Key Points
A large chimpanzee community in Kibale National Park split into rival factions, leading to years of coordinated and deadly conflict.
Researchers, including Aaron Sandel and John Mitani, found that the violence involved strategic attacks, alliances, and territorial control—mirroring human warfare.
The incident echoes the famous Gombe Chimpanzee War documented by Jane Goodall, offering insights into the evolutionary roots of conflict.
It is animal nature to engage in vicious fights over food and resources and social hierarchies. The concept of War— exemplified by territorial occupations, planned lines of attack, and formation of alliance— has long been considered an exclusively human concept. However, long-term research conducted by the Kibale Chimpanzee Project in Uganda’s Kibale National Park shows that this is not the case.
Deep within the forests of this national park, the largest known community of wild chimpanzees has split into two rival groups that have been locked in brutal warfare over several years. The intensity and complexity of the aggression, along with the breakdown of previously strong social bonds, have led many to compare this conflict to human civil wars.
For nearly two decades, the Ngogo chimpanzee community lived in relative peace, with strong social relationships between each other and high levels of cooperation amongst them. However, this harmonious bind began to fray over time, particularly between 2015 and 2018. According to the study ‘Lethal conflict after group fission in wild chimpanzees’ from the Department of Anthropology at the University of Texas, the deaths of key older males who had served as ‘social bridges’ played a major role in triggering the chaos within the community.
"Biting, pounding the victim with their hands, dragging them, kicking them - mostly adult males, but sometimes adult females participate in the attacks," said Primatologist, Aaron Sandel, lead author of the study.
These were chimps that would hold hands, now they're trying to kill each otherAaron Sandel, Primatologist and Leader Author of the study
Co-author of the study Primatologist John Mitani noted, “They will do this even when those neighbors are former friends and allies,” highlighting how these chimpanzees shifted from peaceful coexistence to violence and aggression toward one another.
As leadership weakened and power dynamics shifted, the once-unified society fractured into two rival factions.
The Worsening Situation
The resulting behaviour was far from random or mindless violence. Instead, it involved coordinated and strategic attacks. The smaller group carried out targeted assaults, often on isolated individuals. Over the course of the conflict, as many as 24 chimpanzees, both adults and infants, were brutally killed.
These actions closely resemble aspects of human warfare, including territorial incursions, formation of allianced, and infanticide. The violence appeared deliberate, with the chimpanzees strategically aiming to weaken their rivals.
This situation is reminiscent of the famous Gombe Chimpanzee War documented by English primatologist Jane Goodall, in which former chimp companions turned against each other.
The Ngogo chimpanzee civil war offers important insights into the evolution of conflict. Researchers have found that chimpanzee wars often arise not only due to external pressures, but from internal factors such as social stress, volatile hierarchies, competition, and limited resources. In this particular case, Aaron Sandel explained that the loss of key individuals weakened social bonds, making the community more vulnerable to division and lethal conflict.
With the shrinking habitat of chimpanzees and rising environmental pressure, experts predict that such conflicts will only increase further.
This incident reiterates the fact that even highly organized hierarchical societies— whether human ones or animals— are susceptible to fragility and breakage over time.
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