Why People Believed Hippos Were Related to Whales

Name: Why People Believed Hippos Were Related to Whales
Uploaded: 2018-09-13
Duration: 91650
Description: Hippos were once believed to be related to whales. They're both mammals, they both sleep underwater, and they both rise to breathe in their sleep, without waking.

Hippos were once believed to be related to whales. They're both mammals, they both sleep underwater, and they both rise to breathe in their sleep, without waking. (01:31)