Archive for the ‘Homo sapiens’ Category
women and the future
8,000 years ago….
My previous post reminded me of some pieces I wrote (about a year ago), which I’ll reference below. I’m quite proud of these pieces – it seems indignation can bring out the best…
By the way, what happened to evolutionary psychology? To judge from Ryan Ellsworth’s efforts, it was a questionable enterprise, especially in trying to cement patriarchy into our biology. I would guess that it was never a ‘field’ that attracted female intellectuals. Here’s a passage from Ellsworth in his critique of a book by Susan Block called The Bonobo Way, which I criticised (his critique, not the book) in my earlier piece. Obviously I’m still fuming!
Block refers to babies to care for, and reputations to protect, but does not seem to understand the significance of these two things for understanding human sex differences in sexual desire. Perhaps she privately does, but to acknowledge the significance of these forces on the evolution of human sexuality would severely compromise her arguments, as it demands recognition of the fact that women are not expected to have desires for sexual variety and quantity identical to men. To argue that females are as interested as males in sexual variety is to buy into a sexist worldview wherein the male is the typical specimen of the species by which to compare females (Saxon, 2012). Although ostensibly parading under the guise of liberation, such a position is no less sexist or anti-feminist than is the oppression of women’s sexuality.
One has to read this passage a couple of times to let it sink in. Or at least I did – smarter people might’ve recognised the bullshit straight away. It’s there in the first two sentences (okay, the second sentence takes up most of the passage). The first sentence states as fact that there are ‘human sex differences in sexual desire’. So that must be why it’s okay to call men ‘studs’ and women ‘sluts’, or as Ellsworth puts it, we must recognise the fact that ‘women are not expected to have desires for sexual variety and quantity identical to men’. And it would seem to follow that if they have such desires they should be ostracised and shamed. Ellsworth even tries to argue that to suggest that women might have such pluralist desires is sexist because it (sort of) turns them into men, stripping them of their identity as caring mothers or potentially caring mothers, which is their evolutionary role.
Evolutionary psychology doesn’t seem to have lasted long, which I think is a good thing. It seemed to be wanting to find an evolutionary explanation for what many might find to be shifting social-psychological phenomena, and I don’t think that works. For example, in the WEIRD world we’ve shifted from larger families to smaller, often single-parent families, and family roles have changed. Marriage isn’t so essential to the reproductive process as it was, and of course it only came into being relatively recently, and as for monogamy, we have no idea whether that was practiced by humans, say 200,000 years ago. None of this has to do with evolution in a Darwinian sense – we often describe society as having ‘evolved’ in the last couple of centuries, but this nothing to do with the Darwinian concept.
So, back to monogamy. It’s seen as the norm for we humans, especially when it comes to bringing up children. And yet, neither chimps nor bonobos are monogamous, and clearly they manage to reproduce, and their offspring are just as well-adjusted as their parents. So when and why did we or our ancestors become so, and will we ever cease to be so? Ellsworth claimed in his essay that there have never been any successful or lasting matriarchal societies, but absence of evidence isn’t evidence of absence, and of course it would not be of interest to him to mention the controversial but undeniably thought-provoking finds at Çatalhöyük suggesting plenty of goddess-worship. As I’ve often pointed out, the double male god-worship that constitutes Christianity was both born of and a template for thousands of years of patriarchy, still championed by the Catholic Church, so it’s intriguing to wonder about the society around Çatalhöyük, a mere 9,000 years ago. Believing in females with godly powers just doesn’t fit with a male-dominated society, and even those who argue against evidence that the undoubtedly remarkable society that created Çatalhöyük was matriarchal tend to argue for gender egalitarianism, which is remarkable in itself (though I’ve read anthropological studies on some Australian Aboriginal societies that have come to similar conclusions).
All of this makes me wonder again about early humans and their ancestors, Australopithecus and the like, especially considering that bonobos are clearly matriarchal and chimps are clearly patriarchal. Of course, size matters, pace bonobos, and it has recently been found in a study published last year that both A. afarensis and A. africanus, and especially the former, were more sexually dimorphic than present-day humans. But size matters less in the modern WEIRD world, where brute strength is of decreasing importance. I suppose these days we should be looking more at brain size, or rather brain complexity, and I very much doubt if we found any real difference there, which is doubtless why nobody much studies gender-based brain complexity, whether in dogs, cats or humans (I did once have a university friend who seriously asserted that men were naturally more intelligent – and she spoke of neurological complexity – than women; but she was young, and I let it pass, probably due to shock).
Generally, though, I feel optimistic about the greater empowerment of women in the future (the future is long, and I’m getting old, so I’m not worried about being proved wrong). This in spite of Trump and Putin and the Ayatollahs and the Sudanese and so many other African and Middle Eastern nations/regions. We describe them as living in the past for a reason. And Australia, far from the madding crowd of backward-facing nations, with more and more women in government, both nationally and in my home state, can and hopefully will set a small example that exhausted and disillusioned humanists elsewhere might take notice of…
References
Angela Saini, The Patriarchs: how men came to rule, 2023
the language apes – how we differ from bonobos etc
It seems that language is what separates us from every other species, and what has enabled us to dominate our planet. I suppose that’s stating the obvious, but how this language feature of ours evolved isn’t so obvious, as we can’t examine the brains of our more recent hominin ancestors, or listen to them talk, if they could, to connect all the dots. All we have to go on is an increasingly detailed knowledge of the neurological correlates to human language, and similar brain regions in chimps and bonobos. It’s an enormously complicated subject for the brain of a near 70-year-old ignoramus to dive into, so let’s do it.
What is ‘theory of mind’? It’s the ability to attribute mental states to others. We can do this with dogs and cats and other creatures we’re familiar with, in a vague way, but our fellow humans communicate this – not always accurately or honestly of course – with language. Certainly language is a tool that gives us an incalculably enormous advantage over other species, and we have created many thousands of them – languages, that is. It helps that we have brains some three times the size of our closest living relatives, but size isn’t everything, as we know, for example, from corvids and other smart species.
So we’ve been studying certain areas of the brain, such as Broca’s area, involved in language production, and Wernicke’s area (language reception) for many decades, and have found similar regions in other primates, though there are important differences. The human Broca’s area is larger in the left than in the right hemisphere, and there are similar but different enlargements for the left Wernicke’s area. The same asymmetry exists for their smaller, less developed analogues in other primates. Interestingly, left-handed types, like myself, have less asymmetry (or I’d prefer to say, more symmetry) than right-handers.
Sadly, we can’t study the brains of Neanderthals or any other extinct hominid in close relation to H sapiens to determine whether they had anything like our language skills, or indeed whether the first members of our species had them. According to AI (never lies), gathering info from such sources as the Australian Museum, Reddit, Wikipedia, Science Daily and Discover Magazine, ‘complex’ language (as opposed to complex language) was in operation among humans from 200,000 to 50,000 years ago, so it’s all a bit vague.
Exploring the issue by way of brain processes is more than problematic because I can’t see how we’ll ever have evidence outside of modern H sapiens, but what about the physical structures required to produce speech? There’s a difference, at least in my mind, between speech and language in that speech doesn’t necessarily involve grammar, it just starts with vocalisations representing objects, states (fear, pleasure, anger, warning etc). To produce these requires particular ‘hardware’. Here’s AI again:
The ability to speak required specialized “hardware” that differs significantly from other primates:
- Lowered Larynx: In humans, the larynx (voice box) is positioned lower in the throat, creating a larger space (the pharynx) that allows for a wider range of resonant sounds.
- Tongue and Mouth: Unlike other mammals, the human tongue is thick, muscular, and almost circular, allowing it to move vertically and horizontally to shape complex sounds like vowels.
- Breath Control: Humans evolved finer control over the muscles used for breathing, which is necessary to sustain the long exhalations needed for sentences.
The third item mixes hardware with neural developments, no doubt, but our current and perhaps permanent inability to trace these developments back in time is teasingly frustrating.
One interesting finding has to do with the FOXP2 gene, aka ‘the speech gene’, which we share with Neanderthals. It’s so named because it encodes the FOXP2 protein (Foxhead box protein P2), which is found in many vertebrates, and is associated with vocalisation, including birdsong and echo-location.
References
https://med.stanford.edu/news/insights/2025/09/speech-gene-foxp2-huntingtons-wysocka.html
a closer look at bonobos, enfin
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
discovering the disappearing simian sulcus in humans
dropping off the perch? the lunate or simian sulcus in humans and chimps, FWIW
As an amateur everything, I’ve decided to be more upfront about my amateurishness instead of hiding behind those fictional gropers after truth, Canto and Jacinta, who’ve become sick of being manipulated little poppets. So for the time being I’m going to focus on aspects of evolution as that’s where my reading is currently taking me.
I’ve noticed on my shelves a book, The antecedents of man, by W E Le Gros Clark, FRS, first published in 1959, this second revised edition published in 1962. I don’t know how it came into my possession, I certainly didn’t buy, borrow or steal it (though the third might be the most likely option, but that would’ve been in another life). Mr Le Gros Clark, FRS (aka Sir Wilfrid, bien entendu) was clearly no low-class plodder, and has deserved a wee Wikipedia bio. He was a professor of anatomy at Oxford, but his chief interest was evolution, on which he published many papers (and at least one book, unmentioned in Wikipedia). He was one of the three scholars who exposed the Piltdown Man hoax in 1953.
I’m finding the book, thus far, complex but intelligible, and stimulating. And so to the simian sulcus, something new to me:
In the brains of apes and monkeys there is a very distinctive folding of the cerebral cortex which is often called the simian sulcus. A superficial study might suggest that this is a specialised trait peculiar to apes and monkeys, and one that has been avoided in the evolutionary development of the human brain (which in this particular feature, therefore, would appear to be less specialised). In fact, however, traces of the sulcus are commonly to be found also in the human brain (though they are extremely variable – a characteristic feature of degenerative structures in general), and in the brains of some human races it may on occasion be almost as well developed as it is in the anthropoid apes. It can be inferred, therefore, that the simian sulcus is a primitive element of the brain of the higher Primates and that it has undergone a secondary retrogression in the modern human brain.
So far, so complicated, but I noticed the term ‘some human races’ and their similarity, as regards this feature, to the anthropoid (human-like) apes. Of course, humans are apes, so Clark (to bring the name down a notch) presumably means our ape cousins and ancestors. Race, however, is now regarded as a ‘folk’ category, abandoned by the scientific community.
So what do we now think or know about the simian sulcus? Also known as the lunate sulcus, it’s a ‘fissure in the occipital lobe’, that’s to say, the lobe at the back of the brain, primarily associated with vision. It’s one of the four major lobes of the cerebral cortex, the others being the frontal, temporal and parietal lobes. The lunate sulcus is ‘variably found’ in humans (it’s generally larger in other apes and monkeys) and has been ‘pushed back’ due to the shift in the V1 area, the primary visual cortex or Brodmann area 17. This in turn may have been pushed back to allow for the expansion of the brain’s language regions in the prefrontal cortex and parietal lobes. Let’s face it, the prefrontal cortex is where the human action has been in the pst several millennia.
So, continuing with definitions, what’s a sulcus and what does lunate mean? The cerebral cortex consists of folded grey matter, and the material at the top of the fold is called the gyri, while the grooves at the bottom are called sulci. The term lunate means ‘crescent-shaped’ and there are questions as to whether a lunate sulcus even exists in modern humans, as it has been in a sense obliterated by the relatively rapid expansion and development of the cerebral cortex, a feature unique to the human species. This expansion may have occurred to the slight detriment of the visual cortex in the occipital lobe (actually a pair of lobes separated by a cerebral fissure). So, basically, the lunate sulcus seems to have become increasingly difficult to differentiate from other sulci, and its existence and/or significance is a matter of individual variation in the no doubt highly variable brains of modern humans, not forgetting that said brain is the most complex organ in the known universe (which is but an infinitesimal fraction of the unknown one).
All very fascinating, and I just want to live forever….
References
W E Le Gros Clark, The antecedents of man, 2nd edition, 1962
bonobos, an outlier in the primate world, and yet…
any excuse for a nice bonobo pic
In trying to develop a bonobo world with human characteristics, or perhaps more realistically a human world with bonobo characteristics, I suspect it’s best not to start by disparaging the male (human) brain as ‘unevolved’ or distinctly inferior to that of the female – something I heard in an interview with a male psychotherapist recently. Firstly, it make no sense to say that a brain, or a human, or a dog, a dolphin or a donkey is ‘unevolved’. This is a fundamental misunderstanding of evolution, which is about ongoing change to most effectively adapt to a changing environment. And this includes social environments. The Andamanese, a tiny population living on scattered islands in the Bay of Bengal from about 25,000 years ago, and driven almost to extinction in the 18th and 19th centuries by the introduction of measles, influenza, pneumonia, and alcohol, have recovered somewhat and preserve their simple lifestyle via extreme hostility to interlopers, and are no more unevolved than were the ancient Hominins who once lived on the Indonesian island of Flores. It’s true, of course, that evolution can be competitive, and some species – or sub-species or cultures – can win out over others, but to describe this as due to being ‘more evolved’ rather over-simplifies matters. Each species evolves to survive and thrive in its own niche, and may thrive in that way for an eon, but may be swept away by another invasive species, or by relatively sudden climate change, or by very sudden events such as meteor showers or volcanic eruptions.
In the same interview, the psychotherapist described the male brain, including his own, as sick and in some sense mentally unbalanced compared to the female brain. And you can go onto YouTube and other sources to find dozens of mini-lectures and expert opinions on the male versus the female brain.
However, it might surprise people to know that there is no categorical difference between the male and female brain, at least not in the sense there is, usually, between a male and female body. Put another way, if a neurologist with decades of experience was given a disembodied brain and asked about its sex, she wouldn’t be able to say, categorically, whether it was male or female. There are statistical differences – males have, on average, more ‘grey matter’ (individual neurons) while females have more ‘white matter’ (myelinated axons connecting neurons) – but there is great diversity within this frame, which should hardly surprise us. Our brains develop within the womb, subject to the diet and environmental conditions of our mothers, and genetic and epigenetic factors have their role to play. In early childhood neural connections multiply rapidly in response to a multitude of more or less unique conditioning factors, and new connections continue to be made well into adulthood, resulting in more than eight billion tediously unique noggins clashing and combining in tediously unique ways.
So, to me, it’s behaviour that we need to start with. Of course I’m interested in the nervous system and the endocrine system of bonobos, but that’s because I’m first and foremost taken by their behaviour. I’m encouraged by what I see as changes in male behaviour in the WEIRD world, but then I was told recently that male violence against women is actually increasing. Of course these things are hard to measure as not all violence is reported, and the very concept of violence may be disputed, but a quick look at figures for Australia, which surely qualifies as a WEIRD nation, suggests that my sense of things is right:
Experiences of partner violence in the 12 months before the survey (last 12 months) remained relatively stable for both men and women between 2005 and 2016. However, between 2016 and 2021–22 the proportion of women who experienced partner violence decreased from 1.7% in 2016 to 0.9% in 2021–22.
Australian Institute of Health and Welfare (Australian Government)
Whatever one might think of these figures, there’s little evidence of an increase in male violence (against females), at least here, in this teeny WEIRD nation. So maybe it’s places like Australia, and New Zealand, far from some of the major global threats, slowly building a multi-ethnic culture (largely proof against the massive social divisions stifling the divided ‘USA’), an oasis of 26 million compared to the bonobo oasis of maybe 20 thousand, a region that still likes to think of itself as ‘young and free’, and prepared to experiment with our politics and culture, maybe it’s here that bonobo-style caring-and-sharing behaviour can start to make some headway (but of course even as I write this it strikes me as ridiculous).
The trouble, of course, is that it’s hard to focus on such a possible future without sex rearing its not-so-ugly head. In human culture we’re obsessed with beauty (both male and female) in a positive way (though bad luck if you happen not to be physically attractive), and obsessed with sex in a much more confused but largely negative way (‘licentiousness’, a very human term, is generally condemned in all societies). Do bonobos distinguish between each other in terms of ‘good looks’? If not, when did we, or our ancestors start to do so? There has of course been much talk of ‘sexual selection’ in anthropology, going back to Darwin, but in bonobo society, where female-female sex predominates but sex, generally in the form of mutual masturbation, occurs among and between all age groups and genders, sexual selection (for breeding purposes) would only occasionally operate. And after all, masturbation is about one’s own erogenous zones, which, like being tickled, are best aroused by another, no matter what they look like. Think of a dog masturbating on your leg.
One might argue that religion has a lot to answer for, in so firmly linking sex to shame and transgression, while another might argue, along with Freud, that sexual sublimation was a necessary prerequisite for human civilisation. I’m still trying to work out my own view on this, but I’d surmise that the link between sex and shame existed in humans long before the Abrahamic religions took it to extremes. And unfortunately, much of the online material on our history of sex and shame contains a lot of bollocks, so I’ve reached a dead end there.
So here’s some guesswork. It may have started with the wearing of minimal clothing to protect the reproductive parts, both from damage and from gawkers – out of sight, out of mind. Perhaps this was initiated by females, but more likely (in the case of female genitalia) by males. On this topic I’ve often read claims that pre-agricultural or non-agricultural societies were less patriarchal, and I’ve even adopted that view myself, but I suspect the difference was only in degree, not in kind.
As to patriarchy itself, consider this. Bonobos and chimps split from each other 2 million years ago, at most. From that time on, bonobos survived and thrived in a relatively circumscribed, densely forested region south of the Congo. Chimps on the other hand are more numerous and wide-ranging (with more varied habitats), and are currently divided into four sub-species, from the west to the east of sub-Saharan Africa, and their number in the wild, though hard to determine with any precision, is generally estimated as about ten times that of bonobos. And all chimps are patriarchal.
The dating of the CHLCA (the last chimpanzee-human common ancestor, and note that bonobos are excluded from this reference) has been a subject of ongoing debate and analysis. Here’s how Wikipedia puts it:
The chimpanzee–human last common ancestor (CHLCA) is the last common ancestor shared by the extant Homo (human) and Pan (chimpanzee and bonobo) genera of Hominini. Estimates of the divergence date vary widely from thirteen to five million years ago.
Obviously, this was before the chimp-bonobo divergence, and considering speculation by anthropologists that bonobo ‘female power’ might be linked to a more frugivorous diet and less of a hunting-killing lifestyle (due to their restriction to an area rich in fruits, nuts, seeds and small game), it seems likely that the CHLCA was already more patriarchally inclined. Consider also that the genus Homo sapiens, long believed to date to no more than 200,000 years ago, and arising in eastern sub-Saharan Africa, has recently been dated to over 300,000 years from remains found in faraway Morocco. That suggests the traversing of vast regions, and a diet much richer in meat than that of bonobos. So, while the hunter-gatherer term has been passionately disputed by some, it’s generally accepted – and it makes sense to me – that there was some division of labour, as implied by the term, and that it would likely be largely gender-based. So, our history, and our ancestry, has been almost entirely patriarchal.
However, this doesn’t define our future. Patriarchy is breaking down in the WEIRD world, albeit slowly. And there are, depressingly, many forces in opposition to female empowerment, especially in the non-WEIRD world. I’ll focus on that in my next post.
Homo naledi – an enigma shrouded in mystery
remains of at least 18 individuals found
Jacinta: So, having watched the much-discussed Netflix film, Cave of bones, describing and indeed taking us into the depths of the Rising Star underground cave system, frequented by the very enigmatic and so controversial Homo naledi species of hominin, and knowing that there is ‘blowback’ (presumably an Americanism) about the claims made re burial practices and lithic tool-making dating back a possible 300,000 years by this small-brained creature, remains of which have never been found above-ground, as far as I’m aware, we’ve decided to do one of our shallow dives into the claims and counter-claims…
Canto: So the researchers featured in the film include Lee Berger and John Hawkes, both names to reckon with in paleoanthropology, and they present a claim that they found evidence of burial practice in the Dinaledi Chamber at the barely accessible base of the complex Rising Star system. The film, I have to say, is edge-of-the-seat absorbing, though its intense focus on this one possible child-burial site, and the possible stone tool buried with the child, means you’d be forgiven for not having a clue about the broader perspective. That’s to say, that –
the Dinaledi Chamber of the Rising Star Cave has yielded 1550 identifiable fossil elements – representing the largest single collection of fossil hominin material found on the African continent to date.
Jacinta: Yes, that’s from University College London, but are they all from H naledi, I wonder? Apparently so, according to the Australian Museum:
The remains of at least 15 individuals were found in the Rising Star cave system in South Africa and announced as a new human species in 2015. The remains are the largest assemblage of a single hominin species yet discovered in Africa. Homo naledi combines primitive with modern features and is not a direct ancestor of modern humans.
They’ve been dated to between 335,000 and 236,000 years, but that presumably only indicates the dates in which the cave system was used. In another underground cave nearby (Lesedi cave), remains of at least two adults and a juvenile were found – also H naledi. Attempts to extract DNA have so far failed. And the fact that no fossils of these species have been found elsewhere isn’t perhaps surprising, caves being the place for such finds. But there’s hope for the future, according to the museum:
As only small parts of both caves were excavated, many more bones remain for future expeditions to recover.
Canto: So, in the film, Berger, Hawkes and their team reflect at large on ancient burial practices and religion and how far back they can be traced in hominin ancestry, but a very recent article in Nature throws something of a wet blanket over all this conjecture.
Jacinta: Yes, the film, which I have to say is very engaging, and even quite emotional for me, for some reason, came out at about the same time as peer reviews of an article by the researchers in an apparently controversial journal, eLife. These reviews were all pretty negative, as reported in Nature. Here’s one response:
“I want to understand how the H. naledi fossils got there. They are very important fossils, and critical to understanding human evolution,” says Jamie Hodgkins, a palaeoarchaeologist at the University of Colorado Denver, who was one of the study’s four reviewers for eLife. However, “there just wasn’t any science in the paper ultimately”.
And being still under the sway of the film, I feel a bit defensive for Berger and co. I know that Berger has a bit of a rep for being a rebel in the field, but I was interested in the possibilities raised by the film, which are somewhat similar to the conjectures being raised by Rebecca Wragg Sykes in her Neanderthal book, Kindred, especially in the chapter entitled ‘Many Ways to Die’, which explores possibilities re Neanderthal burial practices, as well as other ways of treating the dead, such as a kind of devotional cannibalism…
Canto: Mmmm, tasty.
Jacinta: Sykes cites many cases of Neanderthal cannibalism, and speculates as to the purpose. She considers that it was rarely out of hunger, and makes this interesting observation re our favourite rellies:
Bonobos once again provide an intriguing counterpoint. There are no recorded infanticides, yet several cases of mother-infant cannibalism exist, which also featured meat-sharing. In one situation, following a baby’s natural death the group spent an entire morning eating much of the body, before the mother carried away the remnants on her back.
Kindred, p 309
Canto Yes, well, I don’t think we’ve reached that stage of advancement.
Jacinta: Anyway, Sykes doesn’t go beyond speculation as to Neanderthal burial, but Berger et al really push their case hard, in their paper for eLife, titled ‘Evidence for deliberate burial of the dead by Homo naledi’. And via a very long and painstaking video analysis of the paper and its peer reviews by the intellectually and otherwise alluring ‘Gutsick Gibbon’ (aka Erica, I believe), which I’m only halfway through watching, I’ve become convinced that the evidence presented in the film isn’t convincing. As to the paper itself, I’m only getting snatches of it through the commentary. I was prepared to believe, before watching this video, that there was a bit of professional jealousy going on, due to Berger’s paleontological superstardom (given that the H naledi discovery, which Berger more or less owns, really is pretty mind-blowing), but the reviewers, being expert in such essential fields as archaeothanatology, sedimentology, micromorphology, palaeo-osteology and commonsensology, really focus on the failings, the lack of support for bold assertions, in very professional and indeed enlightening ways.
Canto: Yes, it actually made me want to read more papers on some of these subjects, and to be involved – to be young would be very heaven… The major theme of the response, to me, was ‘more research needed’, and especially from more specialised experts. And the film made me aware of how difficult – and dangerous – in situ research is for this site.
Jacinta: Yes it seems to be only the beginning with Homo naledi. But I think the criticism was more pointed, along the lines of ‘extraordinary claims require extraordinary evidence’. The signs of possible Neanderthal burials, which Sykes is quite carefully speculative about, at various sites (Sima de las Palomas, La Ferrassie, Shanidar), are all dated to less than 50,000 years ago, while the H naledi ‘burials’ – or is there only one? – are more than 5 times further back. Unlikely – though the brain size thing is a bit of a red herring to me. Think H floresiensis – too primitive to survive, or just island dwarfism?
Canto: Who knows, but it’s a good point. Island dwarfism occurred in the past, e.g. with elephants, but were they made less intelligent thereby? Surely not. And corvids have walnut-brains, with as many neurons as some monkey species. Size isn’t everything, check this out.
Jacinta: Please put it away. And nobody is saying that H naledi were dwarf hominins. Anyway, the major takeaway, comme on dit, is that this is just the beginning for Homo naledi. They need to be more disciplined about their claims, and maybe Berger’s enthusiasm, as evidenced in the Netflix film, is getting the better of his professional judgement. There will be further exploration of this challenging environment, and more and more incisive technology will be developed, as alway seems to happen.
Canto: So, in Gutsick Gibbon’s video we get to Berger at al’s response to the criticisms, with their main argument (about their contention that this was a deliberate burial) seeming to be that ‘there may be more types of burial on earth than are ever comprehended in your philosophy’, if I may murder Shakespeare, and that it might even be expected that a species far removed from H sapiens would have such quite different burial processes. And yet they’re claiming recognition of these more or less unrecognisable processes.
Jacinta: Yeah, it’s a bit like saying ‘there are aliens among us, but people are too dumb to see them – but we can see them’. Or maybe not. As Ms Gibbon points out, why didn’t the team stick with the original null hypothesis, that this was a sort of dumping ground, albeit a sorta respectful one, for their dead? That null hypothesis, by the way, might sit somewhere in the grey zone between, or sort of combining, the cultural and the natural.
Canto: Yes, Gutsick Gibbon weighs in on the question of whether we should look at sites of early hominins such as Australopithecus with more of a cultural null hypothesis than a natural one. She thinks ‘natural’, but I’d be more agnostic, partly because I’m too ignorant of palaeontology to take a strong stand, but also, as with my interest in bonobos, I’m prepared to take the widest possible view of culture.
Jacinta: Yes, in that disturbing chapter of Kindred which presents quite extensive evidence of Neanderthal cannibalism, and explores the reasons for such behaviour, Sykes suggests something in that cultural/natural grey zone. Again, she compares observed behaviour of bonobos and chimps:
For both bonobos and chimpanzees, the bodies of the dead evoke many emotions. Even if the process often begins with trauma and confusion, typically corpses shift to a liminal status; not alive, but equally not a lump of meat. They’re more intensively manipulated than hunted animals, and carried for longer. In some – if not all – cases, the eaters must know what and who they’re consuming. Cannibalism is very probably a powerful means by which individuals and groups process the impact not only of killings carried out on emotional impulses, but other deaths too. In other words, it’s about grieving.
Kindred, pp 309-10
Canto: Yes, I’m not sure what to think of that thesis, I’m not entirely convinced, but my mind is open and my brain’s not falling out. We’re only at the beginning, with H naledi and so much more…
References
https://www.netflix.com/au/title/81473682
Kindred: Neanderthal life, love, death and art, by Rebecca Wragg Sykes, 2020.
https://australian.museum/learn/science/human-evolution/homo-naledi/
humans and neanderthals and chimps and bonobos
We now know for sure that humans and neanderthals interbred. How much, we don’t know, nor do we know the nature of the interbreeding. The spectrum presumably goes from love and flowers to warfare slaughter and rape, and I recently heard one pundit arguing for the latter option, and I tend to agree, especially given what information ancient DNA is providing about human populations over the last 50,000 years or so – that’s to say, it appears that it was much less a case of cultures and practises spreading from one place to another than populations replacing earlier populations. And it may well be that we’ll get a more gory-detail picture of human-neanderthal intimacies in the foreseeable.
We’ve also learned that chimps and bonobos bonked after their separation due to the creation of the Congo River between one and two million years ago. I wish I’d been there to see it. My guess is that would’ve been far less traumatic, though perhaps not too lovey-dovey either.
So if we accept that violence was involved – who were the perps and who the victims? My feeling is that humans were the rapists, for the simple reason that we’re still here. Neanderthals disappeared some 40,000 years ago, though a remnant population appears to have survived in the Iberian Peninsula for another few thousand years. With chimps and bonobos it was probably more fifty-fifty, though I’m prepared to accept that nothing is ever that simple.
The fact that many of us – I don’t know about me – have some neanderthal DNA is probably a mixed blessing (some genes for absorbing sunlight may have predisposed us to skin cancer, others may have affected our ability to process carbs), but it hasn’t prevented us from quadrupling our population in the last century. And since we’ve produced the first whole-genome sequence of the neanderthal genome, they’ll soon be back with us, so no worries. Unfortunately, their memories of what we did to them will have been wiped, but we’re working on it.
Seriously, humans most likely were one of many contributors to neanderthal extinction. The two species shared similar European territories for the last few millennia before their disappearance, with human numbers apparently growing as neanderthals dwindled. Maybe they were out-competed in hunting big game, and small, as their diets would’ve been more or less identical to ours. Studies of neanderthal teeth from different environments (north-west and south-west Europe) indicate that they were opportunistic dieters, eating more meat in some regions, less in others, not all-out carnivores as previously thought, so this brings them even closer in line with humans, and in competition with them when habitats overlapped. And if anything, ancient DNA is telling us that our human ancestry was even more violent than previously thought – and we’ve long known how bad it was.
We don’t have any direct evidence that modern humans killed neanderthals, and we may never have such evidence. Professor Chris Stringer of London’s Natural History Museum argues that, as we now know that both species inhabited Western Europe for about 10,000 years before neanderthals died out, there was more likely a kind of awkward balance between the two species for much of that time. So, maybe killing but not outright extermination. Of course the same can be said for the large mammals that humans hunted. There was never any intention to exterminate them, but the pressure they were put under did for them in the end.
With chimps and bonobos, that seems to me even more of a mystery. What does a chimp look like to a bonobo, and vice versa? Most of us wouldn’t be able to tell one from the other, but that’s because we’re humans. In the past, Europeans used to say that all Chinese looked the same. Back in Darwin’s day and before, the people of Africa, Australia and Indonesia were collectively termed ‘savages’ by ‘white’ people. It’s taken a while for us dumb humans to become more discriminating. So it’s hardly surprising that bonobos weren’t recognised as a separate species from chimps until well into the twentieth century. Speciation itself is a rather more complicated and questionable affair than it was thought to be in the time of Linnaeus – and it wasn’t particularly simple then. Here’s an interesting quote from a Science article on chimp-bonobo interbreeding:
These findings come on the heels of other genome analyses—such as between coyotes, dogs, and wolves—showing such gene flow between species. “The more we look at genomes, the more it seems to be found,” [Professor Jim Mallet] says. “It’s going to be pretty common,” he predicts.
An article in earth.com, a popular science site, linked below, provides a summary of the physical and social differences between bonobos and chimps, though I can’t vouch for its accuracy – for example it claims that bonobo males and females are ‘much closer in size’ than chimp males and females. I’d always thought that the sexual dimorphism difference was slight, now I’m not so sure. Another interesting difference, that I’d not noticed before in my reading, is that bonobos have dark faces from birth, whereas chimps’ faces are lighter, and darken with age. I can well believe though that there are individual differences, in this as in robustness and gracility, bonobos being in general more gracile. Of course, chimp males are more dominant, so I can well imagine chimp-bonobo interbreeding to be a violent affair. And with bonobo females tending to stick together it would’ve been difficult to pick off an isolated female. Perhaps we should build a few Pan-friendly bridges across the Congo River and see what happens….
References
https://www.americanscientist.org/blog/science-culture/neanderthals-in-prime-time
https://www.science.org/content/article/chimps-and-bonobos-had-flings-and-swapped-genes-past
https://www.earth.com/earthpedia-articles/chimpanzees-vs-bonobos-whats-the-difference/
Did bonobos do it with chimps? Well, duh
bonobos or chimps? Or both? Or neither? What’s in a name…?
Canto: So we’ve been learning than we did it with Neanderthals, and that Neanderthals did it with Denisovans, and I remember hearing an anthropologist or palaeontologist saying that it’s likely that our split with our last common ancestor with chimps and bonobos – they call it the CHLCA (chimp-human last common ancestor, eliminating bonobos altogether, sigh) – wasn’t necessarily a clean break, which surely makes sense.
Jacinta: Well, yes, as we’ve read, the split was caused by the relatively sudden creation of the Congo River, but the word ‘relatively’, is, well, relative. So this raises the question of speciation in general. Think of those Galapagos finches that so intrigued Darwin. All about differently-shaped beaks, but it didn’t happen overnight.
Canto: Right, so here’s what a website with the rather all-encompassing title “Science” says about our topic:
Tens of thousands of years ago, modern humans slept around with Neandertals and swapped some genes. Now, it turns out one of our closest living relatives, chimpanzees, also dallied with another species. New research reveals that chimps mixed it up with bonobos at least twice during the 2 million years since these great apes started evolving their own identities. Although it’s not yet clear whether the acquired genes were ultimately beneficial or harmful, the finding strengthens the idea that such cross-species mating played an important role in the evolution of the great apes.
Jacinta: Interestingly this Congo River separation which led to a completely different species was repeated by other separations which led to four sub-species of chimps. Which leads me to wonder – what’s the difference between a new species and a sub-species? Why are bonobos ‘deserving’ of being called a different species?
Canto: Well the Science article has some fascinating further information. This was the work of Christina Hvilsom and colleagues, described as ‘conservation geneticists’. They were using any genetic differences they could find to work out where particular chimps were being caught or hunted. But, since the interbreeding of humans and Neanderthals, proven by DNA, had hit the headlines, Hvilsom wondered about the DNA of chimps. So, using the same methods that uncovered Neanderthal in humans –
she and her colleagues determined that 1% of the central chimpanzee’s genome is bonobo DNA. The genetic analysis indicates that this inbreeding happened during two time periods: 1.5 million years ago bonobo ancestors mixed with the ancestor of the eastern and central chimps. Then, just 200,000 years ago, central chimps got another boost of bonobo genes, the team reports today in Science. In contrast, the western chimp subspecies has no bonobo DNA, the researchers note, suggesting that only those chimps living close to the Congo River entertained bonobo consorts.
Jacinta: What this highlights, more than anything to me, is the importance and excitement of genetic and genomic analyses. Not that we’re experts on the topic, but it has clearly revolutionised the science of evolution, complicating it in quite exciting ways. Think again of those Galapogos finches. Separation, some interbreeding, more separation, less interbreeding, but with a few kinks along the way.
Canto: And we’re just beginning our play with genetics and genomics. There’s surely a lot more to come. Ah, to live forever…
Jacinta: So how did they know some inbreeding occurred? Can we understand the science of this without torturing ourselves?
Canto: David Reich’s book Who we are and how we got here tells the story of interbreeding between human populations, and how population genetics has revolutionised our understanding of the subject. With dread, I’ll try to explain the science behind it. First, the Science article quoted above mentions a split between bonobos and chimps 2 million years ago. Others I’ve noted go back only about a million years – for example a Cambridge University video referenced below. The inference, to me, is that there was a gradual separation over a fair amount of time, as aforementioned. I mean, how long does it take to create a major river? Now, I can’t get hold of the data on chimp-bonobo interbreeding in particular, so I’ll try to describe how geneticists detect interbreeding in general.
I’ll look at the human genome, and I’ll start at the beginning – a very good place to start. This largely comes from Who we are and how we got here, and the following quotes come from that book. The human genome consists of a double chain of 3 billion nucleobases, adenine, cytosine, guanine and thymine. That’s 6 billion bases (often called letters – A, C, G and T) in all. Genes are small sections of this base chain (called DNA), typically a thousand or so letters long. They’re templates or codes for building proteins of many and varied types for doing many different kinds of work, although there are segments in between made up of non-coding DNA.
Researchers have been able to ‘read’ these letters via machinery that creates chemical reactions to specific DNA sequences:
The reactions emit a different colour for each of the letters A, C, G and T, so that the sequence of letters can be scanned into a computer by a camera.
What anthropologists want to focus on are mutations – random errors in the copying process, which tend to occur at a rate of about one in every thousand letters. So, about 3 million differences, or mutations, per genome (3 billion genes, coding or non-coding). But genomes change over time due to these mutations and each individual’s genome is unique. The number of differences between two individuals’ genomes tells us something about their relatedness. The more differences, the less related. And there’s also a more or less constant rate of mutations:
So the density of differences provides a biological stopwatch, a record of how long it has been since key events occurred in the past.
As Reich recounts, it was the analysis of mitochondrial DNA, the tiny proportion of the genome that descends entirely down the maternal line, that became a corner-stone of the out-of-Africa understanding of human origins, which had been competing with the multi-regional hypothesis for decades. ‘Mitochondrial Eve’ – a rather ‘western’ moniker considering that the Adam and Eve myth is only one of a multitude of origin stories – lived in Botswana in Southern Africa about 160,000 to 200,000 years ago, given the variability of the genomic ‘clock’ – the mutation rate.
So, what does this have to do with chimps and bonobos? Well, The exact detail of how Hvilsom et al proved that their (slightly) more recent interbreeding events occurred is hidden behind a paywall, and you could say I’m a cheapskate but the reality is I’m quite poor, trying to bring up seven kids and a few dozen grandkids in a home not much bigger than a toilet, so… but truthfully I’m just getting by, and I just want to know in general the techniques used.
First, they have to find ancient specimens, I think. But, in a video referenced below, they raised the question – Can we ‘excavate’ ancient DNA from modern specimens? We’ve learned that many modern humans have a certain percentage of Neanderthal DNA, say around 2%, but each person’s 2% may be different. Aggregating those different segments can, if we analyse the genomes of enough humans, create a whole Neanderthal genome, though not one of any Neanderthal who ever lived! At least that’s how I’m reading it, in my dilettantish way. So what exactly does this tell us? I’m not at all sure – it’s a relatively new research area, and completely new to me.
The presenter of this video uses the heading, at least at the beginning of his talk, ‘A little Archaic introgression goes a long way’. So now I need to know what introgression means. A quick look-up tells me it’s:
‘the transfer of genetic information from one species to another as a result of hybridization between them and repeated backcrossing‘.
I’ve bolded two key words here. Hybridisation, in mammals, is ‘breeding between two distinct taxonomic units’. Note that the term species isn’t used, presumably because it has long been a questionable or loaded concept – life just seems too complex for such hard and fast divisions. Backcrossing seems self-explanatory. Without looking it up, I’d guess it’s just what we’ve been learning about. Canoodling after speciation should’ve ruled canoodling out.
But, looking it up – not so! It’s apparently not something happening in the real world, something like backsliding. But then… Here’s how Wikipedia puts it:
Backcrossing may be deliberately employed in animals to transfer a desirable trait in an animal of inferior genetic background to an animal of preferable genetic background.
This is unclear, to say the least. How could an animal, even a human, deliberately do this? We could do it to other animals, or try it, based on phenotypes. We’ve been doing that for centuries. What follows makes it more or less clear that this is about human experimentation with other animals, though.
Anyway, I’m going well off-topic here. What I wanted to do is try to understand the proof of, or evidence for, bonobo-chimp interbreeding. I accept that it happened, well after the split between these two very similar-looking species. What could be less surprising? Along the way I’ve been reminded inter alia, of homozygous and heterozygous alleles, but I’ve been frustrated that straightforward information isn’t being made available to the general public, aka myself. I’ll pursue this further in later posts.
Jacinta: What a mess. Phenotype isn’t everything my friend. To a bonobo, a chimp probably looks like a neanderthal – a real bonehead… They probably only had sex with them out of pity. ‘Boys, we’ll show you a good time – like you’ve never had before.’
References
https://www.science.org/content/article/chimps-and-bonobos-had-flings-and-swapped-genes-past
David Reich, Who we are and how we got here, 2018
https://www.newscientist.com/article/2110682-chimps-and-bonobos-interbred-and-exchanged-genes/
love, monogamy, marriage and bonobos
To claim that a union founded on convention has much chance of engendering love is hypocritical; to ask two spouses bound by practical, social and moral ties to satisfy each other sexually for their whole lives is pure absurdity.
Simone de Beauvoir, The Second Sex, p 478.
Discuss…
Canto: So we’re reading Beauvoir’s The second sex, inter alia, and though things have changed a bit in the WEIRD world over the past seventy-odd years, the section titled ‘The Married Woman’ does give something of a historical perspective, via the writings of such males as Montaigne, Balzac, Diderot and Kierkegaard, on the perceived differences between love and marriage and the problems that arise from these differences.
Jacinta: Yes, and marriage and monogamy are something of a mystery, historically, in spite of arguments such as those of Ferdinand Mount in The subversive family, that they are a more or less natural element of human life. We don’t know much about the state of affairs of early Homo sapiens or their ancestors and extinct cousins vis-a-vis monogamy. We do know that our closest living relatives, the bonobos and chimps, aren’t monogamous. And as to the claim, made by some, that humans are meant to be monogamous, that’s of the same type as, say, that humans are meant to be bipedal. No, it’s just something that we evolved to be, as some, but not all of us, socially evolved to be (more or less) monogamous.
Jacinta: The question is when? I suppose an obvious answer is when the concept of property became important, and the handing down of property to offspring. So that families started to become powerful rather than individuals. The beginnings of agriculture?
Canto: Some say division of labour may have played a part, though I’m not sure why…
Jacinta: Scientific American has an interesting online article from a few years ago reporting on studies that ‘aimed to find the best explanation for monogamy among three persistent hypotheses: female spacing, infanticide avoidance and male parental care’. So female spacing is just what it says: according to SciAm:
The female-spacing hypothesis posits that monogamy arises after females begin to establish larger territories to gain more access to limited food resources and, in the process, put more distance between one another. With females farther apart, males have a harder time finding and keeping multiple mates. Settling down with a single partner makes life easier, reducing a male’s risk of being injured while patrolling his territory and enabling him to ensure that his mate’s offspring are his own.
Canto: Females began to do that? In the bonobo world, female closeness was the key to their success – the females I mean, but perhaps also bonobos in general. It seems to me more likely that women would work in teams, helping each other to find and exploit resources, or am I being too hippy-happy-clappy?
Jacinta: Yeah maybe, but I note also the assumption here that males would have a hard time keeping multiple mates – the assumption being that early humans were already male-dominated.
Canto: Yes that quoted paragraph is all about the males… though to be fair most primate species are male-dominated. Still, one can’t assume…
Jacinta: Well, the proponents of this hypothesis did a statistical analysis of couple of thousand mammalian species, and found, apparently, that they started out solitary, but many, or some, switched to monogamy during their evolutionary history. How they proved that I’m not sure. They claimed that ‘monogamy most frequently occurred in carnivores and primates…’
Canto: Hang on. Isn’t it true that most primates are not monogamous?
Jacinta: Ahh, you’re probably thinking only of apes. There are hundreds of primate species, and they’re still being discovered. Three more were added in the last couple of years.
Canto: Shit! It’s all so hard to keep up with.
Jacinta: Lorises and lemurs, tarsiers and hatfuls of monkeys. Simians and prosimians, old world and new world, greater and lesser apes, etc. And actually, most primates are monogamous.
Canto: Well, I don’t think we should let it bother or constrain us. If we don’t feel monogamous, I mean individually speaking, we don’t have to be so.
Jacinta: But there are social constraints. They’ve loosened, no doubt, in the WEIRD world, but they’re there still. Besides, it’s convenient to settle down with one person, especially as you get older. It’s hard work trying to impress one partner after another into canoodling, what with rivalries and jealousies, and children who end up not knowing who’s what.
Canto: Well, yes – it does spice up life a bit, but too much spice can be overly acidic, or something. Still, I cling hopefully to the bonobo way…
Jacinta: Anyway, let’s get back to the second hypothesis – infanticide avoidance. I don’t think there’s much in this, re humans, but here’s the rationale:
Primates are uniquely at risk for infanticide: they have big brains that need time to develop, which leaves babies dependent and vulnerable for long periods after birth. And the killing of babies has been observed in more than 50 primate species; it typically involves a male from outside a group attacking an unweaned infant in a bid for dominance or access to females.
I suppose early hominids lived in smallish groups, like troupes of other primates, and I never considered that there’d be an alpha male among them, but I suppose it makes sense. But the bonobo part of me is in denial….
Canto: Well, warfare goes back a long way and capturing and raping women has always gone along with that, and it’s often been about capturing and expanding territory – e.g. Putin and Ukraine – and in those earlier times when resources were scarcer and harder-won, children, that’s to say the children of the defeated, would’ve been a burden. And the winners knew they could make more of their own with the captive women. It’s all quite plausible. I saw it in Empress Ki!
Jacinta: Hmmm. Having it off with captive women – essentially rape – doesn’t really fit with monogamy. In those Korean historicals you love there are wives and also concubines, and your alpha-maledom would be defined by the number of concubines you commanded, I’m guessing. So the male parental care hypothesis is most palatable to us moderns, I hope. Here’s what the SciAm site says:
When a baby becomes too costly in terms of calories and energy for a mother to raise on her own, the father who stays with the family and provides food or other forms of care increases his offspring’s chances of survival and encourages closer ties with the mother. A related idea… holds that the mere carrying of offspring by fathers fosters monogamy. Mothers have to meet the considerable nutritional demands of nursing infants. Yet for primates and human hunter-gatherers, hauling an infant, especially without the benefit of a sling or other restraint, required an expense of energy comparable to breast-feeding. Carrying by males could have freed females to fulfill their own energetic needs by foraging.
Canto: Yes, that’s a much more Dr Feelgood hypothesis, but interestingly this assumes an understanding of the relationship between sex and offspring. Males wouldn’t want to be caring for someone else’s kids, would they? And I’m sure I read somewhere that even some cultures living today, or at least not so long ago, aren’t clear about that relationship.
Jacinta: Well, and yet I’ve heard that bonobo females try to control who their adult sons mate with, as if they have an inkling… Bronislaw Malinowski (the first anthropologist I ever heard of) claimed that Trobriand Islanders thought that males played no role in producing children, but that’s been found to be a bit questionable. Seems plausible to me though. And something to aim for.
Canto: One thing anthropologists seem to say nothing about in these reflections on monogamy is love. This eternal bonding force that unites Romeo and Juliet, Antony and Cleo, Sonny and Cher…
Jacinta: Yeah, hormones they say. And when offspring come along, a certain force of duty, often reinforced by the community, or the State. So the male parent ends up staying, not really knowing whether it’s because he wants to or not. And one of the forces, a principle force, is societal, or cultural. He sees pairings-off all around him, physically reinforced by separate houses, fenced in. It’s the ‘norm’. With bonobos, no physical or, apparently, ethical barriers have been erected against polyandry/polygyny – to use human terms that would be meaningless to them. Does that mean no love? Of course not – on the contrary, our cousins can still teach us a thing or two about love…
References
Simone de Beauvoir, The Second Sex, 1949
Ferdinand Mount, The subversive family, 1982
https://www.scientificamerican.com/article/human-monogamy-has-deep-roots/
Human origins far from being resolved – it just gets more fascinating (part 1)
yeah – a few ‘awkward’ species missing from this group
Canto: So we’d all like to solve the riddle – or many riddles, of human ancestry, but the problems are manifold, it seems.
Jacinta: Yes, we’re not just talking about Homo sapiens, or H sapiens sapiens as some would put it, but the whole Homo genus, including neanderthalenis, denisova, floresiensis, naledi, heidelbergensis, rudolfensis, erectus and habilis, and I’m not sure if I’ve got them all.
Canto: Yes and there are lumpers and splitters, but I’m talking even further back, to Paranthropus and the Australopithecines. I watched a DW doco recently that piqued my interest, making me wonder at what date, round-about, did the Homo genus emerge, and what genus did it emerge from?
Jacinta: Well this is a problem for all species and genera really. Think of our favourite apes, the bonobos. In the book Who we are and how we got here, which is all about the new science of genomics and how it’s transforming our understanding of human populations , David Reich wrote of –
a new method to estimate the suddenness of separation of the ancestors of two present-day species from genetic data… When they applied the method to study the separation time of common chimpanzees and their cousins, bonobos, they found evidence that the separation was very sudden, consistent with the hypothesis that the species were separated by a huge river (the Congo) that formed rather suddenly one to two million years ago
D Reich, Who we are and how we got here, p46
Which is all very fascinating, but one to two million years is rather a long time frame.
Canto: Yes, in the DW doco the time frames were also rather flexible – which I suppose needs must. Australopithecines were described as emerging perhaps 3 million years ago and disappearing 2 million years ago, with the Paranthropus genus preceding them by about a million years – or was it the other way around?
Jacinta: And other types are mentioned – often from the most meagre remains. Sahelanthropus, Orrorin, Ardipithecus, and Danuvius guggenmosi, beloved of Madelaine Böhme among others.
Canto: Well D guggenmosi was an interesting but isolated find, dating to around 11.6 million years ago, and of course the remains are fragmentary so there are arguments about its bipedalism and other features. It was a tiny ape, quite a bit smaller than bonobos, the smallest of the extant great apes. Böhme is arguing, I believe, that these discoveries (three specimens were discovered) could push the chimp-human last common ancestor (CHLCA) back a few million years. The CHLCA date is usually given as between 6 and 7 million years ago, but Wikipedia is, currently at least, being more open to a wider range:
The chimpanzee–human last common ancestor (CHLCA) is the last common ancestor shared by the extant Homo (human) and Pan (chimpanzee and bonobo) genera of Hominini. Due to complex hybrid speciation, it is not currently possible to give a precise estimate on the age of this ancestral population. While “original divergence” between populations may have occurred as early as 13 million years ago (Miocene), hybridization may have been ongoing until as recently as 4 million years ago (Pliocene).
Chimpanzee–human last common ancestor, Wikipedia Jan 21 2023
Jacinta: Interesting, and it suggests a lot of work still to be done, and that’s just in relation to the Homo genus. I’d certainly be interested in pursuing the evidence and the debate in future posts, but for now I’m wondering about the immediate ancestors of our species.
Canto: Well, the book Who we are and how we got here tries to sort all that out through the study of population genetics and genomics, though much of it, so far, deals with migratory populations over the last tens of thousands of years…
Jacinta: Homo heidelbergensis has struck many palaeoanthropologists as the likely common ancestor of both H sapiens and H neanderthalensis. The Smithsonian dates the species to about 700,000 to 200,000 years ago, but there’s also this from their website:
This species may reach back to 1.3 million years ago, and include early humans from Spain (‘Homo antecessor’ fossils and archeological evidence from 800,000 to 1.3 million years old), England (archeological remains back to about 1 million years old), and Italy (from the site of Ceprano, possibly as old as 1 million years)
Canto: So yes, again, lumpers and splitters, and we’re no experts. From the term Homo antecessor I’d conjecture that they’ve been hailed as direct antecedents…. but other specimens, named H cepranensis, and H rhodesiensis, as well as H heidelbergensis, are in the mix, and the remains are often hard to identify and date, with DNA and the proteins made from them being tricky to isolate from warmer climes…
Jacinta: The Australian Museum gives us this interesting info about H heidelbergensis versus H antecessor, in describing the largest find of specimens:
- The remains of at least 6 individuals found at the site of Gran Dolina, Atapuerca, in Spain. They lived about 800,000 to 1 million years ago in Europe and are the oldest human remains found in that continent. Although many experts consider these remains to be part of an early and variable Homo heidelbergensis population, the discoverers believe the fossils are different enough to be given a new species name Homo antecessor.
Canto: I’m wondering about that Morocco specimen that has recently, no doubt controversially, been reclassified as H sapiens, though it dates from 320,000 to 300,000 years ago, pushing the age of our species back by a hundred thousand years or so.
Jacinta: Yes you’re talking about the finds at the Jebel Irhoud site, and it’s complicated, because most researchers don’t identify that region as the birthplace of H sapiens. They mostly agree that the species was ‘born’ in southern and Eastern Africa. The Smithsonian seems to me a bit confusing and unconvincing on this point:
The remains of five individuals at Jebel Irhoud exhibit traits of a face that looks compellingly modern, mixed with other traits like an elongated brain case reminiscent of more archaic humans. The remains’ presence in the northwestern corner of Africa isn’t evidence of our origin point, but rather of how widely spread humans were across Africa even at this early date.
They’re saying that the oldest human remains found are in north-west Africa, but humans probably originated in south-east Africa, though we haven’t got specimens from there that are older than 260,000 years, at most. Hmmm.
Canto: The paucity of the fossil record is probably to blame. But then – Homo naledi. I’ve just watched John Hawks giving a talk on naledi in 2017 – Hawks is a hero of mine, I used to follow his website regularly – and he talked of more and more discoveries in that diabolical underground cave system called – maybe ironically? – Rising Star, in South Africa. They now have more fossil remains of naledi than of any other ancient Homo apart from neanderthalensis. And they’ve managed to narrow the dating from about 320,000 to 240,000 years ago, from memory. So they may well have lived alongside the earliest H sapiens.
Jacinta: Complexifying the picture in ways some find fascinating, others frustrating. And they were much smaller and smaller-brained, right? Like floresiensis, another mystery. So there will be questions about how ‘advanced’ they were. Is there evidence of tool use? Of fire? And remember, it’s not brain size that matters so much but brain organisation. Think of corvids – tool users, problem solvers, complex family systems, brains the size of a walnut but packed with as many neurons as some monkey species.
Canto: Yes, I agree, we can’t make too many assumptions based on size. Bonobos females are smaller than the males but much smarter, right? But one major difficulty about the naledi lifestyle is that we know nothing about it. It seems these remains were placed, or dropped, in the cave after death. And as far as I know, we have no trace of naledi above-ground, which is kind of bizarre.
Jacinta: Okay, so I’m watching the ever-reliable North 02 vid on naledi. They first thought these remains were probably well over a million years old, due to various features, especially skull size, though there were plenty of anomalies, but they were eventually able to date some of the teeth, using electron spin resonance and uranium-thorium dating, and yes, your dating is about right. As to skull or brain size, smaller than habilis and quite a bit smaller than erectus, but actually larger than floresiensis, which clearly tells us, doesn’t it, that there hasn’t necessarily been this enlargement of brain size over time for all members of the Homo genus.
Canto: Yes, interesting – floresiensis, do we know anything of their lifestyle, tools, decorations…?
Jacinta: The most recent dating of floresiensis has them living until about 50,000 years ago at the latest. So much more recent than naledi. The cave where they were found yielded over 10,000 stone artefacts similar to those associated with the much larger-brained H erectus, from whom they may have learned a few things. With a brain quite a bit smaller than that of H naledi. Surely a cautionary tale.
Canto: Right – and they’re not even looking at brains, they’re looking at skulls, and making possibly unwarranted assumptions.
Jacinta: Okay so there’s a lot more to say on this topic – about Homo naledi alone, never mind the many other species or pseudo-species, so we’ll have to turn this into an ongoing series. I’ve been reading and listening to a lot of very smart people, which has made me feel quite dumb and shallow on the topic – no Dunning-Kruger effect for me at least.
Canto: Well, even as dilettantes we’ve come up with some reasonable skeptical queries – about brain size, and more on that next time, about tool use or the lack of evidence for it, and the lack of evidence of anything re H naledi outside of Rising Star. So, next time…
References
How did humans come to be? DW documentary
D Reich, Who we are and how we got here, 2018
M Böhme et al, Ancient bones, 2020
https://en.wikipedia.org/wiki/Chimpanzee–human_last_common_ancestor
https://humanorigins.si.edu/evidence/human-fossils/species/homo-heidelbergensis
https://australian.museum/learn/science/human-evolution/homo-antecessor/