Finally remember to feed the forlorn pet hamster? (6)
I believe the answer is:
rodent
'hamster?' is the definition.
(hamster is a kind of rodent)
'finally remember to feed the forlorn pet' is the wordplay.
'finally' suggests the final letters.
The last letters of 'remember to feed the forlorn pet' are 'RODENT'.
(Other definitions for rodent that I've seen before include "E.g. hamster" , "Small gnawing mammal" , "Mouse, squirrel or rat" , "Creature such as a rat" , "Rat perhaps" .)