874 Animal Behaviour, 37, 5

Visual Behavior in Salamanders. By GERHARD ROTH. Studies ofBrain Function. Vol. 14. Berlin: Springer-Verlag (1987). Pp. xi+302. Price DM 198.

There are many times when those of us who work on the behaviour of newts or salamanders have cause to doubt whether these animals have brains at all. Because they typically lead rather secretive lives in habitats that tend to be overlooked, there is a widespread assumption, even among biologists, that the urodeles (tailed amphibians) have less sophisticated nervous systems and behavioural repertoires than their more extrovert relatives, the anurans (frogs and toads). Gerhard Roth sets out to dispel this myth and succeeds in showing that salamanders are capable of sensory feats that are a match for anything a frog can do, and that they are equally capable of modifying their behaviour through learning. This book is concerned solely with vision but, as Roth reminds us, urodeles have highly developed olfactory and vibrational senses as well as possessing an electromagnetic sense that appears to be as sophisticated as that found in any other taxon.

A welcome feature of this book is that the author has set out to ‘go to the field’ and relate our knowledge of physiological mechanisms to the problems that salamanders face in nature. These primarily concern prey detection and capture, but there is a brief mention of mate recognition. Throughout the book there is an emphasis on the ecological relevance of sensory processes, an approach that is enhanced by a comparative approach in which the mechanisms found in differ- ent species are related to their contrasting ecolo- gies.

The book opens with a brief review of the taxonomy, geography and ecology of salamanders. The second chapter, on visually guided behaviour, begins with a review of feeding mechanisms that is primarily an account of the morphology of the bones and muscles that are involved in prey capture by the tongue. The salamander visual system has to guide a protrusible tongue to its target and the rest of this chapter describes how prey preferences, visual mechanisms, the olfactory system and learn- ing interact to achieve this. Chapters 3 and 4 deal with the detailed functional anatomy of the eye and the visual system, respectively. Even to one who has studied urodeles for several years, the neural complexity and sophistication revealed in these chapters is astonishing. Equally impressive is the ingenuity and skill deployed by Roth and others in the experimental work involved in under- standing such a complex system in rather small animals.

Chapter 5 describes electrophysiological pheno- mena at the neuronal level in the retina, the diencephalon and tectum opticum and shows how our understanding of visual pathways is enhanced by electrical stimulation and lesion studies. Finally, chapter 6 brings together all the behavioural, anatomical and physiological data, from anurans as well as urodeles, to construct a general model of how the nervous system controls visual behaviour. This model differs in important ways from that developed by Ewert for prey recognition and capture in toads. Whereas Ewert has suggested that there are rather specific units in the visual system that act, for example, as ‘worm detectors’, Roth argues for a more generalized ‘prey analyzer’ system that is activated by any potential prey item.

This is not an easy book to read. It is packed with information, much of it highly complex, and it is easy to lose track of the underlying themes that the author is trying to develop. Neurophysiologists will no doubt find it readily accessible but its value to those primarily interested in behaviour is, unfortu- nately, diminished by the book’s lack of summary sections that could usefully have extracted general- ized principles from the mass of detailed data. This is unfortunate because ethologists, particularly those of us who see immense value in relating sensory mechanisms to the functional concerns that have come to dominate the subject, have much to learn from the kind of studies that are reviewed in this book.

TIM HALLIDAY

Brain and Behaviour Research Group, Department of Biology, The Open University, Milton Keynes MK7 6AA, U.K.

Elephant Memories. Thirteen Years in the Life of an Elephant Family. By CYNTHIA Moss. London: Hamish Hamilton (1988). Pp. 336. Price f15.95.

This book takes an original approach to the subject of behavioural ecology, resulting in a cross between an anecdotal description of wildlife and a serious scientific report. The author provides a chronologi- cal account, extending over 13 years, of the lives of the members of a group of elephants living in the Amboseli National Park in southern Kenya. The elephant population in the Park is unusual in that it has been relatively free from the heavy poaching that most other populations have suffered and consequently, the elephants continue to live a normal social life. The elephant family of the book

Book Reviews 875

constitutes a ‘bond group’, which is defined as a number of family units that are believed to be related and which show a closer association with each other than they do with other groups. Members of each bond group in Amboseli have been given names beginning with the family letter, in this case T, chosen because the oldest matriarch had a torn ear and hence was known, reasonably enough, as Torn Ear. At the beginning of the study there were 23 elephants in the four T family units and at the time of writing there were 22 in three units. There are approximately 600 elephants in the Amboseli National Park and each one is known individually and named by the researchers. All have been subjected, since 1973, to a conti- nuous, and continuing, study by the author and a succession of ethologists. Such a detailed dossier on an animal population can have few parallels in sociobiology and this book illustrates with great clarity the importance of long-term studies for the proper understanding of ,animal behaviour.

Each chapter begins with a semi-fictional account of an event in the lives of the elephants to illustrate a particular theme, such as migration, which is considered in general terms later in the chapter. Most chapters deal with a single year and end with an account of the fortunes of the elephants making up the T family in that year. Consequently, the book reads almost like a novel and I found it difficult to stop reading long after I normally turn off the bedside light. It is, however, by no means light-weight. Cynthia MOSS wears her learning lightly and on finishing the book, the reader will find that a great deal of knowledge of elephant behaviour and ecology will have been absorbed. Amongst the topics discussed are drought, migra- tion, mating, social relationships, births, deaths, population dynamics and interactions with people. The book finishes with a powerful and passionate appeal for the conservation of elephants and considers the vexed question of culling in a humane yet realistic fashion. Evidence that the Amboseli population is in any way excessive is unimpressive and the author has convinced me that culling in the Park is out of the question.

This book can be unreservedly recommended to interested layman and research biologist alike. Both will learn much from it, not least that we have more in common with our fellow creatures than we may have thought.

S. IL ELTRINGHAM Department of Applied Biology, University of Cambridge, Pembroke Street, Cambridge CB2 3DX, U.K.

The Evolution of the Amphibian Auditory System. Edited by BERND FRITZSCH, MICHAEL J. RYAN, WALTER WILCZYNSKI, THOMAS E. HETHER- INGTON & WOLFGANG WALKOWIAK. New York: John Wiley (1988). Pp. xiii+705. Price $95.

In March 1986, a team of researchers with back- grounds ranging from neuroanatomy to beha- vioural ecology met at the University of Bielefeld, West Germany, to discuss their common interest, the amphibian auditory system. This splendid book, linking together themes from several disci- plines is the outcome of that workshop. It admir- ably shows that the amphibian auditory apparatus has become an important model for exploring problems in neural, behavioural and evolutionary biology.

The book’s 28 chapters are divided up into six sections, organized as a progression of topics that lead the reader through anatomy, physiology and development to behaviour and evolution. Several chapters stress the close link between the design of the auditory system and the design features of the signals themselves, emphasizing the way in which behaviour may be constrained by anatomy and physiology. In my opinion this is the strongest and most rewarding feature of the book for it is only too frequently that evolutionary biologists pay lip- service to physiological constraints that may re- strict an animal’s behavioural possibilities without really saying how these constraints operate. In this book, however, the bare bones (and wires) of the amphibian auditory system are painstakingly laid out well before embarking on a discussion of evolutionary constraints.

A nice example of this approach appears in Zakon & Wilczynski’s chapter on the physiology of the anuran auditory nerve, in which they discuss the implications of auditory physiology for mecha- nisms of reproductive isolation and sexual selec- tion. In general, they explain, frogs possess two auditory organs, the amphibian and basilar papil- lae, the nerve fibres of which display different properties. While the amphibian papilla is tonoto- pically organized (much like the mammalian coch- lea) and tuned to a whole range of best frequencies, the basilar papilla, on the other hand, is effectively ‘tone deaf and functions mainly as a resonator. The vocalizations of many frogs simultaneously excite both papillae, but there are some species in which calls excite only one, either the basilar or amphibian papilla. Not surprisingly, this physiolo- gical variation correlates with differences between species in the ability to resolve the frequency content of calls, and thus to discriminate among males of different body size (larger males usually have calls of lower frequency). As Gerhardt points