Since 1995, researchers have been tracking the Ngogo chimpanzee group in Uganda’s Kibale National Park - one of the largest and most studied chimp communities in the world, featuring in the 2023 Netflix documentary Chimp Empire. But the latest finding from this long-running study is unlike anything scientists have documented before.

Chimpanzees are our closest living relatives, sharing roughly 98 percent of human DNA. Previous Ngogo research has already uncovered deeply human-like behaviours - male chimps forming long-term bonds through years of hunting and patrolling together, and female chimps experiencing menopause, something never before documented in any primate outside of humans. Every major discovery from this group has forced scientists to reconsider what makes humans unique. The Ngogo group once numbered over 100 chimpanzees spread across roughly 10 square miles - an unusually large community. Around a decade ago, the group fractured into two factions. Since then, the conflict between them has been sustained, widespread, and highly lethal in ways scientists have never observed in chimps before. Researchers believe further study could offer real insights into the evolutionary roots of warfare in human beings.

The Ngogo chimps did not read history. They have no ideology, no religion, no politics. If our closest relatives can go to war without any of the reasons humans use to justify it, the question science is quietly asking is a difficult one - is conflict something we chose, or something we inherited?