River-dwelling mammal

I believe the answer is:

(Other definitions for hippo that I've seen before include "22 aquatic animal" , "Thick-skinned type" , "Semiaquatic animal" , "Large semi-aquatic pachyderm (abbr)" , "Wallowing mammal" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.