Studies of our closest living relatives, chimpanzees and bonobos, have been influential in efforts to understand the evolution of aggressive behaviour in our own species. In recent years, however, the validity of these studies has been questioned by proponents of the human impacts hypothesis, which argues that the occurrence of violence in chimpanzees is mainly the result of human activities. Now a meta-analysis of studies on chimpanzees and bonobos across Africa reveals that aggression between chimpanzees is the normal and expected product of adaptive strategies to obtain resources or mates, and has no connection with the presence or otherwise of human beings.