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Scientific name: Dedeliphis virginiana
Common name: 
Virginia Opossum

(Information in this Species Page was compiled by Ms. Alaina Knochel in Biology 220W, Spring 2000, at Penn State New Kensington)

The Virginia opossum (Dedeliphis virginiana) is North America’s only marsupial (“pouched”) mammal. It is found often very abundantly throughout the eastern and midwestern United States westward into Colorado and Texas. It is also found in the western coastal states of California, Oregon, and Washington and in the southern regions of British Columbia. It is not typically found in mountainous regions, in extreme deserts, or in the high northern sections of the United States. Susceptibility to frostbite (with resultant tissue damage and debilitating infection) is the primary reason for this species restriction from high altitude and high latitude ecosystems.

Appearance
Adult Virginia opossums are between 24 and 40 inches long. This overall length includes a 10 to 12 inch long tail. They weigh between 4 and 12 pounds with males being larger than females. They have long, coarse dark gray to white-gray outer body fur with a black or dark brown underfur. This darker fur, then, predominates on the legs. Each foot has five toes. The first toe of each hind foot lacks a claw and is opposable (“thumb like”). They have large, black, hairless ears, small black eyes, and white, fur covered faces. Their snouts are long and pointed and tipped with a distinctive, pink nose.

Habitat and Diet
Opossums are incredible generalists with regard to their habitat and food preferences. They can live almost anywhere within their general geographic distribution. They are found in open woods, brushy shrub lands, farmlands, parks, suburbs, and even in urban areas. They may occupy abandoned subterranean dens of other species, or live in hollow logs, tree holes, or under porches or in crawl spaces. They are almost always, though, found relatively close to a reliable water supply of some type. Opossums eat almost anything that they can find. Depending upon availability and opportunity an opossum will eat insects and other invertebrates, fruits, small mammals, birds, bird eggs, carcasses, garbage, and even other opossums. An opossum will very rarely starve. Opossums have a home range of about 50 acres. These ranges change with food availability and do not seem to be intensely contested in territorial disputes.

Opossums are nocturnal foragers. They are often observed by their distinctive eye shine in the illumination of car headlights or flashlights. They are excellent climbers and rapid, if somewhat clumsy, runners. They are active year round and may even extend their activity periods into daylight hours during the winter.

Opossums have excellent night vision but relatively poor distance vision and overall visual acuity. They have excellent hearing and outstanding senses of smell and touch which they use extensively to find and evaluate food.

Reproduction
Opossums are solitary animals except during their breeding seasons which may occur anytime between the months of February to August. A female will reach sexually maturity by one year of age and may, in a good year, have two litters of young. Gestation lasts only 12 to 13 days at which time the tiny newborns crawl their way up into their mother’s fur-lined pouch where they will be nurtured by her mammary secretions. In the pouch the young grow rapidly but will typically remain in the pouch for 8 or 9 more weeks. By 14 weeks of age the young opossums are weaned and are left to fend for themselves. An average litter size is 8 but litters up to 14 young are possible.

Behavior - "Playing Possum"
Opossums make few vocalizations. When aggravated they may hiss, growl, or snap their teeth. Mothers also make a purring sound for their young. When they are disturbed opossums may, if they are unable to make a quick escape, salivate copiously as they hiss and growl and open their mouths very wide to show their rows of 50 teeth. Opossums may also go into an inactive, death-like state under extreme provocation (“playing possum”). In this inactive state the animal will lay limply and motionless on its side with its mouth open, tongue hanging out, and its feet clenched. While in this state the opossum’s respiration is so slow and shallow that it is hardly detectable. Sometimes the opossum will also release a musky odor to add to the overall unpleasantness of its body. The opossum can stay in this state for a few minutes or for several hours. This behavior can, on occasion, sufficiently confuse a predator to allow an individual to survive a potentially fatal encounter.

Life Span, Predators, and Human Interactions
Opossums can live from five to seven years in captivity but probably only live for slightly more than a year in the wild. Natural predators of opossums include foxes, bobcats, and owls. Hawks can also take opossums in the dusk or dawn overlappings of their respective activity periods. Hawk predation could be especially heavy in the winter when the opossums are active during the daylight hours. Domesticated and feral dogs and cats also kill substantial numbers of opossums each year. The opossum’s most significant cause of mortality, though, is the automobile. Opossums crossing roads or feeding on road-kill carrion at night are very commonly struck by passing cars and trucks. Humans seldom hunt opossums although they are edible and have pelts that have been compared favorable to those of mink or silver fox. Most experts agree that the opossum is, if anything, increasing in numbers and that it is expanding the edges of its range throughout North America.


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This page was last updated on July 12, 2006  

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