves cannot outrun pronghorns, but a pack may cooperate to ambush them and run one in circles until it tires. Fawns are also very vulnerable to coyotes and eagles. Most pronghorn deaths, however, occur during the winter months, when snow covers their forage and decreases their advantage in speed. Their worst problem is deep snow drifts, where they can become trapped, and crusty snow, which their sharp hooves break through (but a wolf's pads don't). During the winter, pronghorns seek shelter in the forested hills or deep ravines, and move away from the blizzards in the unprotected plains. Their hollow hair shafts give them excellent insulation, trapping air like a down jacket. However, in severe storms their fur becomes wet, and many pronghorns freeze to death. DEER TO US ALL From the prehistoric cave paintings that Cro-Magnon men used to help their hunting, to Santa's reindeer, Bambi, and Bullwinkle the Moose, deer have long been a part of human culture. Cave paintings from ten to twenty thousand years ago clearly depict various species of deer. Red deer remains have been found on more than 95% of all European Paleolithic and Mesolithic archeological sites. Deer were so important in the Middle Ages that Norman kings planted special forests in southern England as their exclusive game reserves. Besides hunting deer for meat, hides, sinew, and bone, Pleistocene and early Holocene humans also apparently gathered the shed deer antlers in large quantities. Antlers could be carved into a variety of tools, such as picks

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Figure 4.14. A. Each year, cervids must grow a new set of antlers from scratch. By late summer, this elk's antlers are nearly complete, but covered with their coating of "velvet" under which the rapid bone growth occurs. (Photo courtesy B. O'Gara.) B. In the fall, the bucks shed their "velvet" in long strips as they begin to battle for breeding rights. (Photo by D. R. Prothero). and other digging implements, needles and fishhooks, atlatls (spear throwers), and spear straighteners. The strong but resilient nature of antlers made them ideal for use as handles for stone knives and axes. Deer are still the most popular large game animal in many parts of North America and Europe. The annual fall deer hunt is still an important ritual for many American males, as depicted in the Oscar-winning Vietnam War film "The Deer Hunter." Other wild hoofed mammals, such as pronghorns and bison, have been displaced by domestic cattle and sheep. But deer still thrive, because they browse mostly in forested habitat, and do not compete with domestic grazers for open grasslands. The true deer, family Cervidae, are unique among ungulates in bearing antlers. These are structures growing from the head of the animals, somewhat analogous to horns. But unlike horns, which consist of permanent bone covered with a sheath of keratin or skin and remain on the animal for life, antlers consist of deciduous bone (Fig. 4.14). The outer layer is composed of compact bone surrounding a spongy core. Once fully grown and in place, antlers lack a covering sheath of any kind, and they are lost (leaving only a short protuberance, known as the pedicel, at the base) and regrown each year. Antlers are found only in males, except

in the case of reindeer, where both sexes have antlers. Antler is said to be one of the fastest-growing animal tissues known. In the common European red deer (Cervus elaphus) the antlers are cast or shed in the late winter or early spring and new antlers begin to grow. As they are growing the antlers are covered with velvet (fur-covered skin) and the growing bone is well-supplied with blood vessels. By around August the antlers are fully grown and the velvet dries up and begins to peel off in long strips of dead skin; the animal may rub its antlers against trees and other vegetation in order to wear off and remove the velvet (Fig. 4.14). The male deer (stags) are now ready for the rut (mating season), prepared to use their new antlers as weapons to fight with each other for the possession of females. Antler growth appears to be controlled by growth and sexual hormones, and as the male deer matures every year he will typically grow larger sets of antlers with more bifurcations and projecting points. Why are antlers lost and regrown each year, rather than being permanent appendages as are typical horns of other ungulates? Perhaps it is to give all males (especially older males) another chance if their antlers are damaged during the rut in any particular year. In the red deer, for instance, it is known that rutting success is reduced for the season if the individual's antlers are dam-

78

HORNS, TUSKS, AND FLIPPERS

Figure 4.15. The "Irish elk," Megaloceros, was neither an elk nor strictly Irish. It was a huge Ice Age deer with moose-like palmate antlers that were gigantic, but proportional to its huge size. (Photo from Millais, 1897). aged. This reduced success would be permanent (because the damage to the antlers would be permanent) if the antlers were not lost and regrown each year. The Ii ving red deer, the moose, and the reindeer can produce huge antlers year in and year out, but antlers of some extinct deer were phenomenal. Perhaps the most famous example is that of the extinct giant deer, Megaloceros giganteus, from the Pleistocene of Great Britain and continental Europe (Fig. 4.15). Often misnamed the "Irish Elk," it was neither an elk, nor exclusively Irish. (It was probably related to the fallow deer). The mature males of the giant deer commonly bore antlers that exceeded 11 feet (3.5 m) across, and weighed 100 pounds (45 kg)! As in other species of deer, these antlers were lost and completely regrown annually. Scientists have long thought that this beast was an example of evolution run amok-its antlers seemed too large to have any function. Stephen Jay Gould has shown that its antlers were scaled appropriately to its huge size, and were valuable for impressive displays for females and competing bucks. There is no reason to think that they were "maladaptive" or caused extinction. At certain times of the year, it seems that the ground should literally be covered with shed antlers where deer are abundant. However, once a deer loses its antlers, it will typically gnaw at them, and consume most or all of the antlers (if left alone and not disturbed). Presumably this is done in order to retrieve the mineral content of the old antlers which

can then be put to use in growing new antlers. Rodents are also responsible for gnawing at antlers and recycling them. It has been suggested that in prehistoric times (such as during the late Pleistocene), perhaps this eating of the antlers was unnecessary if the soil and vegetation at that time contained a higher mineral content than do many of the relatively depleted soils of today. Among modem deer, the antlers will be stunted or dwarfed if the animal's diet is inadequate or lacking in the necessary vitamins and minerals. The earliest deer share a common ancestor with other cervoids (moschids, pronghorns) in the late Oligocene of Eurasia. Although the late Oligocene Mongolian antlerless ruminant Eumeryx is often called the first deer, it is actually the oldest known cervoid. The oldest cervid relative, Amphitragulus, is known from the late Oligocene of Europe. By the early Miocene there were deer such as Palaeomeryx in Asia, Dicroceros in Europe, and the bizarre Prolibytherium in North Africa. Prolibytherium had two long parallel front-to-back-pointing horns over its head that looked a bit like a TV antenna. Long considered a primitive giraffe by most scientists, Janis and Scott have suggested that it is a cervoid related to Palaeomeryx and the North American dromomerycids, or "pseudo-deer." By the middle Miocene deer were flourishing all over Eurasia with over a dozen different genera. Most of these primitive deer had tusks like the antlerless Ii ving Chinese water deer, Hydropotes. If they had any, their simple antlers had only one fork, and were usually borne at the end of a long bony pedicel, like the living barking deer, or muntjacs (genus Muntiacus). Muntjac-like deer, like the extinct form Euprox, were common in the late Miocene of Eurasia. From one of these forms evolved a more modern deer, with no tusks and larger antlers anchored to a short pedicel. The most spectacular of these Plio-Pleistocene Eurasian deer were the "Irish elk" mentioned above, and Eucladoceros, which had as many as twelve tines on each antler! Close

Figure 4.16. Hoplitomeryx was a truly bizarre deer, with five horns and long curved canines. (From Leinders 1984).

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WHERE THE DEER AND THE ANTELOPE PLAY

.

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Figure 4.17. The deer-like dromomerycids of the Miocene of North America sported an amazing variety of cranial appendages. (From Scheele, 1955). relati ves of the true deer were the bizalTe five-horned Hoplitomerycidae, from the late Miocene of Italy (Fig. 4.16). Hoplitomeryx had long curved canines, a backwardcurved horn over its eyes, and two sets of horns over its ears: the inner set curved backward, and the outer set curved forward. This animal takes the prize for one of the weirdest horn combinations ever seen. Deer relatives migrated to the New World on two occa-

sions. The first was during the earliest Miocene, about 22 million years ago, when the earliest pronghorns and moschids also arrived. The immigrants Barbouromeryx, Aletomeryx and Sinclairomeryx established a new sidebranch of native North American "pseudo-deer," known as the dromomerycids (Fig. 4.17). Like American pronghorns, the dromomerycids evolved an amazing variety of horn types, since they had no competition from Eurasian cervids

HORNS, TUSKS, AND FLIPPERS

80

Figure 4.18. Collection).

Muntjac~

(From the IM31 Master Photo

in the Miocene savannas and forests of North America. According to Janis and Scott, they occupied the browsing woodland habitat along with the protoceratids (discussed in Chapter 3). However, unlike other cervoids, the males did not have antlers, but permanent bony horns. Some dromomerycids, such as Aletomeryx, occur in huge numbers in a single early Miocene quarry in western Nebraska. Aletomeryx had short multi-tined horns on long bases, and apparently lived in large, mixed-sex herds in open habitat, rather than defending territory. Others had inwardly curved horns, like Dromomeryx or Rakomeryx, or broadly palmate incurved horns, like Drepanomeryx. Matthomeryx had gazelle-like horns, and Sinclairomeryx had forward-curved horns. The most spectacular of the dromomerycids were the cranioceratines. In addition to a long horn over each eye tipped with a forked tine, they had a long curved horn originating from the back of the head! Dromomerycids reached their peak of diversity during the middle Miocene, then declined and went extinct during the terminal Miocene event that wiped out so many other native North American groups we discuss in this book: rhinos, most camels and horses, protoceratids, most pronghorns, and many others. In the early Pliocene, a second wave of immigration of deer from Eurasia took place. This established the modern deer of North America, the odocoilines, along with another extinct deer, Bretzia. In fact, the genus Odocoileus (including the living white deer and mule deer) dates back to the beginning of the Pliocene on this continent. When the Panama land bridge reconnected, deer continued their invasion and soon spread all over South America as well. Today, native wild deer are common on every continent except sub-Saharan Africa, Australia, and Antarctica. The last two have long been isolated from the Eurasian homeland, but the exclusion of deer from sub-

Figure 4.19. Fallow deer (From Whitehead 1972). Saharan Africa is probably due to the competition with true " antelope, which dominate the forest browsing niche. Among the approximately three dozen species of living deer (usually classified in about sixteen different genera) there is considerable diversity in size and external morphology. They range in height and weight from 15 inches (38 cm) at the shoulder and a weight of 17-18 pounds (about 8 kg) in the case of the southern pudu (Pudu pudu), to 9 feet (about 2.6 meters) and some 1,750 pounds (800 kg) in the case of the moose (Alces alces). Deer are best known for their antlers, but in some deer (such as the pudu), the antlers are nothing more than simple spikes and Chinese water deer (Hydropotes inermis) lack antlers altogether. Four subfamilies of deer are recognized. The most primitive are the Chinese water deer (Hydropotinae) and the muntjacs (Muntiacinae). As mentioned above, they are both relicts of the Miocene deer radiation in Eurasia. Males in both subfamilies have long canines, like tragulids and moschids. Chinese water deer weigh less than 30 pounds (13 kg), and live in swamps and reedbeds in China and Korea. They escape by humping their backs and leaping like rabbits. In addition to the long canines, muntjacs (Fig. 4.18) also have long antler pedicels, with a short branched antler at the tip. Weighing about 20-40 pounds (9-18 kg), the seven species of muntjacs live mostly in dense jungles of southeast Asia, browsing on leafy vegetation and tender shoots. Their habitat is similar to that of the tragulids of the jungles of Africa and Asia. Muntjacs are also known as "barking deer," because bucks emit a deep barking sound during breeding season or when they are alarmed. They will bark for over an hour if they sense a predator, such as a tiger, in the area. Most Old World deer are members of the subfamily Cervinae. The most familiar include the typically European fallow deer (Dama dama) and red deer (Cervus elaphus),

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81

Figure 4.20. Mule deer (From the IMSI Master Photo Collection).

Figure 4.21. The pudu deer, showing its tiny antlers. (Photo by D.R. Prothero).

which are mixed grazers/browsers living in dense forests, and open woodlands and grasslands (Fig. 4.19). With their distinctive spots and antlers flattened into a "hand" with "fingers," fallow deer are easy to recognize. There are a number of rarer species of the genus Cervus in southeast Asia, including the Japanese sika deer (Cervus nippon), the endangered marsh-dwelling Eld's deer (Cervus eldi), the Indian sambar (Cervus unicolor) and the little-known Indonesian rusa deer (Cervus timorensis), the endangered barasingha, or swamp deer (Cervus duvauceli) of India and Nepal, and the "humped" Thorold's deer (Cervus albirostris) of Tibet. The most familiar member of the genus Cervus, however, is the American elk (Fig. 4.14) or wapiti (Cervus canadensis). Although it is found in China and Mongolia, it crossed the Bering land bridge (along with mammoth, bison, and others) late in the Ice Age and established itself as the only New World cervine. During the summer, wapiti roam the mountain pastures of the Rockies, and in the winter, they shelter in the valleys. Their distinctive thick antlers, heavy build, shaggy neck, and famous bugling during mating season have long given wapiti a place in Western lore. The common deer in India is the axis deer, or chital (Axis axis), a mixed. feeder which is easily recognizable by the distinctive white spots in the adults. Closely related is the hog deer (Axis porcinus), so-called because it is heavily built with a short face and legs, and has a pig-like habit of charging head down through the brush, rather than leaping like a typical deer; it is characteristic of the rice paddies and grasslands of southeast Asia. Except for the wapiti, New World deer are members of the subfamily Odocoilinae. The most familiar of these is the genus Odocoileus, which includes the white-tailed deer (Odocoileus virginianus), denizen of the eastern deciduous forests, and the big-eared mule deer (Odocoileus hemionus), found all over the montane western states (Fig. 4.20). South America is home to a number of distinct types of deer, including the rare marsh deer (Blastocerus dichotomous) of

the floodplains of Brazil and northern Argentina, the endangered Pampas deer (Ozotoceros bezoarticus), which grazes in the pampas of Argentina and Paraguay, the two species of high-altitude Andean huemul (Hippocamelus) , the three species of brocket deer (Mazama), and the two species of tiny pudu (Pudu) (Fig. 4.21). Both brockets and pudu have simple unbranched spikes for antlers, and are typical forest dwellers. The most unusual of all deer is the moose (Alces alces), with its huge set of palmate antlers (Fig. 4.22). Its characteristic broad snout is suited for eating water vegetation, willows and poplar branches and bark, in the lakes and marshes it calls home. A male moose can also be recognized by the hump on its shoulder, and the thick flap of skin beneath its throat, known as a "bell" or dewlap. Found all over the northern hemisphere, moose are particularly common in the dense northern forests of Canada and Siberia. Originally, the Europeans called them "elk," and the wapiti was mistaken for a moose when explorers first came to NOlth America. As a result, the word "elk" means moose in Europe, and wapiti in North America. (This is also why the giant deer was called an "Irish elk," because its palmate antlers looked more like those of a moose.) Deer have marked differences between sexes, since bucks are usually larger than does and only they bear antlers (except in reindeer). While some deer are primarily solitary (such as the moose), many species form small groups (perhaps composed of a stag and his harem) or even small herds. Deer which live on patchy food supplies, such as moose, pudu, brockets, and white-tailed deer, live singly or in small groups. Those which live in more open habitats and depend heavily on grazing (such as wapiti and Sika deer) live in large herds. Wapiti are the most polygamous of all, with a single bull defending sixty or more cows. Although there is tremendous variability in the social and reproducti ve behavior of the 36 different species of deer, there are also some patterns that are typical. Bucks and does have a very different yearly cycle. Males of temperate species are seasonal

82

HORNS, TUSKS, AND FLIPPERS

4.22. The moose is a deer with thick, palmate antlers; it is adapted to browsing tender vegetation in northern swamps and bogs. (Photo courtesy B. O'Gara).

breeders, spending most of their spring and summer feeding alone, building up strength and waiting for their antlers to grow. In the fall, as their testosterone levels increase, they scrape the velvet off their antlers, and become aggressive. They then fight pitched battles with other males, sparring with their antlers locked, and sometimes dueling to the death. Stags eat little during the rut, so by the end they are gaunt and worn out. Some deer, such as red deer, defend harems against other bucks; muntjacs defend a fixed territory within overlapping female ranges; white-tailed deer stags defend an individual female. Once mating is completed, most bucks have little or no further parental investment in their offspring. Their antlers are shed, and they devote their solitary existence to surviving the winter and preparing for the next rut. They do not even recognize their own offspring, and behave with hostility toward them. Tropical deer do not have a fixed breeding season, so they invest even less energy in their young. By contrast, the doe spends nearly her entire year in some aspect of reproduction. After copulation in the fall, the female struggles to survive through the winter while she is pregnant. Gestation in most deer is 210-240 days, so that she gives birth in the spring. She then must leave her normal range and remain solitary for weeks while she protects her fawn. The fawn lies motionless for the first few weeks, concealed by its lack of scent and its white spots, which blend in with the dappled light on the forest floor. The doe returns to suckle it until it is able to keep up with her. Lactation lasts about 7 months, so the fawn is not weaned until the doe

comes into heat for the next mating season. Because body size is critical to mating success in males, they either have a more rapid growth rate or a longer growth period than do females. Their gestation period is also longer, and there is good evidence that the does devote more attention to their male offspring. Most young male deer must survive several years in bachelor herds before they are large enough to challenge and displace a stag with his harem. They usually do not succeed until they reach full adult size at about the fifth or sixth years. Since harems are typical of many species, most males do not mate in a given year, and many will never successfully overthrow a dominant buck and acquire does of their own. Deer use their senses of smell, hearing, and (to a lesser extent) sight to detect predators or other danger. In communicating and signaling to members of their own species, smell may be especially important. Most deer have facial glands, located in front of the eyes, and various glands on the feet and legs. These produce odoriferous secretions that are used to leave scent trails and mark territories. Many deer, such as the white-tailed and mule deer, flash their white rump patches when they run, signaling danger to their herd. Despite humanity's close association with deer for tens of thousands of years, these animals (with the exception of the reindeer, discussed below) were never domesticated. Why? As Juliet Clutton-Brock has pointed out, deer tend to be territorial and are not predisposed to being herded and led by a single leader (unlike goats and sheep). Ultimately,

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Figure 4.23. The reindeer is the only cervid in which both males and females have antlers, presumably because they use the long palmate front tines for scraping away snow to find food. (Photo courtesy B. O'Gara.)

because of their innate social disposition and their unpredictable behavior in captivity, it is virtually impossible to convince typical adult deer that they are to form a pal1 of a larger, human-oriented society. Fully domesticated animals (dogs or horses, for instance) come to accept their role within human society. As noted above, antlers are found only in males with the exception of reindeer (Fig. 4.23), Rangifer tarandus (commonly called the caribou in NOl1h America). Why should this be? Yet even in the reindeer, the antlers of mature males are typically larger than those of mature females. To survive in the harsh environment they inhabit, reindeer differ from the remaining deer in other important ways also. Unlike other cervids, reindeer are highly gregarious (travelling in large herds) and non-territorial. They spend most of their time browsing on the short grasses and herbs of the northern tundra. It has been suggested that for reindeer the antlers serve a different purpose than that for most deer-to gather food. In the winter reindeer congregate in large, mixed-sex herds and males and females alike use their antlers to dig under the snow and reach the sparse vegetation below. The reindeer are also the exception among the deer

family when it comes to domestication. Unlike most deer, reindeer travel in large herds that are easily directed by humans, are nonterritorial, and are relatively tolerant of human intruders entering their herds. In Lapland and pal1s of Russia, reindeer are used in the same manner that cattle (and horses to a lesser extent) are used in warmer climates. They can be milked and the meat eaten; they serve as pack and draft animals; they can be ridden; and their hides, bones, and hooves are used as raw materials. The domestication of reindeer may have occurred relati vely recently, however. This is suggested by the fact that the bones of domesticated reindeer are virtually identical to those of wild reindeer. The domesticated reindeer have not been bred over a long enough period to accumulate significant anatomical changes. The various uses for reindeer parallel those of domesticated cattle and horses, which is what would be expected if the latter were domesticated earlier. Indeed, some researchers suggest that the "domestication" of the reindeer is little beyond the stage of simply taming wild animals. For millennia bands of human hunters may have migrated with reindeer herds, taking individuals as necessary, and also helping to provide the herds with food (perhaps by scraping snow from vegetation during the winter).

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Figure 4.24. The endangered Pere David's deer, showing the peculiar?multipronged antlers and long tail. (From Whitehead, 1972). Eventually, rather than simply following the herds, humans may have begun to direct and control the movements of the herds, even driving them into corrals at times. From this stage of contact between humans and reindeer further taming and eventual domestication could easily develop. ABBE DAVID AND HIS DEER Perhaps one of the most elusive members of the deer family, Pere David's deer (Elaphurus davidianus) has never been known in the wild, but it has never been domesticated either (Fig. 4.24). For centuries the only living members of this strange deer lived in the huge Imperial Hunting Park, known as the Nan-Hai-Tze, south of Peking (modern Beijing), China. Until the end of the nineteenth century this park was surrounded by walls forty-five miles (72 km) long, guarded by Tartar soldiers-nobody, either Chinese or foreign, was allowed into the park, or even to look over the wall. This was the exclusive domain of the Imperial household. A French Catholic missionary priest and naturalist, Abbe Armand David, is credited with being the first Westerner to set eyes on what was within the park. It is said that while travelling in China in 1865, Abbe David bribed the guards of Nan-Hai-Tze and thus was allowed to scale the wall and have a look over the side. Presumably just at the moment that Abbe David looked over the wall, a herd of strange deer passed by within the enclosure. These deer were nothing like any that Abbe David was familiar with, and he was familiar with all of the types of deer then known from China. They were heavily built deer with long tails, broad hooves, big ears, and what seemed like antlers that were put on backwards. At first Abbe David thought that they might be a new species of reindeer. When he asked the

guards about it, he was told that the animal was called the sse-pu-hsiang which translated as "not a deer, not an ox, not a goat, and not a donkey" in reference to the animal's bizarre appearance. Abbe David was also told that the punishment for killing one of these remarkable animals was death. Abbe David was intrigued by this new animal, and made it known that he would like to obtain an example of the species. He persuaded the French embassy to officially ask the Chinese emperor and government for a specimen of the sse-pu-hsiang. In 1866 a couple of skins and three live specimens (which subsequently died on the way to France) were obtained by Abbe David and the French embassy, and were shipped back to Paris to be studied by the great zoologist Henri Milne-Edwards, who named the new species after Abbe David (Elaphurus davidianus). However, in his article Milne-Edwards incorrectly stated that the Chinese called this deer mi-lou (milu), a name actually used by the Chinese for the much better known sika deer (Cervus nippon) of China, Korea, Japan, Vietnam, Manchuria, and adjacent areas. Yet once the name mi-lou was applied to Pere David's deer in the western literature, it stuck. Once Pere David's deer was known to western science, many European diplomats requested live deer for their zoos. By the middle 1890s there were perhaps a dozen individuals of the species in various zoos in France, Germany, and Great Britain; in addition the Duke of Bedford was able to obtain specimens which he raised on his private estate at Woburn Abbey in Bedfordshire, England. At Woburn Abbey, the Duke revelled in his private collection of exotic animals. The specimens reached Europe just in the nick of time. In 1894-1895 disaster struck the deer population in China. The Hun-Ho River flooded and destroyed part of the wall that surrounded the Nan-Hai-Tze park, and a majority of the herd escaped. As the deer left the park, most were killed by hungry Chinese peasants. It is estimated that only some twenty to thirty Pere David's deer remained alive by the time order was restored. In 1900 the deer were again threatened. The Boxer Rebellion erupted in China, and an international coalition of European troops were sent to Peking to help control the situation. What exactly happened at Nan-Hai-Tze park is unclear-Chinese soldiers, Boxer rebels, Tartar guards, and the European troops have all been blamed for the tragedybut by the end of the conflict all that remained of the Pere David's deer herd was a sole female. She reportedly died of old age in 1920. Unfortunately, the specimens of Pere David's deer scattered throughout various European zoos did not do well, and slowly their numbers decreased. They did not breed adequately because individuals were dispersed among many different zoos, and no one zoo had an actual breeding herd-a necessity for properly producing healthy offspring. In fact the only place where an actively breeding population of Pere David's deer existed was on the private estates at Woburn Abbey. At the beginning of World War I almost

WHERE THE DEER AND THE ANTELOPE PLAY ninety deer lived at Woburn Abbey, while they were virtually extinct everywhere else. Even the Woburn herd almost perished. During World War I the Duke of Bedford could not obtain adequate food for his deer, and to make matters worse the British government used the estate's pastures to feed cattle. As a result many of Pere David's deer starved to death, and in 1920 the Woburn herd numbered only about fifty individuals. In the

85

last seventy years Pere David's deer have readily multiplied, increasing their numbers by at least an order of magnitude. From Woburn Abbey, living deer were sent to various zoological parks around the world, and in 1960 Pere David's deer from Woburn Abbey were reintroduced to China. If it had not been for Abbe David, and a private collector of exotic animals, the sse-pu-hsiang would be extinct.

Figure 5.1. The bison has long been a symbol of wildlife on the American plains. (Photo courtesy B. O'Gara.)

5. Hollow Horns

A WORLD OF BOVIDS "Perched on the lofty rim of Tanzania's Ngorongoro Crater to watch the ant-like movements of untold thousands of wildebeest milling about on the distant crater floor, is to me one of the unforgettable experiences of Africa. Here, captured in this vast amphitheatre like some gigantic fishbowl, one can see at a glance the character of wild Africa, with its antelopes-antelopes in countless numbers. Antelopes which once roamed all over this vast continent; through its woodlands, its plains, and even its deserts; in an exuberance of forms that have been with us for over fifteen million years. God may have had an inordinate fondness for beetles, as J.B.S. Haldane, one of England's great biologists once remarked, but luckily for us, when it came to Africa He was equally fond of antelopes. At least 74 species greet the eye, ranging in size from the 4 kg pygmy antelope to the giant eland weighing almost a tonne; and with some species reaching concentrations which make those of the American bison look impoverished by comparison. Who could fail to be captivated by this vast assemblage; their colours, their graceful forms and soft brown eyes, and above all, their striking horns, twisting and curling in a baroque extravaganza of shapes?" (Spinage, 1986: 1). The Bovidae are the most diverse and species-rich family of ungulates. Since most of our domestic animals (cattle, goats, sheep, yaks, and water buffalo) are bovids, they are also the most important mammals for human society (Fig. 5.1). There are approximately four dozen genera of living bovids, consisting of well over a hundred species: domesticated and wild cattle such as buffalo and bison, various forms of gazelles, antelopes, duikers, goats, and sheep. The Bovidae are primarily an Old World family found all over eastern Europe, Africa, and Asia, although they also occur naturally in North America (mountain goats, bighorn sheep, and bison). Because of man's influence, domestic bovids (especially cattle, sheep, and goats) roam every continent except Antarctica. Most living bovids are adapted to deserts, grasslands, and scrublands, although some inhabit such

diverse habitats as swamps, forests, and the arctic tundra. Despite their diversity, all bovids share a few features in common. Bovids are true ruminants with four-chambered stomachs, and most are grazers or browsers. Most living bovids have two horns (except the four-horned Tetracerus of India) composed of bony cores encased in hollow sheaths of horny material, keratin. The detailed internal structure of the horns distinguishes bovids from other types of ungulates. Among the bovids, however, there is considerable variation in the sizes and shapes of the horns. Like most ruminants, bovids have no upper front teeth (canines or incisors) on their skulls. Instead, they have a tough, horny pad against which their lower incisors bite. They use their rough tongues to pull grass and leaves into the mouth, and the lower incisors to shear it off at the base. Many bovids have highcrowned cheek teeth, typical of animals that live on gritty vegetation, especially grasses. Bovids have elongated limbs with the main foot bones fused into a single "cannon bone" and the lateral toes either reduced or absent. Some bovids can run very quickly, while others are very agile climbers and leapers. Most bovids tend to be gregarious, social animals that live in herds. Many have scent glands on their hooves that release chemical substances to the ground that other members of the same species can smell. An individual separated from its herd may find its way back to its compatriots by scent. A few bovids are either primarily solitary or Iive in small groups. In the early Miocene in Eurasia bovids began diversifying from cervoids and giraffoids. A number of poorly known early Miocene fossil teeth and jaws have been identified as bovids, but without the bony horn core, they could just as easily be cervoids or other types of primitive ruminants. By the late early Miocene, about 20 million years ago, there were undoubted primitive bovids in Africa and Eurasia. The best known of these was Eotragus, a small bovid about the size of a Thompson's gazelle (40 pounds, or 18 kg) with simple, straight horn cores about 3 inches (8 cm) long. Horns were found only in males; females were hornless. Eotragus was common during the middle Miocene in Europe, and it has also been reported from Africa. By 16 million years ago bovids are known from the Siwalik Hills of Pakistan, and they appear somewhat later in the middle Miocene in China. Living in woodland savannas, these early

HORNS, TUSKS, AND FLIPPERS

88

Antilopini Reduncini

Aepycerotini

Cephalophini Neotragini

Tragelaphini

Hippotragini

Figure 5.2. Relationships of the bovids (based on Vrba and Schaller, 2000). Note the differences between this classification and the others discussed in the text.

bovids were moderately diverse, with perhaps 15 different genera, mostly found in Asia and Africa. Among these middle Miocene genera was Gazella, the genus of the living gazelles. By the late Miocene, about 10 million years ago, bovids began an explosive evolutionary radiation, with over 70 new genera. This great diversification is clearly a response to the late Miocene climatic drying and expansion of grasslands and savannas, which led to a much greater diversity of habitats. As we have seen, the North American savanna saw a similar late Miocene diversification, except that there were no native bovids. Horses, camels, dromomerycids, and pronghorns acted in their stead. Bovids remained a tropical/subtropical group in Eurasia through most of the Miocene and Pliocene, just as cervids have dominated the temperate latitudes. When the ice sheets advanced during the Plio-Pleistocene a number of different kinds of bovids became adapted for cold climates as well. Today, yak, muskox, and many types of sheep and goats are tolerant of cold mountain peaks and tundra. Increased tolerance of cold climate also allowed bovids to cross the Bering land bridge during the Pleistocene and invade the New

World for the first time. Although only a few types of bovids reached this continent, they were very successful. Muskoxen dominated the Arctic tundra (along with caribou), and bison were the dominant ungulate on the Great Plains. Bighorn sheep and mountain goats are practically the only hoofed mammals that thrive in steep mountainous habitats. Bovids never reached South America before Europeans introduced domestic cattle and sheep, but bison did reach as far south as EI Salvador. With so many different species of bovids, we obviously cannot describe them in the same detail as the ungulates in the rest of this book. Instead, we will discuss the major groups of bovids in general terms, and concentrate on some of the better-known species. Currently, there are six major subfamilies (indicated by the -inae suffix, or "-ine" informally, and shown in bold face below) and 14 tribes (indicated by the -ini suffix, or "-in" informally, and shown in italics below) of the family Bovidae recognized by most specialists: 1. The Bovinae, which include the primitive Boselaphini (the four-horned antelope, and the nilgai, relicts

HOLLOW HORNS of the Miocene); the Tragelaphini, or Strepsicerotini, the spiral-homed antelopes (bongo, eland, kudu, nyala, sitatunga, bushbucks); and the familiar Bovini, the cattle, bison, and buffalo. 2. The Cephalophinae, or duikers, small, short-homed forms which live in dense jungles in tropical Africa. 3. The Hippotraginae, or grazing antelopes, including the aquatic Reduncini (reedbuck and waterbuck), and the horse-like antelope, or Hippotragini (oryx, addax, sable and roan antelopes). 4. The Alcelaphinae, including the gigantic herds of Alcephalini (wildebeest and hartebeest), and the leaping Aepycerotini (impalas). 5. The Antilopinae, or true antelopes, including the Antilopini (gazelles, blackbuck, springbok, gerenuk) and the Neotragini or dwarf antelopes (dik dik, klipspringer, Royal antelope, steenbok). 6. The Caprinae, or goat-like forms, including the Saigini, with their inflated nostrils; the mountain-dwelling Rupricaprini (chamois, mountain goat, serow, goral); the Ovibovini, or muskoxen and takins; and the Caprini, or true goat tribe (sheep, goats, and the ibex). Although the fossil record is excellent for most of these groups, there is no consensus as to how they are interrelated. Wildebeest and impalas are usually placed together, but most specialists are noncommittal about a family tree which ties all six subfamilies together. This seems surprising, since most of these groups can be traced back to the late Miocene. However, the fossils of these animals consist mostly of teeth, horn cores, or isolated limb elements, and these features tend to be highly stereotyped into characteristic subfamilies and tribes early in their history. Jonathan Kingdon published his version of bovid phylogeny in his multi-volumed East African Mammals. He sees a major division between the Bovinae and the rest of the family early in the Miocene, with the major bovine radiation in Eurasia, and the rest concentrated initially in Africa. According to Kingdon, the Eurasian bovines were suited to cooler, moister habitats characteristic of temperate regions, whereas Africa was colonized by small antelopes, which were physiologically superior in the drier African habitats. Bovines, for example, appear to sweat to cool their bodies by evaporation, while the others do it by panting. Kingdon places the cephalophines, neotragins, and reduncins in one group descended from a dwarf antelope ancestor, and the antilopins, alcelaphines, hippotragins, and caprines in another group descended from an antilopin ancestor, with both groups splitting off during the middle Miocene. In 2000, Elisabeth Vrba and George Schaller published another phylogeny of the ruminants, based largely on behavioral characteristics (Fig. 5.2). Sable antelopes and wildebeests were grouped together in a larger group that included the caprines, while the impalas and antilopins were grouped with the reduncines. The cephalophines form yet a third group, and the bovines form the other major group of ruminants. In addition to the formal zoological classification of

89 bovids, there is also an ecological classification based on their choice of habitat and mating strategy. This system was first introduced by Peter Jarman in 1974 and discussed in the previous chapter. It is very useful in noticing the similarities between unrelated ruminants. As extended by Christine Janis in 1982, the categories are as follows: Category A: tiny ruminants that live singly or in pairs in the deep forest; they selectively forage non-fibrous leaves and fruits over a wide area, so they do not defend a restricted territory; there is little difference between sexes, so they either have simple cranial appendages, or large canines instead. These include tragulids, musk deer, water deer, muntjacs, certain cervids such as the pudu, huemal, and brocket deer discussed in the previous chapters, and a variety of bovids, including all the duikers and dwarf antelopes. The extinct gelocids, leptomerycids and hypertragulids were probably also Category A, as were the early Eocene ancestors of almost all perissodactyls and artiodactyls, including the dichobunid "bunny deer," and the earliest horses and tapirs. Category B: slightly larger (above 33-44 pounds, or 15-20 kg body weight) closed-canopy woodland browsers; males patrol a small territory of choice bushes, so they may have spectacular horns; females are hornless; small polygamous herds are guarded by a single dominant male. These include some tragelaphins (lesser kudu, bushbuck, sitatunga), some antelopins (gerenuk), most reduncins (reedbuck, reebok, waterbuck), and most cervids. According to Janis, the extinct dromomerycid "pseudo-deer" of North America were probably also in this category, as were the extinct protoceratids with their bizarre slingshot horns, the tiny twohomed rhinoceros Menoceras, the oreodonts, and the browsing three-toed horses. Category C: medium-sized to larger (average about 190 pounds, or 85 kg) open-canopy woodland browsers and grazers, in which males hold territories part of the year, but form mixed herds the rest of the year. Males are slightly larger than females, with more elaborate horns. These include impalas and most antilopins (gazelles, springbok), some tragelaphins (greater kudu, nyala), and some reduncins (some waterbuck, puku, lechwe). Besides bovids, this category may include pronghorns, guanacos and vicunas, most extinct giraffes and camels, and most rhinos and tapirs. Category D: larger grazing antelopes (average about 330 pounds, or 150 kg) which roam over open grasslands; males defend a small territory only during the breeding season, and there is no difference in males or females in either size or horns. Among bovids, most alcelaphins (wildebeest and hartebeest) fall in this category. According to Janis, grazing forms among the horses (including zebras and most equines), deer (caribou and reindeer), rhinos, and camels also fall in this category. Category E: the largest homed ruminants (average about 880 pounds, or 400 kg) which have no territories, but feed over open grasslands; the males are much larger in size than females, with larger horns, and fight among themselves

HORNS, TUSKS, AND FLIPPERS 90 for dominance of the herd. These include the grazing bovins about 1-1.5 inches (2.5-4 cm) tall, and rear pair that may be (Cape buffalo, bison, eland) and some hippotragins (oryx, 3-4 inches (8-10 cm) long. Four-horned antelopes tend to be relatively solitary creatures (thought to be an evolutionarily gemsbok). Notice that these categories are purely ecological, rather primitive feature) whereas among the larger nilgai (head and than taxonomic. Category A, for example, includes families body length on the order of 2 meters), the females and their from all over the Ruminantia: Tragulidae, Moschidae, four calves often congregate in herds. In the wild bovins (members of the Bovini) occur in groups of cervids, and two tribes of bovids. Clearly, a given niche can be occupied by animals of different descent when North America and Mexico, Africa, Europe, Asia, and the the opportunity presents itself. In addition, Jarman's classi- islands of the Philippines and Indonesia. (Domesticated fication was originally worked out mostly for savanna and forms have been introduced to South America, Australia, woodland habitats. Obviously, it is less relevant to other and New Zealand as well). The typical bovin is a relatively large, stout beast bearing horns on its skull (although hornhabitats, such as mountain peaks or swamps. less breeds of cattle have been developed). Some bovins, such as the bison, can reach shoulder heights of 6 feet (2 m) BOVINES The quintessential bovids are the domestic and wild cat- or more, and a number of bovins can reach maximum tle and their close relatives, classified as the subfamily weights in excess of 2200 pounds (1,000 kg). The bovins Bovinae. Since we depend on their beef, milk, manure, and probably originated as warm temperate creatures of the leather, bovines are the most familar ungulate for most of us. Eurasian plains. While most cattle, wild or domestic, are At present there are well over a billion, and perhaps closer fairly tolerant of cold weather, a few forms (such as the yak to 1.5 billion, domestic head of cattle on Earth (as compared and bison) have become adapted to harshly cold climates. In to the 2001 human population of approximately 6.2 billion). the tropics most bovins di vide their time between eating and The living members of this subfamily are conventionally attempting to stay cool-for instance by wallowing in mud grouped into three tribes: the primitive Boselaphini, the spi- or water, and concentrating much of their activity at night. Bovins tend to congregate in herds centered,on females ral-horned Tragelaphini (or Strepsicerotini), and the Bovini. The Bovini include the various forms of wild and domesti- and their young. Depending on the species, such herds may cated cattle proper (the "true cattle") of the genus Bos, the number from less than a dozen individuals to hundreds of water buffaloes of the genus Bubalus, the African buffalo of animals or even more (such as the enormous bison herds that the genus Syncerus, and the European wisent and American once roamed the plains of North America). Such herding behavior serves, at least in pat1, as a defense against predabison (sometimes called "buffaloes") of the genus Bison. The Boselaphini currently consists of only two species, tors. The genus Bos includes not only the domestic cattle the four-horned antelope (Tetraceras quadricorfJis, also known as the chousinghas or the guntada), and the nilgai (Bos taurus) and their ancestor, the aurochs (Bos primige(Boselaphus tragocamelus). Both from India, they are living nius), but also the shaggy Himalayan yak (Bos grunniens) relicts of the animals which evolved into the true cattle and three rare species of cattle in southeast Asia. The Indian (Bovini). The four-horned antelope is a moderate-sized ani- gaur (Bos gaurus), resembling a large black bull, is the mal (with a head and body length of about a meter) distin- largest of bovids, weighing over a ton (900 kg) and reaching guished by two pairs of short, conical horns on the skulls of six feet (2 m) at the shoulder. It once frequented the upland adult males-a pair of horns in the front that are usually bamboo forests and glades of India, Burma, and southeast

Figure 5.3. The water buffalo, Bubalus bubalis , the main beast of burden in Southeast Asia. (Photo by D.R. Prothero).

Figure 5.4. The Cape buffalo, Syncerus caffer, has a distinctive "helmet" of horn over its forehead. (Photo courtesy A. Walker).

91 HOLLOW HORNS Although the deadliness of Cape buffalo has certainly been exaggerated, they are still the major source of death among humans, surpassing even the lion. However, in the protection of game reserves, Cape buffalo spend their daylight hours grazing the savanna and blissfully wallowing in water holes. Even when their excellent senses pick up humans, they ignore them. Only after repeated persecution by hunters do they become wary and aggressive, fighting for their lives. Most of the time, however, they hide from humans, and if the hunter misses, they usually retreat. A close relative of the Cape buffalo is the extinct giant ox, Pelorovis, which flourished in East Africa during the Ice Ages. This immense beast had horn cores which curved forward in front of the head in a great arc, and spanned 13 feet (4 m); with the keratin sheaths, its horns may have spanned 17 feet (5 m)! Peloravis has been found in Olduvai Gorge, where some of the earliest human remains are also found, and Louis Leakey even discovered shattered Peloravis leg bones among the stone tools in Olduvai Bed II. Presumably our ancestors butchered the beast and took the leg bones home to get at the marrow. Figure 5.5. The eland, Taurotragus derbianus, is the The final subgroup of living bovines are the spirallargest of all antelopes, weighing as much as a ton; it horned antelopes, Tribe Tragelaphini (or Strepsicerotini). is more closely related to cattle than it is to other Just as the relatively primitive Boselaphini are believed to antelopes. (Photo by D. R. Prothero). be representative of the ancestral stock of the true cattle, so too they are believed to be representative of the ancestral stock of the African Tragelaphini. Thus these three groups, Asia. The banteng (Bos javanicus) looks more like a lightcolored Jersey cow, and is endangered in the jungles of the true cattle, the four-horned antelope and nilgai, and the Indonesia and Malaysia. The kouprey (Bos sauveli) hid in nine species of spiral-horned antelopes are united in the sinthe deep forests of Cambodia and Laos until 1937 when a gle subfamily Bovinae. The spiral-horned antelopes include the elands (genus specimen was sent to a zoo in Paris. It looks like a large brown ox with a long tail, and the horns of the bulls burst Taurotragus) and the bongo, bushbuck, kudu, nyala, and open at the tips, exposing the black core. Fewer than 200 of sitatunga (genus Tragelaphus), among other species. These animals tend to be more slender and graceful than the true these endangered cattle survive in the wild. cattle, with long faces and beautiful spiraled, often More typical of Asia are the true buffalo, genus Bubalus. The water buffalo, Bubalus bubalis, with its huge corkscrew-shaped horns. In social organization they tend to arc of horns, is the most familiar form because of its domesbe nonterritorial (unlike the Boselaphini) and generally gretication (Fig. 5.3). There are also two endangered species of garious, but tend to congregate in somewhat smaller groups than do the true cattle. Spiral-horn antelope species have anoas, or dwarf water buffaloes. The lowland anoa (Bubalus become adapted to all of the major habitats found in Africa depressicornis) lives in the coastal swamps of northern Celebes in Indonesia. The mountain anoa (Bubalus quarsouth of the Sahara Desert. lesi) is restricted to the mountain slopes of Celebes. The The largest of all the antelopes is the eland (Fig. 5.5), which reaches 6 feet (2 m) at the shoulder and may weigh a tamarau, or Philippine pygmy buffalo (Bubalus mindorensis), is a small but aggressi ve nocturnal ox found only in the ton (990 kg). Although it has straight horns with a tightly bamboo forests and marshes on the Philippine island of spiraled surface, its heavy, bull-like neck and ox-like size Mindoro. Little is known of its biology and it is extremely remind one more of cattle. Yet it has the speed, grace, and agility typical of antelopes, not cows. Their light tan coat is endangered. crossed by vertical white stripes. Elands are remarkably Wild African cattle are represented by the Cape buffadocile, and yet have never been domesticated, despite the lo, Syncerus caffer (Fig. 5.4). It is distinguished by the fact that they provide excellent milk and meat and are much broad horns which form a boss over the head, and may span over three feet. This beast is infamous among hunters for hardier in the harsh African savanna climate than domestic fighting back more fiercely than any other wild animal of cattle. Kudus are slightly smaller, with horns that make a Africa, including lions and leopards. Legends and stories recount the anger of the wounded Cape buffalo goring and broad corkscrew spiral reaching 60 inches (150 cm) in length, and a long fringe of fur at the throat (Fig. 5.6A). trampling hunters, sneaking up on them for revenge, or even Bushbucks and nyalas are solitary animals which live in attacking unprovoked.

HORNS, TUSKS, AND FLIPPERS

B

Figure 5.6. A. A male greater kudu, Tragelaphus strepsiceros, shown atop a mound guarding its territory. (Photo courtesy C. Janis). 8. The beautifully striped bongo. (Photo by D.R. Prothero).

deep forest. They are about 3 feet (1 m) at the shoulder, with dark brown fur covered with white stripes and spots. Their horns are only about 18 inches (45 cm) in length, and go through a single spiral. Sitatungas are very similar, except that they are beautifully adapted for living in marshy habitats. They have banana-shaped hooves over 7 inches (18 cm) long which prevent them from sinking into the mud, but make them awkward runners. One of the most beautiful of the tragelaphins is the bongo (Fig. 5.6B). Despite the fact that it is over 4 feet (1.2 m) at the shoulder, with a rich chestnut coat broken by white stripes, this animal is so elusive that it is rarely seen by humans in the wild. AUROCHS AND WISENT Before recorded history there lived in Europe, north of the Alps, two ferocious animals commonly known as the aurochs (plural, aurochsen) or urus (Bos primigenius, the ancestor of common domestic cattle), and the wisent, wysent, or European bison (Bison bonasus). Both of these species survived into historical times, but the former is now extinct and the latter has only just been saved from extermination by the intervention of concerned zoologists. Across the Atlantic in North America an estimated 40 to 60 million head of the mighty American bison (commonly called the "American buffalo," but technically Bison bison) once roamed the continent. In the nineteenth century these beasts were destroyed almost to the last individual. Again, we are indebted to the extraordinary efforts of a few concerned individuals for the preservation of this species in recent times. Julius Caesar wrote in his Commentaries on his wars in Gaul (mid first century B.C.) that the aurochs resembled a

bull, but was nearly as big as an elephant, extremely strong and swift (Fig. 5.7). These animals were said to be hunted by the natives via the use of pits in which they could be trapped and then slain. While the slain animals were eaten, and the thick hides used for various purposes such as the covering of shields, the horns in particular were highly valued. Caesar reported that hollow' aurochs horns were edged with silver along their bases and used as drinking vessels at feasts. During the late Pleistocene and into the early Holocene the aurochs was in fact a very common species throughout the Old World Northern Hemisphere. The wild aurochsen tended to look very similar to modern domesticated common cattle-their descendants-but were larger (males reached six and a half feet, or 2 m, at the shoulder), and were presumably fierce, temperamental beasts. The coats were often black or brownish red, with a lighter line down the back, and sometimes a large saddle of lighter hair on their back. Aurochsen were hunted during the Stone Age and right up into historical times. As human populations increased, and "civilization" spread, the size of aurochsen populations steadily decreased and became more and more restricted in range. During the Middle Ages the aurochsen were being rapidly driven to extinction, especially by the destruction of the dense forests in which they had taken refuge. Their populations were progressively restricted. In sixth century France they were already extremely rare, and by the fourteenth and fifteenth centuries they were confined to a few protected forests in Central Europe. Successive monarchs (such as the princes of Masovia in Poland) prohibited the general hunting of aurochsen; that privilege would be reserved for royalty.

93 By the sixteenth century living aurochsen were restricted to the forest of Jaktorovka in Masovia, near Warsaw, Poland. There they Ii ved in a protected reservation, provided with hay in the winter by the local villagers. Royal officers took periodic censuses of the aurochsen, and these numbers record the sad decline and eventual extinction of this magnificent species in grim detail. In 1557 there were approximately fifty aurochsen, in 1562 the number had declined to thirty-eight, and by 1599 there were only two dozen aurochsen known to be alive, despite the numerous decrees issued in an attempt to save the species. Two years later, in 1601, a plague killed twenty of the aurochsen, so that only four remained (three bulls and one cow). In 1630 the officer in charge of the preserve could find no living aurochsen, and he was told that the last individual (a female) had died three years earlier. Thus the year 1627 marks the extinction of the aurochsen. Even before the aurochs was actually extinct, it had become a beast of legend and a source of confusion. This was in large part because another large wild bovin, the wisent or European bison, also inhabited Europe. From early times some travellers, writers, and reporters confused the two types of beasts. In 1837 the Polish paleontologist Georg Gottlieb Pusch even tried to prove that the aurochsen, or the urus, had never existed. The core of his proof was that the Polish name for the aurochs, tur, and the Polish word for the wisent, zubr, were etymologically derived from the same source-thus there was only one animal (the European wisent) which had engendered legends of the mythical aurochsen. It is clear now, however, that the aurochs and the wisent were two distinct animals. The European wisent is a shaggy-furred relative of the American bison or "buffalo." The two types of beasts not only look remarkably similar, but in fact are very closely related. Indeed, the wisent and American buffalo will readily interbreed producing fully fertile offspring, and for this reason some zoologists consider them to be simply different subspecies of a single species. In fact, many of the species, and even genera, of Bovini are very closely related and can interbreed to a greater or lesser extent. In some cases hybrids can be produced between parents of different species, but these hybrid offspring may be sterile. Just as the European and American bisons can interbreed fully, so can common European domestic cattle, Bos taurus, and Indian humped cattle or zebu, Bos indicus, and some zoologists accordingly classify these two species as one. The American buffalo has been crossed with domestic cattle, producing the so-called "catalo." Like the aurochs, the wisent was once abundant in the forests of Europe. Caesar also wrote of the wisent in his Commentaries. From physical appearance the wisent seemed more wild and ferocious than the aurochs, though in fact the opposite was true. After all, the aurochs looked like an overgrown domestic cow while the wisent was nothing like any beast seen before. During the height of the Roman empire wisent and aurochs bulls were brought to Italy for

Figure 5.lA. Reconstruction of the extinct European aurochs, or urus, as drawn by Hamilton Smith. (Neg. no. 316032, courtesy Department of Library Services, American Museum of Natural History). B. The wisent (Photo by D.R. Prothero). use in gladiatorial combats. As civilization advanced and forest area diminished, wild wisents were confined to ever more restricted areas. In the seventeenth century they were still fairly numerous, but by the next century they were greatly reduced in numbers. The last pockets of wild wisents were in Prussia, Hungary, along the Polish-Russian border (in the forest of Bialowiecza, or Byelovyeh), and in the Caucasus. By 1755 wisents were extinct in Prussia, and by 1800 there were no more left in Hungary. In the early nineteenth century the Bialowiecza Forest was under Russian control, protected from tree felling and hunting by anyone other than the czars themselves and their privileged family and friends. In 1830 there were close to 800 wisents in the forest, and by mid-century about 1500, but by the beginning of World War I the number had dropped again to approximately 750. The primary reason for the decline in the wisent population, despite its protected status, was that other game animals were introduced into the forest and competed with the wisents. An overabundance of red deer, which the czar and his associates hunted, was apparently destroying the forest vegetation upon which the wisents fed. With the outbreak of World War I in August of 1914, the wisents of Bialowiecza were immediately put in danger. The next year the battlefront moved through the forest, and

94

HORNS, TUSKS, AND FLIPPERS

in September of 1915 it was captured by the Germans after heavy fighting and severe losses on both sides. Of the 770 wisents that are recorded in the park on the eve of the battle, 650 were killed. German zoologists were as concerned about protecting the wisents as had been the Russian czar, and they immediately pressured the German High Command to take actions to protect the wisents. The population of wisents increased during the next few years under German protection, until they numbered 185 when the Germans withdrew in November 1918. Unprotected, the wisents were killed by peasants and soldiers, both for their hides and their meat. The new Polish government issued orders protecting the wisents, but still they continued to be poached until the last survivor was shot by a former Russian forester, one Bartmoleus Szpakowicz, on 19 February 1921. The other herd of wild wisents that survi ved into the twentieth century was located in the Caucasus Mountains. This herd was virtually unknown to western scientists before the middle of the nineteenth century, although in fact it had first been discovered during a scientific expedition to the Caucasus during 176~ to 1773. The story goes that after one of the many Polish insurrections of the middle 1800s against their Russian overlords, a Caucasian lieutenant fighting alongside the Russian soldiers visited the museum in Lublin (Poland) and saw a specimen of a wisent from the forest of Bialowiecza. He mentioned to museum officials that he was familar with similar beasts from his native land, and the reports from the previous century were confirmed. A herd of perhaps a thousand wisents lived in the Caucasus region. Unfortunately the Caucasian herd fared no better than the Polish herd. Most of the beasts were wiped out by military machine-gun hunts during the period 1918-1919, and the last known wild Caucasian wisent was reported to have been killed in 1926. By the 1920s all known wild wisents had been exterminated. But were all wisents exterminated? There were a few small captive herds at the beginning of the century, notably at Tachina (Tashina) Park near St. Petersburg, at Minsk, and a small herd on the Crimea. But all of these Russian animals were killed during the Russian Civil War, most either by Cossacks or the Red Army. At Mezerzitz, on prope11ies split between Poland and Germany, the Prince of Pless had a herd of some fifty-five or fifty-six wisents that had originated from four animals donated by Czar Alexander II in 1869. But this herd too largely succumbed to the political turmoil of the times. When it was all over, only three animals survived, all with machine gun bullets in their bodies. Fortunately a few dozen wisents still survived in capti vity in various zoological parks and preserves, such as England, in the Budapest zoo and forest park, and in Swedish preserves. Planned breeding was can ied out, and by 1939 there were about ninety-four purebreed European wisents (along with some animals that had mixed wisentAmerican bison blood). Then World War II broke out and their numbers again suffered. In the next couple of decades, however, the breeding programs rapidly progressed and the 4

wisent numbers multiplied. Herds have now been reintroduced into the Bialowiecza Forest, the Caucasus, and other parts of the former U.S.S.R. After a very close call, it seems that we can optimistically say that the European wisent has been saved from extinction. WHERE THE BUFFALO ROAM The story of the decline and subsequent resurrection of the North American bison, the American "buffalo," is perhaps even more dramatic than that of the European wisent. It has been estimated that only a few centuries ago some 40 to 60 million bison (Bison bison) roamed through North America. Two subspecies inhabited the continent. The more numerous plains bison lived mainly east of the Sierra Nevadas and inhabited most of what is now the United States, except for the Great Lakes area, New England, and parts of the southern East Coast (Figs. 5.1, 5.8A, B). The plains bison extended north into Manitoba, Saskatchewan, and eastern Alberta (Canada). The woodland, wood, or mountain bison (of the same species, but generally considered a distinct subspecies from the plains bison) inhabited the Rocky Mountain region in Alberta and even further north. Bison first crossed the Bering land bridge to\America in the middle Pleistocene, about 500,000 years ago. Here they radiated into a number of different forms, adapted for the full spectrum of climates in North America. Perhaps the most spectacular was the giant bison, Bison latifrons, found from Mexico and Florida to Alberta during the last interglacial. Its huge horns spanned over almost 7 feet (200 cm wide), compared to 2 feet (65 cm) for modem bison (Fig. 5.8C)! The giant bison became extinct at the end of the last Ice Age, but the ancestral Bison priscus probably evolved into modern Bison bison before the beginning of the Holocene, about 10,000 years ago. For thousands of years these animals flourished, but due to American efficiency in their slaughter, they were all but extinct by the end of the nineteenth century (Fig. 5.9). Europeans and European descendants were not the only people to hunt the bison en masse. Bison were probably hunted from the arrival of the first humans on the American continent. Certain Native-American (Amerindian) tribes survived almost exclusively by hunting the bison, often utilizing the entire carcass of the animal for everything from food to fuel to shelter to tools. Indeed, in the midst of continuing hostilities with the indigenous cultures, the principal motive for the white man's destruction of the bison herds during the nineteenth century was to starve the Indians into submission. In 1869 General Phil Sheridan declared that, "Every buffalo dead is an Indian gone." In 1875 he said, "Those buffalo hunters have done more in a few months to bring about peace with the Indians than the whole Army could do in thirty years!" At any rate, buffalo hunting was certainly not confined to those of European extraction. There is a site in southeastern Colorado, dating from about 6500 B.C., where Paleo-

HOLLOW HORNS

95

Figure 5.8. A. A herd of American bison (Bison bison); note the distinctive shaggy hump and beard in the adults, and numerous calves. B. Two bison bulls battling for supremacy over the herd. (Both photos courtesy B. O'Gara.) C. A paleontologist measures the hornspan of the giant Ice Age species Bison latifrons. The total span would be even larger if the length of the horn sheaths is added to the bony horn cores. (Courtesy University of Nebraska State Museum).

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HORNS, TUSKS, AND FLIPPERS

A

B

Figure 5.9. A. Native American warriors hunting bison with their traditional bow-and-arrow methods, as recorded by George Catlin in the 1830s. B. When the railroads came, shooting stampeding bison from the train became a popular "sport" which decimated the herds in just a few years. (Both images courtesy Library of Congress). Indians drove a herd of close to two hundred bison to their death over the edge of a gorge. Unlike proper, ecologicallyminded "noble" savages, these Paleo-Indians removed only a portion of the meat from the animals they killed, and left the rest to rot. In historical times the North American Indians were known to hunt down bison in huge numbers. After the Spaniards introduced horses to the continent in the sixteenth century, the Plains Indians took up hunting bison with bow and arrow from horseback. Subsequently, the Indians adopted firearms which increased the kill. As late as the autumn of 1883, when the bison was virtually extinct, Sitting Bull and his comrades took about two months to decimate a herd of about ten thousand in North Dakota. Despite these abuses by the aboriginal peoples of the continent, the major blame for the near extinction of the North American bison must lie on the heads of the white men. The first European sighting of an American bison was, of all places, in a private zoo in Mexico. In 1521, upon reaching the Aztec capital, Hernando Cortez found a "rare Mexican bull" in King Montezuma's personal menagerie. It was almost another decade before a European laid eyes on a wild American bison. As the continent was settled, the bison quickly declined. The first major impact was along the east coast, so that by about 1800 the bison was extinct east of the Mississippi River. Elsewhere in North America, as late as the 1860s, bison were extremely abundant. On the plains dense herds of bison were described as being on the order of twenty-five miles (40 km) in breadth and some fifty miles (80 km) long, and the animals were so closely spaced that "the whole country was covered with what appeared to be a monstrous moving brown blanket" (letter from Col. C. Goodnight to Martin S. Garretson describing a herd in the early 1860s). In 1871 Col. R.I. Dodge watched a herd pass through the valley of the Arkansas River. It took several days to pass, and may have included four million animals.

Yet in less than 20 years-from 1865 to 1884-over sixty million bison were wiped out. The introduction of the railroad to the West provided an easy means of transportation for professional hunters to reach the herds, and a method to ship bison products back East. In the late 1860s the first transcontinental railway divided the Plains bison into two major "herds": a southern herd and a northern herd. It is reported that in 1871 five thousand professional buffalo hunters left from Kansas City to begin the slaughter of the bison in earnest. The professional hunters were joined by perhaps an equal number of amateur hunters. Hundreds of thousands, then millions of bison fell to the hunters. Carcasses were left to rot on the plains. Settlers complained of the stench. By 1875 only a few percent of the original bison population in the southern herd were left, and both Kansas and Colorado passed laws attempting to protect the bison. Still, a hundred thousand more bison, almost all that remained of the southern herd, were killed during the winter of 1877-1878, and at most a few hundred animals remained. These few surviving animals made their way to Texas, but by 1889 they too had been shot-and so ended the southern herd. Between 1881 and 1883 there was a massive attack on the less numerous northern herd. While white man and Indian fought each other, both waged war on the bison. Many bison were slaughtered in the area of Yellowstone National Park, and as mentioned above, Sitting Bull and his people did their part to reduce the bison population. By 1884 the northern herd that had inhabited United States territory was virtually wiped out. Conditions were no better in Canada. By 1885 the wood or forest bison of Canada was almost extinct in the wild. Why were the bison hunted so heavily? Although in many cases most of the bison carCass was wasted, virtually all of the animal could be put to a useful purpose, as the American Indian knew. Some hunters went after the meat in

HOLLOW HORNS 97 particular, for which there was a considerable market. A Roosevelt) quickly acted to increase bison population nummeat hunter often took only the tongue and the choice cuts bers. Reservations were established for the bison, and they of the hindquarters and the hump ribs-the rest was left to were provided with shelter and fodder. Results were rot. Others went after the hides which could be shipped back achieved quickly, since under favorable natural conditions and made into good leather that might go into numerous the typical bison cow will bear a new calf each year. In 1910 products, from machinery belts to shoes, saddles, or hol- there were over 2,100 bison in North America, and by the sters. There were fur traders that sought "buffalo robes" to 1930s there were over 20,000. Today ranchers keep herds be used as overcoats and wraps. Buffalo fat could be used in throughout the continental United States, from Florida to the manufacture of soap and candles, and buffalo horns were New York, to Texas, Wyoming, and California, and there are used in hat racks. sizable herds in government reservations such as Many bison were killed for pure sport which, it was Yellowstone Park and the Wood Buffalo Park in Alberta, claimed, could become highly addictive. Chasing and shoot- Canada. Buffalo meat is actually quite popular in some parts ing bison from horseback was considered great fun by some of the west, and bison are much easier to ranch, since they persons. Plinking expeditions were arranged where interest- are hardier than domestic cattle. ed parties could test their shooting skill, and have a bit of A sad footnote to the otherwise· happy story is the fact adventure, by slaughtering wild bison from a railway car. that the wood or forest bison no longer exists as a distinct Besides, it was thought to be in the best interests of the subspecies. The last remaining herd of pure forest bison United States to destroy bison and devastate the Native inhabited the Wood Buffalo Park, but unfortunately in the American populations. They depended on the bison for their 1920s plains bison were introduced to the same park. livelihood but were the enemy at that time. Naturally the two subspecies mixed and hybridized, so the Even after the bison were gone, these beasts still made rarer forest bison ceased to exist as a purebred form. a direct impact on the homesteaders of the prairies. In many areas the grounds were literally covered with scattered bison CATTLE CALL bones. The bones were collected and burnt as fuel, and they The modem domestic cattle are among the most versawere also shipped back East by the train load. These bones tile animals used by humans, and consequently they have could be ground up and used as fertilizers; they were used in been important to many societies for thousands of years. sugar refining (to neutralize acids produced during the refin- Modern Europeans and Americans tend to consider domesing process); the hoofs and horns were used in the manufac- tic cattle primarily as providers of various food stuffsture of glue. Well into the twentieth century bison bones milk, cream, and their derivatives such as butter and cheese, were being shipped to the East for commercial use. and meat-and to a lesser extent providers of leather. In According to one estimate more than 175 million bison large areas of central Africa and in eastern and southeastern skeletons may have been commercially processed-several Asia, however, there is no tradition of milking cows and times the estimated number that ever roamed the continent ingesting dairy products, and it is common for people to sufat anyone time. How could this be possible? The dry air of fer from lactose intolerance. Rather, in much of the world the plains could preserve bison skeletons for decades, so it cattle are viewed primarily as draft animals. Cows and oxen is feasible that this many skeletons accumulated before the (usually the castrated males) pull plows, turn threshing bone hunters came in earnest. mills, draw carts, and perform other heavy labor. The The demise of the North American bison occurred in a manure is used on the farm to replenish the soil, or it may be flash, and only after the fact did the Canadian and United burned as a fuel, or even used as a building material. Old and States governments intercede to try to halt the destruction. feeble animals are killed for their meat and the raw materiCanada passed legislation to protect the bison in 1885, while als they provide: horns, bones, and hide can be used to manthe United States did not move to protect the bison until as ufacture various goods; hooves are traditionally used for the late as 1899. By the 1890s there were only two groups of manufacture of gelatin and glue; and the fat may be used to bison remaining in North America: a mixed lot of plains and produce tallow that can be used in lighting devices, as a forest and wood bison in Canada, ,and a small herd of plains lubricant, or to make soap. bison in Yellowstone Park. At the close of the nineteenth The earliest unequivocal evidence of the domestication century William T. Hornaday, director of the New York of the aurochs-which would eventually lead to all of the Zoological Park, made a census of all known living North various European breeds of cattle, and possibly the Indian American bison. He found that there were just under 1,100 humped cattle or zebu-comes from 7000 B.C. in archeobison alive scattered among the "wild" herds in Canada and logical sites in Turkey. The other domesticated cattle of Yellowstone, those kept in zoos, and a few maintained on Asia-the yak, the water buffalo, the mithan, and Bali catprivate ranches. In 1905 Hornaday founded the American tle-arose from wild progenitors other than the aurochsen. Bison Society, the primary goal of which was to save the From Paleolithic rock paintings found in Europe, we American bison from extinction. know that our Pleistocene forebears hunted the wild The American Bison Society, with the support of some aurochsen. But as Juliet Clutton-Brock has pointed out, it is people in high places (such as President Theodore really very difficult to imagine how or why early humans

HORNS, TUSKS, AND FLIPPERS 98 switched from hunting these beasts to eventually domesti- to note that at present humped cattle are becoming increascating them. After all, the wild aurochs was a large, fierce ingly popular with certain groups of American farmers. beast that would be difficult to capture alive and also diffi- Driving through the Carolinas, for instance, one may cult to constrain once captured. Even if young calves were observe both European and Indian cattle, along with hybrid captured, tamed, and raised by humans they would probably forms, grazing in the fields. Theoretically if European domestic cattle, Bas taurus, mature to fierce adults. Early domesticated cattle could also prove something of a nuisance for early farmers. Cattle are the direct descendants of the aurochs, Bas primigenius, would tend to destroy crops if not properly fenced and then a common genetic heritage is shared between the two secured, and penned groups, perhaps composed of a large forms. For this reason, some scientists do not recognize the proportion of calves, might attract large and troublesome extinct aurochs as a separate species from European domespredators (such as big cats and wolves) to early human habi- tic cattle. Perhaps all the genes, that in the right combination tations. Cattle would also have to be kept away from human made an aurochs, are still carried within living domestic cattle-but simply diffused throughout the different breeds. water supplies which they might otherwise foul. Clutton-Brock also questions what captive aurochsen Looking at modern breeds of cattle, some have large horns would be used for. Even if a cow were tamed, she suggests shaped like those of aurochsen. Some have the size and genthat it would be very unlikely that one could milk it. Even eral build of aurochsen. Some have the coloration patterns of today it takes considerable effort to milk a "primitive" breed aurochsen, and so on. The reason aurochsen per se are conof domesticated cow that has not been explicitly bred for sidered "extinct" is because there is no longer a single breed milk production-the cow must be extremely relaxed, the of cattle that carries the full combination of aurochsen charpotential milker must be familiar to the cow, her calf must acteristics. But if we could select out the aurochsen characoften be present, and 'it may be necessary to stimulate her teristics from various domestic breeds and combine these genital area in order to induce the secretion of milk. characteristics into a single breed, then effectively the At the ancient site of Catal Hliylik, in present-day aurochs would be resurrected-or at least so the Heck brothTurkey, there is a famous shrine composed of Bas primige- ers reasoned. nius horn cores dating to approximately 6000 B.C. Perhaps The zoologists Lutz and Heinz Hecht, of the Berlin and the earliest semi-domesticated cattle were kept primarily for Munich Zoos respectively, had the idea of reconstituting ritualistic purposes, being sacrificed as needed. Subse- aurochsen in the 1920s, and each tested the idea starting quently they may have been used as a ready source of fresh from different breeds of domestic cattle. Amazingly, by meat "on the hoof' as well as for other materials, as men- crossing different breeds with supposed aurochsen traits, tioned above. Over the generations, increasingly tame ani- and artificially selecting the offspring for further breeding, mals could be harnessed and put to work. As aurochsen were both brothers (independently of each other) were able to penned and bred in captivity, it may have been found that the produce a strain of cattle that bred true and looked remarksmaller animals were easier to handle and thus selected by ably like the extinct aurochsen. Before their final extinction humans for further breeding. This is confirmed by the fact true aurochsen had been observed and described several that there was a dramatic decrease in the size of cattle as times, and a remarkable oil painting of an aurochs, apparthey became domesticated during Neolithic times. By the ently done from life by an anonymous Polish artist of the fourth and third millennia B.C. fully domesticated and dis- late sixteenth or early seventeenth century, was discovered tinct breeds of cattle had been developed in Egypt and by the English zoologist Hamilton Smith in a used bookstore Mesopotamia. These civilizations milked their cows, mark- while visiting Germany in 1827. So zoologists have a pretty ing the earliest evidence for the consistent use of dairy prod- good idea of what a living aurochs should look like, and the ucts. Heck brothers' creations certainly did look like aurochsen. The domestic humped or Indian zebu cattle (variously Furthermore, it is reported that these newly bred aurochsen referred to as Bas indicus or Bas taurus indicus) are gener- not only resembled the extinct forms in external appearance, ally thought to have been domesticated separately from but they also took on the personality attributed to the ancient European cattle. They may have originated either in India or aurochsen. They were fierce, shy of humans, and somewhat in southwestern Asia, and their ancestor is thought to have temperamental. Some of these beasts were even allowed to been the Indian aurochs (variously referred to as Bas primi- run wild in the Bialowiecza Forest, just as the true aurochsen genius namadicus or simply Bas namadicus). Zebu cattle once had. appear as early as 3000 B.C. on cylinder seals of ancient While not everyone even agrees that the effort expendIndus Valley civilizations such as Mohenjo-Daro and ed on attempting to "reconstitute" the aurochsen was worthHarappa, although their origin may be older still. Within the while, and virtually no one would claim that true aurochsen general category of "zebu cattle" there are a number of have been "brought back to life," ce11ainly the Heck brothbreeds found throughout the world today. In ancient times ers performed a fascinating experiment. Perhaps their work zebu cattle were introduced to Africa from India or the foreshadows the proposed (but still in the very early stages Middle East, and they were particularly popular in Egypt of development) reconstitution of extinct species by bioduring New Kingdom times (ca. 1500 B.C.). It is interesting medical cloning of preserved tissue fragments (such as those

HOLLOW HORNS

Figure 5.10. A blue duiker (Cephalophus monticolaJ, showing the typical coloration and short horns. (Photo by D. R. Prothero). of woolly mammoths and woolly rhinos recovered from the far North), or (perhaps even farther in the future) by biochemical engineering involving the manipulation of "ancient" or "ancestral" genes still found in the DNA of living organisms. DIVING BUCKS In Afrikaans they are called duikers (pronounced "dikers") which translates to "divers" or "diving bucks." These generally small, shy, agile antelopes are named after their habit of darting or diving quickly into dense vegetation if disturbed. Duikers have relatively short fore-legs, an arched back, longer hind-legs, a large brain-size to body-size ratio relati ve to other antelopes, and a short pair of unbranched spike horns that project backwards from the skull (Fig. 5.10). They are typical Category A ruminants not only in lacking large horns, but in their ecology as well. Distinct from all other bovids, duikers have been relegated to their own subfamily, the Cephalophinae. Within the family seventeen species are recognized, the sixteen species of the forest duikers (genus Cephalophus) and the common, bush, or savanna duiker (Sylvicapra grimmia). Duikers are found throughout Africa south of the Sahara. While there are no genuinely large duikers, among the species of duikers there is a considerable range in body size. The shoulder height of adults can range from about 14-25 inches (35-67 cm), the length of the head and body ranges from slightly over half a meter to almost a meter and a half, the tail length is in the range of 2.8-7 inches (7-18 cm), and the adult weights of various species can be anywhere from 9-175 pounds (4-80 kg). There is also considerable variation in the pelage. Some duikers are light buff or tan (almost white), while others range through various shades of yellow, orange, brown and reddish brown to almost black. Many

99 species have a stripe down the middle of the back, and the zebra duiker has dark ve11ical zebra-like stripes along its back against an orange coat. Duikers also vary in the habitats they prefer, some Ii ving in the dense forests (species of Cephalophus) while others live among the scattered trees and brush or on the open savanna (primarily Sylvicapra). At least some species of duiker are apparently primarily nocturnal. Their diets are quite varied. Like other Category A ruminants, they browse on high-quality foods such as leaves, shoots, fruits, buds, seeds, and bark, but unlike most ungulates they will also occasionally eat insects and carrion, and are even reported to kill and eat birds and rodents. Relatively little is known about the social habits and general natural history of duikers in the wild. They are usually observed alone or in pairs, and some species may be monogamous and mate for life. They appear to hold and defend small (on the order of 2 to 4 hectares), stable territories, and will show marked aggression toward other members of their species. Duikers have scent glands under their eyes, the secretions from which they apparently use to mark their territories; some species will even press the glands against other individuals so as to mark each other. Such mutual marking may occur between mates, or between male rivals before active fighting breaks out. F.W. Fitzsimons describes Cape duikers as: "solitary by habit, but a pair may be seen now and then together. I have on many occasions surprised several browsing in company in the forest glades during the early evening. Occasionally these duikers venture forth and nibble the young crops in cultivated fields in close proximity to their brushy homes. They do not venture abroad by day except just after sunrise and before sunset. During rainy weather, or when the sky is very overcast, they sometimes are seen on the move. Their food consists of tender shoots, leaves, wild berries, and fruit. This duiker is never found in dry districts where there is no permanent supply of water. It rests during the day in a cosy lair in the midst of a mass of dense, tangled, or creeper-covered scrub, and when startled, makes rapid rushes through the bush, meanwhile emitting a peculiar sniffling sound. Its cry, which is not often uttered, is a sharp whistle, but when caught by dogs or wounded and overtaken, its cry of terror is deep and rough, quite unlike the shrill, terrified scream of the Cape duiker. The chief enemy of the duiker is the python snake, which levies a heavy toll upon it. The python lies in ambush for it along a branch overhanging one of its beaten tracks through the forest, or hidden in the scrub on the ground. This crafty snake often submerges itself in the water at one of

HORNS, TUSKS, AND FLIPPERS mon is neck fighting (as we have seen in camelids), where they use their necks to pin down their opponent's head, and try to throw him off balance. Sometimes, they also try to bite their opponents, especially in the front legs. According to Valerius Geist, these are the primitive fighting positions for bovids, and when they began to develop longer, sharper horns, these strategies became too dangerous. Consequently, most horned antelopes fight head-to-head, so that their weapons are not directed at the vulnerable flanks, but at their foe's strongest point. There are three variations on this headto-head style of contest. The most common is a pushing or Whereas duikers are not generally sought by "sports- wrestling match, where the opponents try to capture their men," since they do not possess the large horns that are rival's head between their horns, and they lock together in a often prized in head trophies, they are taken by native sub- test of strength. This is seen in many kinds of antelopes, sistence hunters. They are said to be relatively easy to catch from elands to gazelles. The second variation is ramming, at night using bright lights that blind or dazzle them, or by where the opponents run together and clash at the base of driving them into nets, and their meat is popular among the their horns (which are enlarged and thickened to take the indigenous peoples. The rarest species of duiker, Jentink's blows). This is particularly common among sheep and goats. duiker (Cephalophus jentinki) of Liberia and the West Ivory Ibexes, on the other hand, rise up on their hind legs for fightCoast lowlands, is considered officially endangered, where- ing. The third kind of fighting is fencing, where the horns as the zebra duiker (Cephalophus zebra) is considered vul- meet in the center of the shaft, and the antelopes use their nerable in the wild. As of 1986 only nine and twelve, respec- horns like dueling sabers to deliver and ward off blows. tively, of these animals were reported alive in zoos (World Fencers tend to have long, spear-like horns, often bent backResources 1990-91), but there have been successful captive ward like a saber. Sable antelopes kneel down on, their front legs and fence in a stooped position. births of both species. Antelopes try to avoid inflicting wounds with their sharp horns, and have many other ritualized behaviors that "BRIGHT EYES" The Greeks first referred to a semi-mythical creature establish rank without dangerous conflict. Most antelopes that lived along the banks of the Euphrates as antholops, or show a "submissive" posture, with the head down, when "bright eyes." Sometimes combined with the legendary uni- they wish to avoid conflict, or raise their head and horns to corn, this myth probably had its origin in the Arabian oryx, maximum height when they challenge. In the greater kudu, which looked one-horned in profile. So struck were the the males use ritualized "neck-fighting" to push down the Greeks and Romans by· their large eyes that they referred to head of the female as a prelude to courtship. Several the gazelles as dorcas, from the Greek for "I see clearly." antelopes "kick" with their foreleg, often in an exaggerated The word "gazelle" itself comes from the Arabic ghazal, slow-motion manner, against the female's hind legs. This is which also means "bright eyed." Indeed, the large eyes pro- used as a ritualized courtship gesture, but it evolved from a trude from the skull, and give the animal an almost complete fighting method. In many courtship rituals, the males then view of its surroundings without moving its head. For most "hide" their horns by raising their noses high, presumably to antelopes, which live in open terrain and must see danger "assure" the females that they will not use their horns to coming, such large eyes are essential. harm them. Although antelopes must have horns for defense and Bullfighters take advantage of these instinctive rituals fighting rivals, their great variety of shapes are not con- to kill the bull when it is vulnerable. When the bullfighter strained by these basic functions. In fact, studies have shown steps aside, he refuses to take part in the head-to-head conthat most antelopes do not even use their horns against pred- test, and thus violates the bull's "fighting ethic." When he ators; most flee and rarely turn at bay. As we have seen in kneels down in front of the bull, the audience mistakenly deer, the details of the shape-whether spiraled, or S- applauds his courage. In fact, this kneeling is a submissive shaped, or hooked, or branched, as well as all the ornamen- posture which reduces the bull's aggression, and when he tal rings, bulges and ridges-are primarily for species recog- jumps up and stabs the bull, he has an unfair advantage. nition, and for advertising the age and status of an individ- Although bullfighting has long been deplored as a sadistic ual (especially dominant males). Yet even here, battles spectacle, it is even more abominable because the bullfightbetween rival males do not involve active stabbing with the er unfairly exploits the bull's instincts for a "fair fight." True antelopes (not including pronghorns) are comhorns, but ritualized fighting. The simplest of these behaviors is pushing body-to- monly classified in one of three subfamilies: the Antilobody, seen in hornless females, as well as the hornless bose- pinae, or gazelles and dwarf antelopes; the Hippotraginae, or laphines. Rivals stand parallel to each other, head-to-rump, grazing antelopes; and the Alcelaphinae, or wildebeest and and push and shove until the rival is off balance. Also com- impalas. These three groups make up a major radiation of 100

the favorite drinking places of this handsome little antelope, its nostrils alone being above water. When the unsuspecting buck is drinking, the snake seizes its nose or one of its forelegs with its jaws, which are armed with sharp recurved teeth, and with lightning rapidity its coils are around its victim. The leopard, serval, and ratel also prey upon this antelope. Eagles occasionally succeed in pouncing upon them in the early mornings (Fitzsimons, 1920: 35-36)."

101

Figure 5.11. The waterbuck (Kobus ellipsiprymnus), a typical water-loving reduncin. (Photo courtesy C. Janis). bovids that presently covers Africa and extends into Arabia and Sinai (in the form of the Arabian oryx, Oryx leucoryx). These groups trace their origins back at least six million years ago, to the late Miocene. Today there are 16 species of hippotragines, 10 species of alcelaphines, and over 30 species of antilopines, and dozens of recognized subspecies and varieties of each. The hippotragines are divided into two tribes: the Reduncini (reedbucks, waterbucks, and related species), and the Hippotragini (the horse-like antelopes, which include the oryxes and addax). The Reduncini consists primarily of the reedbucks (genus Redunca) and the waterbuck, kob, and lechwe (genus Kobus). In the reduncins only the males have horns, and the animals tend to inhabit the wetlands, tall grassland, woods, and savannas near lakes and rivers. The various reedbucks tend to be relatively small and graceful animals, often with a shoulder height somewhat under a meter and weighing around 110 pounds (50 kg). Waterbucks (Fig. 5.11), kobs, and lechwes tend to be larger; they may have a shoulder height of up to 4.3 feet (1.3 m), and may weigh up to 550 pounds (250 kg). The horns are considerably longer in Kobus, but in both genera they are heavy and ridged. Reduncins are territorial, with the dominant males holding and defending the same piece of property for several years. They will sometimes congregate into small herds of females and young, or bachelor males that lack territory. Sometimes included as a member of the Reduncini is the vaal (or gray) rhebok. The name rhebok (also spelled Reebok, source of the name for the athletic shoes) comes from the Afrikaans for the European roe-buck, or roe-deer. However, this species is markedly different from all other antelopes and is perhaps best classified as the sole species of a distinct, unnamed tribe. The vaal rhebok (Pelea capreolus) is a small antelope (shoulder height about 28 inches, or 70 em, weight about 46 pounds, or 21 kg) that inhabits rocky

Figure 5.12. A. The sable antelope. (From the IM31 Master Photo Collection). B. Like many hippotragins, the Arabian oryx (Oryx leucoryx), showing the typical horse-like body and long straight horns which in this side view could have led to the unicorn myth. (Photo by D. R. Prothero). areas, mountainsides, and high plateaus in South Africa. The males have short (8-10 inches, or 20-25 em long), vertical horns-the females are hornless-which they use very aggressively. During the rutting season male vaal rheboks may fight to the death, and it is reported that sometimes they will attack and kill goats and sheep. Outside of the rutting season the rheboks form small groups, usually of related animals, or small herds of a few dozen individuals. The Hippotragini are the horse-like antelopes that inhabit the open grasslands, savannas, and relatively dry countryside of Africa and Arabia. These are the roan (horse) and sable antelopes (genus Hippotragus) (Figs. 5.2, 5.12A), the oryxes (Fig. 5.12B) and gemsbok (genus Oryx), and the addax (Addax nasomaculatus). As their common name implies, members of this tribe somewhat resemble horses

102

HORNS, TUSKS, AND FLIPPERS

B

Figure 5.13. Typical examples of the Alcelaphini. A. A female topi (Oamaliscus lunatus) guarding her young calf. B. A herd of wildebeest, or gnu (Connochaetes gnou), the most abundant antelope of the African savanna. (Both photos by D. R. Prothero). (they even bear manes), but from the skulls of both males and females grow long, ridged horns that are either straight or scimitar-shaped (Oryx), curved dramatically backwards (Hippotragus), or spirally twisted (Addax). Shoulder height of hippotragins ranges from about 3-7 feet (1-2.2 m), and adult males of some species can weigh up to 620 pounds (280 kg). In coloration, members of the tribe can range from white with a "wig" of chestnut hair in the addax, through colorations of gray, black, and white, through reddish browns and jet blacks covering almost the entire upper body (with the underbody and belly typically being white or at least lighter in color). Although both males and females have horns, the males are larger in body size. Male sable antelopes are deep black, but the female is brown with a black mane; both have white faces. Hippotragins have tight, hierarchically dominated social structures and typically form herds of no more than a couple of dozen individuals led by a dominant male. Oryxes, addaxes and gemsboks, in particular, are adapted to the very dry, desert conditions of the Sahara or the Kalahari. Here temperatures reach 118-122°F (48-50°C) in the daytime and freezing at night, the wind and dust blow constantly, and rain may not fall for years. They feed on whatever vegetation they can find, and it is said that they can go for much of their lives without drinking water (they derive all their moisture requirements from the food they eat). The desert hippotragins have white coats for camouflage, and to reflect the sunlight, and broad hooves to avoid sinking into the sand. They can walk for hours on end to find food, covering 20 miles (32 km) in one night. Most of their daylight hours are spent sleeping or chewing their cud. They are small enough that they can creep into the shade of acacia bushes, excavating a scraped area to put their bodies against the cool sand underneath. This also reduces their surface area exposed to the hot dry winds. They "fine-tune" their heat regulation by timing their movements to take

advantage of breezes, and seeking shade earlier on hot days. Their barren environment means that their herds are small (10-20 individuals or less), and must spread out over a wide area to get adequate fodder. To minimize conflicts,'they have a strict hierarchy of dominance from the alpha male on down, so they spend much less energy defending turf or their herd. Like many large African mammals, the hippotragins have been seriously threatened by humans. Most of the Ii ving populations are at critically low levels. The scimitarhorned oryx is extinct north of the Sahara, and along with the addax, it is in danger of total extinction. Oryx horns were once particularly prized because of their legendary status as "unicorn" horns (even though oryxes are artiodactyIs, not horses, and have two horns, not one in the middle of their forehead). Most of these antelopes were only hunted by nomads on camels seeking trophies, so they thrived until the advent of motorized hunting and automatic weapons in 1945. The last wild Arabian oryxes were lost in 1972, although luckily this species has survived from captive animals which have since been culti vated into herds. Operation Oryx managed to build the captive populations up to the point that they were reintroduced to Oman in 1982. Unfortunately such actions did not save the bluebuck of the Cape Province (Hippotragus leucophaeus), known from historical accounts and mounted specimens. By the end of the eighteenth century, the bluebuck was exterminated due to the pressure of expanding human populations. The Alcelaphinae includes the various types of hartebeest (genus Alcelaphus), the hirola (Beatragus hunteri, sometimes called a Hunter's hartebeest), the wildebeest or gnu (genus Connochaetes), and the topi and bontebok (genus Damaliscus) (Fig. 5.13). Typically the size of medium or large reduncins, alcelaphins differ from members of the former tribe in that both males and females bear horns, the shoulders tend to be a bit higher than the hindquarters,

HOLLOW HORNS the face is slightly elongated, and the females are typically slightly smaller than the males of the same species. Alcelaphins are typically grazers and inhabit primarily open woodland and adjacent moist grasslands. Males are seasonally territorial, although this trait is expressed to different degrees depending on the species. Male topis may hold a territory, apparently continuously, for several years whereas some gnus may hold small, temporary territories during the rutting season only-and then these territories may. be held for only a matter of hours. Wildebeest are legendary for forming herds of hundreds to thousands across the grasslands. In the Serengeti, these herds move in response to rains and the grasses they bring. From January to May, the wildebeest are out on the open plains, mixed with herds of plains zebras, topi, Cape buffalo, and Thomson's gazelles. Buffalo and zebra consume the tough tops and stems of grasses, clearing these away so that wildebeest and topi can eat the tender leaves nearer the ground. Thomson's gazelles then eat the broadleaved herbs and forbs that are revealed by the other grazers. By the end of May, the short grasses and waterholes have dried up, and almost a million animals move about 150 miles (240 km) to the northwest to seek permanent water in the river beds of the Serengeti. These migrations once staggered hunters like Theodore Roosevelt, who enthused that he had seen "a Pleistocene day." During this migration they may cross swollen rivers, and many are drowned by the panic of stampeding animals trying to cross. After mon~hs of enduring the biting flies of the wooded areas near the flvers, the wildebeest become restless again. The second rainy season occurs in November, triggering a migration back to the short-grass plains. Here the females drop their calves, who must be able to stand up and run within seven minutes after birth. Their migrations do not always cycle this precisely, especially if the rains are not on schedule. However, they are almost continuously on the move, and seem to travel well over 1000 miles (1600 km) in a typical year. When they stop to feed, males hold territories of about 130 square yards. In the center of his territory, the male reigns in his bare patch known as a "stamping ground," where he rolls in the dust and marks his turf with urine, feces, and scent from his preorbital and hoof glands. When other males get too near, the territory-holder and intruder go through a long display ritual, challenging each other, urinating and sniffing the scent with their upper lips rais~d. in Flehmen, and standing side-to-side with their heads snIffIng the opponent's rump and marking him with their facial scent glands. They also drop to their front knees and face each other. These rituals allow the males to determine the opponent's hormonal levels, sexual status, and maturity without fighting. Wildebeest males may even displace aggression to the ground, but they seldom fight for any extended length ~f time. Although wildebeest seldom fight each other, they wIll charge at predators-but they usually stop short, since they are fundamentally timid. More often, they flee the lions, hunting dogs, and hyaenas which depend upon them for

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Figure 5.14. Only male impalas (Aepyceros melampus) have horns. Impalas are found in thick brush, which they leap with ease. (Photo courtesy A. Walker). their primary sustenance. However, wildebeest are so numerous that they continue to thrive in spite of predation; in fact, the predators cull the weak and aged from the herd, as well as hold down population growth by picking off the young. Because of their similar diets, the alcelaphins are seen as competitors for the same foods and resources as domestic cattle. Accordingly, they are hated by cattle ranchers. As the domestic cattle populations have burgeoned the antelope populations have contracted. A number of subspecies of antelopes belonging to the Alcelaphini have become rare and endangered, and at least one subspecies (the bubal or Northern hartebeest) is already extinct. Sometimes included within the Alcelaphini, but now more commonly relegated to its own closely-related tribe (the Aepycerotini) is the impala (Aepyceros melampus) of central and southern Africa (Fig. 5.14). Impalas stand one meter at the shoulder, and weigh in the range of 143-165 pounds (65-75 kg). Prominent horns are borne by the males only, and are shaped like a long, graceful lyre. In color the upper part of the body is fawn or reddish, the legs, thighs, and underbelly are whitish, and there are distinctive black vertical stripes on the sides of the thighs (seen from behind) and the tails. Impalas, similar to alcelaphins, inhabit open woodlands and savannas, grazing and browsing on grass and leaves of various bushes and shrubs. Especially during the dry season, impalas associate in large herds of a hundred or so individuals, mostly females and their young. These herds subsequently split into smaller groups of one or two dozen animals led by a dominant male. Impalas are known for the huge jumps that they can make; it is reported that they can take leaps nine meters (30 feet) in length, and they routinely jump over one another. Fitzsimons reports three successive bounds of 26, 16, and 28 feet, for a total of 70 feet (8, 5, and 8.5 m for a total of 21.5 m); in another case, an impala cleared an 8-foot (2.4 -

HORNS, TUSKS, AND FLIPPERS

B

Figure 5.15. The dwarf antelopes, or neotragins, include: A. Tiny Kirk's dik-dik (Madoqua kirki) defecating to mark a territorial boundary; B. The steenbuck (Raphicerus campestris) lowering its head in threat gesture; C. The klipspringer (Oreotragus oreotragus) lives among the rocks in its habitat. (Photos A and B courtesy C. Janis; photo C by D.R. Prothero.)

a

m) fence, and then jumped on the roof of a shed 9 feet (2.7 m) high. Given a clean run, impalas will clear a 12-foot fence easily. Impalas are also known for their speed. When they run, the black-and-white-striped rump and tail, and the black spots on the hind heels flash, alerting the rest of their herd, and allowing them to follow each other more easily. Elisabeth Vrba has used the evolution of alcelaphins and impalas to demonstrate some interesting evolutionary principles. Alcelaphins are quite diverse, with at least 32 different species in the last five million years. They show a wide variety of hom shapes, from simple spikes to backward curves, to the broad upcurved horns typical of wildebeest and the backward-curved S-shapes of hartebeest. By contrast, impalas have only one lineage (sometimes split into three species) for the same five million years, all with the same gently S-shaped horns. Vrba points out that alcelaphins are specialized grazers, whereas impalas are generalists, feeding on a variety of vegetation in the transition zone between grasslands and woodlands. During the

last five million years, Africa has seen tremendous vegetational changes in response to climatic changes associated with the Ice Ages. Not surprisingly, specialists such as the alcelaphins are vulnerable to extinction when their narrow niches disappear, but generalists such as the impala can always find something suitable to eat, no matter how climate changes. The contrasts between the patterns of evolution in alcelaphins and impalas furnishes a good example of how two closely related groups of animals respond differently to the same evolutionary stresses. Because of their ecological narrowness, alcelaphins respond by forming new species, or by going extinct. Evolutionary trends are accomplished by a succession of rapidly evol ved new species occupying changing niches. Impalas, on the other hand, have such a broad niche that stabilizing selection prevails, and they change very little. Either way, there is no predetermined "direction" built into evolution. Instead, long-term trends in specialization are simply an "effect" of evolution of new species in response to environmental change, or by "species selection" among the many competing species, weeding out those which are less adapted to unanticipated environmental stresses. The dwarf antelopes (Tribe Neotragini) and gazelles (Tribe Antilopini) together compose the subfamily of bovids known as the Antilopinae. Dwarf antelopes inhabit a variety of environments on the African continent, from the open grassy plains through the dense forests to rocky and moun-

HOLLOW HORNS tainous areas. There are about a dozen living species of dwarf antelopes, classified into six genera. Better known forms include the various dik-diks (genus Madoqua) (Fig. 5.15A). The name dik-dik is an onomatopoeic version of the call these animals make when startled and in flight. There are also the Royal and pygmy antelopes, and suni (genus Neotragus), the klipspringer (Oreotragus oreotragus), the steenbuck (Fig. 5.15B) and grysbucks (genus Raphicerus), and the oribi (Ourebia ourebia). As their common name implies, all dwarf antelopes tend to be small. Like the duikers and many other tiny forest ruminants we have seen, most neotragins are classic Category A ungulates. The smallest of the dwarf antelopes (indeed, the smallest of all living homed ungulates) is the poorly known Royal antelope (Neotragus pygmaeus) of western Africa (Sierra Leone, Liberia, the Ivory Coast, and Ghana). The Royal antelope stands only 10-12 inches (25 30 cm) tall at the shoulder, and weighs just 3-7 pounds (1.53 kg). Its diminutive pair of straight horns are only a couple of centimeters tall. The largest member of the tribe is the oribi of eastern southern Africa, which has a head and body length of about 3-4.6 feet (1-1.4 m), may stand 20-28 inches (50-70 cm) at the shoulder, and can weigh from 31-46 pounds (14 - 21 kg). Dwarf antelopes are unusual in that the females are often somewhat larger than the males (the reverse being the case in most ungulates). This is probably the case because the living dwarf antelopes are descendants of larger species (among which presumably the males and females were either subequal in size, or the males somewhat larger). As dwarf antelope species got smaller, perhaps in response to the decreasing extent of the African forest cover (which is their primary habitat) over the last ten to twelve million years, there has been a lower limit on how small females can be and still easily handle the strains of bearing young. Also in many species of neotragins the males bond for life with one or a few females, and therefore they are not subject to intrasexual selection for large size as are male ungulates that routinely fight with each other over the control of females. Because of their generally small size (which means that food passes relatively quickly through the gut, and in addition smaller mammals are characterized by higher metabolic rates), dwarf antelopes tend to feed on a diet that is of high quality and low in fiber, such as fruit, buds, young leaves, and tender new grass. Only the oribi, the largest of the dwarf antelopes, can afford to graze. In order to feed from the scattered patches of high quality food, the typical dwarf antelope comes to know its local habitat very well. Furthermore, it excludes potential competitors by defending its resources, so dwarf antelopes are territorial. Dwarf antelopes are well endowed with scent glands that they use to mark their territories. Of particular importance are the preorbital glands Gust in front of the eyes), the secretions of which are rubbed onto stems and branches, as well as on females by males, to mark a particular dwarf antelope's property. Glands on the hooves mark the ground

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along major dwarf antelope paths. Dwarf antelopes also deposit their feces and urine at particular spots, probably helping to further mark their territories and send a message to potential intruders. One of the most amazing dwarf antelopes is the klipspringer (Fig. 5.15C), whose name means "rock jumper" in Afrikaans. These tiny antelopes live exclusively on rocky outcrops, except when drought dries up their small drinking pools and forces them to migrate. Their peculiar habit of rock jumping is described by F.W. Fitzsimons in The Natural History of South Africa: "When surprised at the foot of their rocky fastnesses they, with elevated head, bound off with the most astonishing daring and agility, leaping like animated rubber balls from boulder to boulder, and from one pinnacle of rock to another. Poising with all four hoofs on a point of rock an inch to two square, this wonderful little animal launches itself into space to a similar point of rock. Balancing for an instant on a projection of rock on the very edge of a vast crevass, the nimble little creature bounds off from ledge to ledge and.point to point in a manner impossible to describe. That an animal with hard cloven hoofs is able to traverse these precipitous hills, abounding in chasms into which the slightest slip of foot would launch them, is almost beyond belief. In agility and surefootedness amongst the rocky fastnesses which are their home, they equal the famous chamois of Switzerland. The hoofs of the klipspringer are nearly rectangular in shape, with a narrow sole, and are on a line with the legs, making them excellently adapted for balancing the body on points of rock. Klipspringers, during the heat of the day, seek the shade afforded by rock crevices, or the cool shade of some deep cavern, or the bush which invariably grows at the foot of their rocky, elevated homes. When disturbed in these situations, they instantly spring off and away up the hillside. Their strength, vitality and energy is astonishing, for, without any apparent effort, a klipspringer will bound up the face of a hill covered with smooth, slippery rocks, and so steep that no animal other than a baboon could possibly find a foothold. The latter animal has hands and feet specially adapted for gripping the smallest projection of rock, but the klipspringer has no such aids, which makes its performance amongst the crags and crevasses so marvellous" (Fitzsimons, 1920: 46-48). Some dwarf antelopes have elongated snouts, most pronounced in certain species of dik-diks where an actual small tapir-like proboscis is developed. The large snouts may be simultaneously an adaptation for cooling, or for increased

HORNS, TUSKS, AND FLIPPERS

Figure 5.16. The gazelles, or antilopins, include: A. Thomson's gazelle (Gazella thomsoni), the commonest small gazelle of the African savanna; B. the gerenuk (Litocranius walleri), shown in its characteristic pose stretching for high vegetation. (Photos courtesy A. Walker).

sensitivity of smell, or for selectively feeding on only certain parts of plants. The gazelles (Tribe Antilopini) range throughout Africa and into the Arabian peninsula, Palestine, the Middle East, and through the Indian subcontinent into Tibet, China, Mongolia, and Inner Mongolia (Fig. 5.16). There are about 18 species, including such forms as the various species of gazelles proper of Africa and the Middle East (genus Gazella), the gerenuk (Litocranius walleri), the dibatag

(Ammodorcas clarkei), the springbok (Antidorcas marsupiaUs), the Tibetan, Mongolian, and Przewalski's (Chinese) gazelles (of the genus Procapra), and the Indian blackbuck (Antilope cervicapra). Gazelles tend to have slender bodies, long \lecks, and long legs, and unlike their fellow dwarf antelopes, the males are on average larger than the females. The horns are often S-shaped and ringed, and (again in contrast to the dwarf antelopes) in most species females as well as males bear horns, although the horns are shorter and thinner in females. Various species of gazelles range in shoulder height from about half a meter to just over one meter, and they can range in weight from about 66 pounds (30 kg) to over 180 pounds (80 kg). With the exception of the Indian blackbuck (which is black with a white belly and highlights), gazelles are shades of brown with lighter underparts, and some species have a prominent horizontal stripe or band of a darker color on each side (for example, in the springbuck). Gazelles have white rump fur with black tips on the tails, and sometimes other dark spots. Gazelles are also characterized by the gait they adopt when alarmed-they bounce on straight, stiffkneed limbs, landing on all four feet simultaneously. This is known as pronking or stotting, and it is thought to possibly serve several functions: it may give the animal a better view of potential danger, since it raises the animal relatively high in the air; it apparently communicates concern or alarm to other gazelles; and it may even intimidate or confuse a potential predator. Gazelles tend to feed on a mixture of vegetational types, browsing on virtually anything that is green. Certain species of gazelles, such as Thomson's gazelle (Gazella thomsoni) are primarily grazers, feeding almost exclusively on grasses. Other species take in mostly young shoots and leaves (Fig. 5.16A). The most unusual of the gazelles is the gerenuk (Fig. 5.16B), which browses on the tops of bushes using its long slender neck, and by rearing up on its hind legs. As we mentioned in the previous chapter, this kind of

HOLLOW HORNS

Figure 5.17. Springboks (Antidorcas marsupia/is) showing their characteristic "pranking" gait. (After Millais, 1895). feeding behavior may have also occurred in certain extinct camels and giraffoids. Dominant males are territorial, particularly during the breeding season. Similar to dwarf antelope behavior, gazelles mark their territories with gland secretions (they too bear preorbital glands) and piles of dung and urine. Territorial males will joust and fight over females and resources, placing their heads near the ground, interlocking horns, and twisting and pushing one another. Nonbreeding males (bachelors) that lack territories will associate together in groups, as will groups of females and their young offspring. Outside of the breeding season gazelles may associate in mixed sex and age groups. Pronking is peculiar to the springbok, which gets its name from this odd behavior (Fig. 5.17). When springbok pronk, they raise a crest of white fur along their spines, flashing white to inform the herd of danger. Then, as they race away, the crest folds down and disappears underneath black hairs. This maneuver is so characteristic of them that young springbok practice it in play when they are only a few days old. At one time springbok were phenomenally abundant in southern Africa, and held great migrations that outnumbered even the Serengeti herds. Four great springbok treks occurred in the Karoo District of the Cape Province between 1887 and 1896, and as described by T.B. Davie, they were literally overwhelming. "When the trek was in full move nothing but springbok were to be seen for miles upon miles at a stretch. The whole country seemed to move, not in any hurry or rush, as is generally associated in people's minds with a springbok, but a steady plodding walk march, just like locusts; no other animal or insect life can afford so apt an illustration. The writer has seen them in one continuous stream, on the road and on both sides of the road, to the skyline, from the town

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ofPrieska to Draghoender, a distance of 47 miles, plodding on, just moving aside far enough to avoid the wheels of the cart. On this occasion, the owners of the farm Witvlei were all sitting in a ring round the top of the well, which at that time was uncovered, the father, son and son-in-law armed with rifles, firing a shot now and then, and the women folk with sticks and stones trying to keep the 'boks' away. This was the family's only water supply left, as the 'boks'had already filled up the dam, thousands being trampled to death in the mud as they pressed on over one another to get to the water. At last the 'boks' beat the farmers, and got to the well and in a few minutes it was full of dead and dying 'boks.' However, the trek passed before evening with the exception of a few stragglers and the Witvlei people soon had their well cleaned out and rendered serviceable. In the course of a few days the trek seemed to melt away. They disappear, nobody knows where they have gone to" (Cronwright-Schreiner, 1925). The cause of these great springbok treks is unknown, and their herds are now too small to ever do it again. Perhaps they occurred when unusually wet years in South Africa led to a population explosion, and when dry times returned, the springboks were forced to migrate and seek new grasses. During their peak, the migrations covered about 100 miles (160 km) a day, a moving avalanche that carried along cattle, sheep, lions and even people until they were exhausted and trampled to death. Some treks moved westward right into the sea like lemmings. On one occasion along the Namaqualand coast near the mouth of the Orange River, millions of springbok drowned and their bodies formed a wall that extended 30 miles (48 km) down the coast! Unfortunately, human activity continues to reduce gazelle populations in the wild such that currently several species are considered to be endangered. Outright hunting, increasing cultivation of land which destroys the natural habitat, limited access to fresh water, and competition with domestic bovids (such as cattle and especially sheep and goats) all threaten the wild gazelles. MOUNTAIN MONARCHS The final subfamily of bovids is the Caprinae, which includes the goats, sheep, musk ox, and many other goatlike animals. Most caprines are adapted for living in mountains and steep terrain, and are rather stocky in build, with thick fur coats. They all have thick, curved horns that are suitable for ramming and wrestling. Some, like the ibex, have long arcuate horns, and others, like the bighorn sheep, have spectacular spiral "ram's horns." Although caprines are known from the middle Miocene of Africa, they flourished primarily in the mountainous regions of Eurasia. Tossunoria, from the middle Miocene of China, shows fea-

108

HORNS, TUSKS, AND FLIPPERS

Figure 5.18. Saiga antelope (Saiga tatarica) , with its characteristic bulbous nose. (Photo by D. R. Prothero). tures that are primitive for all caprines, including the short, slightly recurved horns. Their greatest success has been during the last 2 million;years of the Ice Ages, when glaciers and cold climates favored the cold-adapted caprines. From a primitive goat-like animal, they radiated into a variety of body forms and habitats all over Eurasia. Caprines are proverbial for being able not only to exist, but flourish, in the harshest of conditions. Most remained denizens of cold mountains, but some (such as the muskox) became adapted for the cold, flat tundra; others became adapted for desert mountains. In addition, they spread to North America, where we now have bighorn sheep, mountain goats, and the muskox. Twenty-six species in four tribes of Caprines are generally recognized. They include the Saigini, or big-nosed saiga "antelope;" the Rupicaprini, or chamois and mountain goat; the Ovibovini, or musk ox and takin; and the true goats and sheep, or Caprini. The tribe Saigini, sometimes classified with the Antilopinae (gazelles and dwarf antelopes), is typically associated with the Caprinae. Saigini include the chiru, or Tibetan antelope (Pantholops hodgsoni) and the saiga (Saiga tatarica). Chirus inhabit the Tibetan high plateau, and somewhat resemble a moderately large gazelle (they stand about 31 inches, or 80 cm at the shoulder and weigh 90-110 pounds, or 40-50 kg). They are perhaps most notable for the long (20-28 inches, or 50-70 cm), slender, almost straight vertical black horns carried by the males. At a distance, when viewed from the side, the two horns may appear as one and thus it has been suggested that the chirus was the original inspiration for the story of the unicorn. The saiga is presently found in Sinkiang (China), southwestern Mongolia, Kazakhstan, and in the northern Caucasus (Fig. 5.18). Formerly its range was reported to extend west into Poland. Saigas are famous for their huge, inflated nose that forms a proboscis in which the nostril openings point toward the ground. It has been suggested that the proboscis serves the purpose of warming and moistening air as it is inhaled, and saigas also have a very well-developed sense of smell. Comparable to the chirus in size, saigas

Figure 9. A. The Asian serow. (Photo by Prothero). B. The North American mountain goat (Oreamnos americanus) is found in the highest peaks and cliffsides. (From the IMSI Master Photo Collection) . grow heavy, light-colored buff coats, and they are fast runners-reportedly capable of reaching speeds of 37 mph (60 km per hour). The horns, found only in males, are 8-10 inches (20-25 cm) long, pale amber in color, and sometimes translucent. For centuries saiga horns have been used by Chinese pharmacies in much the same way as rhino horns and "dragon's teeth," so saiga have been over-hunted in the past. The horns were thought to act as an aphrodisiac among other uses. In the early nineteenth century hundreds of thousands of saiga horns were used in China each year. From prehistoric times nomadic tribes of the Russian steppe have hunted the saiga for its meat and hides. Since about 1920, however, they have been protected in the former Soviet Union and are reportedly the most abundant wild ungulate in that country. While unrestricted general hunting of the saiga is not allowed, they are selectively culled and thousands of tons of saiga meat is taken each year for human food. The members of the tribe Rupicaprini are generally considered the most primitive of extant caprines, and include the Asian serows (genus Capricornis) (Fig. 5.19A),

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HOLLOW HORNS

Figure 5.20. The bizarre dwarfed goat Myotragus balaericus, which lived on the Balaeric Islands near Spain in the Pleistocene. It has unusually stunted limbs, and a peculiar face. (From Bate 1909). the goral of the Indian subcontinent to Siberia (Nemorhaedus goral), the chamois that ranges through southern and central Europe (Rupieapra rupieapra), and the American mountain goat (Oreamnos amerieanus) (Fig. 5.l9B). In size rupicaprins range from the goral with a shoulder height of 24-28 inches (60-70 cm) and a weight of 50-70 pounds (22-32 kg) to the American mountain goat which can stand 4 feet (1.2 m) at the shoulder and weigh 165-310 pounds (75-140 kg). In rupicaprins there is little distinction between the sexes in size or appearance. Both sexes have horns, for instance, which tend to be short and curve slightly backwards. Rupicaprins often live on steep slopes, seek out shrub or tree cover, and browse on whatever plant resources are available-from grasses to shrubs and trees, sedges, lichens, and so on. Mountain goats will seek shelter in caves if the weather is bad. Rupicaprins are often referred to as "resource defenders." They live in and defend with their short but strong and sharp horns small areas that contain productive food supplies. In some cases they may be extremely aggressive, fending otf not only potential competitors of their own species, but also even large carnivorous predators. The mountain goat has been known to fight off a large grizzly bear, and in at least a few instances, kill it with multiple punctures to the heart from its sharp horns. All rupicaprins have an amazing ability to climb in terrifyingly steep terrain. Owen Wister, author of The Virginian, wrote of the mountain goat: "They chose places to lie down where falling off was the easiest thing you could do...The individual tracks we have passed always choose the inclined plane where they have a choice between that and the level ... If they play games together, it is probably to push each other over a precipice, and the goat that takes the longest to walk up again loses the game." The great naturalist Ernest Thompson Seton wrote, "If, on some lowering morning when clouds and flying scud are drifting low over Manhattan, one could look from the Times Building, out

and up to those higher peaks, the Equitable, the Metropolitan, and the Woolworth [this was before the Empire State Building was built], and see white creatures-goats, incredible goats-crawling along the cornices, pulling themselves up the turrets, or calmly chewing their cud as they lay looking down from the weather vanes, we should have much the same sensation as in watching the bearded mountaineer in his cloud-hung, perpendicular home." Mountain goats travel in small family bands, moving slowly and carefully as they pick their footholds. At treacherous crossings, they string out single-file, with the old billy goat leading, and the kids in the middle. Their hooves are very narrow for excellent traction in tight spaces, and they have suction-cups in their concave toes that improve traction. When their trail. ends in an abrupt drop, they can rear up and wheel around, or climb to a higher level. Because of their abilities to climb, mountain goats have few predators. Until the development of the long rifle, humans could not hunt them easily. Most hunters ignore them, because their meat is gamy tasting, and their horns are not spectacular trophies. Only the mountain lion or lynx attempt to scale their rocky habitat, and eagles will sometimes snag an unprotected kid. When mountain goats descend to valleys to find mineral licks, then they face bears, wol ves and coyotes. Their greatest natural enemies, however, are avalanches and landslides, which are hard to avoid in their craggy habitat. The strangest of the extinct rupicaprins was the cave goat, Myotragus balaerieus (Fig. 5.20). Found only in Ice Age deposits in caves in the Balaeric islands of Mallorca and Menorca, this beast is one of the strangest examples of what animals can evolve on islands. The cave goat only reached 50 cm at the shoulder, so it was probably a dwarfed descendant of one of the mainland rupicaprins, such as the chamois. Its legs are so short and stumpy that they resemble the bizan e Ancon, or otter sheep, which have been bred until their legs are too short to jump fences. In the otter sheep, this kind of aberrant limb development is called achondroplasia, and is caused by a single recessive· gene. For this reason, the shortened limbs of the cave goat have also been attributed to achondroplasia, probably associated with their dwarfing. Curiously, this same shortening of toe bones occurs in the cave bear and cave hyaena. The most bizarre feature of Myotragus, however, is its lower front teeth, or middle incisors, which have grown into huge chisel-like teeth similar to those found in rodents. The second pair of incisors were so small that they were mere vestiges. No one knows what they gnawed with these chisels, but there have been suggestions that they lived on lichens and mosses on rocks, or on the barks of bushes and trees. Whatever they ate, their food was highly abrasive, since their extremely high-crowned molars are highly worn. The musk ox group (Tribe Ovibovini) consists of but two living species: the takin (Budoreas taxieolor) of western China, Bhutan, and Burma, and the musk ox (Ovibos mosehatus) currently found in the tundra of northern 4

110

HORNS, TUSKS, AND FLIPPERS

Figure 5.21. The ovibovins include: A. the takin (Budoreas taxie%r) , found in the high alpine bamboo forests of the Himalayas. (Photo by D. R. Prothero); B. The musk-ox (Ovibos mosehatus) , forming their characteristic defensive circle to protect their calves. (From the IMSI Master Photo Collection).

Canada and Greenland. Fossil ovibovines include the bizarre Tsaidamotherium from the late Miocene of Mongolia, a beast which had strange horn asymmetry: the right horn was a large, blunt conical feature in the center of its head, and the left horn was a tiny vestigial point slightly to the front of it. During the Pleistocene, the musk ox or a closely related species was found throughout Eurasia (e.g., France, Germany, England, Siberia) and North America. As their name implies, these animals, especially the musk oxen, exhibit characteristics that make them look physically more like cattle than goats or antelopes. They are both large, heavy-set animals. Takins (Fig. 5.21A) have a shoulder height of up to a meter and can weigh up to 600 pounds (275 kg), whereas musk oxen can reach a shoulder height of 5 feet (1.5 m) and weigh over 880 pounds (400 kg). In both species the males and females are similar in appearance, but the adult females are typically smaller than the adult males (females may be only 60% of the comparable male weight). The takin lives in dense thickets and bamboo forests at the upper limit of tree growth (about 7800-14,000 feet, or 2,400 to 4,250 meters in elevation). They have thick, shag-

gy fur that can range in color from yellowish white to a very dark brown. An oily, strongly smelling substance is secreted over the entire body. They have massive, thick horns that sweep outward, backward, and upward. Takins will gather in large herds above the tree line during the summer months, but in the winter tend to live in smaller groups in valleys at lower elevations. Musk oxen (Fig. 5.21B) bear very thick, highly protective coats that are composed of two parts. The dark brown outer guard hairs are coarse and long (almost dragging on the ground-single strands may be two feet long); this outer coat protects against rain and snow and covers the inner hairs. The inner coat is a very dense mat of soft, fine, light brown hairs that keeps cold and moisture from reaching the animals' bodies. The legs of musk oxen bear a lighter fur than the rest of the body, and generally only the feet and lower legs are seen from under the long shaggy coat. The neck and tail are short, the face large, and there is a hump over the shoulders. Their horns meet in the middle of the head and then curve down each side of the head before flaring out at a level below the eyes, so a musk ox appears to be

HOLLOW HORNS

111

B

Figure 5.22. A. The ibex (Capra ibex) , characteristic of the high Alps (Photo by D. R. Prothero). B. The markhor sheep, with its twisted horns. (From the IMSI Master Photo Collection).

wearing a helmet. Musk oxen are gregarious, and they may gather into herds of up to a hundred or more. If a herd is attacked or disturbed by wolves or bears, the musk oxen will form a defensive circle, with horns pointed outward, sheltering the young inside. If a herd is approached too closely by the curious human observer, the males may threaten to attack. As one of us (Schoch) has found by experience on Ellesmere Island in the Canadian Arctic, having an angry musk ox coming at you can be a bit frightening! However, if captured and raised as young, musk oxen are actually fairly docile and easy to tame. Experimental breeding farms have raised musk oxen in Alaska, Quebec, Norway, and Siberia. It is possible that someday a strain of these animals may become fully domesticated. The main incentive to tame and raise musk oxen is for their undercoat which is a very fine wool ideally suited for certain garments. This undercoat is naturally shed in the spring and can be easily gathered from the animals at that time, without killing them or even shearing them. The Caprini (Fig. 5.22) include most domesticated and wild goat species (genus Capra), the domesticated and wild sheep species (genus Ovis), the tahrs of the Himalayas, India, and the Oman district of Arabia (genus Hemitragus), the Barbary sheep or aoudad of northern Africa (Ammotragus lervia), and the blue sheep or bharal of the mountains of Asia from the Himalayas to Mongolia (Pseudovis nayaur). Unlike the rupicaprins, the caprins (true goats and sheep) are not resource defenders, but have moved generally into more open landscapes and have taken up grazing on relatively productive grasslands. Caprins form

loose, cooperative herds that serve as protection from predators. There are also major distinctions between the males and females as far as weight, general external appearance, and horn development. The caprins typically are characterized by hierarchical social systems. In shoulder height caprins typically range from about 2-4 feet (0.6-1.2 m), and in weight they can range between 55 and 400 pounds (25 kg180 kg). The true goats (genus Capra) include the ibex (Capra ibex), various other species of wild goats (including the markhor, and the East and West Caucasian turs), and the common domesticated goat. In the natural state, Capra is a widespread genus, extending from Spain through central Europe, the MeditelTanean region, the Middle East, northern Africa, and into India, Siberia, and Mongolia. Of course, domesticated goats are now the scourge of every continent and island where humans have brought them, eating everything in sight, destroying the habitat and all the native animals in the process. A favorite of crossword-puzzle aficionados, the ibex (Fig. 5.22A) is the most spectacular goat, with a long beard, and enormous horns that curve up and backward like a scimitar. Living mostly in the Himalayan foothills, ibexes fear only wild dogs and snow leopards. Ibexes were once found in the Alps as well, but have now been hunted out of Europe, except for a small protected population on the Italian side of Monte Rosa. Another unusual goat is the markhor, Capra falconeri (Fig. 5.22B). Also found in the Himalayan foothills, it prefers the cover near the treeline rather than the open cliffs

112

HORNS, TUSKS, AND FLIPPERS

Figure 5.23. The American bighorn sheep (Ovis canadensis), found throughout the Rocky Mountains. Here, a ram lifts its lip in the Flehmen gesture to detect whether this ewe is in estrus. (Photo courtesy B. O'Gara.) and slopes. Largest of the wild goats, it may stand 40 inches (100 cm) high and weigh more than 200 pounds (90 kg). The markhor has long been a hunter's favorite, both for its bushy beard and throat hair, and its spectacular spirally twisted horns. The tahr (Hemitragus jemlaicus), on the other hand, is beardless, and has simple short horns. Although it is difficult to hunt in the steep Himalayas, its bones are prized in India for treating rheumatism. True sheep (genus Ovis) include such wild forms as the Middle Eastern and Asian urial, argalis, mouflon, and snow sheep, the North American bighorn sheep, as well as the common domesticated sheep. The details of sheep (and goat for that matter) taxonomy are very complicated and controversial. There are many different species, subspecies and races of both sheep and goats recognized by various authorities; not all sheep even have the same number of chromosomes. In the wild, sheep species are found predominantly in the Middle East, Asia, and the northern and western portions of North America. Sheep have been introduced to Europe by humans on at least several different occasions since their domestication, and domesticated sheep are now found wherever humans can raise them. Of the wild sheep, the most familiar are the bighorn sheep (Ovis canadensis) of North America (Fig. 5.23). They are famous among hunters for the spectacular ram's horns

on the males, which are used in mating fights. During the rutting season in December, the younger males begin to challenge the old rams with females. The challenger butts the old ram in the side, and they face off. Eyes flaring, they back off to about 40 feet (12 m) apart, then charge each other at 20 mph (32 km/hour). At the moment of impact, they rear up and then drop on all fours. The crash can be heard for miles, echoing off the cliffs. Dazed, they stand side-to-side and eye each other, then back off for another charge. Chips and splinters fly from their horns, and blood oozes from ears and noses; they reel drunkenly. The battle may rage over an hour, until one male has had enough. Falling to his knees, he is driven down by a pile-driving blow from the victor. Sometimes the vanquished is killed by these combats, but most live to see another day (if not to breed again). By January the mating season is over, and the rams return to bachelor herds. Two lambs are born to each female in Mayor June. Minutes after birth, the mother licks the lamb from head to toe, a ritual called "owning the lamb." Not only does this get rid of amniotic tissues, and fluff-dry its fur, but it also gives the lamb its mother's scent, and prevents blowflies from laying eggs on it. Before the day is out, the lambs are running with their mothers. They form small flocks during the summer, led by one of the grandmother ewes, who keeps constant watch over her charges.

HOLLOW HORNS Bighorn sheep are even better climbers than mountain goats. They bound over their rocky homeland, equipped with elastic pads on their feet which absorb the shock of their bouncing gait and provide traction on hard, rough, or slippery surfaces. Bighorns can skip up narrow canyon walls, ricocheting to the top, and never come close to falling. They balance on tiny footholds, and leap chasms over 15 feet (4.6 m) wide. John Muir describes a flock of bighorns plunging off a ISO-foot (46-m) cliff, "descending in perfect order ... controlling the velocity of their half-falling, halfleaping movements by striking at short intervals, and holding back with their cushioned, rubber feet upon small ledges and roughened inclines until near the bottom, when they 'sailed off' into the free air and alighted on their feet, but with their bodies so nearly in a vertical position that they appeared to be diving." Occasionally a ram is killed in one of these amazing plunges, but barring an accident, they have few threats on their lives; their only predators are wolves or bears. Before telescopic sights and high-powered rifles, most mountain sheep lived long, untroubled lives on the sunlit mountain tops, reaching their prime at 10-12 years, and living to 20 years in some cases. Bighorns spend most of their time migrating with the seasonal vegetation. Winter is spent down in the shelter of the timber and lower valleys, and summer up in the grassy meadows above the timber line. All of this migration, however, takes place within a well-marked home range, since territory is one of the prerogatives that rams must guard in order to keep their harems. Goats, as compared to sheep, tend to be better suited to cliffs and more rugged terrain; sheep prefer more open and rolling country. Whereas female sheep and goats often appear to be very similar, male goats tend to have chin beards and long, backward-arching horns; in comparison, male sheep lack chin beards and have massive, curled horns. Male goats also tend to exude a strong odor (sometimes enhanced by the male spraying himself with urine). Along with horses and cattle, sheep and goats are among the most familiar ungulates-primarily because the domesticated species of these bovids have been closely associated with humans for some 10,000 years. The common domestic goat, Capra hircus, and the common domestic sheep, Ovis aries (there are innumerable varieties and breeds of both species) are extremely closely related. As was discussed above, both are classified as members of the tribe Caprini, subfamily Caprinae, family Bovidae. And both domesticated goats and sheep appear to have been derived from wild forms that inhabit the mountains of western Asia, namely the Bezoar goat (Capra aegagrus) and the Asiatic mouflon (Ovis orientalis) respectively. Unlike most ungulates, wild goats and sheep have a social system and behavioral repertoire that is ideally suited to potential domestication. They are accustomed to a single dominant leader (young wild animals that are tamed and

113 reared by hand will "imprint" on a human as their leader). Eurasian sheep have a natural submissive posture (which aids in taming and domestication) and they are gregarious but nonterritorial. This last point is extremely important because in territorial species (such as most species of antelopes, gazelles, and deer), even if otherwise gregarious and social, the males in particular will defend a set territory-and this makes these animals particularly unruly and difficult to manage in captivity. In contrast, goats and sheep have home ranges within which they wander in search of food, but they do not defend territories. Likewise, human pastoralists and hunter-gatherers may have home ranges, but not defended ten~itories. Simply by living in the same area sheep, goats, and humans may have grown used to each other, leading the way for domestication. Domestic sheep are particularly useful to humans as meat and also for their wool. Wild progenitors of the domestic wool-bearing sheep have a stiff, bristly, long outer coat of hair (known as kemps) that covers the fleece-the woolly undercoat. Primitively the fleece is shed in the form of dense mats each year, and early humans found that it could be spun into thread or made into felt. Certain domestic forms have been bred such that they lack the kemps and the fleece grows continuously, and is not shed naturally; humans cut it as need be. Wild goats have many features like wild sheep that make them especially amenable to domestication. Goats are adapted to living in harsh mountainous areas, browsing on brush and scrub. Goats are well known for being extremely hardy-they seem to eat virtually anything, and they can survive a wide range of temperatures. Goats can provide humans with everything from meat and milk to hides and bone for clothing and tools, to manure. Furthermore, goats and sheep will naturally complement each other under domesticated conditions. While the flock of sheep concentrates on grass, the goats will browse on the brush. It is little wonder that goats and sheep seem to have been domesticated at about the same time, perhaps around 8000 B.C. at the beginning of the Neolithic. Because of their tendency to eat virtually anything in sight, it has been suggested that goats may have helped early farmers clearland. On the negative side, browsing domesticated goats have been seen as a major contributing factor in the expansion of desert areas in North Africa and the Middle East. Since the late Miocene the globe has become a world of bovids. There are more species of bovids than any other family of mammals, and given their large size, versatile ecology, and geographic spread, they are now the most important large herbivorous mammals in just about every part of the globe. Since domesticated cattle, goats, and sheep are now replacing almost all wild hoofed mammals (whether bovid or not) wherever humans settle, it is fair to say that this planet will continue to be a world of bovids-even if humans don't outlast them.

Figure 6.1. The Eocene archaeocete whale Basilosaurus. Although it was fully aquatic, it still had tiny vestigial hind limbs, and a mesonychid skull. (Painting by Z. Burian).

6. A Whale's Tale

"As on land there are some orders of animals that seem formed to command the rest, with greater powers and more various instincts, so in the ocean there are fishes which seem formed upon a nobler plan than others, and that, to their fishy form, join the appetites and the conformation of quadrupeds. These are all of the cetaceous kind; and so much raised above their fellows of the deep, in their appetites and instincts, that almost all our modem naturalists have fairly excluded them from the finny tribes, and will have them called, not fishes, but, great beasts of the ocean. With them it would be as improper to say men go to Greenland fishing for whale, as it would be to say that a sportsman goes to Blackwall a fowling for mackarel. But it is not only upon land that man has exerted his power of destroying the larger tribes of animated nature, he has extended his efforts even into the midst of the ocean, and has cut off numbers of those enormous animals that had perhaps existed for ages. We now no longer hear of whales two hundred, and two hundred and fifty feet long, which we are certain were often seen about two centuries ago. They have all been destroyed by the skill of mankind, and the species is now dwindled into a race of diminutive animals, from thirty to about eighty feet long" (Goldsmith, 1825). DR. KOCH'S "SEA SERPENT" In 1845 the talk of Philadelphia was the skeleton of a gigantic beast that the showman "Dr." Albert Koch called Hydrarchus, the great "sea serpent." It stretched 114 feet (35 m) through three rooms, and at the front were great flippers and a gaping maw. The masses flocked to see the marvel, and most thought it proved that sea serpents still roamed the oceans. However, Koch had bought the bones from local farmers who had excavated them from Eocene beds in Alabama. He was no~natomist, but he was definitely a good promoter. By cobbling together the bones of several skeletons he could make the animal look much longer and more serpentine. [He had previously done the same with several

mastodont skeletons, making a giant composite he called the "Great Missourium." We will discuss this animal further in Chapter 8]. Koch brought one of his great "sea serpents" to Europe, where he presented it to King Frederick William IV of Prussia in 1847 as the "behemoth of the Bible." The King was so impressed that he gave Koch an annual pension of one thousand imperial talers. Most people thought the King was getting a bit senile, and this reinforced their opinion. The scientists protested that the specimen was a fraud, but the King did not back down. Koch kept moving from Dresden to Breslau to Prague to Vienna, because scientists in Berlin and London were denouncing him for this forgery, as well for his "Great Missourium" fraud. In each city, an indignant Gideon Mantell (discoverer of the first dinosaur) warned them about the damnable swindler. When Koch brought the wonder to New York, the anatomist Jeffrey Wyman demonstrated in a learned article that it was not a reptile, nor was it from a single individual. When Koch visited Philadelphia the specimen inspired Edward Drinker Cope, then all of six years old, to study fossils. But Mantell's and Wyman's letters had ruined Koch's welcome in the East, so he began touring with the "sea serpent" in rural backwaters, where people were more easily fooled. Finally, he sold the monster to the Wood Museum in Chicago, where it was dismantled. Eventually the specimen was destroyed in the Great Chicago Fire of 1871, triggered by Mrs. O'Leary's cow. Others who had found similar bones before Koch had mistaken them for reptiles too. They were first described in 1834 by Richard Harlan, who named them Basilosaurus, or "emperor lizard." But when the great British anatomist Richard Owen saw the bones in 1839 he realized at once that they were not reptilian. He pointed out that they were the remains of an extinct Eocene whale, which he called Zeuglodon. Unfortunately, the name Basilosaurus is the proper one, since it was used first, even if it is inappropriate to call a whale a reptile. [The reverse is also true. A giant sauropod dinosaur from England was named Cetiosaurus, or "whale lizard," since it was discovered before dinosaurs were understood. Only whales were thought to get that large!]. Today, all of these Eocene whales are called "archaeocetes," or "ancient whales."

HORNS, TUSKS, AND FLIPPERS

116

65 .

60

55

50

45

40

3S

30 million years 'ago

._--------Paleocene

I

I

Eocene

Oligocene

Mesonychlds

Pakicetus

~~~ Ambulocetus Dalanistes

Rodhocetus Ta kracetus

Gaviocetus

~~ Figure 6.2. Family tree of the early cetaceans, showing the remarkable transition between terrestrial mesonychids and advanced whales. (From Zimmer, 1998).

4-2on

:~

Mystlcetes

Although these animals are unmistakably whales, they are very different from Ii ving whales or dolphins (Fig. 6.1). Most Eocene whales did have a streamlined body, with flippers modified from front feet and tiny hind legs, and a fluke on the tail. But their relatively small skulls are still very unspecialized, with nostril still on the tip of the snout rather than having a blowhole on top of their head, nor were their ears specialized for echo sounding. Even more striking are their teeth, which are shaped like triangular blades with

notched edges. Some people have looked at these teeth and speculated that they were used for filtering krill, as the teeth of the seal Lobodon are used. However, a study of the jaw structure by Ken Carpenter showed that fish were a much more likely diet, and that the similarity to krill-filtering teeth is purely superficial. Contrary to "Dr." Koch, large basilosaurine archaeocete whales are now reconstructed at about 80 feet (24 m) long, and weighing about 12,000 pounds (5400 kg), still

A WHALE'S TALE remarkably large. Another group of archaeocetes, the dorudontines, were much smaller-about the size and shape (and probably habits) of a killer whale. Archaeocetes probably had a discrete neck, unlike modern whales, and nasal openings part way back from the tip of the snout. They probably had a humped back or a small dorsal fin, although the fin has no skeletal support to be fossilized. Reconstructing the tail is difficult, but most scientists today believe it had a large horizontal fluke .like that of living whales. Their front flipper structure is more flat-tipped than any living whale. As we shall see below, some had vestigial hind limbs protruding from their bodies. Archaeocete whales are known from Eocene beds all over the world: Great Britain, Germany, North Africa, the United States, New Zealand, Antarctica, and India. They were clearly very successful, and occupied virtually the entire world ocean during the Eocene. However, when they appear in the fossil record they are already very aquatic, with a streamlined body, paddles for front feet and a tail fluke for swimming. How does one get from land-dwelling animals to a whale? And more importantly, why do we say that whales are hoofed mammals? WALKING WHALES? One key to this question lies in the teeth. This kind of teeth is characteristic of an archaic ungulate group, the mesonychids. If you compare the skulls and teeth of some mesonychids with those of primitive whales, they are similar in almost every critical detail. Yet the rest of the mesonychid body is not yet aquatic; instead, they looked very much like large wolves or bears in their body shape. Some were the largest carnivorous land mammals of the Eocene, and must have been the ecological equivalent of bears or hyaenas. Somewhere between the mesonychids and the first aquatic whales, there must have been animals which made the transition to aquatic life. Although this seems far-fetched at first, there are actually modern analogues for the process. A coastal fish-eating scavenger could become more and more aquatic as it wades out to catch live, rather than dead fish. The brown hyaena, which does this along the South African shoreline, is even called the "strand wolf." As this

117

lineage became more aquatic, the feet would become better adapted for swimming (as has happened with the webbed feet in many mammals), and ultimately became flippers (as happened independently in seals and walruses, which are related to bears). The hind limbs are not visible on the body of living whales, but they are still there. Buried deep in their streamlined torso are the remnants of their hip bones and thigh bones. These vestigial bones would not be there if whales were not descended from a four-legged ancestor. Vivid confirmation of this idea has been discovered in recent years (Fig. 6.2). In 1983 Philip Gingerich, Donald Russell, and their colleagues discovered a transitional animal, Pakicetus, from the early Eocene of Pakistan. Although it had an archaeocete braincase, it still had very primitive ears that were incapable of echolocation. In addition, its teeth were intermediate between those of mesonychids and more advanced archaeocetes. Finally, it occurs in river sediments bordering on shallow seaways. Gingerich and his colleagues reconstructed this animal as partly aquatic and partly terrestrial, although none of the skeleton is known. In 1990 new specimens of the archaic whale Basilosaurus from the Eocene deposits of northern Egypt answered more questions about the skeleton. They were more complete than previous specimens, and showed that Basilosaurus had functional hind limbs complete with toes. However, the limbs were so tiny they could not have supported the animal's weight on land. The discoverers suggest that the limbs might have been used to help the male hold the female during mating, as many aquatic organisms do. Eventually, whales lost these limbs completely, and only their vestiges remain within their bodies. In 1994, a specimen of an another Eocene whale, Rodhocetus, was found in Pakistan. It was much more like a modem dolphin, yet it also had the tiny vestigial hindlimbs like Basilosaurus. Since then, several more transitional whales, such as Takracetus and Gaviocetus, have been found, which also retain vestigial hind limbs. The most important breakthrough (Fig. 6.3) was the discovery of a classic "missing link" in Pakistan in 1994. Known as Ambulocetus natans ("walking swimming whale"), it was about the size of a large sea lion, with functioning flippers on both its forefeet and huge hindfeet-

Figure 6.3. A. Skeleton of Ambulocetus natans, the walking whale. (Photo courtesy J.G.M. Thewissen). B. Restoration of Ambulocetus. (From Zimmer, 1998).

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HORNS, TUSKS, AND FLIPPERS

Figure 6.4. The bear-sized carnivorous ungulate Mesonyx, typical of the group from which whales arose. (Painting by Charles R. Knight; Neg. no. 35777, courtesy Department of Library Services, American Museum of Natural History). although it still had tiny hooves on its hindfeet. In addition to this ungulate hallmark, it still had the primitive skull and teeth of the mesonychids, with relatively few whale-like specializations. Based on its highly flexible vertebrae, Hans Thewissen has suggested that Ambulocetus swam with an up-and-down flexure of its body, similar to the swimming motion of an otter, rather than paddling with its feet like a penguin or seal, or wriggling side-to-side like a fish. This would have been a good precursor for the up-and-down motion of the whale's tail when it propels modem whales through the water. A few years after this discovery, another whale known as Dalanistes was found. Like Ambulocetus, it still had full functional front and hind limbs with webbed feet and a long tail. But it was much more whale-like, with a much longer snout that foreshadowed the long snout of archaeocetes. If this still seems far-fetched, there is now good molecular evidence that whales are ungulates. Whenever molecules are compared, whales are always more similar to artiodactyIs than they are to any other living group of mammals. Some molecular biologists have argued that whales are artiodactyIs, since they tend to cluster with pigs and hippos on molecular family trees. Then just before this book went to press, two groups of researchers found skeletons of the

primitive whale Pakicetus and the protocetids. Both animals have the distinctive "double-pulley" astragalus found elsewhere only in artiodactyls. According to Thewissen and others (2001), this suggests that mesonychids are the primitive relatives of both whales and artiodactyls. In addition, whales and mesonychids have numerous features in the skeleton which show they are ungulates more specialized than hyopsodonts or periptychids. These include the loss of the collarbone, a specialized shoulder blade and upper arm bone, and many unique features of the holes in the base of the skull and the arteries that pass through them. Indeed, some mesonychids had claws which were so blunt and broad that they might be called hooves. Mesonychids are unusual among ungulates in that they were probably scavengers or carnivores. Whales, too, live on fish, squid or other invertebrates, but are never plant eaters. ANDREWS' GIANT "BEAR" Roy Chapman Andrews was a dashing explorer who made a reputation traveling "to the ends of the earth." Many consider him to be the model for the archeologist Indiana Jones, played by Harrison Ford in the movies. Andrews visited nearly every remote corner of the earth, braving bandits and horrendous weather. His most famous travels were to

A WHALE'S TALE

119

Figure 6.5. Skull of the giant late Eocene Mongolian mesonychid Andrewsarchus compared with a modern Kodiak bear, the largest living carnivore. (From Fenton and Fenton 1987).

the Gobi Desert of Inner Mongolia, where he led several expeditions for the American Museum of Natural History in New York from 1922 to 1928. These expeditions were the marvel of their time, traveling in early Dodge cars and bringing most of their supplies on the backs of camels. Although they originally set out to find the earliest remains of humans in Asia, they found much greater scientific treasure: spectacular dinosaurs and fossil mammals, including the first known dinosaur nests full of eggs. Andrews' main account of these expeditions, The New Conquest of Central Asia, is full of hair-raising accounts of their exploits, and tales of great discoveries. Typical of these tales was his account of the discoveries at Irdin Manha in 1923: "The day after our arrival at Irdin Manha, we experienced one of the worst windstorms that I have ever seen in Mongolia. At two 0' clock in the afternoon a full gale was raging, and every hour the wind increased. I went out at four 0' clock to find [Walter] Granger, but I could hardly stand against the blasts of sand and gravel which mutilated my hands and feet until they bled. The basin below us was "smoking" as if from a prairie fire; the yellow blanket rolled and swayed, now and then parting for a moment to show a bit of vegetation on the floor, only to have the vista closed as a fresh wave of sediment swirled across to the escarpment's rim. In the tents we were almost buried in the sand; beds, clothes, tables and chairs were thickly covered with a yellow layer. The windstorm gave us an excellent demonstration of the methods by which the depression had been made. Great clouds of sand whirled and eddied over the edge of the escarpment; thus was accumulated sediment carried out. The geologists believe it possible that a river started the excavation, but the enclosed basin must have been scoured out by the wind. Although small stream courses, dry most of the year, led from the sur-

rounding bluffs toward the salt marsh at Iren Dabasu and a certain amount of sediment must be transported by them into the basin, yet the depression does not fill. Only the wind could remove it, as we saw it doing in those gales, which continued for three weeks with only momentary lulls. It was impossible to work except at intervals, and then under the most trying circumstances... Although the beds are richly fossiliferous in certain places, the remains are usually fragmentary. A few limb bones were found intact, but no associated skeletons. Teeth, pieces of jaw and ends of limb bones were the most usual material, although some fine skulls, nearly complete, were discovered. Remains of lophiodonts [discussed in Chapter 13] were extraordinarily abundant, and it was possible to collect a handful of teeth in an hour, at almost any part of the exposure near camp. The entire absence of horses was a surprising feature of this and other early Tertiary faunas of Mongolia... [One] afternoon, we discovered the superb skull of a gigantic beast, which I believed to be a carnivore. The next day Granger dashed our hopes by pronouncing it to be that of a pig, Entelodon [discussed in Chapter 2], which, because of its omnivorous habits, resembled a flesh-eater. However, Morris made a drawing of the skull in situ; this was forwarded to Doctor Matthew at the American Museum. When we returned from Mongolia, a letter was awaiting us, stating that my original supposition was correct, and that the specimen represented one of the primitive creodonts of the family Mesonychidae. Later it was named Andrewsarchus mongoliensis by Professor Osborn, who says that, 'This is the largest terrestrial carnivore which has thus far been discovered in any part of the world. The cranium far surpasses in size that of the Alaskan brown bear, the largest living land carnivore, which when full-

120

HORNS, TUSKS, AND FLIPPERS

grown, weighs 1500 pounds; in length and breadth of skull, Andrewsarchus mongoliensis is double the Alaskan brown bear and treble the American wolf' (Andrews, 1932: 195-196). So Andrews described the discovery of the last and largest of the mesonychids. It is known only from a single skull from the late Eocene of Mongolia. However, what a beast it must have been! The skull is almost three feet long and two feet wide, more than twice the size of the largest bear known (Figs. 6.4, 6.5). Since the skull is wolflike or bearlike, the animal is· often reconstructed as if it were a gigantic bear. If its skeleton were bearlike, it probably would have been twelve feet (3.7 m) long and more than six feet (1.8 m) high at the shoulder! It is unfortunate that no skeleton is known from this animal. Its skull is so whale-like in many features besides its immense size (which is similar to the size of early whales) that one wonders whether its skeleton might have been more adapted for aquatic life. The only evidence against an aquatic lifestyle is the fact that Andrewsarchus is known from terrestrial river sediments. Perhaps it lived in rivers and estuaries, scavenging both land and aquatic animals, as well as turtles and fish. THE PEDIGREE OF LEVIATHAN "When I stand among these mighty Leviathan skeletons, skulls, tusks, jaws, ribs, and vertebrae, all characterized by partial resemblances to the existing breeds of sea-monsters; but at the same time bearing on the other hand similar affinities to the annihilated ante-chronical Leviathans, their incalculable seniors; I am, by a flood, borne back to that wondrous period, ere time itself can be said to have begun; for time began with man. Here Saturn's grey chaos rolls over me, and I obtain dim, shuddering glimpses into those Polar eternities; when wedged bastions of ice pressed hard upon what are now the Tropics; and in all the 25,000 miles of this world's circumference, not an inhabitable hand's breadth of land was visible. Then the whole world was the whale's; and, king of creation, he left his wake along the present lines of the Andes and the Himmalehs. Who can show a pedigree like Leviathan? Ahab's harpoon had shed older blood than the Pharaoh's. Methuselah seems a schoolboy. I look round to shake hands with Shem. I am horror-struck at this antemosaic, unsourced existence of the unspeakable terrors of the whale, which, having been before all time, must need exist after human ages are over" (Mel ville, 1851: 380). Archaeocetes dominated the world ocean throughout the Eocene, from about 54 to 34 million years ago. In the Oligocene, however, they began to decline, and few specimens are known. The last archaeocete, Kekenodon, is known

from the late Oligocene of Oregon, about 25 million years ago, so they straggled on for some time. By this point, however, they were being replaced by a great radiation of modern whales, the mysticetes (baleen whales) and odontocetes (toothed whales). For a long time, there was no fossil evidence about the origin of these two groups, and there was even controversy as to whether they even had a common ancestor. Most scientists today agree that mysticetes and odontocetes are closely related, and descended from archaeocetes, but until recently the fossil record of this transition was remarkably poor. However, the last few years have produced primitive odontocetes in Oligocene deposits of Europe, Russia, California and Oregon, Canada, Japan, Australia and New Zealand (Fig. 6.6). Discoveries by Ewan Fordyce in New Zealand have shown that primitive members of both groups were particularly abundant in the Southern Hemisphere. This makes sense. The beginnings of modem oceanic circulation occurred in the early Oligocene when Antarctica began to separate from Australia and South America. During the Eocene these three continents were joined, and waters from the tropical Atlantic and Pacific mixed with south polar waters and kept the climate warm. During the early Oligocene, however, Australia pulled away and 'Permitted deep water to circulate around Antarctica. As Jim Kennett has shown, this triggered massive changes in oceanic circulation and global climate. The cold polar waters got trapped in a Circum-Antarctic current, circling around Antarctica and trapping cold water (as it does even today), rather than exchanging with the equatorial waters (as it did in the Eocene). Eventually, this led to refrigeration of the South Pole, the first glaciers and ice sheets, and the development of cold bottom waters which sank beneath the surface waters and traveled north. This oceanographic change had a profound effect on world climate, causing a cooling and vegetational change that led to the extinction of many of the animals discussed in this book. However, it had a favorable effect on the whales. The development of the Circum-Antarctic Current and cold bottom waters released an enormous flow of nutrients once trapped on the deep ocean bottom. This upwelling of water and nutrients was the necessary trigger for a huge bloom in oceanic productivity. Tiny microorganisms living in the ocean utilize these scarce nutrients to make their shells, and soon every cubic meter of water was filled with millions of submicroscopic animals and plants. This process is still operating today. The Antarctic is one of the world's richest and most productive regions, even if it appears to be one of the most bleak and inhospitable. The south polar waters are full of plankton, which suppo11s a population of millions of crustaceans and fish. These in turn support much larger predators, including larger fish, penguins, seals, and finally whales. Fordyce suggests that the bloom of oceanic productivity in the early Oligocene created a new source of food for an aquatic organism that could feed on abundant plankton.

121

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Some mysticete whales, with their filter-feeding devices, have taken up the challenge directly. However, the most primitive mysticetes, and the toothed whales have responded to the challenge indirectly by feeding on fish and squid that feed on plankton.

LIFE OF A LEVIATHAN "There Leviathan, Hugest of living creatures, in the deep Strech'd like a promontory sleeps or swims And seems a moving land; and at his gills Draws in, and at his breath spouts out a sea." Milton (1667)

The living members of the order Cetacea (whales, dolphins, and porpoises) are wholly aquatic mammals. None of the approximately eighty species (equally competent authorities disagree on exactly how many living species there are) of living cetaceans can survive outside of water for any extended length of time. The order consists primarily of marine mammals, but a few members live in freshwater rivers. The animals of this order range widely in size, from small porpoises that are only 5 feet (1.5 m) long and weigh about 50 kg to the blue whale which, at a maximum of about 100 feet (30 m) in length and a weight of over 125 tons, or 110,000 kg (and perhaps up to 165 tons, or 150,000 kg), is the largest living animal on Earth, and larger than the largest dinosaurs.

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14".;1- blowhole.. {~::.~..;::..:?'}~S how a python c~n;.,eve.n ..Q.a~t.\lre hyr.axes withi~ their dens in hollow tree trunks, and "should the cavity be large, it enters and forthwith proceeds to swallow every

OUT OF AFRICA dassie in that particular lair." Although hyraxes do not make good eating and are seldom hunted for food, at one time they were hunted for their pelts. It took 20 to 30 pelts to make one fur coat, and 48 animals for one rug. The most serious threat, however, is the rapid deforestation of the central and west African rainforest. The tree hyrax is rapidly moving to the endangered list, along with many animals in tropical rainforests around the world. Tree hyraxes occur in groups of two or three related indi viduals, .which live in a small area of the forest centered around a single tree. They usually mate and give birth during the dry season, which varies from place to place in Africa. A single precocious baby is born after a gestation of 8 months, and they reach adult size after only 120 days. They reach sexual maturity after about a year, and are known to live at least 5-6 years. They have a dorsal gland, whose function is unknown, in the middle of their back. When excited, tree hyraxes tum their rumps to a threat and stiffen the white hairs around the gland, which form a white ring. It is not certain whether this gives a visual signal to the predator, or whether it is connected to a skunk-like smell. This diversity of three genera and seven species in limited habitats is a pitiful remnant of their diversity in the geological past. There were at least 19 extinct genera in the last 40 million years, and they were adapted to a tremendous range of ecological conditions. Some were small and ratsized, but others were gigantic forms (Fig. 7.15), with impressive-sounding names like Titanohyrax, Gigantohyrax, and Megalohyrax. Some of these animals had skulls over 2 feet (60 cm) long, and were as large as modem rhinos. This wide range in size was accompanied by a wide range of adaptations, as they converged on the body forms of pigs, tapirs, horses, and a number of extinct animals, such as chalicotheres (discussed in Chapter 13). Apparently, hyraxes lived in Africa without competition from typical Eurasian mammals during much of the Eocene and Oligocene. Since there were no animals occupying the tapir niche, or the pig niche, for example, hyraxes evolved shapes to replace them. The oldest fossil hyraxes are known from the Eocene of Algeria. The five species include the rabbit-sized Microhyrax, which has very primitive, low-crowned rounded teeth suitable for browsing, and the huge Titanohyrax, which had teeth with sharp crests for grazing. Thus, when hyraxes first appear in the fossil record, they have already started their ecological differentiation caused by isolation in Africa. In the Oligocene deposits of the Fayum, they make up more than half of all the mammals found in the Lower Fossil Wood Zone. There are at least eight hyrax genera in the Fayum, three of which retain low-crowned rounded teeth like pigs, and probably ate a pig-like diet of roots, fungi, seeds, and fruits. The remaining genera had teeth with high shearing crests, adapted for a browsing diet of leaves, like the modern tapir. The largest of these was again Titanohyrax, one species of which was larger than the primi~~'{e prohoscideans foundln the same.clep9sits..The early

153

Oligocene of Africa was certainly the heyday of hyraxes. The same Fayum deposits record their decline as well. In the Upper Fossil Wood Zone, only 16% of the mammals are hyraxes, and only two lineages are left. They apparently encountered increasing competition with Eurasian mammals (the hippo-like anthracotheres, discussed in Chapter 2, had been there since the Eocene). Their diversity in Africa was even further reduced during the Miocene when they came into competition with ruminants (primitive antelopes, goats, and cattle) and with pigs. One of these survivors was Megalohyrax, which was not only large, but developed long, specialized limbs for efficient running. Apparently some hyraxes became even more specialized in their attempt to compete with immigrant Eurasian artiodactyls. The exchange and competition eventually went both ways. By the late Miocene one group of hyraxes, the pliohyracines, migrated into Eurasia. They spread along the Mediterranean from Spain to Turkey, through Afghanistan and the Soviet Union, and were especially common in the Pliocene of China. The pliohyracines were horse-sized animals whose teeth looked almost identical to those of the chalicotheres (discussed in Chapter 13). This convergence was so complete that they were not recognized as hyraxes for 37 years after they were discovered. They had a short skull, with eyes and nose high on the top of their head. These features, as well as the rest of the skeleton, suggest that they were aquatic forms, spending much time partly submerged in swampy lowlands feeding on aquatic plants. Pliohyracines became extinct at the end of the Pliocene, probably in response to the climatic changes at the beginning of the Ice Ages. Meanwhile, the African lineage that led to modem hyraxes was still evolving. Although they did not become as peculiarly specialized as pliohyracines in Eurasia, they were still abundant and showed great ecological diversity. There were still large hyraxes with high-crowned grazing teeth, such as Gigantohyrax, which was three times the length of living rock hyraxes. Hyraxes were particularly common in the Plio-Pleistocene cave deposits of South Africa which have yielded some of the earliest human fossils. For example, the famous Taung cave deposit, which produced the first specimen of the early hominid Australopithecus africanus in 1924, is dominated by the remains of baboons and hyraxes. This deposit has been interpreted as the lair of a leopard, with most of the fossils dragged there as prey. If so, then leopards preyed on hyraxes and baboons much as they do today. Undoubtedly, hyraxes were familiar to our earliest African ancestors, and they may have even been an important food item. In summary, hyraxes seem to have diversified from a common ancestor with the earliest tethytheres (including arsinoitheres and proboscideans) and non-hyracoid perissodactyIs in the late Paleocene of Eurasia (especially China) and along the Tethys shoreline. The earliest sirenians were also diversifying by the late Paleocene, because by the early Eocene, theyhad.spr~ad along the4~thY'd-~~'2:\t~.ay:and all the

154

HORNS, TUSKS, AND FLIPPERS

Figure 7.15. Comparison of the skull of a modern Heterohyrax brucei (small specimen) and the giant Oligocene Megalohyrax eocaenus from Egypt. (Photo courtesy D. T. Rasmussen).

OUT OF AFRICA way to the Caribbean. However, hyraxes, arsinoitheres, and proboscideans became restricted to Africa in the Eocene and Oligocene, where they developed into a wide variety of ecologies that completely dominated the environment in the absence of competition from Eurasian perissodactyIs or artiodactyls. By the late Oligocene and Miocene Eurasian immigrants (anthracotheres, ruminant artiodactyls, cats and dogs, and many others) began to invade the African sanctum. As a result, the arsinoitheres became extinct, the hyraxes were greatly reduced in diversity and became more specialized, and the proboscideans became more specialized as the large-bodied herbivore. Throughout the Miocene, more

155

and more Eurasian mammals invaded, and Africa lost many of its peculiarities. One group of hyraxes, the pliohyracines, successfully invaded Eurasia, where they became specialized large-bodied aquatic browsers that were long confused with chalicotheres. Since the extinction of pliohyracines at the end of the Pliocene, however, only a pitiful remnant of hyrax diversity survives in Africa. The sirenians, too, are being pushed to extinction in many parts of the world. The arsinoitheres and desmostylians have long been extinct. Sadly, this fate also seems to be pressing upon the most successful, widespread and popular of the tethytheres, the elephants.

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8. The Origin of Jumbo

GIANTS IN THE EARTH The giant bones that kept turning up in the New World Most cultures around the world have a mythology that were also a source of much mystery and consternation. The includes legends about giants. Typically, the legends hold Indian tribes usually attributed them to giant monsters that in the dark, mysterious past, gigantic races of humans fought by their ancestors, and incorporated them into their lived on Earth. They may have fought the gods, or been folklore. When these bones were first seen by white settlers, destroyed by floods. These legends were reinforced by the they were thought to be the bones of gigantic humans that discovery of gigantic bones, much larger than those of any had roamed Earth in Biblical times. Others thought the giant living human, all over the Mediterranean and Europe. The tusks so revered by the Indians were works of Satan, placed Greek philosopher Empedocles (492-432 B.C.) reported there to tempt the believer. In 1519 Cortez received the bone gigantic bones from Sicily, supposed remnants of a race of of a "giant," a gift from the friendly Tlascalan tribe of giants. The Roman historian Pliny mentioned fossil ivory in Mexico, during the conquest of the Aztecs. He sent it back the ground, and according to the historian Suetonius, to the King of Spain as proof that giants had once lived in Emperor Augustus (63 B.C.-14 A.D.) owned a collection of the New World. In 1706 the Reverend Cotton Mather of the huge bones that had been found on the island of Capri near Massachusetts Bay Colony pronounced them to be "the Pompeii. The skulls of elephants, with their huge central remains of godless giants drowned in Noah's Flood." He opening in front (for the trunk), were often thought to be the sent some bones to the Royal Society in London to have skulls of the one-eyed cyclops. them certified as evidence of this "wicked giant," since During the Middle Ages the huge bones were again some Biblical scholars were calculating Adam's height at attributed to gigantic humans or other monsters, supposedly 123 feet 9 inches. The Royal Society never pronounced its drowned in the Noachian Deluge. According to Genesis 6:4, opinion on the bones, although many members were becom"There were giants in the Earth in those days" [before ing skeptical of literal interpretations of Genesis. The blinding effect of religious dogma about giants and Noah's flood]. Giant tusks from Siberia were thought to be the horn of the mythical unicorn, or the tusks of dragons. In the Flood was complicated by another idea: the notion of some places, gigantic teeth or vertebrae of mammoths were Divine Providence. An omnipotent, benevolent God would revered as the relicts of saints. Nearly every possibility was never allow any creature to become extinct. As the poet suggested except that these were the bones of extinct ele- Alexander Pope wrote in Essay on Man, "Who sees with phants (Fig. 8.1). equal eye, as God of all, a hero perish, or a sparrow fall." In the early seventeenth century some giant bones dug The prevailing concept was that of a "Great Chain of Being" up in a sandpit near Langon in southeastern France became linking the animals to man to the angels to God. Breaking very famous. They were exhibited around France as -the any link in that chain implied the destruction of the whole remains of the gigantic Teutons, Germanic tribes which had chain. In the same poem, Pope also wrote, once roamed Gaul and been defeated by the Romans in 101 "Where, one step broken, the great scale's B.C. But in 1613 the famous anatomist Riolan attacked the destroy'd: prevailing interpretation, and suggested that the bones were From Nature's chain whatever link you strike, from an elephant. This generated a raging controversy Ten or ten thousandth, breaks the chain alike." between the physicians and anatomists, who thought they were elephant bones, and the barber-surgeons, who called By the late 1700s, however, it was becoming more and them gigantic human bones. Others thought that they were hoaxes, or generated by mysterious "plastic forces" which more obvious that many of the recently discovered fossils 'percolated through the earth. Still others attacked the had no living counterparts. The remote corners of the world anatomists for questioning the Biblical account of giants on were being explored, and although many new and surprising Earth. The controversy died down in 1618 without being beasts were discovered, clearly the gigantic mammoths were - _:fesQl:v~d~and_for the next two ceJJ,t~"~:::~~~_,most_J~~?pl~.c()!1_~_ not hiding in South America or Africa or the East Indies. -'Many stran-ge- fossils, such as the bones of hippopotami in tinued to interpret new finds as gigantic humans.

158

HORNS, TUSKS, AND FLIPPERS

Figure 8.2. The "American incognitum ," a mastodon tooth from North America that puzzled scientists for over a century. This illustration is from Button (1778). Paris, were clearly related to tropical animals, but it was assumed that the bones had been washed out of the tropics during the Great Flood. The notion of extinction was still blasphemous. The New World soon provided unequivocal evidence that these large bones were not simply gigantic humans. In 1739 Charles Ie Moyne, the second Baron de Longueil, left Montreal with French and Indian troops to fight the Chickasaw Indians along the Ohio River. Somewhere along the Ohio, he found the remains of what appeared to be three elephants. When the war ended in 1740 he collected them and shipped them to New Orleans, and ultimately to Paris, where they came to the attention of French naturalists. In the 1740s and 1750s English settlers in the region sent more of these bones from Big Bone Lick, Kentucky, off to England and also to Benjamin Franklin in America. Most of the bones (especially the tusks) were clearly like those of elephants and mammoths-but the teeth were puzzling (Fig. 8.2). They were clearly unlike any living elephant, yet they were part of an animal of elephantine size. [We now know that these were specimens of the American mastodon]. Franklin speculated that the teeth were reminiscent of a carnivorous animal, although he and others later decided it was a vegetarian. In 1769 the famous British anatomist William Hunter took the camivory suggestion seriously, and suggested this was not a true elephant, but a "pseudelephant" or "American incognitum" [Latin for "unknown"] which had independently developed ivory tusks. "This monster, with the'agi,l,i4'YJ'aIr~·Jerocityof:a,:tig. ill=-=-;.