Another interesting addition to the 2026 Bingo Card.
Posted by Leslie Eastman
In the depths of Uganda’s Kibale National Park, an extraordinary and unsettling drama is unfolding.
However, this battle is not in a human legislature or courtroom, but is occurring within the world’s largest known community of wild chimpanzees. Once a cohesive society, the Ngogo chimps have splintered into rival factions locked in a brutal, years‑long conflict that researchers are now calling a “civil war.”
A community of around 200 chimpanzees living in Uganda’s Kibale National Park has fractured into two warring factions, with one group launching a years-long campaign of lethal attacks against the other.
The Ngogo chimpanzees have been studied continuously for three decades, but in recent years scientists have watched as a violent split unfolded in slow motion.
From around 2015, what had been a single cohesive group began to polarise. Social ties frayed, neighbourhoods within the community hardened into distinct factions and shared territory became a contested border. By 2018, the break was permanent.
What followed was remarkable – and troubling. The smaller of the two groups – the Western chimps – began making targeted raids into the territory of the larger Central group. Over the next six years, they killed at least seven adult males and 17 infants.
WORLD’S LARGEST WILD CHIMPANZEE GROUP LOCKED IN BLOODY CIVIL WAR
In Uganda’s Kibale National Park, a Ngogo chimpanzee community of nearly 200 split into two rival subgroups in 2018.
A permanent split of a formerly tight knit chimp troop is exceedingly rare.
Since then, the… pic.twitter.com/47JZ4OFb1j
— NewsForce (@Newsforce) April 10, 2026
The news stems from a report published in Science. Lead author Aaron Sandel summarized the sequence of events.
Sandel said he first noticed them polarising in June 2015, when the Western chimpanzees ran away and were chased by the Central group.
“Chimpanzees are sort of melodramatic,” he said, explaining that following arguments there would ordinarily be “screaming and chasing” and then later, they would grooming and co-operating.
But following the 2015 dispute, the researchers saw that there was a six-week avoidance period between the two sets, with interactions becoming more infrequent.
When they did occur, Sandel said they were “a little more intense, a little more aggressive”.
A spate of deaths may have triggered the more recent violence, which appears to be ongoing.
The report suggested several things might have contributed to the split, including the sheer size of the group, which at one point was made up of nearly 200 chimpanzees and more than 30 adult males.
That may have led to “heightened feeding competition”, “reproductive competition” and weakened social ties following the deaths of several chimps in early 2014.
The group is still being observed, according to Dr Sandel.
“And the conflict is ongoing,” he said
Furthermore, according to the Science report, a respiratory epidemic killed off chimps that were connected to two factions that are now warring.
A third factor may have contributed to the fission. In January 2017, a respiratory epidemic killed 25 chimpanzees, including four adult males and 10 adult females (48). Although this occurred after polarization was already underway, it may have hastened the final separation. Two of the adult males that died were part of the Western cluster, and one of them was among the last individuals to connect the two groups. Taken together, these events suggest how networks may fracture in the face of multiple demographic and social changes (11, 49).
As researchers continue to chronicle this unprecedented “chimpanzee civil war,” the Ngogo conflict offers a haunting glimpse into how fragile even the most seemingly cohesive societies can be when stress, scarcity, and loss disrupt their balance.
That being said, I must admit I did not have “chimpanzee civil war” on my 2026 bingo card.
Another interesting item to add to the 2026 Bingo Card. https://t.co/hTTGS0QWfA
— Leslie Eastman ☥ (@Mutnodjmet) April 13, 2026
They are just trying to be more “human” in their behavior.
It would be worth it to take away their arms if it saves just one life.
How could they swing from tree to tree if you take away their arms?
Probably some quarrel over green energy and climate change
Years ago I saw a documentary about bonobos with comparable behaviour. No more idea what region that was.
Primate hunting by bonobos at LuiKotale, Salonga National Park
We observed bonobos hunting at LuiKotale (Figure 1) in the Salonga National Park, Democratic Republic of Congo. Records on monkey hunting were obtained from members of one habituated community consisting of nine reproductive males, 12 reproductive females and 12 immatures. There were three cases of successful hunting when bonobos captured and ate monkeys and two cases in which hunting attempts did not succeed (Table 1). In all successful cases, bonobos obtained immature monkeys.
Further:
Study Alters Bonobos’ Reputation as the ‘Make Love not War’ Ape
Male bonobos actually act more aggressively than male , but the way the two species uses violence or the threat of it differs dramatically, according to a new study in Current Biology.
“This study brings more complexity to the simple image of bonobo as the ‘make love not war’ ape,” says Maud Mouginot, a Boston University postdoc who conducted the observations as part of her Ph.D. research.
I dunno what caused the split and ‘war’. But was curious about the background.
The Ngogo chimp research project was started by Yale in 1995. So 20 years of ‘peace’ before the split and now 10 years of ‘war’ after. The population density was (at the time of the split) >3x the nearby Kanyawara chimp research group, also in Kimbala National Forest .
The Kanyawara research started earlier, in 1987, and that chimp group population has remained constant at ~60.
Looks like population density had something to do with the split into two territories now at ‘war’. A chimpanzee version of ‘Lebensraum’?
That could be, chimpanzee ‘Civil War’ might suggest comparing Victor Davis Hanson’s book, THE FATHER OF US ALL, War and History, Ancient and Modern.
https://www.science.org/doi/10.1126/science.adz4944
“A chimpanzee version of ‘Lebensraum’?”
Or TDS.
Send in the UN
They are good at separating warring parties and maintaining peace. Aren’t they??
That’s a chimp, you chump! (Moe Howard)
I was wondering why Jared Kushner was heading for Uganda.
That’s kinda funny so not sure why you have 2 negative votes. 🙂 I’ll get it back to only minus 1.
I was expecting someone to blame this on climate change. Also, aren’t turf wars common throughout the natural world?
They are, though lots of ideologues refuse to accept it. Their belief that only man fights is almost as impenetrable as their belief that CO2 is the master molecule that controls climate.
Those doing the study probably had firearms, so the chimps didn’t take them on. It probably got up their noses a bit, so they take it out on each other.
Let me guess… the ones that became violent first started coloring their hair purple, piercing their faces, and pretending to be the opposite sex.
Nobody send them AK47s.
It has been pretty clear for some time that chimps can be ultra violent and actually go on raids to adjacent tribes. We humans have that in common. But we are not nearly as violent.
The only saving grace w chimps is that they live in small groups so their damage is limited and also based on group cohesion and survival. Bad leaders will eventually be taken out.They are also not ideologically primed and basically lose interest quickly. Unlike humans whose ‘culture’ quite often solidifies inherent and systemic violence.
Someone here will no doubt point to Pinker’s book. I am aware of those issues.
Indeed, War Before Civilization by Lawrence H. Keeley. I don’t recall him addressing pre-humans though.
If you haven’t seen the 2023 Netflix series “Chimp Empire”, which chronicled this chimp population in great detail, it is strongly recommended.