Deer/swan hybrid responded (8)
I believe the answer is:
answered
'responded' is the definition.
(answering is a kind of responding)
'deerswan hybrid' is the wordplay.
'hybrid' is an anagram indicator (a hybrid is a mixture).
'deerswan' with letters rearranged gives 'ANSWERED'.
(Other definitions for answered that I've seen before include "succeeded" , "Responded to a question" , "Came back" , "Rejoined" , "was sufficient" .)