Wild chimpanzees in Uganda has split into rival factions, engaging in a prolonged and violent “civil war” for the past eight years, researchers have reported in a recently released study.
The conflict involves the world’s largest known group of wild Ngogo chimpanzees community in Kibale National Park, where a once closely bonded group has fractured into opposing sides.
A study published on Thursday in the journal Science, researchers have stated that the reasons behind the split remain unclear.
Since 2018, researchers have documented at least 24 killings, including 17 infants, highlighting the severity of the violence within the population. They describe it as a dramatic change in behaviour, noting that the chimpanzees who once showed close social bonds were now attacking one another.
The findings, published in the journal Science, suggest that such sustained and intense conflict among chimpanzees may offer valuable insights into how early human conflicts may have developed.
What the study say
The study has revealed how social groups among chimpanzees can gradually divide and turn hostile, offering important insights into behaviour that may also help scientists understand human societies.
According to news reports, researchers, including Laura Sandel and her team, examined a rare group split in wild chimpanzees and found that such divisions develop over time rather than happening suddenly.
The study focused on a chimpanzee community in Ngogo in Uganda, one of the largest known groups, with more than 200 individuals. Over time, the group slowly separated into two distinct sub-groups.
Gradual division, then split
The study stated that the researchers found that the split began with subtle changes in social behaviour. Smaller clusters formed within the group, and some chimpanzees moved between them. Eventually, connections between the groups weakened. As key individuals disappeared, including some due to disease, the division became permanent. Relationships between former group members then turned hostile.
After the separation, the two groups began patrolling their territories. This led to aggressive encounters, including lethal attacks, particularly targeting adult males and even young chimpanzees.
The findings highlight how group divisions can escalate into conflict once social bonds break down.
Comparison with Bonobos
The researchers compared chimpanzees with bonobos, a closely related species. Unlike chimpanzees, bonobos tend to maintain peaceful relations between groups.
The study stated that for instance, bonobo communities studied in Central Africa have split in the past but continue to cooperate and interact without violence. This contrast raises questions about how environment and evolution shape social behaviour.
The Goodall research
The findings build on earlier observations by Jane Goodall, who documented a similar chimpanzee group split in Gombe in Tanzania, decades ago, where former groupmates also turned violent after separation.
The journal Science said, “Approximately 50 years ago, primatologist Jane Goodall reported a similar fission event among the Kasekela chimpanzee community in Gombe, Tanzania. Several adult males, adult females, and young individuals splintered into a new group. Many of them were then killed by former groupmates. Sandel et al. studied the social dynamics of the second group split observed in wild chimpanzees, which took place in the Ngogo community in Uganda. This group, which has been followed systematically for nearly 30 years, grew to become the largest habituated community of chimpanzees (a population that tolerates humans) at more than 200 individuals. Then, it began to split into two spatially and socially segregated parts.”
Possible Reasons
It said that one theory suggests that access to food influences group behaviour. However, the Ngogo study showed that even with abundant resources, conflict still emerged among chimpanzees. It suggests that factors beyond food supply, such as social structure and population size, may play a significant role.
The research suggest that it was important to have long-term wildlife studies and conservation efforts.