Water mammal
I believe the answer is:
otter
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">water mammal</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for otter that I've seen before include "Torte (anag)" , "Semi-aquatic creature" , "Water animal with webbed fee, brown fur and flat tail" , "one that eats fish" , "Aquatic river mammal" .)