Mosaic Evolution of Subterranean Mammals — Regression, Progression and Global Convergence.

Eviatar Nevo. Oxford University Press, Oxford. 1999. Pp. 413. Price £95.00, hardback. ISBN 0 19 857572 6.

‘The mole had been working very hard all the morning, spring cleaning his little home. First with brooms, then with dusters; then on ladders and steps and chairs, with a brush and a brimming pail, till he had dust in his throat, small splashes of white-wash all over his black fur, and an aching back and weary arms’. So begins The Wind in the Willows by Kenneth Grahame, creating an evocative image of an industrious creature living in a cosy subterranean home. But to quote the old cliché, truth is often stranger than fiction, and the labours of ‘Mole’ pale into insignificance when one considers the Herculean digging feats of many subterranean mammals, and the complex ‘housekeeping’ of the eusocial naked mole-rat. Furthermore, although predictable and stable, the subterranean niche is a nightmarish one for a terrestrial animal, with its claustrophobic darkness and potentially suffocating gas composition, but it is to this specialized microenvironment that subterranean animals throughout the globe have become exquisitely adapted.

The central premise of Nevo is that the adaptation of mammals to a subterranean life-style can be viewed as a global experiment in evolution, beginning with climatic changes in the Eocene and early Oligocene, with ‘regression’, ‘progression’ and ‘global convergence’ in structure and function, and he presents a wealth of information to support this thesis. From the title it is evident that the aim of this book is an ambitious one, but with 50 years of experience in this field, Nevo is suitably qualified for such a task, and a lifetime of enthusiasm for his subject shines through in the writing. The great strength of the book is its multidisciplinary approach, covering topics as diverse as palaeobiology, ecology, anatomy, physiology, behaviour, population genetics and speciation, all set within the context of evolutionary theory. As Nevo points out, this ‘global experiment’ is a wonderful opportunity to apply the comparative method in evolutionary biology, which is so much in vogue at present. After experiencing many peaks and, I have to say, some troughs during the course of reading the book I think that on balance Nevo largely succeeds in his objectives. The text is prone to become rather unwieldy in places, but in other parts the fascination of the author for the animals sparkles through to liven it. Although much is made of the comparative method, I found disappointingly little evidence of integration of the mass of data presented with the wealth of phylogenetic information that is now out there in the literature. The inclusion of some recent mammalian phylogenies in Chapter 16 seems superfluous, as they are almost totally ignored in the text. It seems a shame that the section of the book (mainly Part VI) containing the cross-taxa analysis was based on a questionnaire put out in 1987, and not updated, as there has been a mass of new papers on subterranean mammals since that time. Furthermore, although some 1999 references are included, disappointingly, these appeared to be somewhat selective, as discussion in some sections of the book were out of date. I also found the sections on the evolution of social structure and eusociality weakly argued and confusing, with several non sequiturs. For example, it is hard to understand how the statement ‘the hystricomorph ovary is highly secretory’ (p. 275) has any bearing on eusociality. I think that these criticisms arise mainly as a consequence of the all-encompassing nature of the book. With such a broad remit covering diverse topics, it is difficult for a single author to please everyone.

The book covers a lot of ground and does contain a mass of information, with many useful pictures and diagrams. The price tag of £95 will almost invariably restrict the book to libraries or dedicated researchers in the field, but it is certainly a valuable first port of call for those interested in subterranean mammals, and should have a broad interest to biologists of many disciplines. I certainly enjoyed just picking it up, dipping in at random and invariably finding an interesting snippet of information provoking further thought.