Chimpanzees are famously territorial. When neighbouring groups meet, the scene is extremely hostile: males tear about with their hair on end, their body language set to intimidate. They scream, bang on trees and will even kill each other. In stark contrast, when bonobo groups meet there is no sign of fighting. ‘They might shout a little bit in the beginning, but very soon it looks more like a picnic than warfare,’ Frans de Waal told me. Albeit a picnic where everyone is having sex with each other.
