The horse was domesticated in southern Ukraine about 5,000 years ago, and domestic horses have been introduced all over the world. The wild horses found in the U.S. are the descendants of domestic horses that escaped to the wild. Ten western states have wild horse populations, where they are sometimes called mustangs. In the East, the little Assateague Ponies are found on several islands off the coast of Virginia and Maryland.
These ARE the wild horses, but some horses are just wilder than others.