Craig Stanford: Apes of the impenetrable forest. The behavioral ecology of sympatric chimpanzees and gorillas

Abstract

It is a curious but basic fact that all of the better-known behavioural field studies of Pan troglodytes and Gorilla gorilla have been carried out under dubious ecological conditions. That is, whether Bossou, Gombe, Mahale, Tai or Karisoke, among others, the studies at each site present only one of these African ape species, while the other is absent. This is notable because the two closely related taxa almost certainly evolved in sympatry in the Congo Basin; consequently, a full understanding of them requires that the chief competitors be present. Comparative ecological studies of the two hominoid taxa have been done, most notably the pioneering efforts of Caroline Tutin and Michel Fernandez at Lope, Gabon, but behavioural detail was lacking. For example, we do not know at this point even if their competition is contest or scramble. Now comes a new book whose subtitle promises to tackle these issues. Craig Stanford, a field primatologist with experience of Asia and Africa, including the chimpanzees of Gombe, has produced a monograph that tackles the gap. It is the fifth in the series of slim paperback volumes on Primate Field Studies, published by Pearson/ Prentice-Hall, the stated aim of which is to revive the scientific monograph in a form accessible to a wider audience than that of fragmented reports in academic journals. To cut to the chase, this volume succeeds admirably on that front, and is user-friendly to students, even undergraduates. The book opens with personal background on the author, positioning him and the proposed field site for the study to come. The qualifying credentials of both Stanford and Bwindi are convincingly proffered, and the conventional wisdom on chimpanzee–gorilla ecological differences, based on allopatric studies, is robustly challenged. For example, both do show arboreality and frugivory. This sets the stage for the next chapter, which explicitly is a primer on the two species of great apes. Not surprisingly, given the experience of the author, the information presented on the chimpanzees is better grounded. For further contrast, brief treatments on bonobo and orang-utan are included. The chapter closes on the core problem: What do we actually know about chimpanzees and gorillas in sympatry? Here, a worrying trend seems to emerge, that of little attention being paid to previous studies, especially the work by Yamagiwa and colleagues at nearby Kahuzi-Biega, the other high-altitude site where eastern chimpanzees co-exist with eastern gorillas. By far the best chapter in the book, from the point of naive students, is Stanford’s frank account of what it takes to get a long-term field project off the ground. His description dispels the misleading impressions given by television documentaries and even by journal articles, that somehow field-sites just spring magically into existence. Stanford’s efforts are a step-by-step model of how such pioneering needs to be done. This narrative thread continues throughout the book, underpinning the science, which covers the basic aspects of diet, habitat, ranging, shelter construction, etc. Perhaps the most controversial of these topics is his treatment of bipedality which, depending on one’s point of view, provides important new insights (e.g. key role of arboreality) or not (e.g. it is all about posture, not locomotion). But what about that key point about niche overlap or competitive exclusion between the two species? As it turns out, the data for direct (contest) competition are too few to draw conclusions, and W. C. McGrew (&) Leverhulme Centre for Human Evolutionary Studies, Department of Biological Anthropology, University of Cambridge, Cambridge CB2 1QH, UK e-mail: wcm21@cam.ac.uk