Initially, I thought there was a full-scale civil war in Uganda, but with humans. That’s not the case. Primatologists are documenting and disturbed by what seems to be a breaking apart of a major chimpanzee community in the country. Their numbers have grown to about 200 chimps, but reports indicate that the group's impressive success may have led to internal conflict. In any case, these primates are fighting each other to the death in the jungles.
It’s like the Planet of the Apes. It’s totally bananas. For 20 years, this community thrived. They lived peacefully, even reportedly using brutal tactics to keep other chimpanzee groups out of their territory. Yet in the mid-2010s, the two factions began feuding, sparked by the deaths of elder males who had been the peacemakers between the groups (via WSJ):
“We’ve known for a long time that chimpanzees will attack and kill their neighbors,” said primatologist John Mitani, professor emeritus at the University of Michigan and a study co-author. “It turns out they will do this even when those neighbors are former friends and allies.”
For 20 years, the Ngogo chimps of Uganda’s Kibale National Park “were living the good life by being together,” Mitani said. They helped one another, dominated and killed apes from neighboring groups, expanded their territory and boosted their babies’ chances of survival.
But in 2015, the group started splitting into two clusters. Several male chimps who had bridged cliques within the larger group died from disease, weakening social ties. Around the same time, a new alpha male rose to dominance.
Changes in the dominance hierarchy can fuel more aggression and tension, said Aaron Sandel, an associate professor of anthropology at the University of Texas at Austin and study co-author. As aggression escalated, the factions drifted into separate areas of the park.
By 2018, the split was complete. The two groups had no remaining social or reproductive ties between them; the last chimp infant with parents from different groups was born in 2015. What was once the center of the group’s territory became a border, which chimps patrolled, the researchers found.
[…]
Members of the smaller of the two groups launched coordinated lethal attacks on the other, aiming to kill rival adult males. By 2021, these raids had expanded to target younger apes, averaging several infant deaths a year since.
More than 24 apes have died so far as a result of the conflict, Mitani said. The true death toll is probably higher; given that there are so many chimps in a large area, some deaths go unrecorded, according to the study.
In 1974, the late Jane Goodall also observed a violent chimpanzee war, known as the Gombe War, which lasted four years and resulted in the destruction of one of the groups. It was one of the events where Goodall said she saw the darker side of chimpanzees.
