As this blog is called what it is, I’ve decided to read the entire, long, Wikipedia article on bonobos to get a more subtle and comprehensive feel for their society and how it shapes their individuality – though of course I’ll continue to write on completely different subjects. What I’m finding so far is that there are nuances, as you would expect, and as we find in human societies. And of course it would be the same with other social species – a member of the normally less dominant gender will, through proven capabilities or particular personality traits, be given a more prominent role than usual, and leadership of or status within the group is not solely based on gender. Ranking may have a degree of fluidity based on behaviour and alliances. Not all males are subordinate and not all females are bosses. Nevertheless, bonobos are definitely matriarchal – just as chimps are patriarchal, also with some fluidity.
It surprised me when I learned, some years ago, that bonobos have a ‘male philopatric’ society. The term conveys a gender distinction – the male stays ‘at home’ for mating and reproduction, while the female moves to another group for that purpose. This occurs in some human societies too. While visiting the Tiwi Islands just north of Darwin, I was told by our islander guide that he had just ‘lost’ his sister, who had moved to another tribal group to marry, meaning that their connection was permanently broken. His culture actually forbade him to have any more contact with her. So the early Catholic Church prohibitions against first, second, third and fourth cousins marrying, as described in Joseph Henrich’s historical account of the WEIRD world, as well as many long-held cultural traditions of Australasia and elsewhere, likely hark back to our hominid ancestors.
In any case, male philopatry doesn’t seem very matriarchal. There are of course good reasons for philopatry (male or female) in general, as well as good reasons for its opposite, male or female dispersal, which inevitably means that these behaviours, their causes and consequences, are widely disputed. I think I’ll return to this issue in another post.
A particularly interesting feature of bonobo culture, fairly recently recognised, is co-operation between two separate groups, or troupes. This was in the Congo’s Kokolopori Bonobo Reserve, which may, I think, represent a space between ‘the wild’ and ‘captivity’, and so may influence behaviour. From Wikipedia:
Over two years of observation, researchers witnessed 95 encounters between the groups. Contrary to expectations, these interactions resembled those within a single group. During these encounters, the bonobos engaged in behaviours such as grooming, food sharing, and collective defense against threats like snakes. Notably, the two groups, while displaying cooperative tendencies, maintained distinct identities, and there was no evidence of interbreeding or a blending of cultures. The cooperation observed was not arbitrary but evolved through individual bonds formed by exchanging favors and gifts. Some bonobos even formed alliances to target a third individual, demonstrating a nuanced social dynamic within the groups.
This contrasts importantly with the deadly clashes between groups of chimpanzees observed by Goodall and others.
Bonobos engage in tongue-kissing, the only non-human creatures observed to do so, at least thus far. And this brings us to sex, a difficult topic to write about, even in a blog nobody reads, given so many cultural and religious tabus swirling around it in human society. So, best just to be descriptive, without making comparisons to H sapiens.
Bonobos aren’t monogamous, and they engage in sexual activity from an early age. It is mostly masturbatory, and indiscriminate, with the possible exception of mothers sexually engaging with adult sons. Heightened sexual activity often occurs when rich food sources are found, in which the masturbatory sex often occurs in large groups, increasing generalised bonding. Female masturbation is helped along by the fact that their clitorises ‘are larger and more externalised than in most mammals’. Well, here, comparison with humans is instructive:
… while the weight of a young adolescent female bonobo “is maybe half” that of a human teenager, she has a clitoris that is “three times bigger than the human equivalent, and visible enough to waggle unmistakably as she walks.
All quotes here are from Wikipedia, unless otherwise stated. The most common sexual combo is female-female. Their face-to-face, body-to-body interactions are referred to as genito-genital (G-G) rubbing, which is often accompanied by loud noises, hopefully of pleasure.
So, while female-female masturbation is the most practised sexual behaviour of the species, enhancing bonding against any male threats, male-male masturbation is also a regular thing:
The most common form of male–male mounting is similar to that of a heterosexual mounting: one of the males sits “passively on his back [with] the other male thrusting on him”, with the penises rubbing together because of both males’ erections
Clearly sexual activity is encouraged and valued as the most essential feature of bonobo society, and is practised in a variety of ways – penis-fencing, rump-rubbing, genital massaging, oral sex (among males) and, as mentioned, tongue-kissing. Adult-child sex is more common in males than females, though there’s no penetration. Is this because they’re avoiding pain, or because they know the connection with pregnancy? The general scientific consensus is that non-human species engage in sex based on instinct, hormones and such – that’s to say, more or less unconsciously without being aware of possible or likely consequences. I’m not entirely convinced, especially re our closest relatives, but how can this be tested? In any case, regardless of all this sex play, bonobo birth rates are no higher than those of chimps.
Unsurprisingly bonobo social relations are just as complex as those of chimps, and perhaps also humans, with personal animosities, rivalries and close friendships within and between genders, and the fact that infanticide in bonobo society hasn’t been observed isn’t proof that it hasn’t happened – after all, we’ve only known of the existence of bonobos for a little under a century. Still, bonobos are definitely different, and in what I would call an inspiring way. You could say that sex becomes a feel-good strategy, but also a way of diminishing any sense of male ownership of offspring. As Wikipedia puts it:
The strategy of bonobo females mating with many males may be a counterstrategy to infanticide because it confuses paternity. If male bonobos cannot distinguish their own offspring from others, the incentive for infanticide essentially disappears. This is a reproductive strategy that seems specific to bonobos; infanticide is observed in all other great apes except orangutans. Bonobos engage in sexual activity numerous times a day.
Anyway, enough of sex, let’s explore violence. Chimps, as mentioned, tend to be hostile to those not in their own troupe, and even patrol their own borders, looking for trouble. Very West Side Story. And yet, to my surprise, bonobos, are more violent in general.
In the wild, among males, bonobos are more aggressive than chimpanzees, having higher rates of aggressive acts, about three times as much. Although, male chimpanzees are more likely to be aggressive to a lethal degree than male bonobos which are more likely to engage in more frequent, yet less intense squabbling. There is also more female to male aggression with bonobos than there is with chimpanzees. Female bonobos are also more aggressive than female chimpanzees, in general. Both bonobos and chimpanzees exhibit physical aggression more than 100 times as often as humans do.
All of this sounds interesting, but ‘aggression’ might be a little more difficult to define than we think. In humans, for example, accusatory or bullying language, or the sharing of images, can be used aggressively without anything physical occurring. It has even been known to cause the victim to commit suicide. We have subtler and often more effective ways to make others suffer, and ‘non-physical’ aggression may have a physical, even deadly, impact. It is also a way of getting around laws prohibiting physical violence.
In any case, surely a major reason for the supposed greater physical aggression of chimps and bonobos, and doubtless other apes, compared to humans, is how we ‘count’ aggression. Is carpet-bombing physical aggression? Nuclear warfare? The wholesale slaughter of the Jews and the Congolese? The massacres of the ‘Crusades’? How can we not count remote, push-button slaughter, or starving people to death behind walls, or burning them to death in buildings, as physical aggression? Methinks there’s need for a rethink.
So let’s turn to something less controversial. Like all the great apes, bonobos pass the self-awareness mirror test, and it’s clear that the variations in their vocalisations have meaning, though whether they rise to the standard of a proto-language is a matter of definition. They also use many meaningful hand gestures.
A famous example of a bonobo being taught to communicate using a keyboard, and to respond effectively to whole sentences, is that of Kanzi:
Kanzi’s vocabulary consisted of more than 500 English words, and he had comprehension of around 3,000 spoken English words… Kanzi is also known for learning by observing people trying to teach his mother; Kanzi started doing the tasks that his mother was taught just by watching, some of which his mother had failed to learn….
Kanzi was also taught how to make simple stone tools, though he found a method of making them in his own bonoboesque way. There seems no doubt that effective rapport between bonobos and humans will benefit both species.
Finally, there’s the ecological importance of bonobos. They’re essentially one of the two apex species of their region, the other being elephants. Both species are frugivorous, and their ecological role is vital:
It is estimated that during its life, each bonobo will ingest and disperse nine tons of seeds, from more than 91 species of lianas, grass, trees and shrubs. These seeds travel for about 24 hours in the bonobo digestive tract, which can transfer them over several kilometers (mean 1.3 km; max: 4.5 km), far from their parents, where they will be deposited intact in their faeces. These dispersed seeds remain viable, germinating better and more quickly than unpassed seeds. For those seeds, diplochory with dung-beetles (Scarabaeidae) improves post-dispersal survival.
Diplochory means two-phase seed dispersal, using more than one vector or carrier.
Anyway, I think that’s more than enough info for one post. The Wikipedia article on bonobos makes for a very solid book chapter, with 178 references, so far. And it ends nicely with informing us all of the annual World Bonobo Day, established in 2017. No prizes should be given for guessing the date!
References
https://en.wikipedia.org/wiki/Bonobo
Joseph Henrich, The WEIRDest people in the world: how the West became psychologically peculiar and particularly prosperous, 2021