Outbreaks of violence between chimpanzees have sparked fierce debate online about the origins of war in humans Published April 23, 2026 6:30AM (EDT) A Congolese Army soldier holds a baby chimpanzee while manning a checkpoint in the entrance to the provincial capital of Goma, Congo on November 6, 2008. (Photo by Yasuyoshi Chiba/AFP via Getty Images) For decades, the 200 Ngogo chimpanzees in Kibale National Park, Uganda, lived what seemed a calm and normal existence. Males and females hunted together, groomed each other and went on patrols through the forest. Within this large group, cliques were formed but they often intermingled and share territory, like something from a simian Pixar film. But in June 2015, something happened and the group split in two. Then, the violence started. The scientists watching this schism aren’t sure why things became so belligerent. It started with members from one group chasing the other and prolonged periods of avoidance.…