Equus (genus) and pioneer spirit of the West" under the Wild and Free-Roaming Horses and Burros Act of 1971, and in "Kleppe v. New Mexico", the United States Supreme Court ruled that the animals so designated were, as a matter of law, wildlife. Equus (genus) Equus is a genus of mammals in the family Equidae, which includes horses, donkeys, and zebras. Within Equidae, "Equus" is the only recognized extant genus, comprising seven living species. The term equine refers to any member of this genus, including horses. Like Equidae more broadly, "Equus" has numerous extinct species known only from fossils. The genus most
Equus scotti assigned fossils from the Anza-Borrego Desert in California, tentatively interpreted to represent "E. bautistensis", to "E. scotti". One of the reported locations farthest south in the Americas is Pali Aike National Park in Chile. Equus scotti Equus scotti (translated from Latin as Scott's horse, named after vertebrate paleontologist William Berryman Scott) is an extinct species of "Equus", the genus that includes the horse. "E. scotti" was native to North America and likely evolved from earlier, more zebra-like North American equids early in the Pleistocene Epoch. The species may have crossed from North America to Eurasia over the Bering land bridge