Definition.com
The Hippopotamus's skin is two inches thick . . . and with a face like that he needs it.
Definition.com
A Hippopotamus is an animal that looks like it's been inflated just past the recommended PSI.
Trivia.com
Hippopotami are able to remain underwater for as long as five minutes
Trivia.com
Hippopotami are able to open their mouths 180 degrees
See also
.com