The hippopotamus, also called the hippo, common hippopotamus or river hippopotamus, is a large, mostly herbivorous, semiaquatic mammal and ungulate native to sub-Saharan Africa. It is one of only two extant species in the family Hippopotamidae, the other being the pygmy hippopotamus.
Ungainly as it is, the hippopotamus is the world's deadliest large land mammal, killing an estimated 500 people per year in Africa. Hippos are aggressive creatures, and they have very sharp teeth. And you would not want to get stuck under one; at up to 2,750kg they can crush a human to death.