Ship carrying animal portions (6)
I believe the answer is:
shares
'portions' is the definition.
(I know this)
'ship carrying animal' is the wordplay.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'carrying' indicates putting letters inside.
'animal' becomes 'hare' (I have seen 'Swift animal ' mean 'hare' so perhaps 'animal' could also mean 'hare').
'ss' going around 'hare' is 'SHARES'.
(Other definitions for shares that I've seen before include "Portions or divisions" , "Distributes, gives portions to others" , "The equal parts forming a company's business capital" , "Possesses in common" , "Apportions, divvies up" .)