Przewalski's Horse in captivity, San Diego Zoo, USA

Przewalski's Horse, also known as the Asian Wild Horse or Mongolian Wild Horse, or Takhi is the closest living wild relative of the domestic horse.
Most "wild" horses today, such as the American Mustang or the Australian Brumby, are actually feral animals, horses that were once domesticated but escaped and reverted to an apparently wild status. The Przewalski's Horse, on the other hand, has never been successfully domesticated and remains a truly wild animal today.