Part of small animal (5)
I believe the answer is:
share
'part' is the definition.
(I know that part can be written as share)
'small animal' is the wordplay.
I cannot really understand how this works, but
'small' could be 's' (abbreviation - e.g. clothes size) and 's' is found in the answer.
'animal' could be 'hare' (I have seen 'Swift animal ' mean 'hare' so perhaps 'animal' could also mean 'hare') and 'hare' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for share that I've seen before include "Helping" , "Give portion to others" , "Divide out, apportion" , "Allotted portion" , "Allocate" .)