Hoepen, 1932] †Vishnutherium Lydekker, 1876 †Vishnutherium iravadicum'' Lydekker 1876 Characteristics The giraffe stands tall, with males taller than females. The giraffe and the okapi have characteristic long necks and long legs. Ossicones are present on males and females in the giraffe, but only on males in the okapi. Giraffids share many common features with other ruminants. They have cloven hooves and cannon bones, much like bovids, and a complex, four-chambered stomach. They have no upper incisors or upper canines, replacing them with a tough, horny pad. An especially long diastema is seen between the front and cheek teeth. The latter are selenodont, adapted for grinding up tough plant matter. Like most other ruminants, the dental formula for giraffids is . Giraffids have prehensile tongues (specially adapted for grasping). The extant giraffids, the forest-dwelling okapi and the savannah-living giraffe, have several features in common, including a pair of skin-covered horns, called ossicones, up to long (absent in female okapis); a long, black, prehensile tongue; lobed canine teeth; patterned coats acting as camouflage; and a back sloping towards the rear. The okapi's neck is long compared to most ruminants, but not nearly so long as the giraffe's. Male giraffes are the tallest of all mammals: their horns reach above the ground and their shoulder , whereas the okapi has a shoulder height of . Distribution The two extant genera are now confined to sub-Saharan Africa. The okapi is restricted to a small range in the northern rainforest of the Democratic Republic of Congo. Although the range of the giraffe is considerably larger, it once covered an area twice the present size — all parts of Africa that could offer an arid and dry landscape furnished with trees. Behavior The social structure and behavior is markedly different in okapis and giraffes, but although little is known of the okapi's behavior in the wild, a few things are known to be present in both species: They have an ambling gait similar to camels, with their weight supported alternately by their left and right legs, while their necks maintain balance. Giraffes can run up to this way and are documented to have covered in the Sahel during the dry season. The dominance hierarchy, which has been well-documented among giraffes, has also been seen among captive okapis. An adult giraffe head can weigh , and if necessary, male giraffes establish a hierarchy among themselves by swinging