Aquatic mammals (6)
'aquatic mammals' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for otters that I've seen before include "Fish-eating water animals, put to rest" , "Or test out these mammals" , "Sleek water-animals" , "Fish-eating mammals" , "Aquatic carnivores" .)
'aquatic mammals' is the definition.
(seal is a kind of aquatic mammal)
This is all the clue.
(Other definitions for seals that I've seen before include "Makes waterproof" , "They make an impression" , "Animals spotted on coast" , "Marine mammals" , "they're impressive" .)