Table Of Content

Cambridge Studies in Ecology presents balanced, comprehen sive, up-to-date, and critical reviews of selected topics within ecology, both botanical and zoological. The Series is aimed at advanced final-year undergraduates, graduate students, re searchers, and university teachers, as well as ecologists in industry and government research. It encompasses a wide range of approaches and spatial, temporal, and taxonomic scales in ecology, including quanti tative, theoretical, population, community, ecosystem, histor ical, experimental, behavioural and evolutionary studies. The emphasis throughout is on ecology related to the real world of plants and animals in the field rather than on purely theo retical abstractions and mathematical models. Some books in the Series attempt to challenge existing ecological paradigms and present new concepts, empirical or theoretical models, and testable hypotheses. Others attempt to explore new approaches and present syntheses on topics of considerable importance ecologically which cut across the conventional but artificial boundaries within the science of ecology. CAMBRIDGE STUDIES IN ECOLOGY Editors: R. S. K. Barnes Department of Zoology, University of Cambridge H.J. B. Birks Botanical Institute, University of Bergen E. F. Connor Department of Environmental Science, University of Virginia R. T. Paine Department of Zoology, University of Washington, Seattle Megaherbivores The influence of very large body size on ecology Also in the series H. G. Gauch, Jr Multivariate Analysis in Community Ecology R. H. Peters The Ecological Implications of Body Size C. S. Reynolds The Ecology of Freshwater Phytoplankton K. A. Kershaw Physiological Ecology of Lichens R. P. Mcintosh The Background of Ecology: Concept and Theory A. J. Beattie The Evolutionary Ecology of Ant-Plant Mutualisms F. I. Woodward Climate and Plant Distribution J. J. Burdon Diseases and Plant Population Biology J. I. Sprent The Ecology of the Nitrogen Cycle N. G. Hairston, Sr Community Ecology and Salamander Guilds H. Stolp Microbial Ecology: Organisms, Habitats and Activities R. N. Owen-Smith Megaherbivores: the Influence of Large Body Size on Ecology J. A. Wiens The Ecology of Bird Communities: Volume I Foundations and Patterns Volume 2 Processes and Variations N. G. Hairston, Sr Ecological Experiments R. Hengeveld Dynamic Biogeography C. Little The Terrestrial Invasion: an Ecophysiological Approach to the Origins of Land Animals P. Adam Saltmarsh Ecology M. F. Allen The Ecology of Mycorrhizae D. J. von Willert et al. Life Strategies of Succulents in Deserts: With Special Reference to the Namib Desert J. A. Matthews The Ecology of Recently-deglaciated Terrain: a Geoecological Approach to Glacier Fore/ands Megaherbivores The influence of very large body size on ecology R.NORMAN OWEN-SMITH University of the Witwatersrand �CAMBRIDGE V UNIVERSITY PRESS CAMBRIDGE UNIVERSITY PRESS CambridNgeew,Y orkM,e lbourMnaed,r iCda,p eT ownS,i ngapore, SaoP aulDoe,l hi, DubaiM,e xTiocCkoiy toy, CambridUgnei verPsrietsys TheE dinburBguhi ldiCnagm,b ridCgBe2 8 RU,U K Publisihnet dh e UniStteadto efAs m eribcya CambridUgnei verPsrietsyNs e,w Y ork ww.w cambridge.org Informatonit ohni tsi dwwe: .w cambridge.org/978052I426374 © CambridUgnei verPsrietsys I988 Thipsu blicaitsii noc no pyriSguhbtj.e tcost t atuteoxrcye ption andt o the provisioncso lolfe clrtieiclveeenv saaignnrtge ements, nor eproducotfai noynp armta yt akpel acwei thotuhte written permission of UCnaimvberriPsdrigetesy s . Firpsutb lisIh9e8d8 Firpsatp erback Ie9d9i2t ion A catalogue recordfo r this publication is available from the British Library Library of Congress Cataloguing in Publication Data Owen-SmiRt.hN ,o rman. Megaherbivtohree si:n fluveenrclyea robgfoe d ys izoene cology R.N ormanO wen-Smith p. cm.- (Cambrisdtgued iinee sc olo)g y Bibliohgyrp:a. p Incluidnedse x. ISBNo 523I6 02x0 ( hardbaoc 5k2)4I;2 6357( paperback) r. Herbivora-2S.iH zeer.b ivora-Eco3l.Uo nggyu.l ata-Size 4. Ungulata-EcoMlaomgmya.l s-5S.i6 z.eM. a mmals-Ecology. I.T itle.I IS.e ries. QL 737.U409I59 88 599.7-dcl9 88-6941 ISBN 978-0-521-H2a3r3d8b5a-c9k ISBN 978-0-521-2Pa7p8e5r8b-a4c k CambridUgnei verPsrietsys hraess pnoon sifboitrlh iept eyr sistence or accuroafcUyR Lsf oerx teronrat lh ird-pianrtteyr net wreebfseirttroee sdi n thipsu blicaatnidod no,e nso tg uaranttheaeat n yc onteonnts ucwhe bsiitse,s or wrielmla ianc,c uroarta ep proprIinaftoer.m atrieogna rdpirnigc tersa,v el timetabalnedos t,h efra ctual infgoirvmeianntt ihoins wioscr okr reactt the timfei rposrfti ntbiuntCg a mbridUgnei verPsrietys s ndootge usa rantee thea ccuroafcsy u cihn formatthieorne after. 'Hints for an agenda: How big is it and how fast does it happen?' (G. Evelyn Hutchinson 1975) Contents Preface xiii 1 Prologue 2 Morphology, evolutionary history and recent distribution 6 Introduction 6 Morphology 6 Evolutionary origins and relationships 16 Paleontological diversity 20 Distribution of extant species 21 3 Food and other habitat resources 30 Introduction 30 Food 30 Water and other habitat needs 45 Comparisons with smaller ungulates so 4 Space-time patterns of habitat use 53 Introduction 53 Temporal patterning of activities 53 Utilization of space 61 Comparisons with smaller ungulates 67 5 Body size and nutritional physiology 69 Introduction 69 Metabolic requirements 70 Gut anatomy 71 Food intake and digestion 72 6 Body size and feeding ecology 82 Introduction 82 Diet quality 82 Foraging time 87 Home range extent 95 Trophic ecology of megaherbivores: summary 98 Contents x 7 Social organization and behavior IOI Introduction IOI Group structure IOI Male dominance relations I09 Courtship and mating l I6 Responses to predators I24 Comparisons with smaller ungulates I3I 8 Life history 133 Introduction I33 Infancy and juvenilehood I33 Adolescence and puberty 138 Reproduction by females I44 Reproduction by males I5I Mortality and lifespan I52 Comparisons with smaller ungulates 159 9 Body size and sociobiology I60 Introduction 160 Grouping patterns 160 Male dominance systems I67 Female mate choice I77 Summary I79 10 Body size and reproductive patterns I8I Introduction 18I Seasonality of reproduction I83 Age at first conception I85 Birth intervals 186 Maternal investment in reproduction I90 Offspring sex ratio 195 Summary 198 11 Demography 200 Introduction 200 Population structure 200 Population growth 2I2 Population density and biomass 22I Comparisons with smaller ungulates 225 12 Community interactions 226 Introduction 226 Impact on vegetation 226 Effects on other large herbivores 239 Comparisons with smaller ungulates 245