All Odd-Toed Ungulates (Perissodactyla)

This group gathers Mammals subcategory members belonging to the order Perissodactyla, the odd-toed hoofed mammals, whose weight rests on an odd number of toes, usually one in the horse family or three in the rhinoceros and tapir families. It spans the horse family, Equidae, including the domestic and Przewalski's horse, the plains zebra, and the donkey, the rhinoceros family, including the white, black, Javan, Sumatran and Bornean rhinoceroses, and the tapir family, whose members retain a more primitive body plan closer to the group's common ancestor than either the horses or the rhinoceroses. Once a far larger and more diverse order, Perissodactyla has been reduced by extinction to these three surviving families, several of whose living species are themselves now critically endangered.