Animal row involves docking tail (5)
I believe the answer is:
tiger
'animal' is the definition.
(tiger is a type of animal)
'row involves docking tail' is the wordplay.
'row' becomes 'tier' (a tier is a row of things).
'involves' is an insertion indicator.
'tail' says to take the final letters.
The final letter of 'docking' is 'g'.
'tier' placed around 'g' is 'TIGER'.
(Other definitions for tiger that I've seen before include "One of the big cats" , "Shere Khan's type" , "Dangerous animal" , "Large cat with black stripes" , "Large forest cat" .)