Shelter in kangaroo's territory (5)
I believe the answer is:
roost
'shelter' is the definition.
(roost is a kind of shelter)
'in kangaroo's territory' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ROOST' is hidden within 'kangaroos territory'.
(Other definitions for roost that I've seen before include "Settle down (on a branch?)" , "Thin paper" , "(Bird) settle for night" , "Resting perch for birds" , "Colony of bats; perch" .)