New Study Shows that Chimpanzees Evolved to be Violent

Is chimpanzee intergroup aggression like primitive warfare, an adaptive strategy that gives the perpetrators an edge, or is it the consequence of human activities, such as provisioning - artificial feeding - by researchers or habitat destruction? 

A new study of the pattern of intergroup aggression in chimpanzees and pygmy chimpanzees (bonobos), their close relatives, finds that human impact isn't the culprit.  

The research project compiled data collected over five decades from 18 chimpanzee (Pan troglodytes) and four bonobo (Pan paniscus) communities.