Cat’s drums (4)
I believe the answer is:
toms
'cat's drums' is the definition.
The answer and definition can be both animals as well as being plural nouns.
Perhaps you can see a link between them that I don't see?
'cat's drums' is the wordplay.
'cat' becomes 'tom' (a tom is a male cat).
'drums' becomes 's' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tom'+'s'='TOMS'
Can you help me to learn more?
(Another definition for toms that I've seen is " Male cats".)