It was already a rare occurrence when a group of chimpanzees murdered one of their own. In a study published in the International Journal of Primatology, researchers recount only the ninth recorded murder of a chimp by its own community.
In 2007, Foudouko was the leader of a group of more than 30 chimps in Senegal, National Geographic reports. He was nicknamed "Saddam," and anthropologist Jill Pruetz tells New Scientist he was "somewhat of a tyrant." But Foudouko was overthrown and exiled for years, living on the edges of his former community.
Then in 2013, he was killed by a group of younger males. Pruetz says she was "really disturbed" for days after watching video of the incident.
Humans may ultimately be responsible for the rare and gruesome violence that befell Foudouko. His community has nearly twice as many male chimps as females, likely due to poachers targeting female chimps.
This increases tensions in the community, and Foudouko may have been killed for approaching a female in heat. Horrifying as the incident may have been, one expert says it can help us better understand how chimp societies function.