The mustang was the only domesticated animal ever to return to the wild in large numbers (The worcl mustang comes from the Spanish word mestenero. A mestenero is a free grazing herd animal.) For years they were the most beautiful and most elusive creatures of the plains. People's imaginations were sparked by this horse. Some swore they had seen fleeing mustags disappear into thin air Others were sure that brave stallions would jump from a cliff to their death rether than be captured. It is not hard to understand these wishful thoughts.