The Ancient Sex Lives Scientists Don't Want You to Know About

[00:00:00]You meet someone, your heart speeds up, your palms  go damp, your brain quietly starts calculating something you are barely aware of. This reaction  is not new, and it might be older than language itself. For most of human history, the question of  who you loved and how looked nothing like a modern romance. Around 34,000 years ago, in what is now  Russia, someone was buried with unusual care.

[00:00:26]Thousands of ivory beads, fox teeth, spears  carved from mammoth tusk. And in 2017, when scientists finally read the DNA hidden inside  those bones, they found something startling. These people were not closely related to each other.  Somebody deep in the ice age was already keeping careful track of who could pair up with whom.  This is Sunung here. A burial site first studied in detail by paleo anthropologist Eric Trink  and later genetically analyzed by a team led by geneticist Martin Sakura published in the journal  Nature. What they found was not romance. It was structure. A network of small bands deliberately  trading partners across long distances so no one had to pair up with a close cousin. Why does this  matter? Because it tells you something most people get backwards about prehistoric sex. It was not  chaos. It was not a free-for-all. Some of it, remarkably, looks like planning. So, where did  pairing up even start? One influential idea comes from anthropologist Owen Lovejoy in a 1981 paper  published in the journal Science. Lovejoy argued that walking upright and pair bonding might  be connected. His reasoning went like this.

[00:01:42]A male who consistently provisioned one female  and her offspring instead of competing loudly for many mates would leave behind more surviving  children over time. That quiet strategy could shape a whole species. It is a compelling idea and  it is also debated. Not every researcher agrees.

[00:02:00]The evidence does not support one single  explanation for why humans pair up at all.

[00:02:05]Primatologist and anthropologist Sarah Blaffer  Herurdy offers a different piece of the puzzle.

[00:02:10]In her book, Mother Nature, she points out that  human infants are unusually needy for an unusually long time. Raising a human child, she argues,  likely required more than one committed adult.

[00:02:23]It required a whole support network, grandmothers,  aunts, older siblings, sometimes fathers who were not biological fathers at all. Researchers call  this cooperative breeding. This is the detail that gets me every time. Long before dating apps,  before marriage certificates, human children may have survived not because of one perfect pair  bond, but because of an entire village quietly showing up. To understand where humans might  sit on this spectrum, researchers often look at our closest living relatives. Pimeatlogist  France Dewal spent decades studying bonobos and famously described them as using sex casually to  ease tension and smooth over conflict within the group. Chimpanzees, a close relative living just  across the Congo River, behave very differently with far more aggression and stricter dominance  hierarchies around mating. Humans are not bonobos and humans are not chimpanzees either. But the  comparison matters because it shows that even among our nearest relatives, there is no single  default. Biology offers a range of possibilities.

[00:03:32]Culture and circumstance decide which ones  actually get used. Now you may have heard a very different story. A popular book called Sex at Dawn  made a bold claim. It argued that ancient humans lived in a kind of promiscuous paradise before  agriculture supposedly ruined everything with jealousy and private property. It is a great story  to tell at a party. Most researchers who actually study the skeletal and genetic record do not think  the evidence holds up. The picture from sites like Sun here does not look like chaos. It looks like  people managing relationships carefully across generations, sometimes across hundreds of kilome.  So, was everyone strictly monogamous? Not exactly, and not everywhere. Anthropologist  George Murdoch's Ethnographic Atlas, a survey of hundreds of documented societies,  found that roughly 80% formally permitted a man to take more than one wife. That number sounds  dramatic. Here is the part that usually gets left out. Within those same societies, most actual  marriages were still one husband and one wife.

[00:04:38]Multiple wives took resources few families ever  had. Permission and practice, it turns out, are two very different things. For a closer look at  how flexible human pairing can be, anthropologist Marjgerie Showstack spent years with the Juanzi  people of the Kalahari recording the life story of a woman named Nissa. It is important to be  clear here, the Juani are not a window into the stone age. They are a contemporary people  living modern lives today and their relevance is only as a useful comparison never a time machine.  Still, Nissa's story as told to Shastak described childhood betroals, multiple relationships before  and during marriage and an approach to love that was pragmatic as much as passionate. There is  no single ancestral template. There is a wide human range. You may have also heard something  else. Parts of the Pacific were once described as a paradise of total sexual freedom, especially  for teenagers. That idea traces largely back to anthropologist Margaret me, whose 1928 book,  Coming of Age in Samoa, described relaxed adolescent sexuality with very little of the  anxiety Western teenagers experience. It became one of the most famous claims in anthropology.  Decades later, anthropologist Derek Freeman challenged me's conclusions directly, arguing she  had been misled by informants and had overstated how care-free Samoan sexuality actually was. That  debate is still not fully settled today. What is clear is this. A single dramatic claim about a  sexually free culture should always be treated carefully, whether it comes from Samoa or from  your own assumptions about the deep past. Sex, of course, had consequences. your ancestors  could not ignore. Evolutionary anthropologist Wenda Travathan has spent much of her career  studying what she calls the obstetric dilemma.

[00:06:34]Human babies are born with unusually large  heads to fit unusually large brains. Human hips, meanwhile, are narrow, built for walking  efficiently on two legs. Something had to give.

[00:06:46]Travathan's research suggests this tight squeeze  may be one reason humans almost uniquely among primates tend to seek help during childbirth. Not  because ancient mothers were fragile, but because the anatomy of being smart and upright made birth  genuinely physically difficult. Assistance was not a luxury. It may have been a survival strategy  built directly into the body. Here is a piece of ancient wiring you were probably carrying  around without realizing it. In the late 1800s, Finnish sociologist Edward Westermark proposed  that people raised closely together from early childhood develop an automatic unconscious  aversion to pairing with one another, regardless of whether they are actually related.  Decades later, sociologist Joseph Shepard tested this idea on Israeli kabutsum communities  where unrelated children were raised together like siblings across thousands of recorded  marriages. Virtually none occurred between children raised in the same peer group from  birth. No rule forbade it. Nobody had to be told. The aversion simply appeared on its own,  shaped by closeness in early life, rather than by biology alone. There is one more oddity worth  sitting with. Compared to many other primates, human ovulation is remarkably hard to detect,  even for the woman experiencing it. Chimpanzees advertise fertility with dramatic visible  swelling. Humans mostly do not. Researchers Richard Alexander and Katherine Nunan writing in  the late 1970s proposed what is sometimes called the paternity confidence hypothesis. The idea is  that hiding the fertile window changed behavior.

[00:08:27]It may have encouraged males to stick around and  invest in offspring year round rather than only during one brief obvious window. Other researchers  have proposed different explanations entirely and nobody has definitively settled the question. Your  body, it turns out, may be running a strategy so old and so subtle that even modern science has  not fully cracked it. So, let's reconstruct an evening tens of thousands of years ago. Somewhere  on the edge of a river valley, a fire is burning low. Someone is repairing a spear shaft by  its light. Nearby, two teenagers are talking a little too carefully and a little too often. An  older woman watches from across the fire, saying nothing but clearly noticing everything. In many  documented traditional societies, elders played an active role in who paired with whom. Not always as  strict arrangers, but often as quiet gatekeepers, weighing alliances between families, available  resources, and yes, whether two people actually seemed to like each other. Attraction mattered. It  simply was not the only thing that mattered. Here is the twist that tends to surprise most people.  The butterflies in your stomach, that rush of attraction, appears to be genuinely ancient and  strikingly cross-cultural. Anthropologists have documented signs of romantic attraction in the  overwhelming majority of societies ever studied.

[00:09:53]But historian Stephanie Counz in her book Marriage  a History draws a sharp distinction. Feeling romantic love is old. Marrying primarily for  romantic love is not. For most of human history, in most places, marriage functioned closer to a  business decision. It secured food, protection, land, and alliances between families. The idea  that you should marry your one great love and nothing else is historically speaking a fairly  recent invention. There is also a less romantic thread running through this history. Skeletal  remains from various preodern populations show evidence of chronic infections, including trepmal  disease, a family of bacterial infections related to what we now call syphilis. Researchers still  debate exactly when and where these infections first appeared in humans, and how they moved  between continents. What the bones do confirm is straightforward. Intimacy has always carried  physical risk right alongside its benefits, and ancient bodies had to negotiate that  trade-off long before anyone understood what bacteria even were. Even the smaller rituals  of modern dating carry old fingerprints. In many documented societies, courtship involved a  formal exchange of goods between families, sometimes called bride price or dowy, depending  on which direction resources flowed. It was not only sentimental, it was a way of formalizing  an alliance and signaling that a family could genuinely support a new household. The bouquet  of flowers on a first date or the effort behind a carefully planned proposal echoes a very old logic  show. Do not just tell that you are serious. Now, here is where this gets a little strange and  honestly a little wonderful. In 1995, biologist Claus Wadekin ran an experiment that has become  famous among researchers, sometimes nicknamed the sweaty t-shirt study. Women were asked to smell  t-shirts worn by different men and rate which sense they found most appealing. On average, women  preferred the scent of men whose immune system genes, a set of markers called the MHC, were  most different from their own. The likely reason, genetic diversity in future offspring may mean  stronger resistance to disease. In other words, part of what feels like pure chemistry on a first  date may be your immune system quietly doing math.

[00:12:19]It inherited from deep in your evolutionary past.  So, what does all of this actually tell you? Not that ancient humans were more chased than you  assumed. And not that they were wilder than you assumed, either. The honest answer is messier  and far more interesting. Pairing up, staying together, choosing who to trust with your body and  your future was never simple. It involved biology you did not choose and negotiation that you did.  It involved elders, alliances, and a stubborn preference wired deep into your senses. For  partners genuinely different from yourself. Modern dating apps, awkward first dates, the nervous  instinct to bring a partner home to meet your family, none of it is as new as it feels. You are  running very old software, dressed up in a very new interface. You meet someone, your heart speeds  up, your palms go damp, and somewhere quietly underneath all of it, roughly 300,000 years of  trial and error are still running the numbers.