Some leporids (5)
I believe the answer is:
hares
'some leporids' is the definition.
(hare is a kind of leporid)
This is all the clue.
(Other definitions for hares that I've seen before include "Shares out the swift little animals" , "Long-eared animals" , "Rabbit-like creatures" , "Swift long-eared mammals" , "Fast-running animals" .)