Ape and essence

Marek Kohn snarls at scientists who pretend that chimps can chat
Demonic Males: Apes and the Origins of Human Violence by Richard Wrangham and Dale Peterson, Bloomsbury, pounds 16.99

Words like "friendship" or "rape" are taboo in most departments of science, but in primatology they are key terms. The effects are remarkable enough in scientific papers; in popularisations, licence sails merrily into ludicrousness. Guess whose inner monologue this is: "It's Carla...She killed Susan's younger sister four years ago, ripped her apart; dead in the middle of her first pregnancy. What a pleasure it would be to get her."

The thinker's name is Sally, but she's not human. Nor even a chimpanzee. Sally is a hyena, a member of an order of mammals not usually credited with the capacity for vengefulness - not in books aimed at people over 12, at any rate. Not only do Richard Wrangham and Dale Peterson put words in animals' minds, but they are convinced that they can read the animals' emotions too. Their conviction arises from observation; 20 years' worth in Wrangham's case.

When chimpanzees attack members of another chimpanzee group, Demonic Males asserts, "their assaults...are marked with a gratuitous cruelty - tearing off pieces of skin, for example, twisting limbs until they break, or drinking a victim's blood". Although it wouldn't make a lot of difference to the victim, there may be an alternative explanation to bloodlust. Chimps co-operate in the kill, but feeding is a free-for-all, with the result that the two activities merge horribly into each other. The best way for an individual chimp to gain from the kill is to tear off parts of the victim: it sounds as though similar moves are triggered in attacks whose goal is not food. But "feeding frenzy" does not have moral force, unlike "gratuitous cruelty", "the mark of Cain", or "demonic". This is about original sin, recast as our Darwinian legacy.

The underlying argument of the book is strong enough to manage without these purple patches, though the seamless way in which they blend into the evolutionary grist suggests complicity on the part of primatology, rather than artfulness on the part of the authors. Demonic Males begins from the proposition that the common ancestor from which humans and chimps are descended was, in fact, very like a chimpanzee. It goes on to argue that the tendency seen in chimpanzee males to form mutually hostile coalitions would have been a persistent theme in subsequent hominid evolution. The principal agents sustaining this theme are not demonic but ecological, notably the density of food plants and the size of primate groups.

One small variable, Wrangham and Peterson suggest, led to the evolution of one species whose "demonism" was "vanquished". During the Ice Ages, the central African forests shrank, eradicating gorillas south of the Zaire river; without gorillas, herbs subsequently flourished. This reliable food supply allowed chimpanzees to travel in more stable groups, which meant they could become the sub-species known as bonobos. Stability allowed the females to spend time together, which allowed them to bond, which gave them power. Female bonding is cemented by sexual activity, which is also a key means of resolving conflict throughout bonobo society. The net result of female power is a lot more sex and a lot less violence.

Wrangham and Peterson suggest that it was a similar twist of ecological fate that turned us away from Bonobo Eden and set us off on a path more like that of common chimpanzees. It's a resonantly mysterious idea, this variable of the Fall, but it distracts us from what may be a vital part of the story. So do flights of rhetorical fancy that put words in non- human minds.

If one's model is a sort of vulgar Darwinism, which sees culture as a veneer on the top of biology in the way that vulgar Marxism saw it as a veneer on the surface of economics, then language and symbolism are not important. But these uniquely human faculties have a profound influence on the character of human violence. Above all, they turn the group into an abstract entity. Chimpanzees can tell allies from enemies in a fight. But, despite a facile remark about seeing male chimps as defenders of "ethnic purity", there is no more reason to think that chimpanzees could grasp the idea of ethnicity than to think that hyenas can talk.

There could never be such a thing as a chimpanzee flag. Nor, according to Wrangham and Peterson, could there be such a thing as a human society in which female bonds are as strong as those among bonobos. Instead, they propose that where possible, power should be shifted from dominant individuals (normally male) to institutions. Frustratingly, that's about as far as they go. Unlike many of those currently aboard the sociobiological bandwagon, Wrangham and Peterson genuinely want to make society better. But, because they lack faith in women's solidarity, their argument follows a path to bathos typical of popular sociobiology: mammoth evolutionary problems, dwarf solutions.