Humans probably didn’t mean to tame sheep and goats

Every domestic animal presents a mystery of how it came to be. Sometime in the distant past, an animal—whether wolf, wild ox, jungle fowl, or boar—started to trot down a road that ended with reliance on, or even trust in, human beings.

In Aşıklı Höyük, a Stone-Age town in the highlands of central Turkey, a team of archaeologists, writing in the journal PNAS earlier this week, have pieced together what that process looked like for sheep and goats, some of the earliest herded livestock. The village, one of many experimenting with raising animals, contains 1,000 years of bones, dung, and settlement all in the same place, allowing archaeologists to assemble a time-lapse of domestication. 

“The puzzle comes together,” says Mary Stiner, a zooarchaeologist at the University of Arizona, and the first author on the new study, “and you get to see the big picture.”

People first moved into the village 10,400 years ago, and set up seasonal homes on the banks of a river. People from Turkey to present day Syria, Iraq, and Iran, were beginning to experiment with food storage in this period, Stiner says, which occurred just after the retreat of the glaciers. The residents of Aşıklı Höyük played with gardening, even growing some forms of wheat, although they still ate mostly foraged plants. Most of their meat came from sheep and goats in the surrounding hills. These horned animals stood on long legs, unlike their rotund cousins you’d see on a farm today.

The relationship with those animals grew out of hunting. At first, the residents of Aşıklı Höyük kept young wild goats and sheep in small pens between their homes, where the captured animals left telltale traces of dung. The people of Aşıklı Höyük raised the animals for only a few months—most of the bones from this period are of adolescent animals, killed on the transition to adulthood.

The puzzle is why people would have raised young animals at all. “We can’t expect people to imagine an outcome”—like a herd of managed animals—”that was beyond any experience people would have had,” Stiner points out.

“It isn’t about turning them into docile domesticated animals,” she says. “It’s about live storage, probably to get through the next winter.” The people of this village may have been spiritually motivated to keep animals, too. Elsewhere in the region, the carcasses of pigs, goats, and sheep were butchered into huge chunks for roasting or smoking—and presumably sharing. That’s a practice that shares some similarities with  ritual sacrifice or other ceremonies. Keeping a few young animals around might have been a way of ensuring that there would be meat for a feast.

Four hundred years later, by about 8,000 BCE, the residents of the village lived there full-time. They began to keep bigger herds, and traces of dung became big piles. A few of those animals started to reproduce, as growing numbers of miscarried sheep and goat skeletons in the settlement show.

[Related: Did humans truly domesticate dogs? Canine history is more of a mystery than you think.]

Those unborn skeletons are also evidence of another kind: a steep learning curve for successfully raising livestock. Other research has found that these early captive animals suffered from joint problems, and the high rate of miscarriages suggests that the goats and sheep weren’t getting the food they needed. “Confinement is taking quite a toll on these animals,” says Stiner. “They’re making a lot of mistakes.”

But over a thousand years, the villagers seem to have figured out the skills they needed to keep the animals alive, and even breed them. Food from different sources—mountain pasture or village gardens—leaves a distinct imprint in the form of isotopes in the bones of livestock, as well as within the humans that eat them. Based on those signatures, as the  settlement neared its end, people were getting almost all their meat from domestic livestock—except in religious ceremonies, where wild cattle seem to have taken center stage.

At the same time, the villagers gave sheep and goats freer rein—they were let out into the forests and grasslands, where they ate wild plants, rather than being penned up near the village. That suggests the animals started to act tame. After all, to bring an animal out to pasture, you have to trust that it won’t run away. But even these mild-mannered animals didn’t look like the animals we know today: the sheep were still long-legged like their wild ancestors, and there’s no evidence that they were being raised for wool.

But by the end of the village’s existence, it seems that both people and animals were beginning to depend on one another.