Frans de Waal stands in a watchtower at the Yerkes National Primate Research Center north of Atlanta, talking about war. As three hulking male chimpanzees and a dozen females loll below him, the renowned primatologist rejects the idea that war stems from “some sort of blind aggressive drive.” Observations of lethal fighting among chimpanzees, our close genetic relatives, have persuaded many people that war has deep biological roots. But de Waal says that primates, and especially humans, are “very calculating” and will abandon aggressive strategies that no longer serve their interests. “War is evitable,” de Waal says, “if conditions are such that the costs of making war are higher than the benefits.”

http://discovermagazine.com/2008/apr/13-science-says-war-is-over-now