The apes who go to war

Tony Blair is not our only demonic male. Atop a dust jacket colour scheme born of a mind not so much demonic as unhinged we are greeted by a snarling Identikit of a chimpanzee fitted with those now notorious demonic eyes. Demonic Males is quite an eye-catcher.

As a thesis on the origins of human violence in our ape ancestry, it is also a great book, a real tour de force of primatology, evolution, ecology and ethnography. It bears no resemblance to the last specific attempt to deal with this question: Robert Ardrey's unsatisfactory and speculative The Territorial Imperative. Richard Wrangham and Dale Peterson explore such diverse topics as the seedy consequences of a westerner, in the shape of Paul Gauguin, transporting himself to a culture of adolescent sexual opportunity. But initially they restrict themselves to a rather special analysis, the comparison of chimpanzee and human violence. Chimpanzees can be pretty nasty. Males will batter or rape females if they can get away with it. Females have killed and consumed each other's babies. But rape and infanticide turn up elsewhere in the animal kingdom; what separates chimpanzees from animals and unites them with humans is the practice of warfare. That is an accurate statement, not a metaphor. All-male bands of chimpanzees penetrate neighbouring territories, quietly, intently, not stopping to feed, and if they encounter a smaller party of males they will destroy it. Well-documented cases right across the African continent show that these incursions often achieve their presumed goal, the complete extinction of neighbouring groups with surviving females having no option but to join the victors. Correspondingly, the book asserts that there are virtually no human societies that do not practise warfare. The Yanamamo are predictably trotted out at this point, a people with few material goods and whose style of warfare appears, in the hands of these authors, eerily similar to chimpanzees. The authors cover many societies, assembling a quirky but convincing case that warfare is a human universal and, furthermore, based on three conditions: coalitionary bonds between males; male dominion over an expandable territory; and variable party size.

These conditions are also met by chimpanzees. Humans and chimpanzees are unusual in their construction of male bonded groups: the mammalian norm is for females to form kin networks in their natal groups and for males to disperse, pursuing their objectives individualistically but not demonically.

By this means the authors argue for a comparative basis for human and chimpanzee shared demonism. This they accompany with an argument by common descent. We do not know for certain whether our hominid ancestors practised warfare. But we do know that both their descendants and chimpanzees do. The authors' compelling observation is that the gap in our knowledge of human behaviour begins five million years ago with a chimpanzee-like ancestor and ends at 7000 bc with the fortified walls of Jericho. Is it thus unreasonable to infer that the path was lined by male aggression that structured our ancestors' social lives, technology and minds? There is a twist to this tale, however. Separated by a huge arc in the river Congo from the chimpanzees whose ancestors they diverged from one and a half million years ago, live the bonobos. There is very little aggression between bonobo groups: homosexual interactions between representative females ("hoka-hoka") are as likely. The males cannot sexually coerce the females within their own group and are not dominant over them. The reason? Female solidarity. Bonobos, the only ape south of the Congo, can exploit evenly distributed herbaceous foods from which chimpanzees to the north are excluded by gorillas. The result is large, stable groups in which females can form networks of support sufficient to thwart male aggression. Maybe its too bad there was not enough terrestrial herbaceous vegetation in the diet of the hominids evolving further east to vanquish their, and our, demonism. But that should not prevent us noting the clear moral of female solidarity provided by the bonobo and recognised long since by feminists.

I anticipate two general objections to Demonic Males. The first comes from science and it is that the thesis has a debating-room feel, switching between generalisation and illustration to potent effect and concentrating on its own strengths rather than weaknesses. In fact, the correct scientific procedure for testing hypotheses is to attempt to falsify them. Demonic Males is dazzling, but this cuts both ways. It is impossible not to be impressed, but the book's virtuoso waltz across the many strands of evidence leaves a distinct feeling of being dazzled. Unaided by anything so drably academic as chapter summaries it is impossible to hold all the threads in mind at once and since none is entirely compelling in its own right, it is difficult to decide whether they add up to a coherent proof or whether the whole is considerably less than the sum of its parts.

The other anticipated objection comes from social science. What have chimpanzees got to do with humans? We are culturally, not biologically determined. War and rape are socially constructed. Yanomamo and chimpanzee may be acting in superficially similar ways but to the agents themselves the acts mean quite different things. And sociobiology is ideologically driven.

The text hints at the author's anticipation of such a response and I empathised at quite a visceral level with this and a collective exasperation among biological anthropologists at the crass division of nature and nurture into mutually exclusive possibilities - a division that largely serves the purposes of social anthropology since who would deny the influence of culture on humans? Human and chimpanzee represent their violent acts differently and one has a vastly superior ability to reason, but might not the emotions that motivate the two species be similar? And of course, social anthropology is equally prone to ideological myopia, as this book's examination of Margaret Mead's well-intended but largely inaccurate account of a self-determined and nonviolent utopia in Samoa demonstrates.

I recommend to sceptics and sympathisers alike that you buy this book and chew it over. You might want turn the dustjacket inside-out however.

Thomas Sambrook is a research associate in anthropology, University of Durham.