Animal Conflict "1,

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Illustrated by Leslie M. Downie Department of Zoology, University of Glasgow ANIMAL CONFLICT Felicity A. Huntingford and Angela K. Turner Department of Zoology, University of Glasgow

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London New York CHAPMAN AND HALL Chapman and Hall Animal Behaviour Series

SERIES EDITORS D.M. Broom Colleen Macleod Professor of Animal Welfare, University of Cambridge, UK P.W. Colgan Professor of Biology, Queen's University, Canada

Detailed studies of behaviour are important in many areas of physiology, psychology, zoology and agriculture. Each volume in this series will provide a concise and readable account of a topic of fundamental importance and current interest in animal behaviour, at a level appropriate for senior under• graduates and research workers. Many facets of the study ofanimal behaviour will be explored and the topics included will reflect the broad scope of the subject. The major areas to be covered will range from behavioural ecology and sociobiology to general behavioural mechanisms and physiological psychology. Each volume will provide a rigorous and balanced view of the subject although authors will be given the freedom to develop material in their own way. To Tim) Joan and Jessica) with thanks) and to all the children who provided inspiration First published in 1987 by Chapmatl and Hall Ltd 11 New Fetter Lane, London EC4P 4EE Published in the USA by Chapman atld Hall 29 West 35th Street, New York, NY 10001

ISBN -13: 978-94-010-9008-7 This title is available in both hardbound and paperback editions. The paperback edition is sold sll~iect to the condition that it shall 110t, by way of trade or otherwise, be lmt, resold, hired out, or otherwise circulated without the publisher's prior consmt ill allY form o/bindillg or cover other thatl that ill which it is published alld without a similar condition illcluding this collditioll being imposed 011 the subsequmt purchaser. All rights reserved. No part of this book may be reprillted, or reproduced or utilized ill atly form or by any. electronic, mechanical or other means, now known or hereafter invmted, including photocopying and recording, or in any information storage and retrieval system, without permission in writingfrom the publisher.

British Library Cataloguing in Publication Data Huntingford, Felicity Animal conflict. 1. Aggressive behaviour in animals I. Title II. Turner, Angela K. 591.51 QL758.5 ISBN-13: 978-94-010-9008-7

Library of Congress Cataloging in Publication Data Huntingford, Felicity. Animal conflict. Bibliography: p. Includes index. 1. Agonistic behaviour in animals. 2. Conflict (Psychology) I. Turner, Angela K., 1954- II. Title. III. Title: Animal conflict. QL758.5.H86 1987 591.51 86-20751 ISBN -13: 978-94-010-9008-7 e-ISBN-13: 978-94-009-3145-9 DOl: 10.1007/978-94-009-3145-9 Contents

Preface Xl Acknowledgements X11l

PART ONE· PATTERNS OF ANIMAL CONFLICT 1 1 Conflict in the animal world 3 1.1 Animal fights 3 1.2 Conflicts ofinterest 5 1.3 Adaptive responses to conflicts ofinterest 6 1.4 The problem of definition 7 1.5 The biological study of animal conflict 11

2 A survey ofanimal conflict 13 2.1 Introduction 13 2.2 Acellular organisms and protists 14 2.3 Sea anemones (coelenterates) 14 2.4 Parasitic worms (acanthocephalans) 16 2.5 Ragworms (annelids) 16 2.6 Limpets, octopuses and squids (molluscs) 17 2.7 Insects 18 2.8 Shrimps and crabs (crustaceans) 22 2.9 Scorpions, mites and spiders (arachnids) 24 2.10 Sea urchins (echinoderms) 26 2.11 Fish 26 2.12 Salamanders and frogs (amphibians) 28 2.13 Lizards and snakes (reptiles) 30 2.14 Birds (aves) 32 2.15 Mammals 35

3 Issues and concepts in the study ofanimal conflict 39 3.1 How do animals fight? 39 3.2 Context - specific agonistic behaviour 46 3.3 Alternative ways ofwinning 53 Vl11 Contents

PART TWO THE CAUSES OF AGONISTIC BEHAVIOUR 55 4 Behavioural mechanisms 59 4.1 Introduction 59 4.2 The systems that control agonistic behaviour 60 4.3 The effects of cues from an opponent 64 4.4 The effects of other stimuli from the environment 79 4.5 The dynamics ofundisturbed fights 80 4.6 Models ofthe control ofagonistic behaviour 82 4.7 Overview 92

5 The role ofhormones 95 5.1 Introduction 95 5.2 Mechanisms 97 5.3 Hormones and the patterns of animal conflict 98 5.4 Reproductive hormones in vertebrates 100 5.5 Adrenal hormones 118 5.6 Endogenous opiates 121 5.7 Other hormones 121 5.8 Invertebrates 122 5.9 Overview 124

6 Neural mechanisms 129 6.1 Introduction 129 6.2 Neural mechanisms and the patterns of animal conflict 134 6.3 Analysing agonistic information 135 6.4 Producing agonistic movements 137 6.5 Producing changes in responsiveness 141 6.6 Effects of fighting experience on brain biochemistry 158 6.7 Overview 159 Concluding comments on the causes of agonistic behaviour 162

PART THREE· GENETIC AND ENVIRONMENTAL INFLUENCES 163 7 Genetics 167 7.1 Introduction 167 7.2 Genetics and the patterns of animal conflict 171 7.3 Identifying genetic influences 171 7.4 Patterns ofinheritance 182 7.5 The route from genes to behaviour 185 7.6 Overview 189 Contents IX

8 Development 193 8.1 Introduction 193 8.2 The agonistic behaviour ofvery young animals 194 8.3 The developmental origin of agonistic movements 196 8.4 Playful fighting 198 8.5 Changes with age 200 8.6 Environmental influences: identifying the relevant factors 208 8.7 Environmental influences: kinds ofidentified effect 209 8.8 Environmental influences: the non-social environment 210 8.9 Environmental influences: the social environment 211 8.10 Overview 216 Genes, environments and agonistic behaviour 221

PART FOUR . CONSEQUENCES, FITNESS AND EVOLUTIONARY CHANGE 223 9 The consequences ofanimal conflict 227 9.1 Introduction 227 9.2 Consequences for individuals 228 9.3 Consequences for populations 231 9.4 Consequences for ecological communities 237 9.5 Evolutionary consequences 242 9.6 Overview 248

10 Evolutionary history 251 10.1 Introduction 251 10.2 Evolutionary origins 253 10.3 Evolutionary diversification 259 10.4 Overview 274

11 The behavioural ecology ofanimal conflict 277 11.1 Introduction 277 11.2 Strategies for resolving conflicts 279 11.3 Costs and benefits ofbeing dominant 287 11.4 Costs and benefits of territorial behaviour 295 11.5 Conflict between the sexes 303 11.6 Conflict within the family 309 11.7 Infanticide and cannibalism 309 11.8 Alternative strategies 312 11.9 Conflict in social groups 314 11. 10 Overview 315 x Contents

12 The biology ofhuman aggression 319 12.1 Introduction 319 12.2 What is human aggression? 326 12.3 Issues and concepts 328 12.4 The causes of aggression in humans 333 12.5 Genes, environment and the development of agonistic behaviour 345 12.6 The behavioural ecology ofhuman conflict 350 12.7 Preventing, predicting and controlling human aggressIOn 358 12.8 Overview 361

References 365 Species index 433 Subject index 443 Preface

In the past twenty years there have been many new developments in the study of animal behaviour: for example, more sophisticated methods of neurophysiology; more precise techniques for assessing hormonal levels; more accurate methods for studying animals in the wild; and, on the functional side, the growth of behavioural ecology with its use of optimality theory and game theory. In addition, there has been a burgeoning number of studies on a wide range of species. The study of aggression has benefited greatly from these develop• ments; this is reflected in the appearance of a number of specialized texts, both on behavioural ecology and on physiology and genetics. However, these books have often been collections of papers by spe• cialists for specialists. No one book brings together for the non• specialist all the diverse aspects of aggression, including behavioural ecology, genetics, development, evolution and neurophysiology. Neither has there been a comparative survey dealing with all these aspects. Therefore one of our aims in writing this book was to fill in these gaps. Another of our aims was to put aggression into context with respect to other aspects of an animal's lifestyle and in particular to other ways in which animals deal with conflicts of interest. Aggressive behaviour does not occur in a biological vacuum. It both influences and is influenced by the animal's ecological and social environment, so we consider both the complex antecedent conditions in which aggressive behaviour occurs, and its ramifying consequences in the ecosystem. Throughout the text common names are used wherever they are available. Scientific names are given in the species index. Acknowledgements

We are grateful to: Jon Barnes, Pat Bateson, Don Broom, Barry Everitt, John Goss-Custard, Mike Hansell, Alasdair Houston and Marilyn Ramenofsky for constructive and very helpful criticism of early drafts; M. E. Archer, T. Bakker, P. Bateson, P. Bronstein, K. D. Browne, T. Caro, D. A. Collins, D. A. Dewsbury, E. G. Dunning, V. Geist, T. Groothuis, T. R. Halliday, I. R. Inglis, J. Lazarus, P. J. Murphy, E. Nevo, P. W. Sherman, P. Thompson, G. A. Van Oortmersson and J. M. Williams for permission to use unpublished data, for papers seen in press and for recent reprints; P. W. Sherman for assistance with references; Neil Metcalfe for permis• sion to use a photograph and H. Dingle, M. Enquist, Charlie Evans, H. W. Fricke, V. Geist, E. B. Keverne and A. Samuels for use of illustrations; Liz Denton and Peter Rickus for preparation of figures, Clarice Swan and Lynn Mackenzie for help in typing figure legends and tables; and Alan Crowden for being a patient and helpful editor.