There Are No More Truly Wild Horses, Study Reports

Przewalski’s horses — a unique equine species from Mongolia — are not as wild as scientists previously thought they were, according to a new study published in the journal Science.

Previously, scientists believed that Przewalski’s horses were the last truly wild horse on Earth. However, it turns out that they are the descendants of the first horses humans domesticated some 5,500 years ago. That is a surprising discovery that reveals, as researchers cannot connect the species to earlier horse populations, humans must have tamed wild horses two different times in history.

The finding alters the way researchers view modern horses and challenges common ideas about how humans and horses are connected. In the study, researchers from the University of Toulouse set out to trace how the horse evolved after it was first domesticated. To do that, they analyzed 88 ancient and modern horse genomes that spanned across more than five millennia. That included 20 horses from the Botai settlements in northern Kazakhstan.

Though the researchers first assumed the Botai horses would be the ancestors of modern horses, they found that they are the ancestors of wild horses instead. Not only that, but the Botai appeared to stop domesticating horses at some point, leading to the feral Przewalski’s horses we have today.

That is important because, while scientists have long believed the Botai culture was the first evidence of horse domestication, they have also wondered about the 1,000 year gap that came before domesticated horses began to regularly pop up in the fossil record. This new study sheds light on that mystery and shows the animals were simply domesticated at two different times in two different regions.

“The first time we saw this result, none of us could believe it,” said study co-author Ludovic Orlando, a researcher at the University of Toulouse, according to NPR. “It was that surprising — this is like turning upside [down] all the theories. We spent a full year trying to kill the evidence we see, and we are very confident that the evidence we see is extremely robust.”