Responded angrily that deer did assume a horse-like gait over there (8)
I believe the answer is:
retorted
'responded' is the definition.
(retorting is a kind of responding)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for retorted that I've seen before include "Made witty response" , "Answered back" , "Came back" , "Made a quick and clever or angry reply" , "Replied" .)