Throw mare out - the poor creature (9)
I believe the answer is:
earthworm
'poor creature' is the definition.
'earthworm' can be an answer for 'creature' (earthworm is a kind of animal). I'm not sure about the 'poor' bit.
'throw mare out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'throw'+'mare'='throwmare'
'throwmare' with letters rearranged gives 'EARTHWORM'.
'the' is the link.
Can you help me to learn more?
(Other definitions for earthworm that I've seen before include "that's throwing up on the lawn" , "Burrowing creature" , "One burrows" , "Soil dweller" , "Creature that burrows in soil" .)