In Uganda, a troop of nearly 200 chimpanzees experienced a sudden outbreak of violent conflict, disrupting years of peaceful coexistence. The incident, documented by researchers, saw the killing of several chimpanzees, including one named Erroll, witnessed by primatologist Aaron Sandel. Sandel, from the University of Texas at Austin, is the lead author of a recent study published in Science, examining this unexpected “civil war” among the Ngogo chimps, a group extensively studied since 1995 in Uganda’s Kibale National Park.
The Ngogo chimps, residing in densely forested terrain, previously demonstrated high levels of cooperation and territorial defense. However, a rift between the central and western neighborhoods within the group emerged in 2015, leading to a prolonged period of avoidance and tension. This division culminated in violent clashes, resulting in the deaths of multiple chimps, including infants, between 2015 and 2018.
Iulia Bădescu, an associate professor at the Université de Montréal, highlighted the unusual nature of the conflict, as the warring chimpanzees had previously close relationships, some even being closely related kin. The shift from camaraderie to hostility was stark and surprising. The study marks a unique case where a cohesive chimp group disintegrated into violence, unlike previous observations of intergroup conflicts among chimpanzees.
The reasons behind the chimpanzee group’s split remain unclear, with researchers suggesting factors like increased group size, heightened competition for resources, and disruptions in social dynamics as potential triggers. The abrupt deaths of key individuals and changes in dominance hierarchy are believed to have contributed to escalating tensions within the group.
Despite the violence witnessed among the Ngogo chimps, researchers like Sandel and John Mitani find hope in the potential lessons humans can glean from chimpanzee behavior. Mitani emphasized the inherent pro-social nature of humans, contrasting it with the aggressive tendencies observed in chimpanzee societies. The ongoing conflict among the Ngogo chimpanzees raises questions about the future and complexities of primate social dynamics.
