Groups of male chimpanzees patrol the borders of their territory in single file
A major study suggests that killing among chimpanzees results from normal competition, not human interference.
Apart from humans, chimpanzees are the only primates known to gang up on their neighbours with lethal results - but primatologists have long disagreed about the underlying reasons.
One proposal was that human activity, including destroying habitats and providing food, increased aggression.
But the new findings, published in Nature, suggest this is not the case.
Instead, murder rates in different chimp communities simply reflect the numerical make-up of the local population.Read the rest of this article...