Ugandan chimps split into two factions, then killed rivals

In a remarkable study published in the journal Science, researchers have documented a significant and troubling division within the largest known community of Ngogo chimpanzees in Uganda. This event mirrors a similar occurrence observed by the late Jane Goodall in Tanzania during the 1970s, where chimpanzees split into two factions, leading to violence and the deaths of rival group members. The researchers, led by anthropologist Aaron Sandel from the University of Texas at Austin, have found that the Ngogo chimpanzees have also fractured into two hostile groups. This split has resulted in violent encounters, including the killing of former group members. Sandel emphasizes the severity of this situation, noting, "What’s especially striking is that the chimpanzees are killing former group members. The new group identities are overriding cooperative relationships that had existed for years." The study analyzed an extensive dataset spanning 24 years of social interactions, 10 years of GPS tracking, and three decades of demographic data related to the Ngogo chimps in Kibale National Park. Researchers identified three key phases in the group's division. Initially, there was a sudden polarization of relationships, creating two distinct clusters identified as Western and Central. Over the next two years, interactions between these rival factions dwindled significantly, with Western male chimps becoming increasingly aggressive and territorial against Central males. By 2018, the division had solidified into a permanent rift, highlighting a striking example of how social dynamics can lead to conflict. Sandel cautions against labeling this behavior as a civil war, but he suggests that the polarization and violence observed in these chimpanzees may offer valuable insights into human social behavior and conflict.