Animal doctor poses naked (5)
I believe the answer is:
moose
'animal' is the definition.
(type of animal)
'doctor poses naked' is the wordplay.
'doctor' becomes 'mo' (medical officer).
'naked' means to look at the middle letters (outside letters removed so centre is unclothed).
The middle of 'poses' is 'ose'.
'mo'+'ose'='MOOSE'
(Other definitions for moose that I've seen before include "Large US deer" , "beasts" , "Large northern deer" , "US deer with enormous antlers" , "North American elk" .)