Chimpanzees in Uganda locked in eight-year 'civil war', say researchers (bbc.com)

by neversaydie 282 comments 439 points
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282 comments

[−] OgsyedIE 35d ago
The primatologist Richard Wrangam once advanced the theory that tribe vs. tribe conspecific homicides - what he called coalitionary killing - are an evolved trait that was selected for in primates by some kind of pro-homicide selection pressures in the ancestral environment (where homicide reliably grants an advantage to the expected relative gene frequency of the perpetrator's genes).

I haven't kept up with biology for years and don't know what the current consensus on the topic is but it's interesting to consider if some environments naturally promote the unlucky inhabitants to harm each other.

[−] Xiaoher-C 34d ago
Worth adding some nuance to the Wrangham framing here — he's not wrong exactly, but de Waal spent decades documenting the flip side: chimps reconcile, console each other, maintain coalitions in ways that don't fit the "demonic males" narrative cleanly. Both are true, and which one you see probably depends a lot on which population you're studying and under what conditions.

Ngogo (which I think this is) is in a fragment under real agricultural pressure. I'd be cautious about drawing evolutionary-psychology conclusions from a group that may be responding to a dramatically compressed territory rather than some baseline ancestral program. Same chimps in intact forest might look quite different.

[−] griffzhowl 34d ago
Good points, but it any case, it's true that chimps in general treat group members very differently to outsiders isn't it? Those behaviours that de Waal mentions seem probably directed towards group members. Are there any documented chimp populations where chimps aren't violently aggressive towards members of other groups?

I remember reading, not sure if it's from de Waal, about chimp "raiding parties", where groups of young males will get excited and loudly vocalise as they gather together and head towards a neighboring territory, but when they get close they all go very silent, and will attack individuals from a neighboring troop if they sufficiently outnumber them. They tend to target the face and genitals when attacking other chimps, a different behaviour to when they're hunting monkeys, for example. I think Wrangham mentions that some chimps will hold the targeted individuals' limbs while others attack.

Aside from the brutality, these behaviours seem too cogently goal-directed and sophisticated to just be responses to environmental pressures. There's some deeper reasons involved, imo, even if the severity of the violence is exacerbated by resource and territorial pressures.

[−] dumah 34d ago
How are resource and territorial pressures not environmental pressures?
[−] griffzhowl 34d ago
They are. I just used different words to refer to the same idea
[−] londons_explore 35d ago
It seems obvious to me - it's the combination of two ideas:

1. When competing for resources, killing your neighbour frees up resources, which you can take. Most species of animal and even plants do this to some extent.

2. By collaborating in a group, you can achieve more than individuals acting alone. This is the idea behind teams, companies, countries, etc.

Combine the two ideas, and you get war.

[−] Sharlin 35d ago
It's definitely not obvious, given that many, many gregarious species may certainly have inter-group clashes and skirmishes at territory boundaries but no full-scale war. Animals in general avoid violence between conspecifics, for the obvious reason that it's rarely worth the risk of being hurt unless you're very sure you're going to win. Dying for your group is something you almost never see outside eusocial species. Never mind dying in your prime reproductive age!
[−] rapidaneurism 34d ago
Don't think of it as individuals, but as individual genes. A group of 10 with the same genes, that can eliminate a group of 10 with different genes by losing one individual (because they were fighting to the death, while their opponents did not) is 9 copies up.

An alternative view is that in groups with alphas that father most offspring, and status is based on the individual's ability to risk death. Genes in an individual of low status are already 'dead' so manufacturing instincts and hormonal responses that increase violence does not have a downside.

[−] Thiez 34d ago
The extreme version of this would be insects like ants and certain types of bees, where the vast majority of individuals are biologically incapable of reproduction, and serve the one or few queens that are capable.
[−] Jensson 34d ago

> Animals in general avoid violence between conspecifics

That seems to mostly just be true for oppressed species that doesn't already dominate. For example Orcas attack each other when they get into each other territory, as do ants. Humans dominate most land animals today so they probably lost most of that since humans already kill enough that killing each other is no longer a benefit for them.

[−] ozim 35d ago
dying in your prime reproductive age!

I guess dying because you think you’re going to impress’s a mate and stay alive is quite common.

[−] Sharlin 34d ago
On the contrary, that's very uniquely and peculiarly human stupidity, possibly caused by the fact that our brains take so long to fully mature. In other species, competing for mates (just like territory) is typically highly ritualized exactly because getting seriously hurt is the opposite of adaptive.
[−] bryanrasmussen 34d ago

>I guess dying because you think you’re going to impress’s a mate and stay alive is quite common.

based on my memory of readings in the matter I don't think so, most animal species "impress a mate" is either

1. do mating ritual better than others

2. actually directly compete with rival who has mate to win mate.

In the second more rare scenario the actually directly compete with rival tends to be very ritualized, and thus when you lose you don't actually get significantly hurt.

In the ritualized combat for mates some species have evolved to points in which accidents become a major problem, for example Stags locking antlers in combat for does.

Obviously this is a scenario where you want to impress and stay alive but it doesn't work out, but it is relatively rare in the species that has evolved antlers to the point where it happens, and it is rare for species to have similar problems, generally the one who loses these competitions does not die, they just assume a lower status.

So all that said the human tactic of Bob, hold my beer while I impress Cindy by riding this croc, is a pretty rare tactic for getting a mate.

[−] dontlikeyoueith 35d ago

> When competing for resources, killing your neighbour frees up resources, which you can take. Most species of animal and even plants do this to some extent.

If anything, I'd say plants do it more. Everything in the garden is trying to kill everything else.

[−] bluegatty 35d ago
Yes, but war is worse for all parties generally.

Lions murdering prey to eat is a stable equilibrium.

Primates fighting each other is not.

Murdering for acquisition of a resource is short term advantage.

We are strongly, strongly evolutionary oriented away from 'murder' - it's the original sin. It's not something we even argue over. Murder = Bad. No disagreement across cultures. Murder = social cheating. No disagreement there either.

Or put another way - the 'self' can gain advantage with murder, but the group and species probably will pay for it long term.

I wonder if there are just things that species really have to learn over and over, particularly things like 'active deconfliction' etc..

[−] sjducb 34d ago
Normally there are more than 2 actors, which changes the reward structure.

X spends resources to kill Y. This benefits X because X doesn’t have to compete with Y anymore.

However Z also gets the benefits because they don’t have to compete with Y either. In addition Z hasn’t spent any resources to eliminate Y so Z wins. The stable equilibrium is 100% strategy Z.

Most animals will use violence in self defence, or when fighting over a specific resource. They don’t kill to remove competition.

Chimps and humans are an exception to this. Likely it’s because the coalitional nature of human and chimp violence reduces the cost of inflicting the violence to near zero, and the costs are spread across the group, so it’s worth doing.

[−] konschubert 34d ago
Important to remember that we as humans no longer compete for resources.

We have more than enough resources to go around for 10 billion people.

The limiting factor is in intelligence and dexterity. In other words, we get richer when we are more.

[−] jvanderbot 34d ago
There's a simple energy argument for both predation and war. It is energetically cheaper to take than to build. If you can take with low risk, there is no (energetic) reason to not do so.

Collaboration is the exception. That collaboration is everywhere in many forms is a testament to the power of natural selection.

[−] the_af 35d ago

>

When competing for resources, killing your neighbour frees up resources, which you can take

I don't think it's that straightforward. War is usually extremely wasteful for all involved, even the victor. Plus it puts the whole group at risk, if it spirals out of control.

[−] JohnMakin 34d ago
orangutans deal with similar and are notorious for being peaceful
[−] hetman 34d ago
Except in this instance the conflict erupted after the population size was reduced due to disease so it's not entirely clear this was caused by the scarcity of resources. Nor is it clear what selective advantage mutually destructive wars would have assuming plenty of resources. The researchers posit group relational dynamics being the primary factor.
[−] voidhorse 34d ago
[flagged]
[−] xg15 34d ago
Given how easily we can separate people into "ingroups" and "outgroups" and always fall into the same behavioral patterns regarding them, even if the actual markers for the ingroups and outgroups are completely arbitrary, it really seems likely this is biological and not just cultural.
[−] everdrive 34d ago
Back in the old days people were much more unabashed about such things. What's the purpose of your very small collection of city states? Obviously to expand, and smash any neighboring states. If you succeed, kill all the men and take their women as slaves. This was much of civilization for a long time.
[−] Culonavirus 34d ago

> primatologist

sometimes I feel like that at work

[−] dboreham 34d ago

> an evolved trait

This is obviously not correct. There's no way to encode "you must hate and kill the tribe next door" into DNA. Clearly this behavior is emergent in the population. Perhaps what's an evolved trait is "have neurons with some mixture of properties, and response to hormones that tends to produce angry homicidal assholes in the presence of competition for resources".

[−] trollbridge 34d ago
Don't ant colonies also go to war? I've seen that happen before and it's quite interesting - I read a theory somewhere that part of the purpose of this was to prevent overpopulation, so in the long run _both_ ant colonies do better since they don't "cooperate" and end up overpopulating.
[−] kjkjadksj 34d ago
For whatever reason, bonobos living under similar environmental constraints don’t do this. This suggests to me that the behavior is strongly controlled by genetics. Makes one wonder about the warmongers in our own species if they harbor some warmonger gene.
[−] JumpCrisscross 35d ago
I’m trying to find the source, but I remember a primatologist claiming that humans and chimpanzees are the only two species that embark on genocide. Not being satisfied with simply defeating the enemy, but actively hunting them down to ensure they can’t harm you again. In other words, precluding retreat. (Which creates its own game-theoretical backlash: never retreat.)
[−] Andrex 34d ago
I mean, kill everyone else and you can be sure your genes are the only one propagating. Makes sense to me.

However there must have been some opposite instinct that prevented monkeys from just wiping themselves out. I hope so, for our sake.

[−] neom 35d ago
Here is the paper: https://www.science.org/doi/10.1126/science.adz4944 - it's interesting.

I noticed there was a respiratory epidemic that killed 25 chimps naturally quickly, one would imagine that would have quite a societal destabilizing impact?

[−] delichon 35d ago
I hope nobody decides to violate the prime directive and take sides in the chimp war.

To the extent that they have good memory, they live in a world of finite resources, and their behavior was shaped by the forces of game theory as applied to tribes, this is more or less inevitable. You can read that as defeatism or just math. We can't overcome the force of game theory, but we can make it work for us by making our transactions increasingly transparent and repeatable, so that cooperation is more successful than defection.

[−] wisty 34d ago
Anyone read Goliath's Curse? The author (Kemp) is extremely opposed to the more Pinker-ish idea that humans in their natural consition led lives that were nasty, short, and brutal; dismissing this sort of thing as overblown.

Kemp had the very anarchist friendly theory that it's states (Goliaths) and / or the conditions that lead to them that lead to violence.

His evidence is most convincing when it's looking at the paleolithic, as h sapiens made its way out of Africa ... but maybe this is not a natural state as they had not yet reached any population limits so migration was always an alternative to conflict?

[−] atentaten 34d ago

>If chimpanzees - one of the species closest to humans genetically - could do so without human constructs of religion, ethnicity and political beliefs, then "relational dynamics may play a larger causal role in human conflict than often assumed", they added.

Aren't religion, ethnicity and political beliefs strong factors in human relational dynamics?

[−] loganc2342 35d ago
If anyone is interested in going more in-depth on this, there's a four episode documentary series on Netflix called Chimp Empire [1]. I just saw it last week and it's fascinating stuff. You get to know the individual chimps in-depth (they all have names) and get to see conflicts in this "civil war" unfold. Plus I learned a lot about social and "political" dynamics among chimps.

[1]: https://www.netflix.com/title/81311783

[−] hn_acc1 35d ago
So wait - after a respiratory virus, let's call it SARS-C, that killed > 10% (25/200 = 12.5%) of their population, they split into two major groups that are now at each other's throats, when before they had a generally-ok alliance / relationship?

Where have I seen this before.. Think.. Think..

[−] asterix99 35d ago
The book Shadows of Forgotten Ancestors by Carl Sagan is a revelation in how close human behaviour is to those of chimps.

https://www.goodreads.com/book/show/61662.Shadows_of_Forgott...

[−] rurban 34d ago
What they don't tell here, but a german researcher told yesterday on radio, was that the initial conflict arose in the 90ies, when one large group of Ngogo chimpanzees raided a nearby group and killed all males. Thus they came later to that insanely large number of 200 members, which a decade later lead to this conflict with the two groups already seperated. Similar to the https://en.wikipedia.org/wiki/Gombe_Chimpanzee_War observed by Jane Godall.

Also missing is the Killer Ape theory of the sixties which led to the research that chimpanzees have much higher lethal conflict numbers than humans.

Also, this Ngogo group is highly researched, and many many films where made about them.

[−] nutjob2 35d ago

> If chimpanzees - one of the species closest to humans genetically

People seem to talk a lot about chimpanzees and their closeness to humans, and comparative behavior, but a lot less is said about the other closest species, the bonobo monkey.

Their society is very peaceful and things like infanticide, a popular pastime in chimpanzee society, is absent among bonobos.

The most notable trait of bonobos is that everyone has sex with every one else, constantly, (almost) regardless of relation, gender or age.

You'd think humans could learn much from such a peaceful species, but most people don't even know they exist.

[−] elcapitan 35d ago
So which side is fighting for our values?
[−] grg0 35d ago
Damn, they've been polarized by social media too? Zuckerberg's greed knows no limits.
[−] laughing_man 35d ago
This doesn't surprise me. We've known for decades that chimpanzees groups make war on other chimpanzee groups. Eight years is a long time, though.
[−] mike_hearn 35d ago
> If chimpanzees - one of the species closest to humans genetically - could do so without human constructs of religion, ethnicity and political beliefs, then "relational dynamics may play a larger causal role in human conflict than often assumed", they added.

That's a weird thing to say. Studies of primitive tribes showed decades ago that they only seem to fight each other for a handful of reasons. Religion, ethnicity and political beliefs aren't among them. Fighting over resources, women and blood feuds are.

Supposedly academic anthropology had difficulties accepting these findings, especially the Yamomamö studies by Chagnon where he documented them going to war to steal each other's women, as it contradicted the popular idea of the noble savage.

[−] ZeidJ 35d ago
Any founders out there using AI to solve this? ;)
[−] clutter55561 35d ago
Say that we, primates, have evolved some sort of social structure that values and depends on ‘us’, and antagonises ‘others’.

That would explain that sort of behaviour as well as our human shenanigans (country/religion/“race”/politics/football team/etc).

Perhaps some groups are biased towards ‘us’ (i.e. more accepting), and other groups are biased towards ‘other’ (i.e. more hostile).

The death of a few key individuals can absolutely remove all the commonality between two groups. Seems to have happened with those chimpanzees, and happens all the time in human groups.

It is sad though that this is happening, on top of all the shit that is going on.

[−] beloch 35d ago
"The third factor was the deaths of 25 chimpanzees, including four adult males and 10 adult females, as a result of a respiratory epidemic, in 2017, a year before the final separation. One of the adult males who died was "among the last individuals to connect the groups", the research paper said."

-------------

There's a theory that humans (and likely chimps as well) have a cognitive upper limit to the number of stable relationships they can maintain (i.e. Dunbar's number[1]). Also, there is the idea that most people have nowhere near that many relationships, but some people are super connectors. They know everyone in the community and tie it together, even if the average member of the community doesn't know most other people in it.

It almost sounds like, before the conflict, the tribe was at or a little beyond their "Dunbar's number"[1] and then several of their super-connectors died. Suddenly the community, despite its losses, was too big and not connected enough to remain stable. Minor conflicts arose, individuals started choosing sides, and there wasn't anyone with connections to both sides able to bridge the gap and calm things down.

I'm not a sociologist/anthropologist/etc., so I'm probably woefully misinformed and spewing nonsense here. I'd love to hear what someone up to date on this stuff thinks actually happened.

_______________________

[1]https://en.wikipedia.org/wiki/Dunbar's_number

[−] jonahbenton 34d ago
Am reading Sapiens now, missed it the first time around. Incredible book. The point it makes isn't the killing among chimps being surprising. It is not relative non killing among humans- current day events notwithstanding. Contra the BBC, various human storytelling manifestations- religion/culture/etc- make large scale coordinated peaceful actions possible.
[−] semiinfinitely 35d ago
we can send them some of that vim donation money
[−] frakrx 34d ago
Funny how many people presume collective conflicts and violence are uniquely a human thing. Chimpanzees, lions, and wolves are some of the species where this kind of behavior is best known and documented.
[−] globalnode 35d ago
fascinating. so if humans are more like chimpanzees than not, then we are a group based animal that distrusts/fears other groups unless some strong leaders are able to bridge the gap? its an over simplification but then you have to ask, what defines a group? language? location? appearance? religion? wrt politicians, their job should be (amongst other things), bridging gaps between groups, instead of what we see going on in the world now.
[−] quietsegfault 34d ago
Can I get involved like an arms dealer and influence the course of chimpanzee history?
[−] zdc1 34d ago
Just like kids on a playground; only more brutal. Thank you, ancient chimp brain.
[−] shevy-java 35d ago
I always wondered when Planet of the Apes would begin. We can see it now:

a) Chimpanzees going to war. b) Humans ending humans.

Both is presently in the making, if one looks at the geopolitical scale and looks at damage caused by drones; a) is probably not yet full scale. Chimpanzees may be better diplomats than humans.

[−] ingen0s 34d ago
I wonder if there is a spill over effect to other species/ ecosystems
[−] classified 34d ago
I don't suppose they would respond to mediation?
[−] timcobb 34d ago

> Commenting on the study in Science, he wrote: "Humans must learn from studying the group-based behaviour of other species, both in war and at peace, while remembering that their evolutionary past does not determine their future."

Why not? On what timescale? Rosy amorphous statements like this are borderline triggering for me these days-- why conclude a piece like this with some sort of unsubstantiated wishful thinking Disney ending? We see what we see, and it's been, oh what, a million years since chimps and humans diverged, and humans are melodramatic and vicious as ever. Why, on top of that, are we so hard into drinking our own Kool-Aid?

[−] Reason077 35d ago

>

”Chimpanzees are “very territorial", and have "hostile interactions with those from other groups"”

So just like humans, then.

[−] dirasieb 34d ago
do they wear red and blue?
[−] cbdevidal 34d ago
We really got Planet of the Apes before GTA VI
[−] eucryphia 34d ago
Can we bet on this yet?
[−] vivzkestrel 34d ago
"give a man a chimpanzee and he ll put it in a cage and feed bananas for 8 years and give a chimpanzee a man and he ll go to civil war for 8 years"
[−] hmokiguess 35d ago
That's absolutely bananas!
[−] Quarrelsome 34d ago
I thought the general premise is that humans can't form social groups bigger than around ~200. Which scans for me personally, its a struggle to maintain so many relationships. At which point group dynamics break down and factions begin to form. We have mental tech to try to minimise these issues, like nationalism or identity politics. We back these through cultural expression like dress, language, writing, the printing press, radio or the internet today.

Personally I feel like the effects of counter-culture are understated in humanity because I think it might drive a lot of human behaviour and its a natural outcome when a grouping grows beyond people's ability to maintain it. Counter-culture also offers a solid explanation for human insanity such as anti-vax which imho makes much more sense couched as:

"I hate that guy and that guy is keen on getting vaccinated, so fuck vaccinations, they're awful".

I would imagine one could find similar outcomes as this study of chimps, in human groupings too, albeit such experimentation would be unethical. Which is why I imagine it will eventually become a reality show someday: Lets play 400 friends or 200 enemies! Day 4: lets reduce the available food by 50% and see what happens... etc, etc.

[−] fguerraz 34d ago
I find it interesting that the BBC published this at a time they are already under heavy criticism for their coverage of the war in the Middle East (where they didn’t blink at Trump’s genocidal threats and published an article claiming that Iranians wanted to be nuked).

Now we’re saying that war is just natural. It must be a coincidence.

[−] broken-kebab 34d ago
I blame social networks!
[−] codevark 35d ago
They've been watching us and what we do to each other.
[−] dontcontactme 34d ago
I don’t consider myself politically correct but this headline is outright racist