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 that the intensity and duration of the violence may inform how early human conflict developed.
Sandel, an anthropologist from the University of Texas and co-director of the Ngogo Chimpanzee Project, notes that chimpanzees are very territorial, leading to hostile interactions with those from other groups. Over several decades, the nearly 200 Ngogo chimpanzees had lived in harmony but began polarizing in June 2015 after a dispute.
Following the 2015 conflict, there was an evident six-week avoidance period between two sets of chimpanzees, with their interactions becoming infrequent and more aggressive. By 2018, the Western group began launching attacks on the Central chimpanzees.
The study identifies three key factors that may have catalyzed this violence: the unexplained deaths of adult males and females in 2014 affecting social ties, a change in the alpha male coinciding with increased aggression, and a respiratory epidemic that decimated 25 chimpanzees in 2017.
The findings challenge our understanding of the origins of human conflict and indicate that relational dynamics may play a larger role in conflict than previously assumed. James Brooks, a researcher at the German Primate Center, highlighted the dangers of group divisions, emphasizing the need for humans to learn from the behaviors of other species.
