Study Examines Internal Conflict Among Ngogo Chimpanzees in Uganda's Kibale National Park

The community, the largest known chimpanzee group with about 160 members, experienced a violent feud that spanned 10 miles of territory. The conflict resulted in the deaths of seven adult males and 17 infants over several years.

The polarization began in 2015, following the unrelated deaths of several key male leaders. This event divided the patriarchal group into two factions. Over the next seven years, one faction conducted 24 attacks on the other, targeting adult males and infants.

Background of the Study The research draws on decades of data, including GPS-based tracking of ranging patterns, 24 years of social network analysis, and three decades of demographic records.

It examines three key periods: the initial shift from group cohesion to polarization, two years of increasing avoidance between factions, and the subsequent phase of lethal aggression. The study highlights that shifting relationships within the group, without external cultural markers, led to the fracture and violence.

Researchers conducted observations without providing food to the chimpanzees, distinguishing this case from prior studies. The findings were published based on this long-term monitoring in central Africa.

Insights into Primate Behavior This conflict represents one of the few documented instances of large-scale violence within a chimpanzee community, as territorial disputes between groups are more common.

The report suggests that relational dynamics alone can drive polarization and lethal conflict in chimpanzees, which lack language, ethnicity, or ideology. Such dynamics may offer insights into similar processes in other species, including humans. The debate on whether war is inherent to human nature continues among researchers.

Some attribute human conflicts to circumstantial factors, while others point to evolutionary roots. This study does not resolve the debate but indicates that cultural differences may play a secondary role in initiating conflicts.

Comparison to Historical Observations The research builds on earlier observations of chimpanzee behavior.

In the 1970s, a four-year conflict known as the Gombe Chimpanzee War occurred in Tanzania, involving killings and territorial changes, followed by eventual reunification. That event involved potential human influence through food provisioning, though its impact remains disputed.

Anne Pusey, a retired primatologist who worked in Tanzania and was not involved in the new study, noted similarities to the Gombe observations.

She described how relationships can break down, leading to antagonisms between previously connected groups. The study underscores the rarity of intra-group wars in chimpanzees and their potential relevance to understanding collective violence.

Ongoing research in primate communities continues to inform broader questions about social dynamics and conflict.