Large seal (3,4)
I believe the answer is:
sea lion
'large seal' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sea lion that I've seen before include "Marine beast, the male having a mane" , "Marine animal, used as a circus performer" , "Is alone (anag.)" , "Large marine mammal" , "Large-eared mammal of Pacific Ocean, like Leo" .)