Ugandan Chimpanzee Population Fractures as Brutal Eight Year Conflict Results in 24 Killings

Researchers in Uganda document 24 killings as the world's largest chimpanzee group splits into warring factions, offering new insights into the roots of conflict.

By: AXL Media

Published: Apr 11, 2026, 8:24 AM EDT

Source: Information for this report was sourced from BBC

A Violent Dissolution of Primate Social Bonds

The once unified community of Ngogo chimpanzees in Uganda has descended into a sustained period of internal warfare, marking a radical shift in primate social dynamics. According to Aaron Sandel, an anthropologist from the University of Texas, the group began a visible process of polarization as early as 2015. While these primates previously engaged in cooperative behaviors such as holding hands and grooming, they have now transitioned into a state of lethal hostility. This civil war has resulted in at least 24 documented killings between 2018 and the present day, highlighting a dramatic breakdown of what was formerly the largest known cohesive chimpanzee group in the wild.

The Deadly Toll of Subgroup Rivalry

The violence has been characterized by targeted aggression from the Western group against the Central group, leading to a significant loss of life within the population. Research findings published in the journal Science indicate that of the 24 confirmed deaths, 17 were infants and seven were adult males from the Central faction. Sandel noted that the actual death toll is likely higher than what has been officially recorded. This shift toward lethal interactions suggests that the territorial nature of chimpanzees can manifest as a deep-rooted fear of those now perceived as strangers, even if they were formerly close allies within the same social structure.

Catalysts of a Fragmenting Community

Scientists have identified several pivotal events that likely triggered the collapse of the Ngogo community's social fabric. In 2014, the unexplained deaths of six adult individuals began to weaken the ties that held the various subgroups together. This instability was further compounded in 2015 by a change in the alpha male hierarchy, an event that Sandel observed coincided with the first significant period of separation between the Western and Central sets. The final blow to the group's unity arrived in 2017 when a respiratory epidemic claimed 25 lives, including a specific male who served as a primary social bridge between the factions.