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BIOLOGY, MEDICINE, AND SURGERY OF

BIOLOGY, MEDICINE, AND SURGERY OF ELEPHANTS

Murray E. Fowler Susan K. Mikota Murray E. Fowler is the editor and author of the bestseller Zoo Authorization to photocopy items for internal or personal use, or and Wild Medicine, Fifth Edition (Saunders). He has written the internal or personal use of specific clients, is granted by Medicine and Surgery of South American Camelids; Restraint and Blackwell Publishing, provided that the base fee is paid directly to Handling of Wild and Domestic and Biology; and Medicine the Copyright Clearance Center, 222 Rosewood Drive, Danvers, and Surgery of South American Wild Animals for Blackwell. He is cur- MA 01923. For those organizations that have been granted a pho- rently Professor Emeritus of Zoological Medicine, University of tocopy license by CCC, a separate system of payments has been California-Davis. For the past four years he has been a part-time arranged. The fee codes for users of the Transactional Reporting employee of Ringling Brothers, Barnum and Bailey’s Circus. Service are ISBN-13: 978-0-8138-0676-1; ISBN-10: 0-8138-0676- 3/2006 $.10. Susan K. Mikota is a co-founder of Care International and the Director of Veterinary Programs and Research. She is an First edition, 2006 author of Medical Management of the Elephants and numerous arti- cles and book chapters on elephant healthcare and conservation. Library of Congress Cataloging-in-Publication Data

© 2006 Blackwell Publishing Elephant biology, medicine, and surgery / edited by Murray E. All rights reserved Fowler, Susan K. Mikota.—1st ed. p. cm. Blackwell Publishing Professional Includes bibliographical references and index. 2121 State Avenue, Ames, Iowa 50014, USA ISBN-13: 978-0-8138-0676-1 (alk. paper) ISBN-10: 0-8138-0676-3 (alk. paper) Orders: 1-800-862-6657 1. Asiatic elephant—Diseases. 2. —Diseases. Office: 1-515-292-0140 3. Captive wild animals—Diseases—Southeast Asia 4. Captive Fax: 1-515-292-3348 wild animals—Diseases—Africa. 5. Veterinary medicine—Southeast Web site: www.blackwellprofessional.com Asia 6. Veterinary medicine—Africa. 7. Veterinary surgery— Southeast Asia 8. Veterinary surgery—Africa. I. Fowler, Murray E. II. Blackwell Publishing Ltd Mikota, Susan K. 9600 Garsington Road, Oxford OX4 2DQ, UK Tel.: +44 (0)1865 776868 SF997.5.E4B56 2006 636.9676—dc22 Blackwell Publishing Asia 2006002167 550 Swanston Street, Carlton, Victoria 3053, Australia Tel.: +61 (0)3 8359 1011 The last digit is the print number: 9 8 7 6 5 4 3 2 1

Cover design by Hank Hammatt Contents

Contributors vii 12. Parasitology 159 Murray E. Fowler Acknowledgments xi 13. Antemortem Diagnostics 183 Introduction xiii Section I: General Techniques 183 01. Taxonomy, Classification, History, and 3 Susan K. Mikota Evolution of Elephants Section II: Radiology 192 Jeheskel Shoshani Laurie Gage 02. Elephants in Captivity 15 14. Postmortem Diagnostics 199 Blair Csuti Richard J. Montali 15. Therapeutics 211 03. Laws and Legislation 23 Susan K. Mikota Denise M. Sofranko Color Section 04. Behavior and Social Life 35 16. Neonatal Care and Hand Rearing 233 Bruce A. Schulte Karen Emanuelson

05. Husbandry 45 17. Multisystem Disorders 243 John Lehnhardt Murray E. Fowler 18. Integument System 253 06. Nutrition 57 Susan K. Mikota Ellen S. Dierenfeld 19. Musculoskeletal System 263 07. Preventive Health Care and Physical 67 Gary West Examination 20. Foot Disorders 271 Susan K. Mikota Murray E. Fowler

08. Physical Restraint and Handling 75 21. Respiratory System 291 Murray E. Fowler Ramiro Isaza 22. Digestive System 299 09. Chemical Restraint and General 91 Genevieve A. Dumonceaux Anesthesia Section I: Chemical Restraint 91 23. Endocrine and Immune Systems 309 Murray E. Fowler and Susan K. Mikota Linda J. Lowenstine Section II: General Anesthesia 110 24. Cardiovascular System 317 Eugene P. Steffey Susan Bartlett 10. Surgery and Surgical Conditions 119 25. Hemolymphatic System 325 Murray E. Fowler Susan K. Mikota 11. Infectious Diseases 131 26. Reproductive System 347 Murray E. Fowler Dennis Schmitt

v vi CONTENTS

27. Reproductive and Diagnostic 357 Appendices Ultrasonography Appendix 1. Abbreviations Used in This 491 Thomas B. Hildebrandt Book Appendix 2. Measurement Conversion 493 28. Reproductive Endocrinology 377 Tables Janine L. Brown Appendix 3. Sources for Agents Used in 495 29. Urinary System 389 Sedating, Tranquilizing, Immobilizing, R. Eric Miller and Anesthetizing Elephants Appendix 4. Toxicology Terms, 497 30. Nervous System 393 Abbreviations, and Equivalents Michele Miller Appendix 5. Elephant Vital Signs and 499 31. Special Senses 399 Physiological Parameters Wm. Kirk Suedmeyer Appendix 6. Glossary of Terms Associated 501 with Elephant Feet 32. Chemical, Tactile, and Taste Sensory 409 Appendix 7. Weight Conversion Chart for 505 Systems Asian Elephants L. E. L. Rasmussen Appendix 8. Conversion Between 507 33. Toxicology 415 Conventional and SI Units, Hematology Murray E. Fowler Appendix 9. Conversion Between 509 Conventional and SI Units, Blood 34. Zoonoses and Human Injury 431 and Fluid Chemistry Joel Maslow Appendix 10. AZA Standards for Elephant 511 35. Veterinary Problems of Geographical 439 Management and Care Concern Appendix 11. Guidelines for Elephant 519 Introduction 439 Management and Care (EMA) Susan K. Mikota and Murray E. Fowler Appendix 12. Guidelines for Comprehensive 525 Section I Africa 439 Elephant Health Monitoring Program Jacobus G. du Toit (AZA/SSP) Section II India 444 Appendix 13. Quarantine Guidelines for 535 Jacob V. Cheeran and K. Chandrasekharan Elephants (AZA/SSP) Section III Indochina and Bangladesh 447 Appendix 14. Recommended Elephant 537 Paolo Martelli Preshipment Guidelines (AZA/SSP) Section IV Indonesia 454 Appendix 15. Transport Guidelines for 543 Yudha Fahrimal and Retno Sudarwati Elephants (AZA/SSP) Section V Malaysia 457 Index 545 Vellayan Subramanian Section VI Myanmar 460 Khyne U Mar Section VII Nepal 465 Sunder Shrestha and Kamal P. Gairhe Section VIII Sri Lanka 468 Indira Silva and Ashoka Dangolla 36. Conservation 475 Simon Hedges Contributors

Susan Bartlett Genevieve A. Dumonceaux 9 Evergreen Lane Busch Gardens Tampa Bay Ithaca, NY 14850 P.O. Box 9158 [email protected] Tampa, FL 33612 [email protected] Janine L. Brown 1500 Remount Road Jacobus G. du Toit Front Royal, VA 22630 P.O. Box 12780 [email protected] Onderstepoort 0110 South Africa K. Chandrasekharan [email protected] “Sarada Vihar” Opposite Mathrubhumi office Karen Emanuelson Veliyannur 370 Mt. Sequoia Place Thrissur-680 021 Clayton, CA 94517 Kerala, India [email protected]

Jacob V. Cheeran Yudha Fahrimal Director of Technical Services Faculty of Veterinary Science Cheerans Lab (P) Ltd. University of Syiah Kuala Animal Health Division Darussalam, Banda Aceh 23111 New Church Street Indonesia Trichur 680 001 [email protected] Kerala, India [email protected] Murray E. Fowler 427 Cabrillo Avenue Blair Csuti Davis, CA 95616 Department of Biology [email protected] Portland State University P.O. Box 751 Laurie Gage Portland, OR 97207-0751 USDA, APHIS, Animal Care 2150 Centre Ave., Building B Ashoka Dangolla Fort Collins, CO 80526 Department of Veterinary Clinical Sciences [email protected] University of Peradeniya Peradeniya, 20400 Sri Lanka Kamal P. Gairhe [email protected] Veterinary Officer Royal Chitwan National Park Ellen S. Dierenfeld Chitwan, Nepal St. Louis Zoological Park [email protected] Forest Park, One Government Drive St. Louis, MO 63110 [email protected]

vii viii CONTRIBUTORS

Simon Hedges Susan K. Mikota Coordinator Director of Veterinary Programs and Research Wildlife Conservation Society Elephant Care International International Programs 438 N. Central Ave. c/o 1 Kearstwick Cottages Waveland, MS 39576 Kearstwick, Kirkby Lonsdale [email protected] Cumbria, LA6 2EB, U.K. www.elephantcare.org [email protected] Michele Miller Thomas B. Hildebrandt Disney’s Animal Kingdom Head, Department of Reproduction Management Department of Veterinary Services Institute for Zoo Biology and Wildlife Research P.O. Box 10,000 Alfred-Kowalke-Str. 17 Lake Buena Vista, FL 32830-1000 D-10315 Berlin, Germany [email protected] [email protected] R. Eric Miller Ramiro Isaza St. Louis Zoos Wildcare Institute Department of Small Animal Clinical Sciences One Government Drive College of Veterinary Medicine St. Louis, MO 63110 University of Florida [email protected] P.O. Box 100126 Gainesville, FL 32610 Richard J. Montali [email protected] 6624 East Wakefield Drive Apt B-2 John Lehnhardt Alexandria, VA 22307 Animal Operations Director [email protected] Disney Animal Kingdom P.O. Box 10,000 L. E. L. Rasmussen Lake Buena Vista, FL 32830-1000 Professor, Department of Environmental & Biomolecular [email protected] Systems Oregon Graduate Institute, School of Science & Engineering Linda J. Lowenstine OHSU-West Campus Department of Pathology, Microbiology & Immunology 20,000 N.W. Walker Road School of Veterinary Medicine Beaverton, OR 97006 University of California [email protected] Davis, CA 95616 www.bmb.ogi.edu/BMB rasmussen.html [email protected] Dennis Schmitt Khyne U Mar Professor, Dept. of Agriculture Institute of Zoology Missouri State University Zoological Society of London 901 South National Ave. Regents Park Springfield, MO 65897 London NW1 4RY [email protected] [email protected] or [email protected] Bruce A. Schulte Paolo Martelli Department of Biology Chief Veterinarian P.O. Box 8042 Ocean Park Corporation Georgia Southern University Aberdeen, Hong Kong Statesboro, GA 30460-8042 [email protected] [email protected]

Joel Maslow Jeheskel Shoshani ACOS for Research Department of Biology, University of Asmara VA Medical Center P.O. Box 1220 University and Woodland Avenues Asmara, Eritrea Philadelphia, PA 19104 Elephant Research Foundation [email protected] 106 East Hickory Grove Road Bloomfield Hills, MI 48304 [email protected] [email protected] CONTRIBUTORS ix

Sunder Shrestha Wm. Kirk Suedmeyer Albert Einstein College of Medicine University of Missouri-Columbia 1300 Morris Park Avenue College of Veterinary Medicine Ullman 1103, lAS Columbia, MO 65211 Bronx, NY 10461 Director of Animal Health [email protected] The Kansas City Zoo 6800 Zoo Drive Indira Silva Kansas City, MO 64132 Department of Veterinary Clinical Sciences [email protected] University of Peradeniya Peradeniya, 20400 Sri Lanka Vellayan Subramanian [email protected] Zoo Negara Malaysia [email protected] Ulu Klang, 68000 Ampang, Selangor Denise M. Sofranko [email protected] USDA, APHIS, Animal Care [email protected] 2150 Centre Ave., Building B Fort Collins, CO 80526 Gary West [email protected] Oklahoma City Zoological Park 2101 NE 50th Street Eugene P. Steffey Oklahoma City, OK 73111-7199 Surgical & Radiological Sciences Oklahoma State University School of Veterinary Medicine College of Veterinary Medicine University of California Dept. of Veterinary Clinical Science Davis, CA 95616 Stillwater, OK 74078 [email protected] [email protected]

Retno Sudarwati Taman Safari Indonesia Jl. Raya Puncak No. 601 Cisarua, Bogor (16750) Indonesia [email protected]

Acknowledgments

The editors express appreciation to the authors of this formats and sizes and scanned at various resolutions, re- book for their willingness to spend countless hours quiring considerable effort to put them into a publish- bringing together the state of the art concerning the able form. wellbeing of elephants. Likewise, those who have con- Thanks also to Audrey Fowler for her support and tributed to the world’s literature have added immeasur- encouragement and to the Alexander Abraham Foun- ably to this collective presentation. dation for its support of Elephant Care International, Special thanks to Hank Hammatt who has patiently which helped to make this work possible. and professionally edited and managed the illustrations Murray E. Fowler for the book. Photographs were submitted in numerous Susan K. Mikota

xi

Introduction

Murray E. Fowler and Susan K. Mikota

Elephants are possibly the most well-known animal in Elephant, 1971), U Toke Gale (The Burmese Timber the animal kingdom. The enormous size, unusual Elephant, 1974), and others certainly contributed to our anatomy, and longevity of elephants have fascinated collective knowledge of elephant care and husbandry at humans for millennia. Today, their intelligence, strong the time. family bonds, and the irresistible appeal of their young But despite the fact that one-third of all Asian ele- continue to endear them to many. phants remaining in the world are in captivity, no mod- Elephants have served man as a means of transport, ern comprehensive text on elephant medicine and sur- a vehicle for carrying soldiers into war, and laborers in gery exists. The editors and contributing authors hope the timber industry. Despite the long association of that this volume will begin to fill that void. Thirty-six elephants with man they have never been truly domes- scientists and clinical veterinarians have shared their ex- ticated. pertise and experiences to compile information on biol- Elephants evoke strong emotions and opinions. ogy, husbandry, and veterinary medicine and surgery of Depending on circumstances, elephants may be viewed the elephant as we know it today. as objects of worship, beasts of burden, food for a village, Each author presents his or her experiences plus an endangered worthy of the highest conserva- those of others expressed in the literature. Although not tion efforts, or as crop-raiding killers. an exhaustive literature review, over 3000 references are The highly specialized morphology of the elephant is cited to provide readers the opportunity to delve more depicted by John Godfrey Saxes’ (1817–1887) poem based deeply into specific topics. The opinions expressed are on the famous Indian fable (see page xv). We chose to those of the authors. present this poem because much like the blind men, Free-ranging elephants face a precarious future. there is still much we do not know about elephants. Habitat loss, poaching, and exploitation are decimating As long as humans have kept elephants in captivity, many populations to near extinction. Elephants and their health care has been a topic of concern. One of the man compete for limited space and resources in Africa earliest recorded treatments of an elephant was of and Asia. Reports of human-elephant conflict appear in “Kadol Etha” belonging to King Dutugemunu (161–137 the news almost daily, with losses incurred on both B.C.). Kadol was treated for wounds sustained from sides. molten metal. The first treatises on elephant health care Captive or “domesticated” elephants in Asia also face were written in Asia over 2000 years ago (the uncertainty because the timber industry in most Asian Hastiayurveda and Gajasastra). Scientific articles began countries no longer requires the labor once provided by to appear in the 19th century. In the 20th century the elephants. Many of these elephants now find them- works of G. H. Evans (Elephants and Their Diseases, 1910), selves in an urban environment with no chance of for- A. J. W. Milroy (Management of Elephants in Captivity, aging for natural feeds and often no access to proper vet- 1922, republished by S. S. Bist in 2002), Francis Benedict erinary care. (The Physiology of the Elephant, 1936), G. Pfaff (Reports on Anecdotal information has always been and will con- the Investigation of Diseases of Elephants, 1940), A. J. tinue to be important to the care of elephants. It is Ferrier (The Care and Management of Elephants in Burma, hoped that this book will open a venue for the greater 1947), Sylvia Sikes (The Natural History of the African sharing of such information. At the same time the

xiii xiv INTRODUCTION paucity of information currently available on some top- ics may help to focus attention on areas of needed re- search. Those with special expertise and experience who have a bearing on the topics involved in the book are in- vited to contact the editors so that a future edition may reflect expanded information and other viewpoints. Elephants deserve our care and our concern for their welfare.

Murray E. Fowler Susan K. Mikota 427 Cabrillo Avenue Elephant Care International Davis, CA 95616 438 N. Central Avenue [email protected] Waveland, MS 39576 [email protected] www.elephantcare.org The Blind Men and the Elephant

It was six men of Indostan The Fourth reached out an eager hand, To learning much inclined, And felt about the knee: Who went to see the Elephant “What most this wondrous beast is like (Though all of them were blind), Is mighty plain,” quoth he; That each by observation “‘Tis clear enough the Elephant Might satisfy his mind. Is very like a tree!”

The First approached the Elephant, The Fifth, who chanced to touch the ear, And happening to fall Said: “E’en the blindest man Against his broad and sturdy side, Can tell what this resembles most; At once began to bawl: Deny the fact who can, “God bless me! but the Elephant This marvel of an Elephant Is very like a wall!” Is very like a fan!”

The Second, feeling of the tusk The Sixth no sooner had begun Cried, “Ho! what have we here, About the beast to grope, So very round and smooth and sharp? Then, seizing on the swinging tail To me ‘tis mighty clear That fell within his scope. This wonder of an Elephant “I see,” quoth he, “the Elephant Is very like a spear!” Is very like a rope!”

The Third approached the animal, And so these men of Indostan And happening to take Disputed loud and long, The squirming trunk within his hands, Each in his own opinion Thus boldly up he spake: Exceeding stiff and strong, “I see,” quoth he, “the Elephant Though each was partly in the right, Is very like a snake!” And all were in the wrong!

xv

BIOLOGY, MEDICINE, AND SURGERY OF ELEPHANTS

Taxonomy, Classification, 1 History, and Evolution of Elephants

Jeheskel Shoshani

INTRODUCTION An example of the applicability of classification and also of phylogeny is in the fields of communicable diseases, Biological classification is categorization and organization zoonotic diseases, susceptibility and resistance to dis- of organisms by their unique characters. A sound classifi- eases in general (discussed later), and organ transplant. cation with standardized scientific names provides a uni- The more closely related two animals are, the more versal language for laymen and scientists alike in cases likely that incompatibility will be reduced and the bet- where common names are not standardized. ter chances for a successful transplant.42 During the 18th and 19th century, however, the con- cept of homology was just beginning to emerge, and grouping of animals was based on external morphology DEFINITIONS and habitat. In this system, manatee was grouped with Clade. A cluster of taxa derived from a single common seals (as “Aquatilia” of Scopolli 1777) or with cetaceans ancestor. (as “Natalia” of Illiger 1811), and elephants were grouped with rhinoceroces and tapirs as “Pachydermes” Cladistic methods. A mode of classification based, in (of G. Cuvier 1800). A summary of these earlier ideas of principal, on grouping of taxa that possess shared, simi- 35 classfication is given in Shoshani. lar (“derived”) characters that differ from the ancestral In modern times, to classify an organism, a re- condition. searcher must follow certain rules and procedures. To facilitate classifications, taxonomists developed guide- Cladogram. A tree diagram representing phylogenetic lines, the Code of Nomenclature (International Com- (or cladistic) relationships among taxa based on their 20 mission of Zoological Nomenclature 1999) (referred to shared-derived characters or synapomorphies. hereafter as “the Code”), which is updated on a regular basis. The Code guides the naming of the taxa, not their Classification. The practice of grouping organisms into discovery and conception. It emerges that classification, a hierarchy of categories ranging from subspecies, taxonomy, systematics, and phylogeny are all interre- species, genera, families, orders, classes, phyla, and king- lated. Information from one discipline can be applied to doms (except for the subspecies, all these are obligatory another; this can easily be understood when comparing categories, see definition below). Taxa included in each their definitions (these terms are defined in the section of these categories are entities to themselves encompass- “Definitions” below). The field of phylogeny, however, ing unique features. Thus, organisms classified in a requires some elaboration. Relationships among taxa species are more similar to each other than they are to can be obtained and tested using cladistic or phyloge- members of other species in the same genus. Similarly, netic methods, employing morphological or molecular genera in one family share more characters with each characters. In ideal situations, results from both ap- other than with genera in other families, and so on. proaches corroborate each other. One school of thought holds that cladistic or phylogenetic relationships Grade. Distantly related or unrelated species (or taxa) should be reflected in the classification (more on that that reach the same level due to parallel or convergent later).16 evolution. The main purpose of classifying animals and plants is to facilitate better communication among scientists. Homology. Shared similarity due to common descent.

3 4 ELEPHANT BIOLOGY, MEDICINE, AND SURGERY

Nomenclature. The practice of giving names to animals belonged to one species. Thus, the name max- and plants. imus given by Linnaeus in 1758 was apparently based on a fetus of an African elephant and a specimen of the Obligatory categories in classification. The major Asian elephant. It is believed that Elephas maximus of ranks (or categories) that are usually employed in classi- Linnaeus combines these two different elephant fication of organisms. They include the species, genus, species—Elephas for the Asian elephant, and maximus for order, family, class, phylum, and kingdom. All other cat- the African elephant, the larger of the two species (de- egories, such as those with the prefix sub- or super- (e.g., tails are given in Shoshani and Tassy,40 pp. 354 and 360). subfamily, superfamily, subclass, and superclass) are not The etymology of the word elephant or Elephas is obligatory of formal, general classification. from ele, a Greek derivative meaning an arch, and phant or phas from the Greek/Latin derivative meaning fantas- Phylogeny. The evolutionary history of common de- tic or huge. Thus, elephant or Elephas translates into a scent or of a lineage (that is, of a species or a group of huge arch (from the shape of an elephant in side view). species) as related to their ancestor-descendant relation- A separate scientific name for the African elephant ships. In a restricted sense, the history of descent of a (Loxodonta africana) was coined in 1827, 69 years later. given set of taxa. The genus name Loxodonta describes the lozenge pat- tern of the enamel loops on the chewing (occlusal) sur- Species. A basic taxonomic category. In the biological face of the tooth, and the species name, africana (note species concept, a species (taxon) includes interbreeding lowercase a) refers to the origin and habitat of this ani- or potentially interbreeding populations possessing mal; it is usually found in savannahs of sub-Saharan unique characters and reproductively isolated from Africa. The other elephant species in Africa is the forest other such groups (taxa), under natural conditions. African elephant (Loxodonta cyclotis), found in forested regions of central and western Africa. The species name Systematics. The study of diversity of organisms and cyclotis describes the roundish shape (cycl) of the ear their comparative and evolutionary relationships (otis). In the africana species the ear has a trapezoidal (= classification and taxonomy). shape. Not all authorities subscribe to the two species concept of the African elephant; some still hold that Taxon (plural taxa). A group of organisms that share there is one species with two subspecies—L. a. africana common characters, included at any level of the classifi- and L. a. cyclotis (more on that below). cations (e.g., species, genus, or family). LINNAEAN CLASSIFICATION AND THE CODE Taxonomy. The discipline including the rules and pro- cedures used to classify organisms. The Binomial Classification, established by Linnaeus in 1758, is the most commonly used system today. The CLASSIFICATION IN HISTORICAL Code of Nomenclature is an attempt to standardize the PERSPECTIVE work of taxonomists and systematists, including no- menclaturists and classifiers, and to provide some pub- Among the earliest attempts to organize and classify or- lished guidelines and rules that are regularly updated ganisms was that attributed to Aristotle, the Greek (see International Commission of Zoological Nomen- philosopher and naturalist (384–322 B.C.). Aristotle, it is clature 1999).20 Binomial Classification and the Code believed, came to view nature as a continuum of organiza- are closely related, but for practical purposes, I present tion, from lifeless matter through the complex forms of the two subjects separately. plants and animals. Carolus Linnaeus (Latinized name from Carolus Linné, lived from 1707–1778), a Swedish Binomial and Trinomial Classification botanist, was the first authority to develop a formal classi- Recall that in this system, each species is given two fication scheme for organisms, giving them two-part names: the genus and the species. Both names must be names (hence the term Binomial Classification); the first is Latinized, although their origin may be Latin, Greek, or the genus and the second is the species, and both are de- another language. The first letter of the genus is written scriptive names. This system is still used by most taxono- in uppercase and all subsequent letters of the genus and mists. The 10th edition of Linnaeus’s book Systema species are in lowercase, even if the species name is after Naturae23 (published in 1758) is considered the primary a locality or a person. For example, the scientific name treatise on classification, and 1758 is taken to be the begin- of the Asian elephant is Elephas maximus and that of the ning date for which published scientific names are valid. American is Mammut americanum (to accen- It is important to keep matters in perspective. tuate the names they are italicized, underlined, or writ- Linnaeus was a devout, religious man. This was reflected ten in different formats from the rest of the text). When in his belief that the number of species created was lim- there is sufficient anatomical evidence to divide a ited. In this context, the African and the Asian elephants species into two or more subspecies, we use three names CHAPTER 1 TAXONOMY, CLASSIFICATION, HISTORY, AND EVOLUTION OF ELEPHANTS 5

(hence the term Trinomial). For example, the scientific phas maximus, the African elephant (Loxodonta afri- name of the Asian elephant from Sri Lanka is Elephas cana), and woolly (Mammuthus primigenius) maximus maximus; other examples are given below. are distinctly unique yet they share similar characters The next step in this process is to place the species in and should be grouped in the subfamily Elephantinae, a higher category. In the Linnaean system of classifica- family . The skeleton of Mammut ameri- tion, the primary or obligatory categories, from higher canum possesses very different sets of characters; thus, it to lower are Kingdom, Phylum, Class, Order, Family, was decided to classify it in another family, the Mam- Genus, and Species. It is not an easy matter to decide mutidae. Elephantidae, , and other fami- into which hierarchy or category to place a newly found lies that share similar characters due to common ances- species. The criteria that govern this decision have to do try were then grouped under the umbrella of a higher with the differences between genus and family level, category, called Order, the . Related orders and they are related to the size of the gap of characters are classified in one Class, classes are grouped under a between different categories. Suffice it to say that in the Phylum, and phyla under a Kingdom. An example of a example of the Asian elephant given above, scientists simplified classification of the Proboscidea within determined that, based on anatomical characters, Ele- Animalia is given in Table 1.1. Note that the suffixes of

Table 1.1. A Partial, Simplified Classification of Proboscidean Taxa*

Category (= Rank) Taxon Kingdom Animalia Phylum Chordata Subphylum Vertebrata Class Mammalia Nonranked Uranotheria (= )a Order Hyracoidea Nonranked Order Sirenia Order Proboscidea Nonranked Mammutidab Superfamily Mammutoideab Family Mammutidaeb Genus Mammutb Species Mammut americanumb,c Nonranked Superfamily Gomphotherioideab Family Gomphotheriidaeb Genus & Species angustidensb Superfamily Family Stegodontidaeb Genus & Species zdanskyib Family Elephantidae Subfamily Elephantinae Tribe Loxodontini Genus & Species Loxodonta cyclotisd Loxodonta africanae Tribe Elephantini Genus & Species Elephas maximusf Subspecies Elephas maximus sumatranusg Elephas maximus indicush Elephas maximus maximusi Genus & Species Mammuthus primigeniusb,j *Refer to Figure 1.1 for depiction of the species on the cladogram; modified after Shoshani 2000, p. 22, and other sources. aAfter McKenna et. al. 1997. b= extinct. cThe American mastodon, now extinct, osteological remains were found in North America. dThe Forest African elephant, living (see text for possible use of the subspecies name Loxodonta africana cyclotis). eThe Bush or Savanna African elephant, living (see text for possible use of the subspecies name Loxodonta africana africana). fThe Asian elephant, living. gThe Sumatran Asian elephant subspecies, living (found on the island of Sumatra). hThe Indian, or mainland Asian elephant subspecies, living (found in India and Indochina). iThe Sri Lankan Asian elephant subspecies, living (found on the island of Sri Lanka, formerly Ceylon). jThe woolly , extinct; remains and intact carcasses were found frozen in the Arctic. The Colombian mammoth (Mammuthus columbi), extinct; remains were found in North America. 6 ELEPHANT BIOLOGY, MEDICINE, AND SURGERY family names in any classification of animals are always F. Cuvier’s work appeared. It was not clear from the text idae and those of subfamilies are inae. These two con- who was the writer who Latinized the name; for this rea- ventional suffixes help identify quickly these categories son, the scientific name of the African elephant appears or ranks. as Loxodonta Anonymous, 182740 (details in Shoshani In this classification (Table 1.1), it is noted that en- and Tassy 1996, p. 361). tries are indented such that the taxon listed below is nested within the taxon listed above it. This system em- NUMBERS OF PROBOSCIDEAN SPECIES bodies the idea that one or more species are grouped in AND SUBSPECIES a genus, one or more genera are grouped in a family, and so on. Some aspects of the process of giving names of Living and Extinct Taxa ranks to certain taxa are discussed below. In 1942 Henry Fairfield Osborn recognized 352 species Table 1.1 also reflects the relationships among and subspecies of Proboscidea, living and extinct. The Hyracoidea (hyraxes), Sirenia (manatees and dugongs), most recent revision was that of Shoshani and Tassy,40 and Proboscidea.26 Shared, derived, characters among where they recognized 177 species and subspecies classi- Hyracoidea, Sirenia, and Proboscidea include serial ver- fied in 43 genera and at least 10 families. Since then sus alternate carpal bones, and affinity between Sirenia Sanders34 named one new genus and five new species, and Proboscidea include bifid heart39 (see also figure on bringing the total to 182 species and subspecies and 44 p. 16 of Shoshani).37 genera. Of these, today there are two extant genera, with three species. Living elephants are listed by CITES The Code (Convention on International Trade in Endangered Being a reference of standard terminologies, recommen- Species of Wild Fauna and Flora) either in Appendix I or dations, and rules, the Code is the authority for a taxon- in Appendix II. Appendix I includes taxa that are threat- omist. An important rule in nomenclature and classifi- ened with extinction and are or may be affected by cation is the Principle of Priority (published in the trade. Appendix II species need not be threatened, but Code, see International Commission of Zoological either require regulation so that they do not become so Nomenclature 1999).20 This principle states that if two or must be listed to help control trade in other species, different names have been given to the same animal or the so-called “look-alike species.”30 The vast majority of plant by two different researchers, the one that was pub- living elephant populations are continuously decreas- lished first is valid. For example, in 1817 the famous ing due to shrinking range or habitat fragmentation. French anatomist Georges Cuvier coined the name Mastodonte for an animal that was found in Big Bone Living Taxa Lick site, not far from the Ohio River, Kentucky, USA. It Generalized Features and Medicine. Today we recog- appears that G. Cuvier and C. S. Rafinesque (who in 1814 nize three living species of elephants, classified in two coined the name Mastodon for the same animal) were genera—Loxodonta and Elephas (Tables 1.2 and 1.3 in- not aware of the publication of Johan F. Blumenbach, a clude differences between these genera). Based on the German naturalist, who, in 1799, named the same ani- available morphological evidence, Loxodonta, repre- mal Mammut. Following the Principle of Priority, the sented by the living African elephant, appears to be older name has prevailed (details in Shoshani and more primitive than Elephas, represented by the living Tassy,40 p. 351). Asian elephants. Both Loxodonta and Elephas originated If only the genus name is employed, the author of in East Africa, and yet Loxodonta is believed to embody the name and the year it was published follows it—e.g., more generalized features than Elephas.25,40 From the Mammut Blumenbach, 1799. If, however, the species medical standpoint, it is noted that generalized mam- name is also to be included, it also is followed by the au- mals (e.g., insectivores) are better adapted than special- thor and year of publication—Mammut americanum ized (e.g., horses) to cope with living in differ- (Kerr, 1792). Note that the author and year are written ent habitats.3,4 It could be argued that generalized inside the parentheses ( ). This is because the original mammals may be better adapted to fight diseases than Type Species name coined by Kerr for the same animal specialized mammals. To test this hypothesis a survey of was Elephas americanus; thus, the credit still goes to the diseases known to occur in the African versus the Asian original author who first named the species, even elephant should be conducted. It is predicted that the though it is no longer a valid original genus name (in African species (L. cyclotis and L. africana) would be this case, Mammut is the valid generic name, see above). more resistant to diseases—including communicable Another important rule in the Code is the Latini- and zoonotic diseases—than the Asian species (E. max- zation of scientific names. In 1825, F. Cuvier coined the imus). Recent investigators have demonstrated different name Loxodonte for the African elephant. This name is susceptibilities to herpesvirus infection in captive Asian not valid because it is not Latinized (Article 11[b] of the versus African elephants32 and the apparent increased Code). In 1827 the Latinized version of this name prevalence of uterine cystic endometrial hyperplasia2 (Loxodonta) was used in the journal where the review of and uterine leiomyomas17 in Asian elephants. These Table 1.2. Major Differences Between the African and the Asian Elephant

7 8 ELEPHANT BIOLOGY, MEDICINE, AND SURGERY

Table 1.3. Major Differences Among Species and Subspecies of Elephants

Within the African Elephants, Loxodonta sp.* Bush Species Forest Species (L. africana)(L. cyclotis) Weight 4,000–7,000 kilograms 2,000–4,500 kilograms (8,820–15,430 pounds) (4,410–10,000 pounds) Height at shoulder 3–4 meters (10–13 feet) 2–3 meters (6 feet 7 inches–10 feet) Skin On average lighter On average darker Shape and size of ears Triangular, extend below line of neck Rounder, do not extend below line of neck Skull, cranium Much pneumatized Less pneumatized Skull, mandible Shorter Longer Tusks Curved out and forward, thicker Straighter, down-pointing, slender Number of naillike Forefeet 4 or 5 Forefeet 5 structures (“toes”) Hindfeet 3, 4 or 5 Hindfeet 4 or 5 in adults

Within the Asian Elephants, Elephas maximus** Sri Lankan Subspecies Mainland Subspecies Sumatran Subspecies (E. m. maximus)(E. m. indicus)(E. m. sumatranus) Weight 2,000–5,500 kilograms 2,000–5,000 kilograms 2,000–4,000 kilograms (4,410–12,125 pounds) (4,410–11,020 pounds) (4,410–8,820 pounds) Shoulder height 2–3.5 meters 2–3.5 meters 2-3.2 meters (6 feet 7 inches– (6 feet 7 inches– (6 feet 7 inches– 11 feet 6 inches) 11 feet 6 inches) 10 feet 6 inches) Skin color Darkest, with large and distinct Color and depigmentation in Lightest with least patches of depigmentation on between the other two depigmentation ears, face, trunk, and belly subspecies Size of ears Most have large ears Vary in size Appear large compared to body size Tusks incidence Lowest Intermediate Possibly the highest Number of ribs 19 pairs 19 pairs 20 pairs *Loxodonta cyclotis is more primitive than L. africana for these reasons: forest dweller, smaller, slender, and down-pointing tusks and other skull characters discussed by Grubb 2000. **Elephas maximus sumatranus is possibly the most primitive Asian subspecies for these reasons: forest dweller, smallest, has largest number of ribs, possibly has highest incidence of tusks, has least depigmented skin and other characters discussed by Deraniyagala 1955.

studies, however, examined only captive individuals in ans to extrapolate drug doses from one species to an- which husbandry and management issues may con- other. Again, little research into the comparative phar- found any genetic or taxonomic effect. Further research macology of nondomestic animals has been done for in this area would be valuable in the practical manage- any species, including elephants. See Chapter 15 for fur- ment of elephant populations as well as enhancing our ther information. general understanding of the association between tax- onomy and the balance between health and disease. The Loxodonta Group. Traditionally, the African ele- Taxonomy’s importance in understanding the po- phant was divided into two subspecies: L. africana tential health problems of elephants is highlighted by africana (the bush African elephant) and L. a. cyclotis the work of Hagey15 who described the unique use of (the forest African elephant, discussion in Grubb14 bile alcohols in elephants and a few of their closest rela- 2000). Recent taxonomic revision within this group is tives, the manatee and hyrax. All other mammals pro- manifested in dividing the African elephant into two duce bile acids as a product of cholesterol metabolism. species: the forest African elephant (L. cyclotis), and the The presence of bile alcohols instead of acids may make bush African elephant (L. africana; see Table 1.3, upper). elephants more susceptible to bacterial invasion and This taxonomy is not agreed upon by all scientists. cholelith formation.1 Grubb and Roca support the species concept,14,33 An understanding of taxonomy is also valuable whereas Debruyne5 provides data in support of the tra- when considering potential metabolic and physiologic ditional subspecies, L. a. africana and L. a. cyclotis. similarities in drug metabolism.21,29 Similar digestive Between the two African species, L. cyclotis is more prim- tracts or similar cholesterol metabolic pathways, for ex- itive than L. africana (discussed in detail by Grubb; see ample, might be empirically expected to absorb or also footnotes to Table 1.3). In addition to the two process a particular drug similarly, allowing veterinari- species of African elephants, Eggert reported on what CHAPTER 1 TAXONOMY, CLASSIFICATION, HISTORY, AND EVOLUTION OF ELEPHANTS 9 might be interpreted as a possible third species of birds28 and mammals13. In captivity, however, the ani- African elephant for the populations of the forest and mals are artificially placed together, and hybrids among savannah elephants of West Africa (these interpreta- animals that will never meet in the wild may occur. tions are not widely accepted).7 These findings are based Such was the case of “Motty,” the only known on DNA extracted from dung of elephants in Ghana, the between a male African elephant, “Jumbolino” Ivory Coast, Mali, and Cameroon. These elephants live (“Bubbles”), and a female Asian elephant, “Sheba.” This in both forest and savannah habitats. The study suggests hybrid was conceived in , England, in that, based on genetic data, the West African popula- 1978.18 Motty lived only 10 days; his skin is mounted at tions have been isolated from other elephant popula- the Natural History Museum (formerly British Museum tions for as long as 2.4 million years. of Natural History, London). Zoo authorities and other people doubted whether it would have been possible for The Elephas Group. We find less controversy in the the two elephant genera to hybridize. Unfortunately no taxonomy of the Asian elephant (E. maximus), where soft tissue samples were kept for future testing, but a Shoshani and Eisenberg (1982) recognized three sub- sample of small dry skin was collected from behind the species: the Sumatran Asian elephant (E. m. suma- ear of Motty and was used in immunological experi- tranus), the mainland Asian elephant (E. m. indicus), ments to test whether Motty was indeed a hybrid. The and the Sri Lankan Asian elephant (E. m. maximus).38 results confirmed that Motty’s tissue behaved like that Evolutionary trend among these subspecies is sug- of a , corroborating that it was a hybrid between gested. Thus, E. m. sumatranus is said to be the most Loxodonta africana and Elephas maximus.24 These results primitive of the three subspecies, E. m. maximus the are not totally surprising because the diploid chromo- most derived, and E. m. indicus an intermediate form. somes number in somatic cells for both elephant species Evidence for this trend includes 20 pairs of ribs in E. m. is 56.19 sumatranus and 19 pairs in E. m. maximus and E. m. indi- 37,43 cus. Other features include forested versus less- A SIMPLIFIED CLADOGRAM OF SELECTED forested dwelling; small versus large body size; ear PROBOSCIDEANS size; possibly high versus low incidence of tusks, tusk size, and shape (e.g., straight versus curved); and least Evolutionary relationship can be depicted either as a versus most skin depigmentation. Additional charac- “family tree” or as a cladogram (Fig. 1.1). A family tree ters and discussion on Asian elephant subspecies were may be compared to a genealogical family tree where provided by Deraniyagala.6 Table 1.3 summarizes these the origins of the great-great-grandparents of an indi- differences betweeen the subspecies of the Asian ele- vidual are being traced. In a family tree, such as the one phant. given in Shoshani37 (pp. 26–27), the direct line of ances- A recent study by Fernando8 concluded, based on try of Elephas (the animal at the center, top) is drawn as DNA isolated from dung, that the elephants from passing through , Gomphotherium, Palaeo- Borneo island (specifically the Malaysian states of Sabah mastodon, and “Ancestral proboscideans.” All other pro- and Sarawak) are “. . . genetically distinct, with molecu- boscideans depicted are side branches and are not a part lar divergence indicative of a Pleistocene colonization of of the main tree trunk. In this kind of illustration the Borneo and subsequent isolation.” These authors sug- main trunk is conceived as an evolutionary grade in- gest “. . . that a formal reinstatement of the E. m. bor- cluding taxa that are not necessarily phylogenetically neensis taxa await a detailed morphological analysis of related. In a cladogram, taxa are depicted successively as Borneo elephants and their comparison with other pop- sister taxa, and the common ancestors are recon- ulations.” This author concurs with Fernando8 that structed, not observed, presumed at the point of conver- there should also be morphological differences among gence of two sister taxa. For example, the common an- the recognized Asian elephant subspecies. Additionally, cestor of Mammuthus and Elephas in Figure 1.1 is it would also be a stronger argument for the proposed presumed at a point just above the tribe name Elephan- subspecies if the recent findings of Fernando would be tini. The branch of the sister taxa Elephantini and repeated and corroborated.8 Loxodontini are joined to form the subfamily Elephan- tinae. The common ancestor of Elephantini and Loxo- dontini may have been an animal that embodied char- CAN THE TWO LIVING SPECIES acters similar to those of Primelephas. INTERBREED? To better understand this cladogram, examine Figure Traditionally, a species was defined as a group of animals 1.1 in tandem with the classification provided in Table (taxon) that possesses unique characters and does not 1.1. In this table taxa are listed in the sequence as they interbreed with other such groups (taxa) under natural would appear on a cladogram from the most primitive conditions.27 Since then it has been observed that hy- or generalized (listed first) to the most derived or spe- brid zones between distinct species in the wild have cialized (listed last). This is a simplified cladogram with been reported for warm-blooded vertebrates, both a simplified table depicting only a portion of the 10 ELEPHANT BIOLOGY, MEDICINE, AND SURGERY

Figure 1.1. A cladogram of se- lected proboscideans (modified after Shoshani and Tassy 2005, p. 14), to be studied in tandem with Table 1.1. Reprinted from Quaternary Interna- tional, Volume 126-128, J. Shoshani and P. Tassy, Advances in Probosci- deans Taxonomy & Classification, Anatomy & Physiology, and Ecology & Behavior, page 14, copyright (2005), with permission from Elsevier.

Proboscidea. When all the 44 genera of Proboscidea are therium was a proboscidean since it possessed unique included, the branching pattern of the cladogram is no proboscidean characters such as a well-developed zygo- longer simple. It would be even more complicated if we matic process of the maxillary bone.12 include all 182 species and subspecies. Migration of Proboscideans EVOLUTIONARY TRENDS AND MIGRATION A map of migratory routes, as those depicted in Figure OF PROBOSCIDEANS 1.3, was constructed based on fossil material discovered at different localities, at different geological times. Thus, Evolutionary Trends the older the fossils, the closer they would appear to the As we proceed from the earliest proboscidean that lived place of origin of the Proboscidea. For example, numi- in early epoch (about 55 million years ago) to dotheres (e.g., , the earliest known pro- the present (), we observe these major evolu- boscidean; Daouitherium; and ) were tionary changes or trends: overall increase in body size; found in Morocco and Algeria, northwest Africa, in the increase of tusk size; development of a trunk, or pro- early-middle Eocene. Africa is believed to have been iso- boscis; and increase of trunk length (these trends are de- lated from other continents during most of the picted in Shoshani,37, pp. 26–27). Table 1.4 elaborates Paleogene (Paleocene, Eocene, and ), and thus on these trends and includes information on gigantism its fauna during these geological epochs was endemic. (over 4 meters shoulder height) and dwarfism (only 1 We are uncertain of the exact origin of Proboscidea. meter tall), coevolution of infrasonic communication Emmanuel Gheerbrant (personal communication, and the ability to store water in the pharynx, and hori- 2005) suggested: “Paleogene proboscideans are repre- zontal displacement of premolars and molars as though sentative of the whole African province, proboscideans they were moving on a slow conveyor belt (Fig. 1.2). are of African origin” (see also 9,10). For this reason, mi- Phosphatherium, the earliest known proboscidean, was gration and dispersal patterns of the earliest pro- about the size of a dog (10–15 kg), but it was not a dwarf; boscideans from northwest Africa during the Paleogene it did not have a trunk, tusks, or horizontal displace- are uncertain (thus the question marks on the map). ment of premolars and molars (these features developed However, one possibility emerges that the northern later within the Proboscidea). Nevertheless, Phospha- shores of the Mediterranean Sea (a remnant of the an- CHAPTER 1 TAXONOMY, CLASSIFICATION, HISTORY, AND EVOLUTION OF ELEPHANTS 11

Table 1.4. Proboscideans Evolutionary Trends*

Increase in size—Earliest proboscideans were about the size of a dog; later taxa became giants, reaching over 4 meters at the shoulders. Dwarfism is observed in certain lineages, perhaps due to isolation (such as, but not limited to, islands); some were only 1 meter tall. Lengthening of limb bones and development of short, broad feet Growth of the skull to extraordinarily large size—This is particularly noticeable in the cranium, where greater surface for muscle attachment was possible. Enlargement of the cranium was facilitated by development of air cells (pneumatized bones), a feature that provides strength without added weight. Another possible function for the development of air cells is the need to protect the sensitive brain tissues from extreme environmental temperatures. The external surface of an elephant cranium can be about 25 cm from the brain; this physical protection with “padding” of air is probably a very important feature in the survival of certain proboscidean lineages. Coevolution of infrasonic communication and the ability to store water in the pharynx—These developments appear to be associated with cranial and otic changes, modified hyoid apparatus, and evolution of the proboscis. Shortening of the neck—The skull and its associated structures (tusks and trunk) became large and heavy and the neck was reduced, probably as a mechanical advantage for leverage. Elongation of the lower jaw (mandible) and secondary shortening of the cranium and mandible was an early primary trait among proboscideans—Secondary shortening of the lower jaw (especially the area of the mandibular symphysis) and shift in the center of gravity of the head posteriorly was a trend associated with parallel evolution in advanced proboscideans. Development of a proboscis—This observation is based on the elevated position of the external naris, enlargement of the infraorbital canal, the connection between frontal and premaxilla bones, and the shapes and sizes of the premaxilla and nasal bones. It is believed that the combination and elongation of the upper lip and nose have evolved to accommodate the distancing of the head from the ground due to the increase in size of the animal. Subsequently, the proboscis is further elongated to form a very mobile trunk, possibly having evolved independently in different lineages. Forward or horizontal displacement of cheek teeth (premolars and molars)—The movement of teeth may be regarded as though they were moving on a slow conveyor belt; the earlier teeth are smaller than later ones. This feature is present in all known Neogene ( through Pliocene epochs) proboscideans, from mammutid through elephantid species. The vast majority of other mammals, humans included, has vertical rather than horizontal tooth displacement. Reduction in number of teeth from the full eutherian dentition—incisors 3/3, canines 1/1, premolars 4/4, molars 3/3— Throughout the history of the Proboscidea, there is a decrease in the numbers of premolars, canines, and incisors. Living elephants have this dental formula: 1/0 0/0 3/3 3/3. Hypertrophy (excess growth) of the middle incisors to form tusks—Some of these were straight, curved downward, or upward and helicoidal; they functioned in food gathering, defense, offense, and display. Enamel covering of tusks decreased to a longitudinal lateral band and then disappeared. Tusks greatly increased in length and diameter; those of proboscideans are the largest known teeth of animals, living or extinct. In a cross section, tusks of advanced proboscideans (from members of Mammutidae to Mammuthus) exhibit Schreger pattern, also known as “engine turning” or guillochage—In this system two sets of lines begin at the center and curve clock- wise and counterclockwise toward the periphery; at the point of crisscrossing each other they form small rhomboid-shaped areas visible with the naked eye. This pattern is also present in dentine of the cheek teeth. Enlargement and specialization of the cheek teeth in proboscideans were achieved by increasing the number of cusps such as central conules, conelets, and the numbers of cross-lophs, or lamellae (from the simple 2 transverse lophs in the earliest members to 30 lophs in the most advanced taxa; large teeth of living elephants may weigh over 5 kg)—This trend was accompanied by molarizing the deciduous premolars and thinning of enamel; it began in the early stages of proboscidean evolution. Parallel evolution, in the increasing number of lamellae, is found among the three genera of Elephantinae (Loxodonta, Elephas, and Mammuthus), and in Stegodon. Rate of evolution in the head, particularly the cheek teeth, has been faster than the rate of evolution of other organ systems in the body, e.g., the digestive system, which is relatively primitive and lags behind dentition. Increase in the value Encephalization Quotient (EQ)—One of the earliest proboscideans, the had an EQ of 0.2. This value increased during the 35–40 million of years and reached the value of up to 2.66 in modern elephantids. *Slightly modified after Shoshani 1998, p. 484.

cient Tethys Sea) might be postulated as the place of ori- (a silhouette of Gomphotherium angustidens appears in gin of Proboscidea (for this discussion, members of Figure 1.1; details in Shoshani and Tassy).40 From the Anthracobunidae are excluded). Northeast Africa Horn of Africa (again following the geological evidence (Egypt, Libya) embodied environmental conditions we have thus far), it is suggested that some proboscideans where fossils of Moeritherium, , Palaeomas- (possibly stock) migrated to what is today todon, and were found in the late Eocene to the Saudi Arabian peninsula (late Oligocene to early Oligocene sediments. It seems plausible that northeast- Miocene) and from there toward the general area of what ern African proboscideans may have migrated to the is today Pakistan. Like the classification and the evolu- Horn of Africa (late Oligocene) and to East Africa (Mio- tionary tree (and cladogram), this map is subject to cene) where centers of radiation of some proboscideans constant changes with the discovery of new fossils (including deinotheres and ) are believed and/or different interpretations of old material. From to have taken place. Another center of radiation of ex- this map of migration routes, we learn that Proboscidea tinct gomphotheres is believed to have occurred in Asia was distributed in all the continents except Australia, 12 ELEPHANT BIOLOGY, MEDICINE, AND SURGERY

Figure 1.2. Diagrams depicting (a) cross-sections of isolated lamellae to reveal pattern of occlusal (chewing) surfaces, a tooth, and a left dentary in a medial view with arrows indicating direction of horizontal tooth displacement; (b) right sides of mandibulae of Loxodonta africana depicting teeth that are present at different ages (a, drawn from specimens by Gary H. Marchant; b, after Laws 1966, after Shoshani and Tassy 1996, p. 13).

Antarctica, and some oceanic islands. Also included on ACKNOWLEDGMENTS this map are locations of pygmy proboscideans and a Special thanks to the editors for inviting me to share the comparison of a typical elephant to a pygmy individual. most recent findings. Heartfelt thanks to Gary H. Marchant for assistance with figure preparation. Dalen CONCLUDING REMARKS Agnew, Emmanuel Gheerbrant, Sandra Shoshani, and Pascal Tassy helped improve earlier versions of this man- Biological classification involves categorization of or- uscript. ganisms by their unique characters; it provides a univer- sal language for laymen and scientists. Classification, cladograms, distribution maps, and suggested migra- tory routes will change as we discover new fossils or REFERENCES form different interpretations of previous data. Of the 01. Agnew, D.W., Hagey, L. and Shoshani, J. In press. Cholelithi- approximately 180 species and subspecies of pro- asis in a wild African elephant (Loxodonta africana). The ele- boscideans that inhabited the earth since early Eocene phants of Zoba Gash-Barka, Eritrea: Part 4. J Zoo Wildl Med. 02. Agnew, D.W., Munson, L. and Ramsay, E.C. 2004. Cystic en- (55 million years ago) only two or three remain today dometrial hyperplasia in elephants. Vet Pathol 41:179–183. and even these are in peril. We only begin to understand 03. Benton, M.J. 2000. Vertebrate Paleontology (2nd ed.). London, the possible relationships between taxonomy and med- Blackwell Science, Ltd. icine; it is plausible to hypothesize that the more gener- 04. Carroll, R.L. 1988. Vertebrate Paleontology and Evolution. alized mammals may be better adapted to resist diseases New York, W.H. Freeman and Company. 05. Debruyne, R. 2005. A case study of apparent conflict between than specialized mammals. Among elephants there is molecular phylogenies: the Interrelationships of African ele- some evidence from captive animals that the African phants. Cladistics 21:31–50. elephant (the more generalized or primitive species rel- 06. Deraniyagala, P.E.P. 1955. Some extinct elephants, their rela- ative to the Asian elephant) is less susceptible to her- tives and the two living species. Colombo, Ceylon National pesvirus infection, uterine cystic endometrial hyperpla- Museums Administration. 07. Eggert, L.S., Rasner, C.A. and Woodruff, D.S. 2002. The evolu- sia, and uterine leiomyomas. Understanding taxonomy tion and phylogeography of the African elephant inferred may help us better recognize the potential health prob- from mitochondrial DNA sequence and nuclear microsatellite lems of elephants. markers. Proc Royal Soc London B 269:1993–2006.