A new study says that a review of all known cases when chimpanzees or bonobos in Africa killed members of their own species shows that violence is a natural part of chimp behavior and not the result of actions by humans that push chimp aggression to lethal attacks

The researchers say that their analysis supports the idea that warlike violence in chimps is a natural behavior that evolved because it can provide more resources or territory to the killers, at little risk. While the study ostensibly is about chimpanzees, it is also the latest salvo in a long and profound argument about the nature of violence in people, as chimpanzees are humans’ closest relatives in the animal world. In studying chimp violence, “We’re trying to make inferences about human evolution,” said Michael L. Wilson, an anthropologist at the University of Minnesota and a co-author and organizer of the study. Male chimps are more likely to kill than females. Killing chimps in other groups is more common than killings within groups. And chimps tend to attack when they have overwhelming odds on their side. Lurking behind the discussion of chimps is a long-running dispute over whether chimp behavior offers insights about human behavior, as well as an even deeper and older philosophical dispute over whether violence and war are natural for human beings.