The world's largest known group of wild chimpanzees has split and been locked in a vicious 'civil war' for the last eight years, according to researchers. It is not clear exactly why the once close-knit community of Ngogo chimpanzees at Uganda's Kibale National Park are at loggerheads, but since 2018 the scientists have recorded 24 killings, including 17 infants. 'These were chimps that would hold hands,' lead author Aaron Sandel said. 'Now they're trying to kill each other.' The study, published in the journal Science, indicates the intensity and duration of the violence may provide insights into the early development of human conflict.

Sandel, co-director of the Ngogo Chimpanzee Project, mentions how chimpanzees are inherently territorial and can have hostile interactions with outsiders, contrasting their past harmony. The researchers noted a polarisation that began in 2015, leading to a split into two groups that began engaging in lethal aggression. Factors such as deaths of key individuals and changes in leadership appear to have rekindled old rivalries, leading to a shocking number of violent encounters since their separation.

According to Sandel and his colleagues, these findings challenge perspectives on human conflict, suggesting relational dynamics might play a bigger role than commonly assumed. 'Individuals who lived, fed, groomed and patrolled together for years became targets of lethal attacks based on their new group membership,' they conclude.