An endangered species of horse -- known as Przewalski's horse -- is much more distantly related to the domestic horse than researchers had previously hypothesized. Credit: Makova lab, Penn State University

UNIVERSITY PARK, Pa., Sept. 7 (UPI) -- An endangered wild horse species in China and Mongolia is not as closely related to the domestic horse as previously thought, U.S. researchers say.

Przewalski's horse -- a stocky, short-maned species named after a Russian explorer who first encountered the animal in the wild -- is down to only about 2,000 population in the wild and a smaller number in wildlife reserves in California and Ukraine, scientists at Penn State University said.


Penn State biologist Kateryna Makova said the species became endangered during the middle of the last century when it experienced a population bottleneck.

"Sadly, this bottleneck was the result of human activity," Makova said. "Przewalski's horses were hunted down for food, and their natural habitat, the steppes, were converted into farm land so the horses basically had nowhere to live and breed. By the late 1950s, only 12 individual horses remained."

Only with great effort has the population been increased to around 2,000 animals, she said in a Penn State release Wednesday.

Many researchers believe the Przewalski species and the domesticated horse, Equus caballus, split as separate species at around the time of the domestication, about 6,000 to 10,000 years ago, but Makova says DNA shows the separation occurred much earlier.

"In fact, they probably shared a common ancestor as far back as 160,000 years ago, long before horse domestication," she said. "This is a major shift in our understanding of the history of Przewalski's horse."