Scientists studying chimpanzees in Uganda's Kibale National Park have documented a decade-long conflict between two splinter groups that has left dozens dead, challenging assumptions about the roots of warfare. The violence began after a once-unified community of around 200 chimpanzees split into rival factions known as the Central group and the Westerners, possibly following the deaths of several stabilising elders.

Researchers report that at least seven adults and 17 infants had been deliberately killed by 2024, with more deaths since. The attacks involve coordinated raids, ambushes and lethal assaults, despite no apparent scarcity of food or mates. The prolonged fighting appears to lack the political, territorial or resource-driven motives often associated with human wars.

Observers have been struck by the ferocity and apparent pointlessness of the conflict, which has included the filmed killing of a gentle male nicknamed Pork Pie. Scientists say the behaviour suggests that lethal intergroup violence may be deeply embedded in chimp biology and, given the shared evolutionary ancestry between chimpanzees and humans, could point to ancient roots of warfare in our own species.

The findings challenge the idea that complex cultural factors are necessary for sustained conflict, instead raising the unsettling possibility that the impulse to form rival groups and engage in deadly aggression may be far older and more instinctive than previously believed.