One who trains and looks after an animal (7)
I believe the answer is:
handler
'one who trains and looks after an animal' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for handler that I've seen before include "good person for Rex?" , "Dealer" , "Boxer's second" , "Someone who directs the activities of a spy" , "Person in charge of police dogs, boxers or spies" .)