Hippopotamus Surprise egg" of the Italian chocolate company Ferrero SpA. Hippopotamus The common hippopotamus ("Hippopotamus amphibius"), or hippo, is a large, mostly herbivorous, semiaquatic mammal native to sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae, the other being the pygmy hippopotamus ("Choeropsis liberiensis" or "Hexaprotodon liberiensis"). The name comes from the ancient Greek for "river horse" (). After the elephant and rhinoceros, the common hippopotamus is the third-largest type of land mammal and the heaviest extant artiodactyl. Despite their physical resemblance to pigs and other terrestrial even-toed ungulates, the closest living relatives of the Hippopotamidae are
Mammal scheme used, are the [[Primate]]s including the [[ape]]s, [[monkey]]s and [[lemur]]s; the [[Cetartiodactyla]] including [[whale]]s and [[even-toed ungulates]]; and the [[Carnivora]] which includes [[cat]]s, [[dog]]s, [[weasel]]s, [[bear]]s, [[Pinniped|seals]] and allies. According to "[[Mammal Species of the World]]", 5,416 species were identified in 2006. These were grouped into 1,229 [[genus|genera]], 153 [[family (biology)|families]] and 29 orders. In 2008, the [[International Union for Conservation of Nature]] (IUCN) completed a five-year Global Mammal Assessment for its [[IUCN Red List]], which counted 5,488 species. According to a research published in the "[[Journal of Mammalogy]]" in 2018, the number of recognized mammal species is 6,495