Archaeologist Sandra Olsen of the Carnegie Museum of Natural History and her team surveyed the Krasnyi Yar site using magnetic meters to map soil irregularities and produce an image of the ancient surface of the site. After mapping 24,300 square meters of the settlement, the researchers identified 54 pit houses and dozens of moulds where vertical posts once stood. Many of these post moulds formed circles, what could have been corrals [see digital reconstruction below]. The scientists proceeded to test the soils within these potential corrals and found unusually high levels of phosphorus--as much as 10 times higher than in adjacent soil--according to a poster presentation of the result at the Geological Society of America meeting this week. Along with more evanescent nitrogen and potassium, horse manure is rich in this element, which can easily be trapped by minerals in the soil and persist for millennia.
The finding adds further evidence that the Botai had domesticated equines. Of the more than 300,000 animal bone fragments found at the site, more than 99 percent are from horses, including backbones and skulls, which Copper Age hunters would be unlikely to lug back to the village if the horses were hunted. And so-called thong smoothers made from bone--a tool used to straighten and stretch a strip of rawhide, perhaps to create bridles or lassos--abound at the site. In previous work, Anthony also discovered microscopic wear on seven horse premolars caused by a bit. Such data, coupled with "soil studies indicating corralling or stabling," evidence of horse carcass butchering over many hundreds of years, and "the appearance of changes in economy and settlement pattern consistent with the beginning of riding together, make a convincing case for horse domestication," he notes.
Nevertheless, the evidence is not definitive. "One should distinguish between keeping horses captive for an unknown length of time and domestication, and much depends on how you define domestication; herding might be a safer term," cautions anthropologist Nerissa Russell of Cornell University. Finding horse fats, however, could seal the case. "Lipids analysis of pottery sherds and soil could identify specifically that horses were there," says Rosemary Capo, a geochemist at the University of Pittsburgh who analyzed the Krasnyi Yar samples. Such an analysis "can distinguish horse mare's milk from [that of a] cow or sheep, for example." After all, one cannot milk a wild mare. But the Botai may not have been first; earlier peoples in what is now Ukraine sacrificed horses in graves and may have domesticated them, considering that they similarly sacrificed domestic sheep and cattle. "If we could find a large settlement of the Khvalynsk people with a large sample of bones," Anthony adds, "we might be able to push the beginnings of horse management back even earlier."