In its low-density populations a territorial system may function, with individuals of the same sex maintaining discrete ranges. In its high-density populations, however, as in parts of New Zealand, there is considerable overlap of home range, both among and between sexes, and territorial behavior is not evident. When mildly disturbed, all species make a metallic clicking sound and then, if further aroused, a series of harsh exhalations with the mouth open. Further disturbance causes the animal to rise on its hind limbs, with the forelimbs raised and outstretched. The possum then extends itself to full height and screams.
All species are powerful fighters.
Females generally attain sexual maturity and begin to breed at 9-12 months, though in some populations this phase is delayed 1 or even 2 years. Both species seem able to live near people and even to expand their range in the face of human development. This species can find shelter in artificial structures and can subsist on garden vegetation, but unlike the Virginia opossum, it now is considered by some to be a major pest. However, this possum is taken extensively in Australia for its pelt. A desire to share in the fur market led to the introduction of T. vulpecula in New Zealand, first in 1840 and more extensively in the 1890s.