The hippopotamus ( Hippopotamus amphibius ) , or hippo , from the ancient Greek for `` river horse '' ( ἱπποπόταμος ) , is a large , mostly herbivorous mammal in sub-Saharan Africa , and one of only two extant species in the family Hippopotamidae ( the other is the pygmy hippopotamus ) .
The hippopotamus ( Hippopotamus amphibius ) , or hippo , ancient Greek for `` river horse '' ( Ιπποπόταμος ) , is a large mammal in Africa that usually eats plants .