Opossum - (Didelphis virginiana)
The opossum is a unique Missouri mammal because it is our only representative of a large group of primitive mammals, the pouched mammals or marsupials, that live mostly in Australia. The females of this group typically have a prominent marsupium, or pouch, on the belly where the young are carried and nourished for a time after their birth.
The common name, opossum, is a corruption of the Algonquian Indian name, apasum.
The opossum is 2-3 feet (609-914 mm) long. Its head is white to yellowish with a pink nose, black eyes and bluish black, naked ears. The long, rather coarse body fur is predominantly grayish white but tends to be darker on the front and hind legs. The long, scaly tail is black at its base, grading to yellowish white or pink for the rest of its length. Opossums weigh 4-l5 pounds (1.8-6.8 kg), males being larger than females.
Distribution and abundance
Opossums live throughout Missouri but are least abundant in the north-western and southeastern parts of the state.
Habitat and home
This mammal prefers to live in wooded areas, mostly near streams. Densely forested sections are not inhabited as much as are farming areas interspersed with small, wooded streams. Timber near other sources of water, such as ponds, lakes and swamps, provides additional habitat.
An opossum's home is any place that is dry, sheltered and safe. Various home sites are dens or nests of other animals, cavities in rocks, brush piles, trash heaps, hollow trees and fallen logs. Inside this shelter, a nest is made of leaves and grass, or sometimes cornhusks. In collecting nesting material, the opossum picks up the leaves with its mouth, transfers them to the front legs, passes them under its body to the hind legs, and then carries the bundle in a loop made in the end of its tail.
This shy and secretive animal is seldom seen because it is abroad mostly at night. Perhaps it is most often observed along highways in the glare of automobile headlights as it feeds on animals killed by traffic. While opossums tend to wander a great deal and shift their home sites frequently, individuals spend most of their lives within about 40 acres (16 ha).
Opossums have traveled as far as 990 feet (301 m) between successive den sites, and a tracked opossum traveled as much as two miles (3.2 km) in one night.
When pursued, opossums often climb trees or brush heaps in an attempt to escape. They have a characteristic reaction known as "playing possum." When frightened, the animal rolls over on its side, becomes limp, shuts its eyes and lets its tongue hang from its open mouth. The heartbeat slows and the animal appears to be dead. Actually, this reaction is nervous shock, but the opossum recovers quickly and is able to take the first opportunity to escape.
These mammals are well adapted for climbing, and the opposable toe on the hind foot assists them in holding onto small branches or similar structures. Opossums can support themselves for short periods entirely by the tail if at least half of it grasps a thick branch.
The opossum eats a variety of foods, but animal matter is preferred. Insects, dead animals, birds and their eggs, frogs, snails and earthworms are the diet during fall and early winter. Corn is eaten most commonly during winter when other, perhaps more desirable foods are not available.
In Missouri, the breeding season begins about the first of February. After only 13 days of pregnancy, the incompletely developed young are born. The average number of young is nine with extremes of five and 13.
At birth, each young is less than 1/2-inch (12 mm) long and weighs only about as much as a dime. With their tiny front feet and claws, the young climb toward the opening of the mother's pouch. Those that find a nipple inside the pouch become firmly attached to it and get nourishment. They do not let go for about 60 days. During this time, they continue their development and growth.
When the little opossums are about the size of house mice, they begin to open their eyes and let go of the nipples for the first time. At 80 days of age, they can leave the pouch for short periods. After the young become too large for all to fit inside the pouch at one time, some ride on the female's back. The young stay with the mother continuously for approximately 100 days. When the young of the first litter are able to live alone, sometime in May, the female mates again. The young of the second litter are sufficiently grown to leave the mother in September.
The opossum is the most common wild mammal in the southern forests of the United States whose fur is used commercially. Although choice skins may be made into coats, the fur is used chiefly to trim inexpensive cloth coats.
The trapping take varies annually due to changes in the demand for long-haired furs and the fluctuating value of the pelts.
Opossums provide sport for night hunters and their hounds. Many people consider the flesh to be good, and baked opossum is a traditional dish in some localities. Although opossums occasionally raid poultry yards, they do little harm otherwise.
Since this species is abundant in Missouri, there is no immediate need for management other than to regulate the harvest.
This series is abstracted from the revised edition of The Wild Mammals of Missouri by Charles and Elizabeth Schwartz. For more detailed information about this species and other mammals in Missouri, refer to this book. Your school library may have it or can borrow it for you from the inter-library loan service. This book can be purchased from the University of Missouri Press, P.O. Box 1644, Columbia, MO 65211, or the Missouri Department of Conservation, P.O. Box 180, Jefferson City, MO 65102.>
This project funded by the 1/8 of 1% conservation sales tax.
© 1981 Missouri Conservation Commission