A community of approximately 200 chimpanzees in Uganda’s Kibale National Park has fractured into two rival factions, leading to a years-long, deadly conflict.

The Ngogo chimpanzees have been under continuous study for three decades, yet scientists have recently observed the violent split unfold in slow motion.

Starting around 2015, this previously unified group began to polarize. Social bonds weakened, neighborhoods within the community solidified into distinct factions, and once-shared territory became hotly contested. By 2018, this division had become permanent.

What transpired next was both surprising and alarming. The smaller faction, known as the western chimpanzees, initiated targeted raids on the territory of their larger rivals, the central group. Over the following six years, they killed at least seven adult males and 17 young children.

This count is likely an underestimate. An additional 14 adolescent and adult male chimpanzees went missing or died unexpectedly between 2021 and 2024, none showing any prior signs of illness.

Today, the Western group has emerged as the dominant force within the jungle.

Recent findings, published in Science, have drawn comparisons to civil wars. Unlike conflicts between strangers, the events at Ngogo involved former allies, groomers, and long-term social partners turning against one another.

Researchers involved in this study estimate that such conflicts occur only once every 500 years.

“One of the most intriguing aspects of this conflict is the so-called ‘friend-to-foe’ transformation,” stated Professor Aaron Sandel from the University of Texas at Austin in an interview with BBC Science Focus. “This provides a rare glimpse into the minds of chimpanzees.”

This research supports the notion that group identities can change, undermining long-held social bonds without the ethnic, religious, or ideological markers typically associated with collective violence.

“It almost facilitates wars between factions,” Sandel commented. “But we remain troubled by civil strife, as it’s often neighbors turning against neighbors.”

He added that insights from chimpanzee behavior could help researchers formulate hypotheses about the factors that drive humans toward or away from similar conflicts.

“By focusing on human interactions and conflict resolution, we may uncover more effective avenues for promoting peace,” he concluded.

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