by Camilla Power
People talk about sex work as the 'oldest profession'. But what does that really mean? It seems to imply that some things about human nature will never change, and that certain relations are a given of human existence. But what kinds of evidence can inform us about the terms of the trade that is as old as humanity? What part did sex play in the earliest economies?
There are three main kinds of evidence for answering these questions: first, the evidence left us by evolution in the shape of our bodies; second, archaeological evidence left by ancestors; and third, what we can learn from the lives - especially sex lives - of people who until recent times have been living in ways that resemble our hunting and gathering past.
As far as our bodies go, we may be 99% similar to chimpanzees in terms of shared DNA. But there are remarkable differences. For one thing, our brains are three times bigger than any chimp's. If you go to the zoo to watch chimps interact you will very soon see obvious differences in sex behaviour. In the few days before, and just when, she is fertile, a female chimp sports a pink sexual swelling the size of a grapefruit. During this period of oestrus, she is busy having sex with all the adult males of her group. And this takes place openly in front of other group members.
Women, by contrast, show no such display marking out the most fertile days of our cycles. We can have sex - or not - pretty much any time. Although it varies between societies, every society on earth has some standard of modesty or discretion surrounding sex, which clearly does not apply to chimps.
Scientists link the large human brain size with these features of sexual behaviour. Very large brains are energy-consuming. A human mother breast-feeding an infant needs a lot of high-quality food to sustain the child's brain growth. Once a chimp gets pregnant, the adult males of her troupe - any of whom might be possible fathers - simply leave her to get on with the job of childrearing all on her own. But a human mother expects others, including men, to help with the energetic burden. The reason why our female ancestors evolved to show no sign of ovulation is that it kept males guessing about when a female might be fertile - and so kept males hanging around, possibly doing something useful. That means sex which was not necessarily fertile or reproductive sex could be used to reward particularly helpful males.
Of course, once a woman is pregnant, gives birth and starts nursing, her male partner/s might be inclined to look elsewhere. This was a major problem for our foremothers in evolution. Females had to breastfeed for years after birth; males would be able to tell which females were fertile, not by signs of ovulation - these had been phased out - but by menstruation. A menstruating female is not fertile immediately, but in a week or two she could be. Therefore, evolving human males would have been eager to bond with any menstrual female, bringing her the Palaeolithic equivalent of flowers and chocolates, more likely to be choice cuts of game meat.
But the females who really needed the extra energy were the nursing mothers. Faced with competition from fertile menstrual females, they had two choices: either, hide the fact another female was menstruating from the males; or, use her attractions to encourage the males to extra efforts. This second strategy gave us the first cosmetics - the earliest kinds of body art and symbolism. All women, whether they were pregnant, nursing or fertile, daubed themselves with blood red colours, using ochre and haematite pigments ground up and mixed with fats as sexual warpaint. In this display, the message of the women - as a group - to the men was: you're not going to separate us; you're not going to pick and choose; you're going to hunt for all of us. And NO sex till you do.
By acting in solidarity, women used sexual display to organise the world's first economy. Hiding, or censorship, if you like, would have got little extra out of men. Collective cosmetic display got men to go hunting, providing energy and vital nutrients for large-brained offspring. As a result, humans thrived, spreading all over the planet.
We are an extraordinarily young species, emerging from Africa just 150,000 years ago. Across southern Africa by 120,000 years ago, archaeologists find widespread evidence for a cosmetics industry of red ochre and haematite. This includes bright red crayons, shaped like lipsticks, used in the first body art and colour design over 100,000 years ago. Instead of Homo sapiens, or 'wise' human, our species could well be called Homo slapiens - 'tarted up' human. Wherever these first humans went, to Australia, the Middle East and Europe, they carried red ochre cosmetics with them. There is even some evidence that Neanderthals picked up and copied our cosmetics when we came into contact in Ice Age Europe some 40,000 years ago. Sadly, the Neanderthals had become extinct just 10,000 years later. Perhaps, they never quite got the hang of putting on make up! Meanwhile our ancestors in Europe produced the great art of the Ice Age, focused on women's ritual solidarity and painted in red ochre.