Family - Hippopotamidae
Hippopotamids are large mammals, with short, stumpy legs, and barrel-shaped bodies. They have large heads, with broad mouths, and nostrils placed at the top of the snout. Like pigs, they have four toes, but unlike pigs, all of the toes are used in walking.
Hippopotamids are unguligrade, although, unlike most other such animals, they have no hooves, instead using a pad of tough connective tissue. Their stomach has three chambers, but they are not true ruminants. The living species are both smooth-skinned, and lack both sebaceous glands and sweat glands. The outer epidermis is relatively thin, so that hippos dehydrate rapidly in dry environments. Both the incisors and canines are large and tusk-like, although the canine tusks are by far the largest. The tusks grow throughout life. The postcanine teeth are large and complex, suited for chewing the plant matter that composes their diet. The number of incisors varies even within the same species, but the general dental formal.
Author: Leiani A.
Photo Credit: http://en.wikipedia.org/wiki/Image:Nijlpaard.jpg