The primate species well known as being most closely related to humans is the chimpanzee.Less well known is that there are two distinct chimpanzee species, the second being the bonobo, which is why the biologist Jared Diamond wrote a book about humans called The Third Chimpanzee. Now the primatologist Frans de Waal, who has spent a lifetime studying the behaviour of both chimpanzees and bonobos in captivity and in the wild, has followed suit.

As he describes it, there are sharp differences in behaviour between our two neighbours. Chimps are larger and more aggressive, bonobos smaller, more social and promiscuously sexually active. It is also - although he does not discuss this in any detail - a bonobo, Kanzi, who has proved the most adept in learning to use sign language to communicate with his human carers.

You can judge to some extent where de Waal is coming from by the title of one of his previous books, Chimpanzee Politics. Chimps and bonobos have complex social lives, with clear hierarchies of power and privilege. Chimps tend to fight their way to the top, bonobos use sex instead where they can - and de Waal is at pains to make clear that any belief that only humans have sex for pleasure and influence, whilst non-humans are exclusively heterosexual and copulate only to reproduce - could not be more mistaken.

An acute observer, de Waal chronicles the details of the lives of his subjects as minutely as Le Roi LaDurie chronicled the doings of the villagers of Montaillou. Into these lives he weaves accounts of affection, jealousy, acts of kindness and spite, transient alliances and betrayals, unity in confronting common enemies, concern over injury and grief over death. And from these microcosms he wishes to draw lessons that are relevant to the human macrocosm.

De Waal is neither the first nor the last to attempt explanations of human conduct on the basis of the study of other species, notably of course primates. Back in the 1960s it was Desmond Morris with his description of humans as naked apes (Morris gives this book a cover accolade), and Robert Ardrey who insisted that human aggression and territoriality had its roots in our African primate past.

Then, in the 1970s came EO Wilson and sociobiology. The sociobiologists dismissed these earlier theorists as crude speculators. However, they argued, human behaviour could only be seen in an evolutionary perspective, which determined the limits to the adaptability of human society, such that the sexual division of labour, like the poor, would always be with us. More recently sociobiology has been rebranded as evolutionary psychology, with its insistence that 'human nature' was fixed in the Pleistocene, leaving us with stone age minds incapable of adapting to meet the challenges that our own cultural and technological development create. De Waal, to his credit, will have none of this, firmly rejecting the cruder claims of evolutionary psychology.

However, he is not averse to drawing his own generalisations about the behaviour of the third chimpanzee based on his studies of the other two. Here he makes the first of his methodological errors. Observers of animal behaviour are constantly advised to avoid anthropomorphising their subjects. De Waal - at least in his popular writing - does so constantly, reading motivation, feelings and intentions - in short, agency akin to that of humans - into his chimps and bonobos. I agree it is difficult to avoid doing so, as any dog or cat owner will attest (I find it a problem even with the day-old chicks I study). But the reader at least deserves a health warning of the problems of inferring such agency in alien species.

Much more serious is the naïveté with which he tries to draw comparisons between his chimps and the way we humans behave. His accounts of the social interactions of our own species read like comic book caricatures, as for example, when he claims that men on meeting for the first time engage in trials of strength, competing not so much by fighting but by arguing and boasting, or his reduction of the complexities of the US-UK attack on Iraq to the battles between tribes of apes.

True, the caricaturists often portray George W Bush as a monkey, but that is their privilege; one should not take it seriously. Thus both the title and the sub-title ('the past and future of human nature') of de Waal's book are vulgarly misleading.

Humans are not merely the outer shell of inner apes, and he has nothing of importance or even credibility to say about human nature, its past or future. But for an enjoyable account of the behaviour of our two nearest surviving evolutionary neighbours, you couldn't do better.