The Pygmy Hippopotamus (Choeropsis liberiensis or Hexaprotodon liberiensis) is a large mammal native to the forests and swamps of western Africa (the species name, meaning "of Liberia", reflects this). The pygmy hippo is a herbivore and also nocturnal. It is one of only two extant species in the hippopotamus family. Unlike its larger relative, the Hippopotamus, relatively little is known about the pygmy hippo's diet or behaviour, although it is clear that the pygmy hippo is adapted to forest environments rather than the more open plains and grasslands that the hippopotamus prefers.