Animal found in middle of mountains, say (3)
I believe the answer is:
teg
'animal' is the definition.
(teg is a kind of animal)
'middle of mountains say' is the wordplay.
'middle of' indicates the central letters.
'say' becomes 'eg' (both can mean 'for example').
The central letter of 'mountains' is 't'.
't'+'eg'='TEG'
'found in' acts as a link.
(Other definitions for teg that I've seen before include "Get a sheep in its second year" , "Young sheep" , "Two-year-old sheep" , "Get around a sheep" , "Second-year sheep" .)