Hippopotamus skull at Disney's Animal Kingdom
Hippopotamus skull at Disney's Animal Kingdom
Photo credit: Mark Pellegrini

The hippopotamus (Hippopotamus amphibius), from the Greek ‘ιπποπόταμος (hippopotamos, hippos meaning "horse" and potamos meaning "river"), is a large, mostly plant-eating African mammal, one of only two extant and three or four extinct species in the family Hippopotamidae.