Animal Behavior (Natural History Library)

ANIMAL BEHAVIOR

THE

NATURAL

HISTORY

LIBRARY

MAKES

AV(\\I-

able in paperback tornzat books ol enduring interest in tlze life and earth sciences. Publishecl in co-operation w*ith The Arnerican lVusettm ol Natural Histor-v by Dcubleday Anchor Books, this series introduces ihe student and the general reatler to the study ol man-his origins, his naiure, and his environment-and to the whole natural world, lrorn sub-ntirroscopic life to the universe et large. The series is guided by a board at The Arnerican Museum of Naiural History consisting of: Franklyn fu{. Branley, Associate Astronomer, Department ol Astronomy; Charles M, Bogert, Chairman and Curator, Department of Herpetology; E. Thomas Gilliard, Associate Curator, Department ol OrnithologJ; Gordon F. Ekholm, Curator ol Mexican Archaeology, ol Anthropology; Department and Bobb Schaefier, Curator, Department of Vertebrate Paleontology.

JosN Plur- Scott, following his graduation from the University of Wyoming, received a Rhodes scholarship to Oxford University, where he took a B.A. degree in the field of zocilogy in 1932. Later he studied genetics under Professor Sewall Wright at the University of Chicago, where he took a pH.D. It was there that he did his first work on behavior, thus beginning a long career of research into the behavior of animals, particularly the effect of genetics and early experience on behavior. He has served as Professor of Zoilogy at Wabash College and is the author of Agression, a book based on his studies of agonistic behavior in mice. He is presently Senior Staff Scientist at the Roscoe B. Jackson Memorial Laboratory at Bar Harbor, Maine, where he lives with his wife, Sally Scott, a well-known author of children's books.

ANIMAL BEHAVIOR

JOHN PAUL SCOTT

PUBLISHED THE

AMERICAN

THE

IN

CO.OPERATION

MUSEUM

NATURAL

HISTORY

ANCHOR DOUBLEDAY GARDEN

& CITY.

WITH

OF NATURAL

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BOOKS COMPANY, NEW

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YORK

HISTORY

Animal Behavior was originally published by The University of Chicago Press in 1958 The Naturai History Library edition is published by arrangement with The University of Chicago Press

Natural History Library edition: L963

Library of Congress Catalog Card Number 63-t2345 Copyright O 1963 by The American Museum of Natural History O 1958 by The Universif

of Chicago

All Rights Reserved Printed in the United States of America

Illustrations redrawn from the original edition bv Russell Francis Peterson

FOREWORD TO THE ANCHOR EDITION

The inquisitive person, whether he is a country or a city dweller, is often intrigued by the actions of the animals he sees about him. Why do robins suddenly reappear in the city parks each spring? Where do they go in the fall and how do they find their way? Why do certain breeds of dogs make good pets for children and others make better watchdogs or hunting dogs? Why does a female cat in heat attract all the males in the neighborhood? Are ants and bees, with their complex societies,creatures of great intelligence? Who teaches a bird to build its nest, incubate its eggs, feed its young, sing its species-specificsong-or is it necessary for a bird to learn this? The answersto these questionsare hard to find. Often they are vague and unsatisfactory-"Because it is nature's way"-or sentimental and anthropomorphic -"The mother bird loves her babies and wants them to grow up to be healthy and strong". Here is a book that answers rnany questions about animal behavior. Dr. Scott describes the work of biologists, psychologists, and naturalists who have scientifically studied the behavior of animals. He explains the methods scientists have used-observation and description, field experiments and laboratory experiments -as well as the answers thev have found.

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ANIMAL

BEHAYIOR

The answers to some questions about animal be* havior become apparent as a resuit of anatomicai and physiologicai studies. It is known that rnoths can locate their mates over a distance of up to one-half a mile. Their highly developed organs of smell located in the antennae enable them to do this. The precise architecture of the honevcomb would not be possible r.vithout the speciaiizedappendagesand relatively iarge brain of the honeybee. Some animals are sensitive to stimuli that the human cannot perceive. For example, bees are able to sense the degree of polarization of light in the sky and use this information to establish the location of food or the hive. Certain types of behavior, such as sexual behavior, are dependent in many animals to a large degreeon secretir:nsof endocrine glands. One of the most interesting areas in animal behavior centers about the problem of learning-what it is, how it occurs, and how best to study it. Dr. Scott defines learning as "the modification of behavior by previous experience." He discussesthe classic conditioning experiments of Pavlov, the more recent conditioning techniques of Skinner, and a variety of other methods of studying learning. The role of heredity in determining behavior has been a subject of much debate among behaviorists. There are those who attribute almost all behavioral traits to genetic factors or inborn characteristics. Others feel that the environment is all important and they minimlu;e the contribution of genetic factors. A more modern idea is to accept the contribution of genetics in shaping the limits of behavior of which an animal is capable. Genetic factors determine the type of sensory and motor organs, the complexity of the nervous system and body form and this raw material is then acted upon by environmental factors to produce the behavior of the animal as we see it. Dr. Scott describes cross-fostering

ix

FOREWORD

and cross-breeding experiments that have shed some light on this problem. The chipmunk leads a solitary existence, rarely forming associationswith his own kind except briefly to mate and during the pre-weaning period when the mother cares for the young. Other animals live in this manner, too-a single individual living in a territory that he defends against other members of the species-but there are also numerous animals, ranging from simple invertebrates to primates and including man, tlat tend to live in groups. These groups may be loosely organized, each individual going his own way, or they may have a complex structure with the roie of different types of individuals rather rigidly determined, as, for example, the social insects. The science of animal behavior is a new and exciting one. The above examples are but a few of the many topics with which it is concerned. The modern behaviorist must be a good observer and experimentalist. Ideally he should be trained in many disciplinesanatomy, physiolory, statistics, psychology, genetics, ecology, and others. However, many important discoveries have been made by relatively untrained individuals who, through long and perceptive observation, have come to understand the behavior of a single species. One of the most valuable features of this book is an extensive bibliography that will help the reader to follow up his particular interests by reading original papers and extensive reviews of subjects that, because of limited space, have only been touched upon in the book. September 1962 Madeline L. Cooper

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PREFACE

This book has been written to answer the general question: What is the study of animal behavior about? It is also intended as a textbook, which means that it attempts to give a fair and accurate picture of a field of knowledge. It is designed for the general reader or the student who wishes to learn something for himself. With this in mind I have tried to use a minimum of scientific phraseology, so that the book can be read without interruptions or outside help. At the same time I have made no effort to disguisethe fact that animal behavior is a genuine science and, as such, must employ clearly defined terms and precise logic in order to produce true general principles. The subject matter is organized according to the groups of factors affecting behavior which operate at each level of biological organization. Some of these can be expressed as basic laws of behavior and are illustrated with examples selected from the animals upon which important research work has been done. These examples do not systematically cover the animal kingdom, and the teacher who uses this book as a text will probably wish to consider it as an outline that he can expand and amplify in his lectures and through additional reading. The bibliography is arranged as a guide to the latter.

AIt

ANI}"{AL

BEH,{VIOR

Animai behavior is coneerned with the at:tiv.'ity of the whcle crganism and cf groups cf organisms. its study therefore involves the use of techniques and principles from all branches of zoclogy-anatomy, physiology, ecology, genetics,and even embryology and taxonomy. It is al'so an interdisciplinary study on a larger scale, involving findings from psychclogy, sociology, and the physicai sciences.In past years there has been a tendency to divide zorilogy into cornpartments, each rvith its corps of specialists following specialized and unrelated problems. It is hoped that in this book the student wili find a glimpse of the essential unity of animai science, which is not the artificial result of applying an oversimplified theory but a natural unity of ideas arising from the effort of explaining the important problem of w&at an organism does. This book is written with the assumption that what an organism does is more important than what it is, and that behavior is one of the central problems of existence. One way of assessingthe importance of a subject is to consider it historically" Science does not exist in a vacuum but is a part of human behavior and particularly part of the behavior of the scientists and students who work with it. These are some of the people who have worked on the science of animal behavior, with a brief account of what they have done. The study of animal behavior has fascinated mankind ever since the times of Solomon and Aesop. By long historical tradition people are willing to learn from the ant or the fox what they refuse to see in their fellows. However, this subject did not receive the serious attention of scientists until the middle of the nineteenth century, when Darwin's theory of evolution placed great stress on the idea of progressively improved adaptation. The adaptation of an animal is, of course, largely accomplished through its behavior, and Darwin himself

PREFACE

Xiii

devoted a great deal of attention to the subject. His books on Formation of Vegetable Mould and The Expression of Emotion in Man and Animals still provide useful and accurate information. His lead was followed by a large number of important European and American scientists, and the bibliography of Jennings' Behqvior of the Lower Organisms, published in 1906, reads like a "Who's Who" of early twentieth-century scientists. Among American biologists appear the names of T. H. Morgan, Jacques Loeb, Raymond Pearl, E. B. Wilson, G. H. Parker, S. O. Mast, and S. J. Holmes, while the Europeans include such distinguished names as Clapardde, Driesch, Lloyd Morgan, Naegeli, Pavlov, Romanes, Verworn, and Von Uexkull. Meanwhile, the psychologists Yerkes and Thorndike were turning their attention to the study of the behavior of the higher animals, and the results of a fruitful collaboration between psychologists and biologists appeared in the lournal ol Animal Behavior, in six volumes published before World War I. Two significant scientific discoveries diverted the attention of these workers into other fields. One was the rediscovery of Mendelian inheritance in 1900, when the majority of biologists, including such workers as Morgan, Pearl, and even Jennings himself, turned their attention to developing the new scienceof genetics.About the same time, the discovery by Pavlov of the conditioned reflex seemed to provide a basis for rapid progress in the scientific analysis of learning. Psychologists such as Thorndike found that the white rat was a convenient and inexpensive animal for these studies and no longer concerned themselves with the broad problems of adaptation. By the end of World War I, interest in the scienceof animal behavior seemedalmost dead. Up to this time the problem of adaptation had been

xl.

ANIMAL

EEI{AVIOR.

approached almast entirely fro*i the vievrpaint cf inciividual survival, and the study cf social behavicr in animals had been so lir*ited tc inseets that it was scarcely inore than a branch of entomology. Around WZA came two new Cissoveries in the behavicr cf birds which indicated that the behavior of other anirnals was significant in the context of a cornplex sociaL crganization. Howard's fresh insights into the significance of song and territory and Schjelderup-Eirbe's description of social dominance in hens were the iirst of a series of exciting new discoveries. Slioitly afterward, Allee pr.rblishedhis first work cn animal aggregations, to be followed by a long series of stuciieson basic animal sociology. C. R. Carpenter nnade a study cf the social relationships and arganrzation of free-living primates, and in 1935 l-orenz published his studies of the formation of primary social relationships in birds. N{eanwhile, progress had not been lacking in the study of the social behavior of insects.Wheeler had presented his theory of trophallaxis as the basis cf social arganuation in insects, to be foliowed by Ernerson's extensive studies on social differentiation in the termite, with consideration of the animal society as the unit of evolution. Schneirla studied the complex societiesof the army ants, and Von Frisch was able to establish experimentally the existenceof a "language" in bees" World War II interrupted many of these studies, particularly in Europe, but sinee then there has been a great revival of interest on both continents. Tinbergen and other European workers have become interested in the problem of instinct as it relates to social behavior and have founded the journal Behnviour, devoted to the study of comparative ethology, or the comparison and analysis of behavior traits in different species. A nurnber of British ornithologists, including Armstrong, Lack, Thorpe, and others, are exploring the alrnost in-

PREFACE

xv

finite variety of social behavior found in birds. A large group of younger American biologists, among whom may be mentioned Calhoun, Collias, Emlen, Nice, Kendeigh, Davis, Guhl, and King, have become interested in the problems of social organlzation and its relation to population dynamics. Another group, of which the author is a member, have devoted their attention to the study of Mendelian genetics and social behavior. Such workers as Beach and Young have made great contributions to the analysis of the physiology of social behavior. By and large, psychologists are tending to leave these studies in the hands of the biologists, but there is a growing number of notable exceptions, such as Hall, Nissen, Liddell, Harlow, Hebb, and Thompson, as well as an active group devoted to the neurological analysis of behavior. For the last quarter-century, the impetus and interest in the study of animal behavior has come largely through the general concepts of social organization and behavior. It is the intention of this book to present some of the most important problems which now face this science.

ACKNOWLEDGMENTS

For the past twelve years I have been associatedwith the Division of Behavior Studies at the Roscoe B. Jackson Memorial Laboratory. From the first, my associates and I have felt that the development of the science of animal behavior is a collaborative enterprise. We have tried to encourage the growth of research at other institutions and have, in turn, been greatly helped by visiting investigators, advisers, and students. In writing this book I have been unusually conscious of the benefits of this collaboration, and I wish here to express my appreciation to all those who have not been mentioned by name elsewhere,and particularly to my present and past colleagues: John L. Fuller, John A. King, Randall M. Chambers, John B. Calhoun, Emil Fredericson, and to the director of the Jackson Laboratory, Dr. C. C. Little. Ralph and Mildred Buchsbaum, who originally suggested that I write the book, have been untiringly helpful as editors and have contributed many beautiful photographs for the illustrations. And, of course, I wish to thank my wife, whose collaboration in the actual writing of this book has made its completion possible. l. P. Scott

CONTENTS

Foreword to the Anchor edition Preface 1. Animal Behavior and Human Behavior

vll

xi 1

2. The Elements of Behavior: Methods of Study

13

3. Differential Capacities: Anatomy and Behavior

38 '75

4. Internal Causes: The Physiology of Behavior 5. Learning: The Effects of Experience

105

6. Heredity and Behavior

131

7. Intelligence: The Organization of Behavior

158

8. Social Behavior and Social Organization

185

9. Communication: The Language of Animals

221

10. Behavior and the Environment

241

11. Behavior and Evolution

275

Bibliography

296

Index

31,3

ANIMAL BEHAVIOR

Chapter 1 ANIMAL BEHAVIOR AND HUMAN BEHAVIOR

A familiar autumn srght in many parts of the northern and central United States is the appearance of great flocks of blackbirds which settle down to feed on the stubble fields. As we look out over the pleasant countryside we can almost always see at least one field carpeted with feeding blackbirds. The group is spread out over a hundred feet or so, and we notice that as the birds hop industriously about, turning over leaves and picking up bits of food, they manage to keep about the same distance apart from each other so that the effect is always that of a compact group rather than a random collection of individual birds. Suddenly a few birds on one edge of the flock become disturbed and fly up. The others next to them lift into the air in successionuntil the whole flock rises and wheels as a unit as it goes off to repeat the performance in some neighboring field. At dusk the flock may come into a nearby town and roost on specially favored shade trees, returning night after night to the same spot, much to the distress of the furrm?r owners who wish to keep the sidewalks clean. As we watch we begin to wonder. Why do the birds stay close together, when an individual bird might easily find more food and have it all to himself? Do all the birds belong to the same species, and do they have a

2

ANrh,{ALBEHAvIoR

leader? How can they co-ordinate thc:ir behavi