A foal of Przewalski's horse is seen with grown-ups at a wild horse breeding research center in northwest China's Xinjiang Uygur Autonomous Region, May 22, 2019. Four foals of Przewalski's horse, a type of endangered horse, have been born since the breeding season starts in May, a breeding center in northwest China's Xinjiang Uygur Autonomous Region said Thursday. Przewalski's horses are the only surviving horse subspecies never to have been domesticated. They have historically lived on grasslands that are now part of China's Xinjiang and Mongolia. (Xinhua/Zhang Hefan)

A foal of Przewalski's horse is seen with grown-ups at a wild horse breeding research center in northwest China's Xinjiang Uygur Autonomous Region, May 23, 2019. Four foals of Przewalski's horse, a type of endangered horse, have been born since the breeding season starts in May, a breeding center in northwest China's Xinjiang Uygur Autonomous Region said Thursday. Przewalski's horses are the only surviving horse subspecies never to have been domesticated. They have historically lived on grasslands that are now part of China's Xinjiang and Mongolia. (Xinhua/Zhang Hefan)

A foal of Przewalski's horse is seen with a grown-up at a wild horse breeding research center in northwest China's Xinjiang Uygur Autonomous Region, May 22, 2019. Four foals of Przewalski's horse, a type of endangered horse, have been born since the breeding season starts in May, a breeding center in northwest China's Xinjiang Uygur Autonomous Region said Thursday. Przewalski's horses are the only surviving horse subspecies never to have been domesticated. They have historically lived on grasslands that are now part of China's Xinjiang and Mongolia. (Xinhua/Zhang Hefan)