Findings of a new genetic study have found that there are no longer truly wild horses that exist today.

Researchers found that the Przewalski's horses in the Mongolian grasslands are just the untamed descendants of the earliest-known species of domesticated horses.

The Last Wild Horse

The Przewalski's horse in Mongolia, which currently has a population of about 2,000, has long been thought to be the last wild horse. It was thought that unlike other free-roaming horses such as the mustangs in the United States that ascended from steeds brought by the Spaniards to North America centuries ago, the Przewalski's horse has no history of domestication.

This idea is now being nullified in a research published in the journal Science.

Family Tree Of Horses

Study researcher Sandra Olsen, from the University of Kansas, and colleagues sequenced the genomes of 42 ancient horse genomes, which include those from the remains of horses unearthed from the archeological site of Botai in northern Kazakhstan.

After comparing the genomes of the ancient horses with those with already-existing sequences, including the Przewalski's horses, the researchers built a family tree of horses that show which breeds were most closely related.

The family tree showed that Przewalski's horses descended from the earliest-known domesticated horses that were kept by the Botai people about 5,500 years ago

No Living Wild Horses

The findings showed that what were popular thought of as wild horses were actually feral. The researchers said that the Przewalski's horses may have eluded domestication, but these were not originally wild.

"This means there are no living wild horses on Earth — that's the sad part," said Olsen. "We thought there was one last wild species, and we're only just now aware that all wild horses went extinct."

The researchers think that Przewalski's horses possibly escaped from domestic Botai herds in Mongolia or Kazakhstan.

Wild Appearance

Olsen said that these animals developed a semi-wild lifestyle, but they still have a wild appearance. They have a dun coat similar to those seen in the Ice Age cave paintings in Spain and France that were made when horses were wild. The animals also have an upright mane associated with wild equids.

The Przewalski's horses' appearance may partly explain why biologists assumed that they were genuine wild horses. The size of these horses, though, is very similar to those in Botai.

"Our data indicate that Przewalski's horses are the feral descendants of horses herded at Botai and not truly wild horses," the researchers wrote in their study.

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