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
Pygmy killer whale Pygmy killer whale The pygmy killer whale ("Feresa attenuata") is a poorly known and rarely seen oceanic dolphin. It derives its common name from sharing some physical characteristics with the killer whale. It is the smallest species that has "whale" in its common name. Although the species has been known to be extremely aggressive in captivity, this aggressive behavior has not been observed in the wild. The species had been described by John Gray in 1874, based on two skulls identified in 1827 and 1874. The next recorded sighting was in 1952 which led to its formal naming by Japanese