The Virginia possums, a creature native to the central United States, has been spreading northward for decades and has established a foothold in Canada. Possums, the only marsupial native to North America, can now be found in southern Ontario and the Lower Mainland of British Columbia, having migrated from the United States.
Possums are especially widespread on Hornby Island, BC. They were first seen there in 1986 and their population grew rapidly because of a lack of competition from native species. Over 600 possums were trapped on Hornby Island in 1988. There is some concern that the possum population will spread from Hornby to nearby Vancouver, but this has not yet happened.
Possums are unlikely to penetrate farther north into Canada because they have difficulty surviving severe cold winters. While possums are not as dangerous to the ecosystem as some other invasive species, they do sometimes carry rabies, they damage local plant and animal life, and they can be a nuisance to homeowners as they eat garbage and crawl into houses.