Homo sapiens trapped Northern Territory's spider (8)
I believe the answer is:
huntsman
'spider' is the definition.
(family of giant spiders)
'homo sapiens trapped northern territory's' is the wordplay.
'homo sapiens' becomes 'human' (humans are the species homo sapiens).
'trapped' means one lot of letters goes inside another.
'northern territory's' becomes 'nt's'.
'human' enclosing 'nts' is 'HUNTSMAN'.
(Other definitions for huntsman that I've seen before include "One chasing quarry" , "One pursuing animals for sport" , "One riding to hounds" , "Who cares for hounds" .)