Pt3: The Status Wars of Apes

and how they use it to acquire sex

Do the great apes rape each other? The answer is depends what century you’re asking in. If you’re in the 1800’s, your conception of ‘rape’ is definitely met by orangutans. By the 1960’s, the sexual revolution would include chimpanzee behavior as a big no-no. Bonobos are the satanic panic of rape if satanic panic were real, where adults do sex stuff with infants. And gorillas are some secret fourth thing, where an invading gorilla will just kill all the babies by grabbing them from their mothers and then slamming them onto rocks. The grieving mothers then stop lactating, return to being fertile again, and then initiate sex with their baby’s killer. I don’t know what time period would point and go ‘oh yeah, classic rape.’ Maybe babylonian? All the time periods in hell?

This is interesting because ability to have sex with females is a limited resource subject to intense competition. What strategies do apes resort to? How does their status in the tribe affect their use of force?

Orangutans are mostly solitary and live on a few islands in Indonesia. They’re one of the few mammals known to regularly engage in physically forceable rape - but interestingly, almost only the low status males do this. When a male becomes the dominant male in his range, he grows the two big flanges on the side of his head. Somehow his biology responds to his position in the dominance hierarchy.

my fav animal

Females will voluntarily mate with the alpha, seeking out sex, riding him cowgirl, just going total slut. There’s some good smutty worldbuilding for erotica somewhere in here. The dominant orangutans will father ~90% of all the children in a given range.

Gorillas live in the armpit section of Africa (armpit of shape, not armpit of emotions). They’re harem-prone, roam around in little bands made out of one dominant male and a bunch of females. Sometimes there’ll be more than one adult male, but those are clearly subordinate and usually his sons. Discarded males will roam around on their own, pestering the edges of other bands, sometimes growing strong enough to take over - upon which they engage in that aforementioned infanticide. Females initiate a lot of sex, typically with the top dude. In general, the dominant gorilla will be the father of 85% of offspring in his group.

As a note, direct physical violence within gorillas and orangutans is relatively rare; usually they evaluate size and social alliances beforehand, make an accurate estimate of who would win a fight, and that will settle the question of rank and access.

Chimps and bonobos are what we’re gonna really focus on, though. A few million years ago their common ancestor ended up divided by a river in central Africa. One side of the river had more food, the other had less (and had gorillas to compete against). The plentiful side turned into bonobos, and the scarce side turned into chimps. Though they look so similar that for a while people thought they were the same species, their behavior is cartoonishly different.

You probably know the tropes. Bonobos are a feminist’s paradise of female bonding, matriarchal leadership, peacefulness, and sex to resolve everything. This is largely true; they have sex on average something like once every 1-2 waking hours, and use it to resolve fights, to express hierarchy, to form alliances. Their dominant leader is nearly always a female, and who ranks over who is very malleable and flexible, with no clear structure. Bonobos so far have never been observed to kill each other.

Chimpanzees, meanwhile, are full of more violence and patriarchy than if you stuffed a 747 full of Andrew Tate clones and launched it into Saudi Arabia. You might know the famous tale of the great Gombee chimpanzee war, which took place around a Jane Goodall-run provisioning site (area researchers camp and supply food to attract primates for more reliable observation).

But if you’re not, it went like this: the Kasakela group, a peaceful, tight-knit community they’d been studying for over a decade(!!), started to fracture. Rifts grew, and eventually it split into two separate groups, and those groups began to war. The larger group went on hunting raids, looking to catch males from the smaller group alone. Over the course of years they would ambush unfortunate solo males (remember: chimp food is scarce, and they have to split up to eat) and beat them to death. After all the males in the smaller group had been murdered, the larger-group males then hunted down the females and either murdered or raped them. And, of course, killed their infants.

Chimps are like morgoth to bonobo’s manwe.

So, knowing the general differences in temperament, it should be easy to predict:

1. Which species sees a lower frequency of violence?

2. Which species is more likely to share food?

3. Which species has more equitable fathering? Orangutans and gorillas have very inequitable fathering, with the dominant male fathers ~90% of offspring. Do bonobos or chimps have more equally distributed parentage?

If you answered ‘chimps’ because you felt like I was setting you up for a trap, you are correct; it was a trap, and the answer is chimps.

To understand why we have such unintuitively equitable, civil outcomes in the horrorland that is chimpanzee politics vs such disparity of fortunes in our bonobo paradise, let us first take look into how status works in both groups.

Chimpanzees have clearly defined status. You can easily tell which chimp is higher status because they are extremely dramatic about it. When a higher-status chimp approaches, a lower-status chimp will do a specific type of pant-grunting, will bow, present their ass for sniffing, will lie on their back with their legs spread, will make anxious facial expressions. The higher-ranking chimp will stand physically over them, hair puffed out, and will accept the submission by grooming the sub. Chimps will do this regularly, multiple times per day.

By this metric, chimp males rank higher than all females; the most powerful female in a chimp community will bow and lie on her back and pant before the lowest-ranking male.

What determines this rank is some fucked up game of thrones shenanigans. Chimps make allies, often by spending time grooming each other and sharing food (as allies are vital in chimp world, you see more food sharing). A chimp and his allies might finally overthrow the aging alpha male, killing him and taking his place. But then after peace settles, plots start forming. The newly dominant chimp might actively foster discontent among his former allies. He might attempt to physically prevent e.g. the #2 and #3 downrank of him from hanging out together, for fear they will start plotting to overthrow him. He must spend his resources keeping enough allies loyal to him such that his coalition can defend his seat as king, should any rivals come to challenge. In captivity, stuff like ‘alpha gets sick’ can throw off the whole balance, cause if he spends a while in the chimp hospital, this means the other males are free to control the power balance in his absence. This doesn’t bode well for him when he returns.

In general, though violence is brutal and often deadly when it happens, it’s not as frequent as it could be, because the rigid hierarchy is stable when it’s stable.

Why play this treacherous war? The answer is pussy (or, more specifically, some pretty grotesque estrus swellings).

In addition to access to those sweet estrus swellings, a dominant male chimp accesses social power. Female chimps make good bargaining chips! If you’re trying to cultivate alliances, the best way to keep your allies happy is to let them mate with females.

Another reason is that keeping an eye on all the females is hard. Chimps do fission-fusion, which means sometimes their tribe spends time together, sometimes it spends time apart - especially when searching for food. This gives lots of opportunity for subordinate males to shoot their shot, if you will. And by shot, I mean violent shot, of a fist, which often precedes the actual sex.

Sexual coercion in chimps is rampant, making up the majority of sexual encounters. According to the Smuts model, which I like a lot, there’s five primary types of sexual coercion, all of which chimpanzees do:

• Physically overpowering force, aka rape classic. While only orangutans do this regularly, chimps are known to sometimes do this in some communities.

• Harassment, where a male follows around a female and pesters her, chasing her, interrupting her eating, slapping her, until she eventually gives up and has sex with him just to make him stop.

• Intimidation, where the males will keep the females in a general state of terror by randomly beating them up. Then, when they want sex, the females are too afraid to resist. This is the theory, because some observations see females more likely to mate with chimps that have been previously violent towards them.

• Attacking females after they mate with other males, so that the females are less likely to do that again in the future.

• Kidnapping/mate guarding, which is basically forcibly hauling the female away from the main group so that nobody can come to her aid when she screams, which they do a lot. This usually happens during her fertile period, which lasts roughly a week or so.

The life of a chimpanzee female is a brutal one; you get used as a pawn, get sexually assaulted, kidnapped, physically beaten on a regular basis. You’d think the extreme control males have over the females would lead to the alpha male exhibiting extreme dominance over reproduction. But in this world, somehow, the dominant male fathers the lowest percentage of offspring compared to all of the other nonhuman great apes.

In contrast, the top male bonobo will likely father more of the offspring in his tribe (~50-60%) than the top chimp will (~30-40%), although the sample size is small and variance is high. This is mostly because bonobo females have sexual choice, and left to their own devices, females will mostly choose to mate with the dominant male.

Bonobo status might be less over-the-top than the chimps, but it’s certainly there. Bonobo status is determined by a mix of seniority and social deftness; the longer you’ve been in a group, and the better you are at making allies, the higher status you are. And if you’re higher status, the more bonobos try to groom and have sex with you, and the earlier in line you can eat from a food supply.

Higher-status bonobos occupy a more central position. This is literal; they are physically in the middle of the group of the tribe more often. This gives them better ability to observe and influence any nonsense they don’t like. Bonobos are more frequently clustered together due to more bountiful food in their environment, so staying in group formation is easier for them.

In bonobos, sex indicates alliance, acceptance, access. (I here am using ‘sex’ to refer to intercourse, lesbian GG-rubbing which is kinda like scissoring, gay male penis-rubbing, as well as regular heterosexual p-in-v as god intended). Sex is good for its own sake, and is something that higher-status bonobos ‘gain access’ to, in a sense, as higher status bonobos tend to be the ones initiating sex. Everybody wants to gg-rub the top mamma.

When a high-ranking bonobo has sex with a lower-ranked bonobo, the higher ranked bonobo typically is quiet, while the lower ranked one makes a whole lot of sex noise. The bigger the power gap, the more noise. The noise also seems to be louder if high-rank bonobos are also watching, which seems to suggest that bonobos use sexual access as a way to announce to everybody that they are very cool. And this does seem to translate to coolness; they’re generally treated better by the others after this.

As a side note, I’m currently pretty confused around some of the bonobo sex incentives. Sex is used as a tool to social climb (benefiting the lower rank), but also traded out to gain access to food (paying the higher rank), apparently? I’ve gotta read more on this, just noting that I do not thoroughly understand yet.

Despite not killing each other, bonobos fight more often, roughly 3x as much as chimpanzees. Male bonobos fight over fertile females, female bonobos band together to discipline uppity males. Partially this is because they’re physically together more often, but also it’s probably easier to fight when you know it’s not going to end in severe injury or death.

Bonobo females rule, overall, but the hierarchies of males and females still significantly overlap. The average female bonobo will be dominant over ~70% of males, and this is primarily because they work together. Female bonobos, much like male chimps, are great at building alliances.

A male bonobo’s rank is largely determined by his mother’s rank, and his mother fights not just for herself but for her son. Mother-son pairs are the backbone of bonobo society. In both bonobos and chimpanzees, the daughters leave their natal group to immigrate to new ones. This is interesting - I could see a world where sons are the ones that leave their natal bonobo group, thus leaving the daughters to form stronger kin-based clans with their mothers. That would be a really powerful explanation for why the females ended up dominant. But no - in bonobo society, immigrant females manage to bond well with the others.

The female dominance does not seem to hold if you split the bonobos off from the group, interestingly enough! In individual female-male pairs, apart from the power of female coalitions, the male almost always dominates. Male submission is not for lack of desire to be dominant, only lack of capacity.

Both female chimps and bonobos have swellings on their butt/genital area that get engorged around the time they’re fertile, and deflate when they’re not. This, understandably, heavily affects the way they’re treated by males - basically only swollen chimp females get kidnapped, for example.

But, despite actual ovulation occurring once, bonobos swell for longer - roughly 2x the length of chimps. Swelling time is super important! The longer you’re swollen, the less confident males can be that they are the ones who get you pregnant, because they’re less sure when exactly you were fertile. This has huge downstream impacts.

There’s various cool incentives that push swelling length longer or shorter. The longer you’re swollen, the longer a period of time you get sexual attention from males. This can be good for you (bonobos like sex) or bad for you (chimp sex is often at the expense of the female); thus there’s likely some incentive for chimps to swell for a shorter time, and bonobos to swell for longer.

But it also obscures paternity! Human women have totally obscured ovulation, which means human men really can’t be that sure if they’re the one who knocked her up. This, combined with men’s tendency to want to invest resources into their kids, results in human males getting really mate-guardy to prevent any possible sexual access to their woman. In many cultures men make their women cover up head to toe, or not be alone in rooms with men, or tend to isolate them from friends and family in extreme cases.

You might think it would be better for females if they could signal ovulation with high confidence (like chimps) - maybe the males wouldn’t get so kidnappy and possessive? But one incentive against precise ovulation signaling is to make the males stop killing your babies. In chimps, not all sex is coerced; females will often solicit sex from multiple males during estrus. The closer to ovulation, the more likely she will have sex with more dominant males. The lower the odds of conception, the more she will have sex with other males, in a sort of proportionate distribution. This means that she’s probably going to bear an infant from the best male, but nobody’s really sure. All the other males she had sex with are now less likely to kill her infant, because there’s a chance it might be theirs. The longer your fertile period, the more you can blur chances of paternity and get fractional buy-in (or at least nonaggression) from all the males who dumped their loads in you.

But swellings are also sensitive and bleed easily and seem overall pretty annoying. They’re a costly signal, and the cost of that signal is certainly a disadvantage.

Overall, the pros and cons of swelling length seem to have balanced out to shorter in chimps vs longer in bonobos. It’s so cool to see how the different incentives shake out given such similar starting conditions! I’m also super grateful human women never evolved sexual swelling, it would be so hard to wear pants.

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In both chimp and bonobo societies, everything in a sense centers around sex and access to sex. The more sex you have with higher quality mates, the higher status you are. Given the basic building blocks of ‘very genetically similar monkeys in woods right across a river from each other’ (bonobos and chimpanzees are similar enough to produce hybrids!), it’s crazy that one ended up with females as functionally sex objects, and the other with females using sex like it’s a drug they’re addicted to.

I love all these monkey facts because it feels like it gives us clues into human status wars, and the role sex plays inside them. I have told you all these monkey facts because I am excited about monkeys and wanted to tell you guys about them, but also because I hope to reference these dynamics in analysis about human interactions in upcoming posts in my status series.