Hippopotamidae

Hippopotamidae is a family of stout, naked-skinned, semiaquatic artiodactyl mammals. Two species survive today, the common hippopotamus of African rivers and lakes and the smaller pygmy hippopotamus of West African forests. Hippos have three-chambered stomachs, walk on four toes on each foot, and despite their pig-like build their closest living relatives are the cetaceans. They have short stumpy legs, barrel-shaped bodies, large heads with broad mouths, tusk-like teeth, and lack sebaceous and sweat glands, which makes them dehydrate quickly outside water.