The name of their order derives from the fact that their middle toe is larger than their others. Both hind and forefeet of a rhino have 3 digits with small hooves on each.
Rhinos have massive bodies, broad chests and short, stocky legs.
Their large heads have 1 to 2 horns, depending on the species. Their solid horns are made of compressed, fibrous keratin, like our fingernails only much, much stronger. They also have small eyes and short but prominent erect ears. Rhinos have very thick skin and are sometimes called pachyderms, like elephants or hippos. Their thick skin is folded or creased, producing the appearance of riveted armored plates in some species.