(subspecies Equus caballus przewalskii), last wild horse subspecies surviving in the 21st century. It was discovered in western Mongolia in the late 1870s by the Russian explorer N.M. Przhevalsky (Przhevalsky, Nikolay Mikhaylovich). Several expeditions since 1969 have failed to find this horse, which probably crossed with half-wild domesticated horses and lost its distinct features. Specimens have been kept and bred in zoos, and Mongolia in the late 20th century attempted to reintroduce them into the wild.