The pygmy hippopotamus (Choeropsis liberiensis or Hexaprotodon liberiensis) is a small hippopotamid native to the forests and swamps of West Africa, primarily in Liberia and small populations in Sierra Leone, Guinea and Ivory Coast.The pygmy hippo is reclusive and nocturnal.etween 1970 and 1991 the population of pygmy hippos born in captivity more than doubled. The survival of the species in zoos is more certain than the survival of the species in the wild. In captivity, the pygmy hippo lives from 42 to 55 years, longer than in the wild.