Why Aren't We Still Talking About the Chimp Civil War?

[00:00:00]I feel very strongly that we are not talking enough about the chimpanzeee civil war that just happened in Uganda.

[00:00:08]Like the internet loves to meme about the concept of chimp war and there are a lot of really good videos about the previous chimpanzeee war that we had but then we get an actual new chimpanzeee war and it's a civil war and people talk about it for like a week and then they move on to other news like the end of the world or whatever. There are a lot of fake chimpanzeee intergroup conflict fans on the internet is what I'm saying.

[00:00:35]Not like me, a real chimpanzeee intergroup conflict fan covering the subject months after the fact. I've been really busy. Hello, my gentle and of course very modern apes. My name is Erica. This is my channel, Gutsy Gibbon.

[00:00:49]And what we do here is I talk to you about the latest discoveries in human evolution and adjacent topics. And I also debunk a lot of pseudocience.

[00:00:58]Today, I would like to take a closer look at a new chimp war that just happened over the past decade or so. And that's what it is. That's not clickbait.

[00:01:07]It's it's chimp war. Let's talk about the chimp war.

[00:01:17]>> Oh boy, an opportunity to monologue about chimpanzeee behavior. I'm even wearing my thematically appropriate custom Willwood t-shirt. Big talk for a chimpanzee and the talk is a declaration of war. Chimpanzees or members of pantroglodites are some of our closest living relatives sharing that position with their sister species paniscus or the bonobos. Our lineage the hominins split from their lineage the panins approximately 7 million years ago and they've been changing and evolving for just as long as we have. Bonobos and chimpanzees are sister species, so they share a lot in common. So much in common that you would be forgiven for thinking that they're more or less the same thing. But they're not. They differ in really important ways. Subtly, the physical ways in which they differ.

[00:02:10]Chimpanzees tend to be more robust and larger than bonobos are. They have longer canine teeth, whereas bonobos are smaller and more grassile. Bonobos have longer head hair than chimpanzees, still pinker lips. But the most striking ways in which these two species differ is their behavior. The historical and overly simplistic summary is that chimpanzees are violent and patriarchal.

[00:02:34]They have an alpha male. And bonobos are peaceful and matriarchal. They have an alpha female. I say it's overly simplistic because species are composed of populations which have their own unique characteristics. And populations are composed of individuals which have their own unique personalities. And we found looking at bonobos and looking at different chimpanzeee subspecies that bonobos can sometimes be pretty aggressive and chimpanzees can be pretty peaceful. Male bonobos can hold some power in bonobo society and female chimpanzees can hold some power in chimpanzeee society. Previously, bonobos were characterized as sort of sexually interesting. And we've since found that chimpanzees can get pretty freaky. And likewise, chimpanzees have been previously characterized as like the cooperative tool users, the hunters. And we've since found out that bonobos use tools and also hunt as well. Still, for all of the nuanced behavioral overlap that we've since discovered with chimpanzees and bonobos, there is still one thing that chimpanzees kind of hold a monopoly on. And it happens to be one of the things that they share with us.

[00:03:45]War and a capacity to systematically wipe out a neighboring group that you don't like.

[00:03:51]>> Okay, here's the thing. I do truly have a pure and kind and loving good heart, but also if I start to feel overwhelmed, I do turn quite evil and sinister.

[00:04:08]And I think God gave me that curse to balance out my pure heart. I'm using these words deliberately. I'm choosing to use them because I think they're appropriate. I don't think what we're looking at here is a case of anthropomorphization.

[00:04:23]Let's back up. Chimpanzees live in complicated social systems characterized by a fision fusion dynamic. What this means is that they live in relatively large groups composed perhaps of dozens of individuals. But that larger group subsets down into smaller groups depending on the time of year.

[00:04:43]Simplistically speaking, when food is abundant, that larger group is maintained. Relationships and connections are reaffirmed. But when food is scarce, that larger group fisions out into smaller groups who forage on their own until a time at which food is abundant again, in which case those smaller groups will fuse back into the larger group again. And so it goes. That larger group's size is the given chimpanzees community. Everybody within that larger group knows one another. And if when they are fishisioned out into their smaller groups, they encounter one another, they will do so typically amicably. Fisioned chimpanzeee groups within a larger chimp community know each other and so oftent times they like each other or at the very least they tend to tolerate one another unless there's a reshuffle for power going on. This tolerance does not cross community lines, however. And in fact, chimpanzeee communities are notoriously violent towards one another.

[00:05:43]Communities occupy a territory. And because these communities are often adjacent to one another, communities feel the need to patrol and guard those territories to prevent chimps from other communities from coming into theirs and like eating their fruit or hunting their monkeys or courting their females.

[00:06:02]Because of this, borders are patrolled by groups of chimpanzees. usually composed of males, although not always, which is interesting in and of itself.

[00:06:12]And if this patrol encounters a foreigner, they will attack them, sometimes killing them. This was originally quite shocking when observed by Jane Goodall and associates decades ago because of how familiar it was. So many animals live in groups from deer to baboons. And of those group living animals, many of them are also territorial. Lions come to mind. A male lion usually guards his pride composed of females who he is monopolizing access to. And while the females are off doing a lot of the hunting, this male will spend time patrolling the territory, making sure other bachelor males don't come in and try to mate with the females or kill his offspring. But this is one male carrying out territorial patrolling behavior. And if he encounters another male, they're going to duke it out. But it doesn't feel quite as personal. And I also use that word deliberately. When chimpanzee patrols happen across a foreigner, they do try to kill that individual oftentimes, especially if that foreigner happens to be a male. But there is a sort of cruelty to it that I don't think we see very often, if at all, in other animals, except for one.

[00:07:28]You can read these accounts in scientific papers, or you can watch some pretty horrific videos found on YouTube or on Instagram or on Tik Tok. But the way that this usually works is there is a lot of beating. There is a lot of finger biting. There's a lot of testicle ripping. There's just a lot of unnecessary violence infliction that is not needed to dispatch of the foreigner. There's torture. And perhaps uniquely among non-human animals, this violence is not limited to strangers at the border. In bids to expand territory, chimpanzeee patrols will push into neighboring communities where they will systematically hunt down and kill members of those communities. And to add to an already familiar picture, these chimpanzees will usually focus the killing on males and infants in hopes of integrating females into their own community. Lions do not do that. We do that. That's war. And to be a little bit more specific, sometimes that's genocide. For those of you currently writing me an essay in the comment section about ants, please be sure to include the citation on ant testicle ripping. Ants do wage war, but they don't wage war like this. Chimpanzeee war, like human war, is predicated on complicated social interactions that take place over weeks or months or years or decades. Those interactions yield relationships between individuals, between small groups, between large groups, the intensity and nature of which determine if and when things get violent. Most humans are willing to sacrifice their life for a family member or for a close friend, members of that immediate inroup. But some humans across space and time have been willing to put their lives on the line for a much larger inroup like their tribe or their country. Which leads us to the second half of this in-group outgroup dynamic, the out groupoup. It's been proposed before that while humans have a uniquely intense altruism for members of our in-roup, we also have a uniquely intense hatred or disdain for members of our out group. Like, it's one thing to sacrifice your life to try to save someone you love, and it's another to sacrifice your life to hurt someone you hate. War in chimpanzees and particularly those preemptive attacks or total wipeouts suggest a very familiar type of cognition as well as a familiar type of group identity to that that we see in ourselves. Primatologists have documented chimpanzees risking their lives to help individuals they aren't even related to but who are a part of their group. And likewise, they've documented chimpanzees systematically torturing and killing individuals who are complete strangers to their community. Okay, so in a rather unflattering blow to human exceptionalism, we find that tribalism and xenophobia and war and genocide are not unique to our species. And in fact, we find them in one of our closest living relatives. That was decades ago.

[00:10:51]So the chimpanzees are doing another war. We've seen that before. What's new about this one? Well, the Kali Chimpanzeee War was larger, extensively documented beginning to end, and thus offer some tantalizing clues as to why chimpanzeee wars happen in the first place, why ape wars happen at all. This new paper's title is lethal conflict after group fishision in wild chimpanzees. And that word fision should be familiar to you because within every chimpanzeee group there are fisions and there are fusions. So what this title is immediately telling you is that there is lethal conflict after a group split. But I just got done telling you amongst many other things that chimpanzeee social systems are characterized in part by frequent splits and then joining back together. So what's different? What changed? Why did this split lead to death? This paper is not open access, so I'm going to do a lot of summarizing, and I'm only going to show figures or paragraphs when I feel that they are necessary to properly communicate this science. We begin as always with the abstract. Here they say territorial conflicts in animals can inform aspects of human warfare but civil war with its shifting group identities or I'll add here shifting inroups and outgroups have not been previously observed. We report a rare permanent fision or splitting apart of the largest known group of wild chimpanzees pantrodites. 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. So they're saying across three years, they watched the largest known the largest observed chimpanzeee community become polarized towards one another. attitudes towards individuals within this group went from sweet to sour and that was followed by a complete and permanent splitting of those two groups. They go on to say over the next seven years members of one group made 24 attacks, killing at least seven mature males and 17 infants in the other group.

[00:13:12]These findings indicate that group identities can shift and escalate into lethal hostility in one of our closest living relatives in the absence of cultural markers often thought necessary for human warfare. Animal groups do split sometimes, often because they get too large. But rarely is this splitting overtly violent. But in humans specifically, groups often fision because of social tension. from internet communities to ancient nations. And those social tensions can and often do lead to violence. But if our model for lethally violent group vision comes from our own species, then it comes loaded with the reasons for those social tensions, which are usually due to things like religious differences or preferences in governing systems.

[00:14:03]Lethally violent group visions or civil wars happen in humans because a group of individuals within a larger group doesn't like the way things are going and they want things to change and they resolve either to take over the larger group by force or try to leave and the larger group doesn't like that. Either way, there's going to be blood. since doesn't like the way things are going historically in humans usually revolves around governance or religion. Can we see a civil war in a non-human animal in non-human apes? This paper demonstrabably shows us that the answer to that question is yes. You don't need a human type of culture to have a civil war. And what that suggests is that civil war is older than homo sapiens.

[00:14:51]And in fact, because it's found in chimpanzees, assuming it's not convergent, it's probably at least as old as our last common ancestor, which means apes have been doing civil war for potentially 7 million years. So, if human style culture isn't required for a civil war, then what is? Why did these chimpanzees fishision so violently, so lethally? The paper responsibly, I think, outlines several reasons as to why this lethal group vision, why this civil war might have occurred. But in my opinion, for whatever that's worth, one reason sort of sticks out. I'm going to sort of work up to it though. First, this chimpanzeee community in Uganda, the indogo community was just too big.

[00:15:37]200 plus individuals as a part of the larger community. That's significantly larger than any other chimp community being studied at present. That's a lot of relationships to maintain. And although there are smaller subgroups within it, this is still the larger population of individuals that are more or less friendly towards one another. A lot to keep track of. That enormous group size alone is enough to explain a fision, but it doesn't really explain the lethality. Number two, as a reason for effision might help with that though, because it has to do with a shakeup in power. A new alpha male had risen up the ranks to be the most dominant individual out of all 200 plus chimps. And that is enough to make anyone anxious. And this is because while across the primate order linear dominance hierarchies in males, in females, and combined differ, in chimpanzees, who is top dog is determined by physical fights. It's determined by beating the crap out of each other. And specifically, it's determined by groups of chimpanzees vying for those top positions, not just one individual versus one additional individual. That means there is a lot of schmoozing. There's a lot of alliance forming. There's a lot of coalitionary attacks between groups of males and sometimes groups of females as well. And who is top dog isn't determined just by who is the strongest, but by who has the most support. So fights for the top position involve many, many chimpanzees and a whole lot of fighting. But that happens all the time in every single chimpanzeee community we've ever studied. Hierarchies are not permanent, especially amongst the males. So that doesn't explain it. No, this chimpanzeee civil war was not caused by the deposition of one important individual, but rather the happenstance deaths of many others. Do you remember how in high school there were a lot of different clicks that were interested in different things? If you have psychologically blocked out high school to protect your own mental well-being, first of all, I get it. Just imagine here any high school sitcom. Those sitcoms usually have like the athletes, the jocks, and then you've got the nerds or the academically inclined. And then there's the theater kids and the band geeks. And you might have the gamers or the goth kids, whatever. There are a bunch of different clicks and they're composed of individuals who are interested in that clicks given subject. But there are also individuals that are a part of multiple different clicks or that migrate between them or that have no click at all but know people in various groups. In a simplistic way, they keep the lines of communication open between these groups that would otherwise grow further and further apart as they invested deeper into their given interest and no other interest. There are people that bridge the gap between clicks, the lynch pins that hold together the larger group by connecting the smaller ones. In a high school, if you remove these bridge individuals, then clicks just further atomize from one another. The show choir doesn't systematically hunt down and dismember the band, we hope. But in chimpanzeee communities, individuals are competing for access to resources and to mates. If they atomize, then they become strangers. Their in-group gets smaller and members that are no longer within their in-roup become the outroup. They become potential competitors and thus they become enemies. Figure 1 reveals that this is exactly what happened in the massive go-go chimpanzeee community.

[00:19:23]It says network and spatial separation precedes a shift from association to violence. And you can see that in 2014, individuals represented by these colored nodes here are all connected to one another either directly or more commonly through intermediary individuals. But as 2014, 2015, 2016, 2017, and eventually 2018 come to pass, we see that these groups are teased apart from one another as critical individuals that previously connected them die. This paragraph in the discussion outlines it even more clearly. They say three additional factors may have acted as catalysts for the split. First, the major network shift was preceded by the death of five adult males and one adult female in 2014. The causes of their deaths are unknown, but two individuals exhibited clinical signs of illness, raising the possibility that some died from disease.

[00:20:16]The loss of individuals, even weekly connected nodes, can disrupt social networks. These deaths representing more than 10% of the mature males may have weakened social ties across clusters and contributed to the increased modularity in 2015. So from 2013 to 2015, several critical individuals died which separated out these nodes and sort of set the stage for the eventual fision and especially for the violence that came with it. Second, a change in the alpha male in 2015 coincided with the first sustained separation between members of the western and central clusters. Changes in the dominance hierarchy can increase aggression and avoidance in chimpanzees. At Indogo, both the outgoing and ining ingoing alpha were a part of the central cluster, although the incoming alpha had been a part of the western cluster before rising up the dominance hierarchy. Although an alpha male change alone does not explain why the indogo group split, it may have amplified tensions between the two clusters. And then they continue on since we already covered that to a third factor may have contributed to the fision. In January 2017, a respiratory epidemic killed 25 chimpanzees, including four adult males and 10 adult females. Although this occurred after polarization was already underway, it may have hastened the final separation. Two of the adult males that died were a part of the western cluster and one of them was among the last individuals to connect the two groups.

[00:21:35]Taken together, these events suggest how networks may fracture in the face of multiple demographic and social changes.

[00:21:42]The reason human civil war is tied to human specific culture is because that culture is how we outline our identities and how we oftent times form or reinforce our relationships. But chimpanzees still have those relationships. They just form and reinforce them through chimpanzee cultural means. Just like humans, chimpanzees form clicks based off of personalities and preferences. And these clicks are connected to other such clicks to form a larger community in part by individuals that bridge them. If you take away the individuals that bridge these smaller groups, the groups atomize and begin to compete. And if they begin to compete, things get violent. As illustrated here in figure 2, the enormous chimpanzeee community at Angogo could be broken down into two smaller subgroups, the clicks of which knew one another. But as the familiarity between these two subgroups, rather the clicks that made them up, was severed due to the deaths of the individuals that bridged them, they started to tease apart without the critical individuals that facilitated the interaction between clicks which otherwise wouldn't have hung out together. Those clicks began to grow estranged. Estrangement leads to fear and fear leads to violence. When tensions are high and competition grows thick, it was a perfect storm. The group was already too large, which meant it was feasible for enough lynchpin individuals, which bridged the gaps between smaller groups, to die, weakening the overall integrity of the larger community. The territory is large because the group is large and time is passing. Which means the more intermediary individuals that die over these periods of time, the less contact these smaller groups have with one another and the less familiar they become. Add to that the tensions of a power struggle. Everybody's already fighting. Everybody's already on edge and alliances are already being made for an unrelated conflict. Fruit availability and mate access fluctuate every year. But one year, a time of scarcity comes along and two chimpanzeee individuals who groomed one another 10 years prior come upon one another again in the forest with their respective groups being from the central and western group respectively and they think to themselves, "How well do I know you really?" Our first behavioral observation suggestive of a split occurred on the 24th of June 2015 when members of the western and central clusters approached each other near the center of their territory. Rather than reuniting in typical fision fusion fashion, the western chimpanzees ran away and the central chimpanzees chased them. A six-w week period of avoidance followed. Such a prolonged period of avoidance had not been observed before and it's all downhill from there. By 2017, after months of coordinated patrols and attacks against one another, two distinct territories and thus two distinct groups were evident. There's no more reproduction between the two groups and there's no more friendly affiliative behavior between the two, not even amongst females. In fact, some of the aggressive encounters that are being carried out, including intergroup killings, females are in attendance and occasionally doing the killing. I actually attended an AABA's talk about that particular subject back in the spring. And it's notable because the females in this fision process are far more aggressive than females in chimpanzees tend to be in the regular run-of-the-mill patrols between two adjacent groups, which suggests that they're more violent and more aggressive when a split is in progress rather than once two distinct groups have been established and regular run-of-the-mill patrols are being carried out. In other words, it's all hands on deck. From 2017 to present, the Western group and the central group have been in civil war with one another. Largely, the Western group is the group carrying out the most lethal attacks, or I should say successful lethal attacks, killing on average one adult male and two infants per year. And they're still at war now because wars rarely end quickly. Whether we're talking about chimpanzees or other violent apes, I'm going to read this line from the discussion/conclusion cuz I think it rocks. Cultural traits remain essential for large-scale cooperation, but many conflicts may originate in the breakdown of interpersonal relationships rather than in entrenched ethnic or ideological divisions. It is tempting to attribute polarization and war that occur in humans today to ethnic, religious or political divisions. Focusing entirely on these cultural factors, however, overlook social processes that shape human behavior. Processes that also present in one of our closest animal relatives. In some cases, it may be in the small daily acts of reconciliation and reunion between individuals that we find opportunities for peace. Why do apes wage civil war? Well, it isn't because of culture. It's not because of government or because of religion. It's because evidently we cease to know one another. We become estranged. And a stranger is a potential enemy. And you know what we do to enemies? We kill them before they kill us. This paper is so cool. Obviously, it reveals that just like everything that we think of as being unique to humans, the origins of things like war are found deeper in the past than we previously thought. Huge round of applause to Sandelle and colleagues, to all of the people who were involved in not just this paper itself, but in every singular observation over the past decade or so that led to the synthesis of this research and this really epic new addition to our understanding of ourselves and our closest living relatives. If you like this kind of thing, you should consider supporting me in the freeway, which is liking, commenting, and subscribing. And if you want to support me in a more financial way, you can join my Patreon. Patrons get early access to videos when I'm on top of things. It's really nice when I'm like working on a big project, or so I've been told. You can also support me by buying like my stickers and stuff from the store. Links in the description. And I'd like to end this by thanking you from the bottom of my gentle and of course very modern heart for being such a curious primate. And I'll see you real soon next time.

[00:28:28]Heat. Heat. Heat.

[00:28:41]Heat. Heat.

[00:28:57]Heat. Heat.

[00:29:18]with you. You crazy boy.