an autodidact meets a dilettante…

‘Rise above yourself and grasp the world’ Archimedes – attribution

Archive for the ‘primates’ Category

kin selection – some fascinating stuff

leave a comment »

meerkats get together for ye olde family snap

Canto: So we’ve done four blogs on Palestine and we’ve barely scratched the surface, but we’re having trouble going forward with that project because, frankly, it’s so depressing and anger-inducing that it’s affecting our well-being.

Jacinta: Yes, an undoubtedly selfish excuse, but we do plan to go on with that project – we’re definitely not abandoning it, and meanwhile we should recommend such books as Tears for Tarshiha by the Palestinian peace activist Olfat Mahmoud, and Goliath by the Jewish American journalist Max Blumenthal, which highlight the sufferings of Palestinian people in diaspora, and the major stresses of trying to exist under zionist monoculturalism. But for now, something completely different, we’re going to delve into the fascinating facts around kin selection, with thanks to Robert Sapolski’s landmark book Behave. 

Canto: The term ‘kin selection’ was first used by John Maynard Smith in the early sixties but it was first mooted by Darwin (who got it right about honey bees), and its mathematics were worked out back in the 1930s. 

Jacinta: What’s immediately interesting to me is that we humans tend to think we alone know who our kin are, especially our extended or most distant kin, because only we know about aunties, uncles and second and third cousins. We have language and writing and record-keeping, so we can keep track of those things as no other creatures can. But it’s our genes that are the key to kin selection, not our brains.

Canto: Yes, and let’s start with distinguishing between kin selection and group selection, which Sapolsky deals with well. Group selection, popularised in the sixties by the evolutionary biologist V C Wynne-Edwards and by the US TV program Wild Kingdom, which I remember well, was the view that individuals behaved, sometimes or often, for the good of the species rather than for themselves as individuals of that species. However, every case that seemed to illustrate group selection behaviour could easily be interpreted otherwise. Take the case of ‘eusocial’ insects such as ants and bees, where most individuals don’t reproduce. This was seen as a prime case of group selection, where individuals sacrifice themselves for the sake of the highly reproductive queen. However, as evolutionary biologists George Williams and W D Hamilton later showed, eusocial insects have a unique genetic system in which they are all more or less equally ‘kin’, so it’s really another form of kin selection. This eusociality exists in some mammals too, such as mole rats. 

Jacinta: The famous primatologist Sarah Hrdy dealt something of a death-blow to group selection in the seventies by observing that male langur monkeys in India commit infanticide with some regularity, and, more importantly, she worked out why. Langurs live in groups with one resident male to a bunch of females, with whom he makes babies. Meanwhile the other males tend to hang around in groups brooding instead of breeding, and infighting. Eventually, one of this male gang feels powerful enough to challenge the resident male. If he wins, he takes over the female group, and their babies. He knows they’re not his, and his time is short before he gets booted out by the next tough guy. Further, the females aren’t ovulating because they’re nursing their kids. The whole aim is to pass on his genes (this is individual rather than kin selection), so his best course of action is to kill the babs, get the females ovulating as quickly as possible, and impregnate them himself. 

Canto: Yes, but it gets more complicated, because the females have just as much interest in passing on their genes as the male, and a bird in the hand is worth two in the bush…

Jacinta: Let me see, a babe in your arms is worth a thousand erections?

Canto: More or less precisely. So they fight the male to protect their infants, and can even go into ‘fake’ estrus, and mate with the male, fooling the dumb cluck into thinking he’s a daddy. 

Jacinta: And since Hrdy’s work, infanticide of this kind has been documented in well over 100 species, even though it can sometimes threaten the species’ survival, as in the case of mountain gorillas. So much for group selection.

Canto: So now to kin selection. Here are some facts. If you have an identical twin your genome is identical with hers. If you have a full sibling you’re sharing 50% and with a half-sibling 25%. As you can see, the mathematics of genes and relatedness can be widened out to great degrees of complexity. And since this is all about passing on all, or most, or some of your genes, it means that ‘in countless species, whom you co-operate with, compete with, or mate with depends on their degree of relatedness to you’, to quote Sapolsky. 

Jacinta: Yes, so here’s a term to introduce and then fairly promptly forget about: allomothering. This is when a mother of a newborn enlists the assistance of another female in the process of child-rearing. It’s a commonplace among primate species, but also occurs in many bird species. The mother herself benefits from an occasional rest, and the allomother, more often than not a younger relation such as the mother’s kid sister, gets to practice mothering. 

Canto: So this is part of what is called ‘inclusive fitness’, where, in this case, the kid gets all-day mothering (if of varying quality) the kid sister gets to learn about mothering, thereby increasing her fitness when the time comes, and the mother gets a rest to recharge her batteries for future mothering. It’s hopefully win-win-win. 

Jacinta: Yes, there are negatives and positives to altruistic behaviour, but according to Hamilton’s Rule, r.B > C, kin selection favours altruism when the reproductive success of relatives is greater than the cost to the altruistic individual. 

Canto: To explain that rule, r equals degree of relatedness between the altruist and the beneficiary (aka coefficient of relatedness), B is the benefit (measured in offspring) to the recipient, and C is the cost to the altruist. What interests me most, though, about this kin stuff, is how other, dumb primates know who is their kin. Sapolsky describes experiments with wild vervet monkeys by Dorothy Cheney and Robert Seyfarth which show that if monkey A behaves badly to monkey B, this will adversely affect B’s behaviour towards A’s relatives, as well as B’s relatives’ behaviour to A, as well as B’s relatives’ behaviour to A’s relatives. How do they all know who those relatives are? Good question. The same researchers proved this recognition by playing a recording of a juvenile distress call to a group of monkeys hanging around. The female monkeys all looked at the mother of the owner of that distress call to see what she would do. And there were other experiments of the sort. 

Jacinta: And even when we can’t prove knowledge of kin relations (kin recognition) among the studied animals, we find their actual behaviour tends always to conform to Hamilton’s Rule. Or almost always… In any case there are probably other cues, including odours, which may be unconsciously sensed, which might aid in inclusive fitness and also avoiding inbreeding. 

Canto: Yes and It’s interesting how this closeness, this familiarity, breeds contempt in some ways. Among humans too. Well, maybe not contempt but we tend not to be sexually attracted to those we grow up with and, for example, take baths with as kids, whether or not they’re related to us. But I suppose that has nothing to do with kin selection. And yet…

Jacinta: And yet it’s more often than not siblings or kin that we have baths with. As kids. But getting back to odours, we have more detail about that, as described in Sapolski. Place a mouse in an enclosed space, then introduce two other mice, one unrelated to her, another a full sister from another litter, never encountered before. The mouse will hang out with the sister. This is called innate recognition, and it’s due to olfactory signatures. Pheromones. From proteins which come from genes in the major histocompatibility complex (MHC). 

Canto: Histowhat?

Jacinta: Okay, you know histology is the study of bodily tissues, so think of the compatibility or otherwise of tissues that come into contact. Immunology.  Recognising friend or foe, at the cellular, subcellular level. The MHC, this cluster of genes, kicks off the production of proteins which produce pheromones with a unique odour, and because your relatives have similar MHC genes, they’re treated as friends because they have a similar olfactory signature. Which doesn’t mean the other mouse in the enclosure is treated as a foe. It’s a mouse, after all. But other animals have their own olfactory signatures, and that’s another story. 

Canto: And there are other forms of kin recognition. Get this – birds recognise their parents from the songs sung to them before they were hatched. Birds have distinctive songs, passed down from father to son, since its mostly the males that do the singing. And as you get to more complex species, such as primates – though maybe they’re not all as complex as some bird species – there might even be a bit of reasoning involved, or at least consciousness of what’s going on. 

Jacinta: So that’s kin selection, but can’t we superior humans rise above that sort of thing? Australians marry Japanese, or have close friendships with Nigerians, at least sometimes. 

Canto: Sometimes, and this is the point. Kinship selection is an important factor in shaping behaviour and relations, but it’s one of a multiple of factors, and they all have differential influences in different individuals. It’s just that such influences may go below the level of awareness, and being aware of the factors shaping our behaviour is always the key, if we want to understand ourselves and everyone else, human or non-human.

Jacinta: Good to stop there. As we’ve said, much of our understanding has come from reading Sapolsky’s Behave, because we’re old-fashioned types who still read books, but I’ve just discovered that there’s a whole series of lectures by Sapolsky, about 25, on human behaviour, which employs the same structure as the book (which is clearly based on the lectures), and is available on youtube here. So all that’s highly recommended, and we’ll be watching them.

References

R Sapolski, Behave: the biology of humans at our best and worst. Bodley Head, 2017

https://www.britannica.com/science/animal-behavior/Function#ref1043131

https://en.wikipedia.org/wiki/Kin_selection

https://en.wikipedia.org/wiki/Eusociality

 

 

 

 

 

When was the first language? When was the first human?

leave a comment »

Reading a new book of mine, Steven Pinker’s The sense of style, 2014, I was bemused by his casual remark on the first page of the first chapter, ‘The spoken word is older than our species…’. Hmmm. As Bill Bryson put it in A short history of nearly everything, ‘How do they know that?’. And maybe I should dispense with ‘they’ here – how does Pinker know that? My previous shallow research has told me that nobody knows when the first full-fledged language was spoken. Furthermore, we’re not sure about the first full-fledged human either. Was it mitochondrial Eve? But what about her mum? And her mum’s great-grandad? Which raises an old conundrum, one that very much exercised Darwin, and which creationists today love to make much of, the conundrum of speciation.

Recently, palaeontologists discovered human-like remains that might be 300,000 years old in a Moroccan cave. Or, that’s the story as I first heard it. Turns out they were discovered decades ago and dated at about 40,000 years, though some of their features didn’t match with that age. They’ve been reanalysed using thermoluminescense dating, a complicated technique involving measuring light emitted from escaping electrons (don’t ask). No doubt the dating findings will be disputed, as well as findings about just how human these early humans – about 100,000 years earlier than the usual Ethiopian suspects – really are. It’s another version of the lumpers/splitters debate, I suspect. It’s generally recognised that the Moroccan specimens have smaller brains than those from Ethiopia, but it’s not necessarily the case that they’re direct ancestors, proof that there was a rapid brain expansion in the intervening period.

Still there’s no doubt that the Moroccan finding, if it holds up, is significant, as at the very least it pushes back findings on the middle Stone Age, when the making of stone blades began, according to Ian Tattersall, the curator emeritus of human origins at the American Museum of Natural History. But as to tracing our ancestry back to ‘the first humans’, we just can’t do this at present, we can’t join the dots because we have far too few dots to join. It’s a question whether we’ll ever have enough. Evolution isn’t just gradual, it’s divergent, bushy. Where does Homo naledi, dated to around 250,000 years ago, fit into the picture? What about the Denisovans?

Meanwhile, new research and technologies continue to complicate the picture of humans and their ancestors. It’s been generally accepted that the last common ancestor of chimps and humans lived between 5 and 7 million years ago in Africa, but a multinational team of researchers has cast doubt on the assumption of African origin. The research focused on dental structures in two specimens of the fossil hominid Graecopithecus freybergi, found in Greece and Bulgaria. They found that the roots of their premolars were partially fused, making them similar to those of the human lineage, from Ardepithecus and Australopithecus to modern humans. These fossils date to around 7.2 million years ago. It’s conjectured that the possible placing of the divergence further north than has previously been hypothesised has much to do with environmental factors of the time. So, okay, African conditions were more northerly in those days…

So these new findings and new dating techniques are adding to the picture without clarifying it much, as yet. They’re like tiny pieces in a massive jigsaw puzzle, gradually accumulating, sometimes shifted to places of better fit, and so tantalisingly offering new perspectives on what the whole history might look like. I can imagine that in this field, as in so many others, researchers are chafing against their own mortality, as they yearn for a clearer, more comprehensive future view.

Meanwhile, speculations continue. Colin Barras offers his own in a recent New Scientist article, in which he considers the spread of H sapiens in relation to H naledi and H floresiensis. The 1800 or so H naledi fossil bones, discovered in a South African cave four years ago by a team of researchers led by Lee Berger, took a while to be reliably dated to around 250,000 years (give or take some 50,000), just a bit earlier than the most reliably dated H sapiens (though that may change). Getting at a precise age for fossils is often difficult and depends on many variables, in particular the surrounding rock or sediment, and many researchers were opting for a much earlier period on the evidence of the specimens themselves – their small brain size, their curved fingers and other formations. But if the most recent dating figure is correct (and there’s still some doubt) then, according to Barras, it just might be that H sapiens co-existed, in time and place, with these more primitive hominids, and outcompeted them. And more recent dating of H floresiensis, those isolated (so far as we currently know) hominids from the Indonesian island of Flores, has ruled out that they lived less than 50,000 years ago, so their extinction, again, may have coincided with the spread of all-conquering H sapiens. Their remote island location may explain their survival into relatively recent times, but their ancestry is very much in dispute. A recent, apparently comprehensive analysis may have solved the mystery however. It suggests H floresiensis descended from an undiscovered ancestor that left Africa over 2 million years ago. Those who stayed put evolved into H habilis, the first tool makers. Those who left may have reached the Flores region more than 700,000 years ago. The analysis is based on detailed comparisons with many other hominid species and earlier ancestors.

I doubt there will ever be agreement on the first humans, or a very precise date. We’re not so easily defined. But what about the first language? Is it confined to our species?

Much of the speculation on this question focuses on our Neanderthal cousins as the most likely candidates. Researchers have examined the Neanderthal throat structure as far as possible (soft tissue doesn’t fossilise, which is a problem), and have found one intriguing piece of evidence that makes Neanderthal speech plausible. The semi-circular hyoid bone is located high in the human throat, and is found in the same place in the Neanderthal throat. Given that this bone is differently placed in the throat of our common ancestors, this appears to be an example of convergent evolution. We don’t know the precise role of the hyoid in speech, but it certainly affects the space of the throat, and its flexible relationship to other bones and signs of its ‘intense and constant activity’ are suggestive of a role in language. Examination of the hyoids of other hominids suggests that a rudimentary form of language may go back at least 500,000 years, but this is far from confirmed. It’s probable that language underwent a more rapid development between 75,000 and 50,000 years ago. It’s also worth noting that a full-fledged language doesn’t depend on speech, as signing proves. It may be that a more or less sophisticated gestural system preceded spoken language.

a selection of primate hyoid bones

Of course there’s an awful lot more to say on the origin of language, even if much of it’s highly speculative. I plan to watch all the best videos and online lectures on the subject, and I’ll post about it again soon.

References

https://www.sciencedaily.com/releases/2017/05/170523083548.htm

https://www.vox.com/science-and-health/2017/6/7/15745714/nature-homo-sapien-remains-jebel-irhoud

Did Neanderthals Speak?

http://www.isciencetimes.com/articles/6557/20131220/neanderthals-speak-like-humans-hyoid-bone-study.htm

https://www.newscientist.com/article/2128483-mystery-human-hobbit-ancestor-may-have-been-first-out-of-africa/

https://www.newscientist.com/article/2128834-homo-naledi-is-only-250000-years-old-heres-why-that-matters/

Written by stewart henderson

July 9, 2017 at 11:14 am

beyond feminism – towards a female supremacist society

leave a comment »

image

Canto: I’ves decided to declare myself as a female supremacist.

Jacinta: Really? I thought you had nothing to declare but your genius. So you’ve come out at last?

Canto: Well it’s not as if I’ve been stifled in the closet for years. I’ve rarely thought about it before. I’ve always considered myself a feminist, but recently we’ve been looking at female-male differences, and it’s been making me feel we need more than just equality between the sexes.

Jacinta: You’ve got a hankering for that bonobo world, haven’t you? Females ganging up on you and soothing your aggressive macho emotions with a bit of sexual fourplay.

Canto: Well, yes and no. I first learned about bonobo society almost twenty years ago, and of course it excited me as a model, but then the complexity of human societies with all their cultural overlays made me feel I was naive to imagine a non-human society, without even its own language, could teach us how to improve our own. And the sex stuff in particular – well, that really got me in, but then it seemed too good to hope for. Too much self-serving wishful thinking, to model our society on a bunch of oversexed, indolent banana-eaters.

Jacinta: Do they have bananas in the Congo?

Canto: Absolutely. They have a town there on the Congo River, called Banana.

Jacinta: Oh wow, sounds like heaven. I love bananas. Let’s go there.

Canto: Anyway, now I’m thinking that a female-supremacist society is what we need today, though not necessarily based on bonobos….

Jacinta: That’s disappointing. I think it should be based on bonobos. Bonobos with language and technology and sophisticated theories about life, the universe and everything. Why not?

Canto: Well then they wouldn’t be bonobos. But do you want to hear my reasons for promoting female supremacy?

Jacinta: I probably know them already. Look at the male supremacist societies and cultures in the world – in Africa, in India, in the Middle East. They’re the most violent and brutish societies. We can’t compare them to female supremacist societies because there aren’t any, but we can look at societies where discrimination against women is least rampant, and those are today’s most advanced societies. It might follow that they’ll become even more enlightened and advanced if the percentage of female leaders, in business, politics and science, rises from whatever it is today – say 10% – to, say 90%.

Canto: Yes, well you’re pretty much on the money. It’s not just broader societies, it’s workplaces, it’s schools, it’s corporations. The more women are involved, especially in leadership roles, the more collaborative these places become. Of course I don’t deny female violence, in schools and at home, against children and partners and in many other situations, but on average in every society and every situation women are less violent and aggressive than men. In fact, all the evidence points to a female-supremacist society being an obvious solution for a future that needs to be more co-operative and nurturing.

Jacinta: So how are you going to bring about the female-supremacist revolution?

Canto: Not revolution, that’s just macho wankery. I’m talking about social evolution, and it’s already happening, though of course I’d like to see it speeded up. We’ll look at how things are changing and what we can hope for in some later posts. But the signs are good. The feminisation of our societies must continue, on a global level!

Written by stewart henderson

September 22, 2016 at 12:06 am

bonobos and us – lessons to be learnt

leave a comment »

image

Let’s be sexy about this

Bonobos separated from chimps maybe less than a million years ago, according to some pundits. We haven’t yet been able to determine a more precise date for the split. So which species has changed more? Have chimps become more aggressive or have bonobos become more caring? Is there any way of finding out?
It’s not just about genes its about their expression. It will take some time to work all that out. Brain studies too will help, as we move towards scanning and exploring brains more effectively and less invasively.
But surely we seek not just to understand the bonobo world but to change our own. Who wouldn’t want a world that was less violent, less exclusionary in terms of sex, more caring and sharing, without any loss of the dynamism and questing that has taken us to to the very brink of iphone7?
That last remark will date very quickly… Nah, I’ll leave it in.
So we can learn lessons, and of course we’re already on that path. Advanced societies, if that’s not too presumptuous a term, are less patriarchal than they’ve ever been, without losing any of their dynamism. On the contrary, it can easily be seen that the most male-supremacist societies in the world are also the most violent, the most repressive and the most backward. Some of those societies, as we know, have their backwardness masked by the fact that they have a commodity, oil, that the world is still addicted to, which has made the society so rich that their citizens don’t even have to pay tax. The rest of the world is supporting tyrannical regimes, which won’t change as long as they feel well-fed and secure. Not that I’d wish starvation and insecurity on anyone, but as Roland Barthes once said at one of his packed lectures, the people standing at the back who can’t hear properly and have sore feet must be wondering why they’re here.
Maybe a bit of discomfort, in the form of completely shifting away from fossil fuels for our energy needs haha, might bring certain Middle Eastern countries to a more serious questioning of their patriarchal delusions? Without their currently-valuable resource, they might wake to the fact that they need to become smarter. The women in those countries, so effective on occasion in forming coalitions to defend their inferior place in society, might be encouraged to use their collective power in more diverse ways. That could be how things socially evolve there.
Meanwhile in the west, the lesson of the bonobos would seem to be coalitions and sex. We’ve certainly arrived at an era where sexual dimorphism is irrelevant, except where women are isolated, for example in domestic situations. The same isolation also poses a threat to children. The bonobo example of coalitions and togetherness and sharing of responsibilities, and sexual favours (something we’re a long way from emulating, with our jealousies and petty rivalries) should be the way forward for us. Hopefully the future will see a further erosion of the nuclear family and a greater diversity of child-rearing environments, where single-parent families are far less isolated than they are today, and males want to help and support and teach children because they are children, not because they are their children…

Written by stewart henderson

September 10, 2016 at 6:54 pm

bonobo society, or how to dominate males when you’re smaller

leave a comment »

SLUG; BONOBOS SCIENCE TIMES A BONOBO FAMILY IN A FOREST CLEARING IN WAMBA, ZAIRE. CREDIT: 1996 FRANS LANTING END CURRENT IMAGE 9700023PhotoOWNFREELANCE Photo Caption: Date: 01/01/97 Headline: RETURN NEGS Assignment Caption:RETURN NEGS TO EDITOR/PHOTOG....01/01/97 - 12/31/97 Photographer: FREELANCE Sack Number: 9700023 Reporter: Slug: OWN Desk: Photo Start: 0223 Until: Change Time: False City: State: Country: Location: Contact: Contact Phone: Reporter There?: False Editor: Photo Editor Date Wanted: 01/01/97 Time Wanted: ASAP Summary: Photographer Type: 2 Shot?: False Number of Rolls: 0 Scanned?: 0 Handouts: False Notes: Clean?: False Assignment: 970101028A Record No: 78654

A BONOBO FAMILY IN A FOREST CLEARING IN WAMBA, ZAIRE.
CREDIT: 1996 FRANS LANTING

Bonobo society has been closely observed both in captivity and, with much greater difficulty, in the wild, and it’s worth comparing it to that of their close relatives, chimps. It’s clear that, though aggression does exist in bonobo society, it isn’t anywhere near as prevalent as in chimps. This is obviously related to the use, mentioned previously, of sex to reduce tension and aggression in situations which would normally lead to competitive activity. It’s the ‘make love not war’ social system that has caught the attention of many beyond ethological researchers.

Now, it’s clear that aggression in all primate societies comes predominantly from males. Looking at human societies, the statistics are universal. There is no human society on earth where the homicide and/or assault statistics are dominated by females as perpetrators.  Up until very recently it was males who went to war, and today it’s overwhelmingly males who joing gangs, go hoon driving or join terrorist cells, just as in earlier times it was men who journeyed off to the adventure of the crusades or joined Boney’s army to devastate Europe. As Melvin Konner convincingly argues, this strongly indicates a biological or genetic basis for male aggression. Much of it seems to be about the expression in males of androgens, the male sex hormones. Now with the way we’re going today in genetics and biochemistry we may in the future be able to tweak the production of androgens to offer a biological solution to male violence – which is already in decline in developed countries. However, their are other solutions, and Bonobo society represents one.

Bonobo society is very close-knit. Male bonobos develop close lifelong ties with their mothers. There’s no relationship with the father, who’s unknown, as the females engage in sex with multiple partners more or less indiscriminately. Of course males will compete with other males for sexual partners, but even this aggression is damped down by sexual relations between males. It’s as if the button has been found to switch off escalating aggression, and that button is connected to the genitals. It would be intriguing to discover what’s going on in the brain, with neurotransmitters and hormones, during this rise and fall of aggressive emotions.

Sex doesn’t just reduce aggression though. It virtually creates the bonobo social structure. As with chimps, bonobos have a fission-fusion society, breaking off into smaller ‘unit’ groups for hunting and foraging in the forest and coming together in larger groups at other times. Individual associations, apart from the mother-offspring dependency, are casual and changeable. However, the larger group, or community, has its limit, and keeps itself separate from other bonobo communities. Another feature of bonobo society is that females emigrate from their birth groups at around 8 years of age, moving to group of virtual strangers, where they have to work to build relationships, particularly with older females. The female-female bond is a central feature of bonobo society and these bonds become much stronger than in chimp society, in spite of the fact that these females, having come from other groups, are less genetically related than the males. This bond is cemented by sex, which creates loosely hierarchical coalitions, with one female dominating, mostly through reproductive success – especially in the production of males. Sisterhood is powerful, and it’s not necessarily about genetics. It’s a great lesson for our society, if we can get over the idea, so prevalent but hopefully fading, that we’re unique in a more unique way than any other species is unique, that we’re civilized, and that we have little or nothing to learn from our primate cousins.

And there’s so much more to learn, as we’ll see.

Resources:

http://pin.primate.wisc.edu/factsheets/entry/bonobo/behav

http://www.scientificamerican.com/article/bonobo-sex-and-society-2006-06/

M Konner, Women after all: sex, evolution and the end of male supremacy

 

 

Written by stewart henderson

September 10, 2016 at 9:03 am

bonobo society, sex and females

leave a comment »

sexual dimorphism - a difference on average, but massive individual variation

sexual dimorphism – a difference on average, but massive individual variation

Men are bigger than women, slightly. That’s how things evolved. It’s called sexual dimorphism. It happens with many species, the genders are different in size, shape, coloration, whatever. With humans there’s a size difference, and something of a shape difference, in breasts and hips, but really these aren’t significant. Compare, say, the deep-water triplewort seadevil, a type of anglerfish, in which the female is around 30 cms long, and the male a little over a centimetre. The difference in mass would be too embarrassing to relate.

Among our primate cousins the greatest sexual dimorphism, in size as well as other features, is found in the mandrills, with the male being two to three times the size of the females. In some gorillas there’s a substantial size difference too in favour of the males, and in fact in all of the primate species the male has a size advantage. But size isn’t everything, and the bigger doesn’t have to always dominate.

Female bonobos are smaller than the males, even more so than in humans, yet they enjoy a higher social status than in any other primate society, probably including humans, though it’s hard to compare, since humanity’s many societies vary considerably on the roles and status of women. So how have females attained this exalted status within one of the most highly socialised primate species?

Bonobos and chimpanzees are equally our closest living relatives. It isn’t clear when exactly they separated from each other, but some experts claim it may have been less than a million years ago. Enough time for them to become quite distinct physically, according to the ethologist Franz De Waal. Bonobos are more gracile with longer limbs and a smaller head, and they have a distinctive hairstyle, with a neat parting down the middle. They’re also more easily individuated by their facial features, being in this sense more like humans. And there are also major differences in their social behaviour. Male chimps are dominant in the troupe, often brutally so, whereas bonobo society is less clearly hierarchical, and considerably less violent overall. De Waal, one of the world’s foremost experts on both primates, became interested in bonobos primarily through studies on aggression. He noted that sometimes, after a violent clash, two chimps would come together to hug and kiss. Being interested in such apparent reconciliations and their implications, he decided to look at reconciling behaviours in other primates. What he discovered in bonobos (at San Diego Zoo, which in 1983 housed the world’s largest captive colony) was rather ‘shocking’; their social life was profoundly mediated by sex. Not that he was the first to discover this; other primatologists had written about it, noting also that bonobo sex was far more human-like than chimp sex, but their observations were obscurely worded and not well disseminated. There are other aspects of the physical nature of sexual relations in bonobos that favour females, such as female sexual receptivity, indicated by swelling and a reddening of the genital area, which pertains for a much longer period than in chimps. Female bonobos, like humans and unlike other primates, are sexually receptive more or less all the time.

This isn’t to say that bonobos are oversexed, whatever that may mean. Sexual relations are far from constant, they are casual, sporadic and quickly done with. Often they’re associated with finding food, and it seems likely that sexual relations are used to reconcile tensions related to food availability and other potential causes of conflict.

So how does this use of sex relate to the status of females in bonobo society. I’ll explore this further in the next post.

bonobo relations - more than just sex

bonobo relations – more than just sex

Written by stewart henderson

September 4, 2016 at 1:32 pm

a statement of intent: blogging on patriarchy

leave a comment »

meg-sullivan-quote-ill-be-post-feminist-in-the-post-patriarchy

Okay I’ve recently become a bit depressed that my blog is heading south, comme on dit, being read by nobody, due largely to my personality. A recent SBS program on the celebrated Dunedin longitudinal study of human behaviour and personality told us that there were five essential personality types. Three were considered ‘normal’, and they were the well-adjusted (40% of the population) the confident (28%), and the reserved (15%). In case you can’t add, this makes up some 83% of the population. The other 17% can be divided into two rather more dysfunctional types, the under-controlled (10%) and the inhibited (7%). You’re more than welcome to be healthily skeptical of these categories, but I’m prepared to take them as granted.

I’m not sure if I’m fully in the reserved category or the inhibited one, but I’m quite certain that most of the problems or failings of my life have been due to inhibition. For example, I live alone, have very few friends and no family connections and I visit and am visited by nobody. I have no sex life but a strong sex drive – make of that what you will – and I like other people very much and have many heroes and heroines, and I believe strongly that humans have gotten where they are through communication and collaboration. We’re the most socially constructed mammals on the planet. I love children and would love to have been a father…

Enough, I hope you get the picture. What’s interesting is that, in accord with Dunedin’s personality types, my character seems to have been fixed in early childhood, which I spent largely enjoying my own company, but also being fascinated by the world, soliloquising on it at delightful length. And sometimes, as I grew older, falling to despair, weeping at night over a projected future of loveless isolation. Oh dear.

So what does this mean for my blog? Writing a blog that’s sent out into the public domain is surely not an inhibited act, and craving attention for it is arguably not what a reserved person does. It’s a puzzlement. In any case, I will try harder to expand my readership by writing shorter pieces and narrowing my focus. I’ve decided, for the time being at least, to confine my attention to a subject I’ve long been bothered by: patriarchy. I want to critique it, to analyse it, to examine what the sciences say about it, to shine lights on every aspect of this, to my mind, benighted way of thinking and being-in-the-world. I’ll take a look at bonobos, the Catholic Church, homophobia, the effects of religion and culture, male and female neurophysiology, history, sex, workplaces, business, politics, whatever I can relate to the main subject, which surely will provide me with a rich, open field. And I’ll try, really try to communicate with other bloggers and commentators on the subject. Maybe I’ll become just a little less reserved before it’s too late. It’ll be a cheaper way of getting myself out of a rut than visiting a psychiatrist, of whom I would be healthily if self-servingly skeptical.

Written by stewart henderson

August 21, 2016 at 5:01 pm