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
Australopithecus africanus and STS 71), but also presents primitive features including ape-like, curved fingers adapted to tree climbing. Instead of it being a direct ancestor of later hominins and thereby of humans, some researchers believe that "A. africanus" evolved into "Paranthropus", and specifically that "P. robustus" descended from "A. africanus". Both "P. robustus" and "A. africanus" crania seem very alike despite the more heavily built (robust) features of "P. robustus", which, like those of the modern gorilla, are adaptations for heavy chewing. "A. africanus", on the other hand, had a cranium which quite closely resembled that of a modern chimpanzee; yet both