1704 Animal Behaviour, 50, 6

Paquette, Gardner & Fouts) are related to human culture or even to each other? The book lacks any central logic that could hold all its very different strands of evidence together. All we are given is a very loose, global definition of culture, followed by a whole catalogue of research on the behaviour of different animals which falls under this general rubric, without any unifying critical analysis.

The editors provide a potentially interesting reason for not stipulating a formal definition of culture. There is a tantalizingly short discussion of the merits of ‘continuous functions’ over an Aristotelian ‘yes-no’ approach. I have some sym- pathy with this position: many hundreds of hours and pages have been spent discussing exactly what constitutes language or culture rather than con- centrating on a detailed analysis of what non- human animals actually do and how closely this approaches our own ability. However, a ‘fuzzy’ definition of culture is insufficient on its own; one must still carefully analyse all the phenomena that fall within this definition and where they stand in relation to one another in terms of underlying mechanisms.

The lack of a central logic would not be so important if the standard of individual articles in the book were uniformly high: unfortunately, they are very variable. Much of the information in some of the best chapters has been printed else- where in a fuller form (McGrew; Marchant & McGrew; Slater & Williams) but with careful mining, it is possible to unearth some nuggets of new information. For example, Prato, Previde & Poli describe a delightful experiment on a socially transmitted foraging technique in hamsters. Fouts provides some very welcome extra information on the teaching of sign language by a chimpanzee mother (Washoe) to her adopted son (Loulis): although one is still left gasping for more. In a very interesting final chapter, Slurink poses many of the questions which should have been considered in the introduction. Overall, this is a rather disappointing and expensive volume which is perhaps only suitable for specialized libraries.

D. CUSTANCE School of Psychology, University of St Andrews, St Andrews, F$e KYI6 9JU, U.K.

Behavioral Mechanisms in Evolutionary Ecology. Edited by L. A. REAL. Chicago: University of Chicago Press (1994). Pp. ix+469. Price $80.00 hardback, $29.95 paperback.

Few studies in animal behaviour incorporate insights from related disciplines, despite the recog-

nized importance of interdisciplinary research to its study. In this book, edited by L. Real, 24 authors present 19 different interdisciplinary approaches to the investigation of various aspects of animal behaviour. Areas of comparative psy- chology, neurobiology, genetics, endocrinology, immunology and community ecology are inte- grated with concepts from behavioural ecology. Species ranging from insects to birds to primates are used to illustrate these synthetic approaches.

For example, Kamil combines comparative psy- chology and behavioural ecology in a ‘synthetic’ approach to the study of animal intelligence. This approach emphasizes the adaptive significance of a cognitive ability. Kamil wants to retain the methodological sophistication of the psychologist, while both expanding the number of species studied as well as examining animals under more naturalistic conditions. It is unclear whether the behavioural experiments he proposes will be able to differentiate between general versus specific learning processes, especially as experiments in the field are less controllable than those in the laboratory. Nevertheless it is an approach that has and will provide new insights into the question of animal intelligence.

Real writes of the emergence of a cognitive revol- ution which will bring together concepts from behavioural ecology, cognitive psychology and economics. Whether some of the mathematical models described in this and other chapters will be useful in predicting how real animals behave re- mains to be tested. Many of these models require unrealistic assumptions and often ignore potent in- fluences on an animal’s behaviour, such as its ability to learn and/or the synergistic interactions between an animal’s environment and its physiology.

Behaviour consists of an extremely complex collection of non-linear processes (e.g. neurobio- logical phenomena), making it difficult to devise mechanistic models that have good predictive power. Cole shows how mathematical methods using non-linear dynamics may lead the way to better models for describing behaviour. For example, these models may suggest that some behavioural processes are chaotic. In these cases, the behavioural outcome would be very sensitive to the initial conditions (e.g. an animal’s behav- ioural state) and often these cannot be controlled by the experimenter. Therefore it would be impossible to make long-term predictions about the expression of these behaviour patterns.

West et al. show the important role played by silent cowbird females during song learning in males. They use this example to illustrate some of the common pitfalls that arise when attempting to study inborn versus acquired traits in animals.

Book Reviews 1705

Ryan suggests that having some knowledge about the neurophysiological processes that underlie behaviour, such as the prevalence of habituation in sensory systems, can help explain innate female preferences for some male traits. For example, some female song birds prefer males with larger song repertoires, even in a species like the grackle in which males have only one song in the field. He suggests that singing multiple songs reduces the possibility that the female will habitu- ate to the male. He contrasts this approach with other theories of sexual selection.

Werner discusses the reciprocal interactions between body size and behaviour, with examples from three different taxa, and the possible effects of these interactions on larger communities. He argues that behavioural ecology should be able to provide a mechanistic basis for community interactions.

Zuk explores the importance of psychoneuro- immunology in non-human vertebrates. She shows that interactions between the immune sys- tem and other physiological systems may inlluence secondary sex characteristics, mate choice and group behaviour.

The chapters are sometimes at odds with one another with respect to their interpretations of data and conceptual frameworks. Foci example, West et al’s demonstration that it may not be possible (or meaningful) to determine the relative contributions of genetic versus acquired abilities to an animal’s phenotype conflicts with Papaj’s mathematical models, which assume that these relative contributions are knowable and additive. These discrepancies, however, benefit the reader. Because each chapter has a different perspective, it is possible to compare a variety of views and develop one’s own idea of the strengths and weaknesses of different interdisciplinary approaches. For this reason, the book is best suited for someone with some familiarity with the relevant literature. It would not be suitable for an undergraduate text.

This is a valuable book for behavioural ecolo- gists, comparative psychologists, population ecologists and behavioural physiologists.

SHELLEY ADAMO Department of Psychology, Dalhousie University, Halifax, Nova Scotia, Canada.

Wild Otters: Predation and Populations. By HANS KRUUK. Oxford: Oxford University Press (1995). Pp. xi+290. Price &30.00.

Until recently there has been hardly any scientific literature on otters. With the growing importance

of nature conservation, however, these fascinating carnivores, which occupy the top of the food chain in most aquatic habitats, have begun to attract the interest of conservationists and other researchers.

Hans Kruuk’s work, which was also inspired by the urgent conservation problems well represented by this species, is in several respects different from previous studies of otters. In particular, the author was uniquely able to study the secretive life of these elusive animals by direct observations in the wild. Although some other otter species, such as the sea otter living on Pacific coasts of North America, or the giant otter living around the Amazon river, have been studied in detail using direct observations, there have been no previous comparable studies of the Eurasian otter. The explanation for Kruuk’s success in this respect lies in his choice of the Shetland Islands as a study area. Probably because of the lack of disturbance along the coastlines of the Shetlands, otters there can be observed by daylight and at relatively close range.

Despite the very general title of the book, the main part of each chapter is based on work done or supervised by the author on a tiny otter popu- lation in the unique environment of the Shetland Islands. Although one should be cautious about generalizing to other populations, Kruuk’s obser- vations highlight many aspects of the otter’s behaviour which have not previously been recorded. It is a great pleasure to read about his exciting personal encounters with these remark- able animals and the results are a tribute to his outstanding fieldwork skills. Kruuk spent long hours daily over several years learning to recog- nize each otter individually and identifying the species and determining the size of the fish prey that were being consumed by his study animals. Previously, spraint analysis has been the most commonly used method of studying the diet of otters, because otter scats are easily distinguished and spraint sites can be readily found. A few attempts have also been made to investigate the feeding behaviour of captive otters. Kruuk’s study is unique in containing not only detailed obser- vations of the feeding behaviour of wild otters but also information about the fish species that dominate the otter’s diet.

The notes made by Kruuk during his obser- vations, some of which are reproduced in the book, give the reader a special insight into the difficulties and pleasures of his project. However, some of the conclusions from these observations are at variance with previous studies. For example, Shetland otters usually build their own holts, digging extensive systems of tunnels and