In this episode of Based Camp, Simone and Malcolm explore the ongoing chimpanzee civil war in Uganda’s Ngogo community—the largest wild chimp group ever studied—and what it reveals about how civil conflicts actually start.

What looks like a random outbreak of violence among chimps turns out to be the mechanical result of a few subtle shifts: the deaths of key intermediary individuals who once connected rival subgroups, a power transition, and the complete breakdown of everyday social exchange. Once those bridging relationships vanished, the community split into hostile blocs that began patrolling, ambushing, and killing with deliberate cruelty—including females participating in infant killings.

The parallel to modern human politics is hard to ignore. When groups stop talking, stop sharing social spaces, and begin treating the other side as non-human, the same fission dynamics appear. Simone and Malcolm discuss the research graphs that look eerily like U.S. political polarization charts, the role of “compromise monkeys” who keep factions stitched together, and why deliberately targeting intermediaries may be one of the most dangerous strategies a side can pursue.

They also dig into practical implications: the value of cultural networks that maintain cross-group exchange, the strategic importance of tech capital and institutional control in a modern “civil war,” and why freezing people out of coalitions is a reliable way to lose.

A darkly fascinating look at primate politics, human polarization, and what it actually takes to keep a society from splitting into permanent, hostile camps.

Show Notes

Major hat tip to Gutsick Gibbon on YouTube for putting this back on my radar.

Chimp Investigation

People are really into studying chimpanzees. They have been studied at roughly 120 field localities across 20 African countries

* This process involves:

* Spending months or even years getting chimpanzees used to humans just being around

* Focal follows, which involves trained observers following one identified individual for extended periods of time, writing detailed notes every 15 minutes for adults and every minute for mother-infant pairs, noting party composition, location, feeding, and social interactions

* Individually identifying and getting to know multiple generations of chimpanzees

* Doing more at-length analysis ranging from use of camera traps to analyzing feces for hormonal shifts.

* Around 10 of these sites have continuous research spanning a decade or longer

* It is one of these sites that experienced the civil war:

This civil war research is discussed in Lethal conflict after group fission in wild chimpanzees, published April 9th in Science.

* The researchers drew on 30 years of behavioral observations of the chimp community involved

The Chimp Civil War

* This civil war began in 2015 in the Ngogo community in Uganda, which had over 200 members

* It’s the largest known wild chimpanzee community ever studied

* Though this is NOT the first chimpanzee civil war; there have been others, such as the “Gombe Chimpanzee War” (1974–1978), which Jane Goodall observed and documented

* While Goodall says it was triggered by the death of the alpha male and an ensuing power struggle and others thought resource (both in terms of food and fertile female chimpanzees) scarcity was at play, others suspected it was downstream of Goodall playing the chimpanzees with food, creating artificial crowding, competition, and violent conflict.

* Later studies using less intrusive observation methods at other sites confirmed that wild chimpanzee societies do naturally wage coalition-based violence, cementing the Gombe war as a landmark case rather than an artifact of the research itself.

* On June 24, 2015 members of the western and central clusters of this community encountered each other

* Instead of reuniting normally, the western chimps ran away and the central chimps chased them

* This was followed by an unprecedented six-week period of mutual avoidance that escalated into controlled patrols and attacks in 2016

* What this looked like in practice was groups of chimpanzees (usually males, though not always) patrolling their territory’s borders and pushing into enemy territory

* When they encounter members of the opposing group, they attack them, often in brutal, prolonged fashion involving beating, biting, and deliberate cruelty beyond what’s needed to simply kill

* Females were also present during attacks and occasionally carried out killings themselves

* They were notably were more aggressive during this fission period than females typically are during normal inter-community patrols

* Over seven years, the Western group made 24 attacks, killing at least 7 mature males and 17 infants

* By 2017 two fully distinct territories and groups were established.

* The civil war has continued from 2017 to the present.

The toupe:

* Because this troupe was large, it was naturally

The timing:

What happened?

What Caused the Chimp War?

The group was getting too big

* But that on its own would not lead to civil war

* Chimp groups divide and recombine all the time

KEY INTERMEDIARY INDIVIDUALS DIED

* This happened in 2014; at least two probably died from sickness

* They played a crucial role in connecting various cliques within the troupe

The alpha male transitioned

* This happened in 2015

* And coincided with the first sustained separation between the western and central clusters.

* This likely amplified tensions, put everyone on edge, and involved various new alliances being forged

THEN EVEN MORE KEY INTERMEDIARY INDIVIDUALS DIED

* A respiratory epidemic hit in 2017, killing 25 chimpanzees

* This ended up killing some of the last remaining key intermediary chimps

* When these go-betweens died, interaction between clicks fell

* And then the clicks became estranged

* And then they began to fear and hate each other

Figure 1 shows how, between 2014 and 2018, individuals in the large Ngogo chimpanzee community became progressively less connected in the social network, as key “bridge” individuals died. The visual demonstrates that once those connecting nodes disappear, the community’s subgroups separate both socially and spatially, and this fragmentation is followed by increasingly violent interactions between the emergent groups.

What Can This Teach Us About Human Civil War?

* The role of lynchpin individuals who connect disparate groups may be underrated in our understanding of human civil war

What are we going to do about it?

* Take our concept of the Index more seriously

* Do more to promote the Covenant of Sons of Man

Appendix: Summary and Abstract from the Research

Editor’s Summary: Group conflict among nonhuman animals from mongooses to monkeys is well known. However, lethal conflict among groups of animals that were once socially affiliated has rarely been observed outside of humans, in whom cultural ideologies can drive divisions among individuals within the same group. Sandel et al. now describe the gradual dissipation of a group of Ngogo chimpanzees over many years, ending with two socially isolated groups, one of which conducted multiple lethal raids upon the other, leading to the death of both adults and infants (see the Perspective by Brooks). The unrelated deaths of key interconnected individuals may have contributed to the eventually violent split. —Sacha Vignieri

Abstract: Territorial conflicts in animals can inform aspects of human warfare, but civil war, with its shifting group identities, has not been previously observed. We report a rare, permanent fission in the largest-known group of wild chimpanzees (Pan troglodytes). Using 30 years of behavioral observations and network analyses, we describe a transition from cohesion to polarization in 2015 and the emergence of two distinct groups by 2018. Over the next 7 years, members of one group made 24 attacks, killing at least seven mature males and 17 infants in the other group. These findings indicate that group identities can shift and escalate into lethal hostility in one of our closest living relatives in the absence of the cultural markers often thought necessary for human warfare.

Episode Transcript

[00:00:00] Malcolm Collins: actually I can just put this graph of chimps next to a graph of the political parties drifting apart.

[00:00:06] Simone Collins: The interchange between these different cliques just ends, and then you just basically see red and blue. Just big old blocks of red and blue.

[00:00:14] But I think a lot of it does have to do with the breakdown of communication between factions and really starting to view the enemy as not human, as other.

[00:00:23] Malcolm Collins: And we’re seeing this radicalization happen with, like, the Anthony trial, right? Where the left is like, “It should be okay to kill white people, of course.” Mm. Right? Like, how dare you punish somebody for killing a white person? Th- they’re actually getting surprised about this, and this is in turn radicalizing

[00:00:40] Simone Collins: the opposite- Oh, God, no, you’re right.

[00:00:41] Like, the fact that they were up in arms about that goes to show, yeah, this complete lack of communication with someone who might hold a different perspective.

[00:00:50] Would you like to know more?

[00:00:52] Simone Collins: Hello...