Researchers document split and lethal attacks in Uganda's Ngogo chimpanzees

Insights

• Researchers have observed the Ngogo community in Kibale National Park since 1995, when it numbered about 200 individuals.
• From 2015 social clusters emerged and by late 2017 the group had split into Western and Central factions.
• Beginning in 2018 the Western faction carried out coordinated attacks on the Central faction, killing at least 28 chimpanzees through 2024.
• Victims included primarily adult males and infants, and additional disappearances suggest some deaths went unrecorded.
• Possible drivers of the split and violence include the original group's large size, intensified feeding and mating competition, illness-related social disruption, and a change in alpha male.
• This case is the first clearly documented instance of a wild chimpanzee community splitting into factions with one side launching sustained lethal aggression, distinct from previously reported, human-influenced events.