Didelphis virginiana - Virginia opossum
Lateral Posterior Mandible
Adult opossums can range in size
from 24 to 33 inches and they weigh between 6 and 15 pounds with the males
generally being slightly larger than the females. Opossums have short legs
relative to their body size. Opossums are covered with long grey to black hairs
with white tips. This variation in color gives the opossum a dark to
grayish-silver coloration. They have long tapered muzzle and their face, neck
and underbelly are a white to yellowish-white color. The ears and tail of an
opossum are naked. The tail is black for the first few inches and then fades to
a white or a cream skin color. The typical dental formula for the opossum is as
The Virginia opossum ranges north
and south from New York to Florida. They range east and west from the Atlantic
coast to the Midwest and down through Texas and into Mexico (Lyon 1936). The
only place in the U.S. where the opossum is not found is in the upper
northwest. All of Wisconsin is considered prime habitat for the opossum.
Opossums have dentition that
suggests omnivory, which is the case for the species. Opossums can survive on a
wide-ranging diet. They consume flesh in the form of dead animals, birds and
their eggs, frogs, worms, snails, etc. They also eat berries and fruits when
present. In agricultural areas they feed on corn. In areas where opossums have
urbanized they subside on refuse and waste from neighborhood garbage cans. This
ability to adapt to a wide variety of foods is part of the reason why opossums
are so far ranging. Most foraging is done at night throughout their home
range. Males typically have a home range of about 105 ha. The females’ home range
is much smaller averaging approximately 51 ha. (Gillette 1980).
The opossum is North America’s
only marsupial. One important character of marsupials is that they have an
epipubic bone attached to the pelvis (Lyon 1936). The female has a posterior
opening pouch which contains 13 teets for nourishing young. Following a brief
gestation of only 12 to 13 days the young are born and immediately crawl to the
pouch and begin nursing. A typical litter consists of 12 to 22 offspring.
Those that are not able to locate and attach to a teet die of starvation.
Ecology and Behavior:
Opossums prefer to live near a constant source
of water such as a river or stream. They nest in standing snags as well as
fallen trees and the abandoned burrows of other animals. Opossums prefer edge
habitat over large expansive forests. Many times they are found near
agricultural fields that produce corn. In urban environments they have been
found to nest in tool sheds and barns. Their ability to adapt and use a variety
of nest sites is another reason why the opossum is so far ranging.
Opossums are usually not social
unless they are actively looking to mate. Males remain ready to mate throughout
the year and must wait for the female to come into estrous to breed (Winegarner
1982). They are slow moving and quiet animals. Opossums are mostly nocturnal or
diurnal. They are not aggressive except for females immediately before and
after estrous. One interesting character of the opossum is their defensive
behavior. When confronted an opossum will roll over and remain motionless as if
feigning death. This curious behavior has coined the phrase “playing possum”
Opossums were at one time valued for their fur,
which was used to make cuffs and collars for jackets and coats. They are still
trapped by some and eaten although they are not regarded as a prime source of
nutrition. They are hunted primarily in the southern U.S. at night with the
aide of hounds and spotlights (Lyon 1936).
McManus, J.J. 1970. Behavior of Captive Opossums, Didelphis
marsupialis virginiana. American Midland Naturalist 84(1): 144-169.
Lyon Jr, M.W. 1936. Mammals of Indiana. American Midland
Naturalist 17(1): 1-373.
Ladine, T.A. and Kissell Jr, R.E. 1994. Behavior of Escape
Virginia Opossums. American Midland Naturalist 132(2): 234-238.
Allen, C.H. et al. 1985. Movement,
Habitat Use and Denning of Opossums in the Georgia Piedmont (in Notes and
Discussion). American Midland Naturalist 113(2): 408-412.
Gillette, L.N. 1980. Movement Patterns of Radio-Tagged
Opossums in Wisconsin. American Midland Naturalist 104(1): 1-12.
M.S. 1982. Seasonal Changes in the Reproductive Tract of the
Male Opossum Didelphis virginiana Kerr in Florida. American Midland Naturalist
written by Michael Hawley, Biol 378: Edited by Chris Yahnke and Jen Callahan.
Page last updated 4-23-04.