Balucatherium, the largest land mammal ever to walk the surface of the earth, belongs to the group of vertebrates termed the Perissodactyls, or the "odd-toed" ungulates. The name "odd-toed" was derived from the fact that the Perissodactyls walk on an odd number of toes, usually either one or three. The Perissodactyls include the horses, the Titanotheres, the Chalicotheres, the Tapirs, and of course, the Rhinoceroses. Today there are only seventeen species of Perissodactyl left. 
(Above Right: A modern day White rhinocerose. Rhinoceroses are one of the last remaining Perissodactyls left on earth)


(Above: An Icelandic horse. A modern day Perissodactyl)

(Above: Included with the horses are zebras. Here a zebra colt is protected by its mother) on icons to navigate