Opossums have a heavy set body that resembles a large house cat. They have a long head with a pointed snout. Their faces have long whiskers. All opossums have long, tapered tails with a scaly appearance. Females have a fur-lined pouch to carry their young (Baker, 1983). The color of the opossum varies by the region. Northern populations have thick underfur that is white in color and has black tips. The pale guard hairs give the opossum a gray appearance. In southern populations, the underfur is much sparser. Both northern and southern populations have white cheek hairs (McManus, 1974). Head and body length varies between 15 - 20 inches, tail length varies between 9 - 20 inches. Weight ranges between 9 - 13 pounds (Wilson and Ruff, 1999).

Opossums are found in a variety of environments, ranging from relatively arid to mesic environments. They prefer wet areas, however, especially streams and swamps. It is hard to determine the exact home range of an opossum because of their unusual movement patterns (McManus, 1974).

Biomes: temperate forest & rainforest

Nearctic: Opossums are found in North America, from Central America and Mexico in the south, through the United States east of the Rocky Mountains and north into southwestern Ontario. Opossums are also found along the west coast of the United States. Their range appears to be expanding northward (McManus, 1974).

The mating season for opossums lasts from January to July. Copulation is usually initiated by the male. After copulation, the female rejects any more solicitations. The egg is fertilized in the Fallopian tubes. Birth occurs about 12.5 to 13 days after copulation. The average litter size ranges from 7 to 9. Depending on latitude, opossums have one or two litters per year. The young opossums weigh about 0.16 grams at birth. They are fixed to the nipple for the first 50 to 65 days of their lives. By 95 to 105 days, the young no longer depend on their mother. There is no maternal bond between the mother and young after they are weaned. Females are able to breed in their first season (McManus, 1974).

Opossums are omnivorous, including a wide variety of food in their diet (Baker, 1983). A majority of their diet is composed of insects and carrion. Opossums are also known to eat plants, including fruits and grains in season.

Opossums are nocturnal animals and have very poor social development. Females tend to live in groups, but the males fight when confined together. Groups of opossums are composed primarily of young because of the short life span of the opossums.

Opossums, both male and female, are very aggressive. They use various forms of intimidation to defend themselves but usually play dead when they encounter a more powerful opponent. Opossums usually travel across the land but will swim in some cases to escape danger. For grooming, opossums use their hind feet to clean their fur and wash their faces with their fore feet. To transport her young, a mother places them on her tail. (McManus, 1974).

Sometimes hunted for sport, especially in the South. Meat is edible, but oily. Occasionally raids poultry yards, but also destroys many mice and insects. Fur of very little value.

Opossums have a defensive tactic called (appropriately enough) "playing possum." In this, the animal fakes death to thwart an attack, and reaches a state of catatonia.

When America was first colonized by Europeans, these possums did not occur north of Pennsylvania. As time passed, they moved north and westward on the Great Plains. In 1890, they were introduced to California from which they spread throughout the west coast.

Rollin H. Baker. 1983.
Michigan Mammals. Michigan State University Press. United States of America.

J. J. McManus. 1974 "Didelphis virginiana." Mammalian Species. The American Society of Mammalogists, 40.

Don E. Wilson and Sue Ruff (Editors). 1999.
The Smithsonian Book of North American Mammals. Smithsonian Institution Press, Washington and London.