World researchers stunned as Ugandan chimpanzees launch vicious ‘civil war’ in Kibaale

Researchers studying chimpanzees in Uganda’s Kibale National Park say they have documented the first clearly observed permanent split of a wild chimpanzee community, followed by years of lethal attacks between the two factions. 

The findings, published in Science Magazine, centre on the well-known Ngogo chimpanzee community, which had been studied since 1995 and at one point grew to about 200 animals, making it the largest known group of wild chimpanzees. �

The researchers revealed that signs of strain began appearing in 2015 as two social clusters increasingly avoided each other. 

By 2018, the split was complete, leaving a Western group and a Central group with separate territories. 

The researchers say the Western group then launched repeated coordinated attacks on the Central group. 

The Science summary says the Western group killed, on average, one adult male and two infants per year between 2018 and 2024, while Reuters reported that the confirmed toll has since risen to 28 after additional deaths in 2025 and 2026. 

What appears to have shaken researchers most is not simply the violence, but the fact that these were not strangers. 

They were former companions. “What’s especially striking is that the chimpanzees are killing former group members,” lead author Aaron Sandel said in a University of Texas statement. 

Reuters quoted senior author John Mitani as saying: “It is hard for me to wrap my head around the fact that yesterday’s friend turned into today’s foe.” 

The researchers linked the rupture to a mix of factors, including the death of older males who may have helped hold the wider group together, a shift in the male hierarchy, and illness outbreaks that may have weakened social bonds. 

Sandel said the findings could offer insight into how social cohesion breaks down, though he also cautioned against casually using human political labels for animal behaviour. 

The study threw a global spotlight on Kibale National Park, one of the country’s best-known primate destinations. 

The Ngogo chimpanzees are already famous internationally and were featured in Netflix’s Chimp Empire, but this new research has recast them as the centre of a major scientific debate about conflict, cooperation and conservation. 

UT Austin said permanent fissions in chimpanzees are extraordinarily rare, with genetic evidence suggesting they may happen only about once every 500 years. 

Conservation experts also note that human pressure, including disease and wider environmental disruption, can weaken the social ties that keep animal groups stable. 

The study quickly travelled beyond science circles and into mainstream global news, with Reuters, The Guardian, The Wall Street Journal, Scientific American, ABC and Live Science all highlighting the extraordinary nature of the split and the violence that followed. 

Much of the coverage focused on the same point: researchers have long known chimpanzees attack outsiders, but seeing former allies turn on one another in this way is something far rarer.

The story also spilled into internet culture. Polymarket posted on X: “JUST IN: Massive chimpanzee group in Uganda has reportedly split into rival factions & descended into a deadly ‘civil war’.” That framing helped drive the story into wider online conversation beyond science and conservation audiences. 

Shock, jokes and Middle East comparisons flood X

On X, reactions mixed disbelief with dark humour. Patrick Christys wrote, “Now that’s a headline,” while another user, Chris LaBossiere, joked: “They must all have @X accounts.” 

Some reactions also drew comparisons to current geopolitical turmoil. 

One X user wrote that the chimp story would “distract” from the Middle East, while another post referenced the “middle east” directly alongside the Uganda chimpanzee story.