At first glance, the pygmy hippopotamus looks like a mini version of its larger relative, the hippopotamus (also known as the river or common hippopotamus). But it differs in behavior and physical characteristics. The pygmy hippo has adaptations for spending time in the water but is much less aquatic than the hippo. Its nose and ears close underwater just like a hippo's do, but its head is rounder and narrower, its neck is proportionally longer, and its eyes are not on the top of its head.