Chimps Plunder Less Pineapple From Friends—and Expect Them to Do the Same

Chimps plunder less pineapple from friends—and expect them to do the same

In recent years, scientists have shown that chimpanzees favor certain peers by picking whom they prefer to groom and selectively sharing food. The behavior offers a glimpse into humanity's prosocial evolutionary past. But a question has lingered: How might a chimpanzee friendship affect antisocial acts?

A study of 26 chimpanzees observed for over 800 hours found they stole food less often from friends than non-friends, while victims calmed down faster when the thief was a friend, suggesting chimpanzee friendships involve expectations of preferential treatment.