Chimpanzee civil war in Uganda offers a Girardian mirror for human group dynamics

Chimpanzee Civil War in Uganda

A cohesive group of roughly 200 chimpanzees in Uganda's Kibale National Park has fractured into two warring factions, with more than 24 deaths recorded since coordinated lethal attacks began in earnest around 2018. The true death toll is likely higher, given the difficulty of tracking deaths across the large study area.

The split began in 2015 when several key male chimps died from disease, weakening the social bonds that had held the group together for two decades. Around the same time, a new alpha male rose to power, triggering escalating aggression and tension within the hierarchy. As tensions mounted, the group drifted into two clusters, separated by geography and eventually by complete loss of social and reproductive ties. By 2018, what was once the group's shared territory had become a patrolled border.

The smaller of the two groups has since launched coordinated raids on the other, targeting rival adult males and increasingly younger apes. Infant deaths average several per year. The smaller faction has paradoxically grown larger through these attacks, killing enough rivals to shift the population balance.

The mechanism behind the split likely traces to the group's own success. The population had grown large enough that even with abundant resources, the chimps may have perceived increased competition for food and mates. The size itself—around 200 individuals—exceeds what researchers call Dunbar's number, the cognitive threshold at which individuals can no longer maintain stable relationships within a group. At roughly 150 members, social cohesion begins to strain. The chimps may have simply outgrown their ability to function as a unified community.

Primatologist Jane Goodall observed what may have been a similar split among chimpanzees in Tanzania in the 1970s, though those findings were complicated by the fact that humans regularly fed those chimps, potentially distorting group composition and aggression levels.

The segment draws a parallel to human group dynamics—specifically, to René Girard's theory of mimetic rivalry and scapegoating. Two groups, once identical in composition and alliance, become rivals precisely because they mirror each other. The conflict then becomes inevitable, requiring violent resolution. Put 200 humans together and the same dynamic would unfold. With 20 humans in an HOA, it happens faster.