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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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