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Didelphis virginianaVirginia opossum

By Toni Lynn Newell and Rachel Berg

Geographic Range

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).

Habitat

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).

Physical Description

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). Total length varies between 350 and 940 mm, tail length varies between 216 and 470mm. Males are larger than females with male weight ranging from 0.8 to 6.4 kg and female weight ranging from 0.3 to 3.7 kg (Wilson and Ruff, 1999).

  • Range mass
    0.3 to 6.4 kg
    0.66 to 14.10 lb
  • Range length
    35.0 to 94.0 cm
    13.78 to 37.01 in
  • Average length
    74.0 cm
    29.13 in
  • Average basal metabolic rate
    5.299 W
    AnAge

Lifespan / Longevity

Virginia opossums rarely live for longer than 18 months. The oldest known opossum in the wild was 3 years old when last captured. Although they are preyed upon by several predators, most are killed by cars.

  • Range lifespan
    Status: wild
    3.0 (high) years

Behavior

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 their short life span.

Opossums, both male and female, can be aggressive when threatened. 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 and back. (McManus, 1974).

Communication and Perception

Food Habits

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.

Predation

Virginia opossums are well-known for pretending to be dead to avoid being eaten by predators. This is called "playing dead" or "playing possum." When a Virginia opossum thinks that it is being threatened it will go into a catatonic state where it appears to be dead, they go limp and their breathing becomes almost undetectable. They re-awaken when the perceived danger passes.

Virginia opossums are preyed on by predators such as coyotes, foxes, large owls, and hawks. As young they may also be preyed on by snakes and smaller birds of prey, such as falcons. Humans hunt Virginia opossums for food.

Ecosystem Roles

As scavengers, Virginia opossums play an important role in the ecosystem by eating foods and garbage that other animals may not. They are important prey items for predators in the areas where they occur.

Economic Importance for Humans

Economic Importance for Humans: Positive

In the southeastern United States, opossums are sometimes hunted for food. Opossums are used as research animals in a variety of laboratories, their fur is used occasionally, and they help to control garden pests. (Wilson and Ruff, 1999)

  • Positive Impacts
  • body parts are source of valuable material

Economic Importance for Humans: Negative

Occasionally opossums have been known to get into human garbage, however their foraging activities are typically not disruptive (Baker, 1983). They are scavengers and rarely prey on live animals. Opossums can carry and transmit human diseases such as rabies, as can most mammals.

Conservation Status

Adapted well to the presence of humans. Opossums appear to be extending their geographic range. The population density in the wild is not very high (one animal per ten acres).

Other Comments

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. They spread on the west coast. Today in Michigan, they are currently spreading into the Upper Peninsula.

Contributors

Toni Lynn Newell (author), University of Michigan-Ann Arbor, Rachel Berg (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

internal fertilization

fertilization takes place within the female's body

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

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

McManus, J.J. (2 May 1974) "Didelphis virginiana." Mammalian Species. The American Society of Mammalogists, 40.

Hartman, C. 1952. Possums. Austin: University of Texas Press.

Wilson, D., S. Ruff. 1999. The Smithsonian Book of North American Mammals. Washington and London: Smithsonian Institution Press.

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