Probably nothing is more certain, more studied or more essentially “human” than war, but new study may change that. Dr. John Mitani of Michigan University recently completed a ten-year look at warfare among chimpanzees, finding that they cooperate to organize themselves with the intent to capture territory, their behavior is adaptive, and that natural selection has therefore hard-wired warfare into their neural circuitry. That’s of particular interest to humans because of the possibility that we both inherited an instinct for aggressive behavior from a common ancestor who lived about 5 million years ago. Chimp warfare heretofore has rarely been observed by humans—Jane Goodall famously witnessed a chimp community in Tanzania’s Gombe National Park split into two and then one group wipe out the other (but those chimps had been fed bananas, leading some researchers to blame the war on this human intervention) and the only other instance involved another Tanzanian chimp group that was wiped out completely, but no bodies were ever found. From what has been witnessed, chimps’ warfare closely resembles that of contemporary human hunter-gatherer societies, so if there is a genetic link, Dr. Mitani’s study raises many more questions—can chimps foresee the consequences of their behavior? Do they calculate the outcomes? And what can they tell us about ourselves and our perhaps inevitable appetite for war.
Sylvia Amsler, primate behavioral ecologist and professor of Anthropology at the University of Arkansas; she was co-author on a report published this week in “Current Biology”