Black-and-white dolphin (4)
I believe the answer is:
orca
'black-and-white dolphin' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for orca that I've seen before include "27 [WHALE]" , "Killer-whale" , "grampus" , "Large mammal" , "ship" .)