Humans may have started tending animals almost 13,000 years ago

Hunter-gatherer groups living in southwest Asia may have started keeping and caring for animals nearly 13,000 years ago — roughly 2,000 years earlier than previously thought.

Ancient plant samples extracted from present-day Syria show hints of charred dung, indicating that people were burning animal droppings by the end of the Old Stone Age, researchers report September 14 in PLOS One. The findings suggest humans were using the dung as fuel and may have started animal tending during or even before the transition to agriculture. But what animals produced the dung and the exact nature of the animal-human relationship remain unclear.

“We know today that dung fuel is a valuable resource, but it hasn’t really been documented prior to the Neolithic,” says Alexia Smith, an archaeobotanist at the University of Connecticut in Storrs (SN: 8/5/03).

Smith and her colleagues reexamined 43 plant samples taken in the 1970s from a residential dwelling at Abu Hureyra, an archaeological site now lost under the Tabqa Dam reservoir. The samples date from roughly 13,300 to 7,800 years ago, spanning the transition from hunter-gatherer societies to farming and herding.

Throughout the samples, the researchers found varying amounts of spherulites, tiny crystals that form in the intestines of animals and are deposited in dung. There was a noticeable uptick between 12,800 and 12,300 years ago, when darkened spherulites also appeared in a fire pit — evidence they were heated to between 500⁰ and 700⁰ Celsius, and probably burned.

The team then cross-referenced these findings against previously published data from Abu Hureyra. It found that the dung burning coincided with a shift from circular to linear buildings, an indication of a more sedentary lifestyle, along with steadily rising numbers of wild sheep at the site and a decline in gazelle and other small game. Combined, the authors argue, these findings suggest humans may have started tending animals outside their homes and were burning the piles of dung at hand as a supplement to wood.

“The spherulite evidence reported here confirms that dung of some sort was used as fuel,” says Naomi Miller, an archaeobotanist at the University of Pennsylvania who was not involved with the study.

Figuring out what animal left the dung could reveal whether animals were tethered outside or not. While the authors propose wild sheep, which would have been more accommodating to capture, Miller suggests the source was probably roaming wild gazelle.

“Spherulites coming from off-site collection of gazelle dung, stored until burned as fuel, is to my mind a more plausible interpretation,” Miller says. Even if kept for a few days, she says, sheep wouldn’t produce large amounts of dung.

“The whole thing is a classic whodunit,” says anthropologist Melinda Zeder, something perhaps DNA analysis could solve (SN: 7/6/17). Gazelle might be the source, she says, and if captured young, the animals may have even been tended for a while — even if they weren’t eventually domesticated.

“The interesting thing is that people [were] experimenting with their environment,” says Zeder, of the Smithsonian Institution in Washington, D.C. “Domestication is almost incidental to that.”