Sex At Dawn, The Prehistoric Origins of Modern Sexuality

Sex at Dawn is a very engaging book about who we are, and why we think about sex all the time. It takes the form of challenge to the standard cultural narrative idea that ‘Man + Woman = Family and always has’. Instead, Christopher Ryan & Cacilda Jethá argue that the monogamous families are a social adaptation to the pressures of agricultural societies which runs contrary to our socio-sexual evolution in small bands of hunter-gatherers.

The Genus Pan, which were we not so self-reverential would probably also include the Homo lineage, is an unusual group of species for whom sex is more about social bonding than reproduction, though many authors have glossed over this part of our make-up, perhaps embarrassed at our nearest cousins’ licentiousness. The authors argue that much of the focus on P. troglodytes’ perceived social and sexual aggression in the wild is in part due to the difficulty of studying groups in the wild without influencing behaviour, and in any case, our genitals and behaviour are in many ways more like that of the rather more peaceable, free-lovin’ Bonobo, Pan Paniscus, who are basically at it, all the time, with anything that moves.

Here’s a video of a Chimpanzee raping a toad, which whilst not strictly relevant to this review, I’ve been dying to shoehorn into a post for a while, and this is as close as it’s going to get.

One area where I question the authors’ conclusions is the degree of sexual dimorphism: They cite around 10-20% difference in body size. I don’t think this is the relevant figure: Human males’ upper body strength ranges from 50%-200% stronger, especially in forearm grip. This is clearly an adaptation to fighting, and even more disturbingly suggests that rape formed part of our evolutionary history. Of course human females are going to be able to keep up on a march, we evolved as free-ranging hunter-gatherers, which is why women have long legs. Just 9% separates Paula Radcliffe and Haile Gebreselassie’s marathon records. The puny female upper body when compared to the (still puny) adult male shows the real sexual dimorphism of the Human species: The Clean & Jerk weightlifting records show a 41% difference between the sexes and the powerlifters’ difference is greater still at over 100% for the deadlift.

This matters because the greater the sexual dimorphism, the greater the degree of Polygamy. Humans are not as co-operative as bonobos, but nor is our natural history one of Harem building, winner-takes-all male competition as extreme as that of the Gorilla. Our genitals certainly point to sperm selection which means an Alpha male cannot guarantee the fidelity of ‘his’ females as can the big silverback, but there is DNA evidence about how few males bred in history: around 40% compared to the female 80% (can’t find citation), This indicates a degree of competition for the spoils amongst our male ancestors, where size and especially strength mattered. The authors reckon we’re more matriarchal Bonobo than patriarchal Chimpanzee. I was not completely convinced. I think we were quite violent even in hunter-gather society.

Anthropologists look at existing cultures and the records of explorers who came across the last remaining hunter gatherer societies and try to interpret the findings through the fog of cultural conceit, misunderstanding and arrogance, but often have their own preconceived ideas too. Megafauna the world over dying out a thousand years or so after humans arrived on any given continent, gives the lie to our ancestors ‘living in harmony’ with nature myth, and I think it is important to reject the ‘noble savage’ in matters sexual too. It is tempting, therefore to engage in wishful thinking that just because the last remaining hunter-gatherers perched on marginal terrain in the Bornean rain-forest or the Botswanan desert don’t fight the neighbouring tribe this doesn’t mean this follows for the prime land now given over to agriculture. Germans and Brits stranded on arctic island weather stations cooperated to survive in 1944 whilst their friends were fighting over France. I contend there’s not much to fight over in the Bornean highlands, but a band of Hunter-gatherers would fight their neighbours for the right to forage in prime riverside forest in the Ardèche. The authors do talk about localised plenty being cause for strife, but don’t follow this through to its conclusion, that our ancestors existed with areas of localised plenty, and would have fought over it.

Any book challenging the recieved wisdom is going to leave itself open to attack on a few matters, but the authors make compelling observations, well backed up by data and certainly along lines that made Kinsey so controversial. You might also be interested in ‘the Mating Mind‘ which deals with the evolution of language and intelligence as a ‘peacock’s tail’, which fortuitously became adaptive after the fact.

The Authors conclusions about modern society’s obsessive focus on fidelity causing of great stress is utterly compelling, especially when compared to societies which use sex as social bonding without the deep taboo about infidelity. Our religious history has poisoned the relationship between the sexes by making females chattels of the males, and we would all be happier if you let your partner have the odd fling once in a while. Ladies, you will benefit from his higher testosterone too, and gents, you can’t have your cake and eat it. Play fair and let her take a lover once in a while! This is especially true now women are in conscious control of fertility. The authors may believe that paternity didn’t matter in highly co-operative bands. It does now, and I can see no way of changing society so that it doesn’t. However, the conclusion stands: We can, if we take care about Pregnancy, STIs and AIDs, build a happier society with a bit of Free Love.

Well worth a read.

4 replies
  1. lost_nurse
    lost_nurse says:

    A related point: we are now the sole remaining example of the Homo lineage. One of the most interesting (if you, er, care about such things) debates in Palaeolithic archaeology is the degree of cultural/genetic admixture between, say, Eurasian Neanderthal populations & incoming (prob African) modern humans during the last Ice Age. Whilst we as a species eventually persist, the process by which that happens (as indicated by the archaeological & fossil records, radiocarbon dating, etc) is still – tantalisingly – vague.


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