http://service.spiegel.de/cache/international/spiegel/0,1518,433327,00.html

Hippy Sex Fiends and Brutal Machiavellians

So if humans evolved from apes, which ones are our closest relatives? Dutch primate researcher Frans de Waal spoke with SPIEGEL about bloodthirsty chimpanzees, sex-crazed bonobos, the origin of the family and the nature of human beings.

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De Waal: By putting on a big show. There is a male chimpanzee in Tanzania's Mahale Mountains who likes to make a huge to-do about throwing boulders into a dry riverbed. Each time he does it a large audience gathers and shows their deference. The chimpanzees bow and chatter, both typical submissive behaviors.

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SPIEGEL: Primatologist Jane Goodall has said: "If chimpanzees had guns and knives and knew what to do with them, they would use them the way people do." Apes tear out their enemies' fingernails, crush their testicles and rip out their windpipes.

De Waal: Oh yes, they can be very brutal. Wild groups of chimpanzees attack their enemies like gangs. What they completely lack, precisely because of their strong territorial behavior, is a friendly relationship with their neighbors.

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We did an experiment in which we gave chimpanzees watermelons and then documented how they divided up the fruit among themselves. In the hours leading up to the experiment, we recorded which animals groomed which other animals' fur. The results were clear. The ape that divided up the watermelon gave significantly more to those apes that had groomed him earlier on.