Again evaluate animals in reserve (8)
I believe the answer is:
reassess
'again evaluate' is the definition.
('assess' can be a synonym for 'evaluate' so perhaps 'reassess' is OK for 'again evaluate')
'animals in reserve' is the wordplay.
'animals' becomes 'asses' (I've seen this before).
'in' is an insertion indicator.
'reserve' becomes 'res' (abbreviation for reserve).
'asses' going within 'res' is 'REASSESS'.
(Other definitions for reassess that I've seen before include "judge again" , "Take stock" , "Revise judgment" , "Have second thoughts" , "reconsider" .)