Herbivorous animal's right at home with endlessly hot housing (5)
I believe the answer is:
rhino
'herbivorous animal's' is the definition.
'right at home with endlessly hot housing' is the wordplay.
'right' becomes 'r' (common abbreviation).
'at' means one lot of letters go next to another.
'home with' becomes 'in' ('he's home' can mean 'he's in'. I am not sure about the 'with' bit.**).
'endlessly' means to remove the last letter.
'housing' is an insertion indicator.
'hot' with its final letter taken off is 'ho'.
'in' put within 'ho' is 'hino'.
'r'+'hino'='RHINO'
(Other definitions for rhino that I've seen before include "thick-skinned creature" , "wild beast" , "greens" , "Cash" , "Horned creature" .)