They have their own Isle, pets (4)
I believe the answer is:
dogs
'pets' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for dogs that I've seen before include "Shadows" , "eg 27 terriers" , "Canines" , "Hounds" , "Pursues" .)