Another type, the Riwoche horse, has been hypothesized to have been developed in isolation to a degree that some claim it is an evolutionary link between the prehistoric wild horse and the modern domestic horse, though it could also be a domesticated variety that reverted to primitive coloring.
The Riwoche horse is hypothesized to be either an isolated breed with a link to the ancient wild horse, or a domesticated horse that has returned to its ancestral coloring.