Hears about animals (5)
I believe the answer is:
hares
'animals' is the definition.
(I have seen 'Swift animals ' mean 'hares' so perhaps 'animals' could also mean 'hares')
'hears about' is the wordplay.
'about' indicates anagramming the letters.
'hears' anagrammed gives 'HARES'.
(Other definitions for hares that I've seen before include "Long-eared animals" , "Shares out the swift little animals" , "Fast-running animals" , "Share of wild animals" , "Rabbit-like creatures" .)