At every chimpanzee site that’s been studied for more than a decade, scientists have observed conflicts that end in death.
But killing within a community is rare.
The incident—described recently in the International Journal of Primatology and whose aftermath was caught on video—is just the ninth recorded case of a chimpanzee community killing one of its own.
“It was incredibly hard to watch,” says study co-author Jill Pruetz, an Iowa State University anthropologist and National Geographic Society grantee. “I was really disturbed for about three days [afterward], as if you had a falling-out with a friend.”
Back in 2007, Foudouko was the leader of more than 30 western chimpanzees (Pan troglodytes verus) living in Fongoli, a 10-square-mile patch of savanna in southeastern Senegal. (Read more about Fongoli chimps in National Geographic magazine.)