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Virginia opossum is a pouched mammal common in the northern America and the size of a cat. It is mostly seen near homes and garbage can scavenging. It is the only pouched mammal in this region.
|Scientific name||Didelphis virginiana|
The size and set of body of a Virginia opossum resembles a house cat. The head is long with a sharp pointed nose. They have whiskers on their faces and long tails which appear scaly. Their ears, tail, and feet do not have fur (Hartman, 1952). They have five toes on every foot with the hind big toe lacking claws. The big toes (thumbs) are opposable and they help in firm grasping of branches during climbing. Females have a pouch to carry premature young ones till they are old enough to fend for themselves. Opossums’ color varies depending on regional location. Those from the north have thick white under fur with black tips. They have guard hairs that are pale giving them the gray color appearance. Southern opossums have sparse under fur. Both populations have white hairs on the cheeks. The length of Virginia opossums varies from 350mm to 940mm while the tail is about 216mm to 470mm. Males weigh about 0.8 to 6.4kg and are larger than females who weigh 0.3kg to 3.7kg (Wilson & Ruff, 1999). They are endothermic. Virginia opossums have fifty teeth with a dental formula of I 5/4, C 1/1, Pm 3/3, M 4/4 X2 = 50. They have thirteen nipples arranged in a circle of twelve and one in the middle.
Virginia opossum is found in North America abundantly in Midwest and eastern United States into Texas and Colorado. It is also found in the states of Oregon, Washington, and California and the British Columbia southern region. Their range is expanding to the north. They are not found in high altitude and latitude areas as they are susceptible to frostbite which results in damage of the tissues and infections. Their biogeographic regions are Nearctic.
Diet, Habitat, and Habits
Virginia opossums generalize their preference in food and habitat. Within their geographic region, they can live anywhere from brushy shrubs, rocks, woodpiles, parks, urban areas, open woods, suburbs, to deciduous forests and farmlands. They occupy dens abandoned by other species, tree holes, crawl spaces, hollow logs, or under porches. They are often found near a dependable water source like swamps, marshes, and streams. They live in temperate regions, and their terrestrial biome is forest; rainforest. Virginia opossum eats almost anything it finds. It will eat invertebrates, carcasses, mice, fruits, insects, other opossums, birds, garbage, small mammals and bird eggs depending on opportunity and availability. It rarely starves. Their scavenging behavior makes them visit homes, dumpsters, and garbage cans in search of food. They hunt worms, chicken, and snakes. Their home range is about 50 acres, which changes with availability of food (Baker, 1983).
Virginia opossums are nocturnal animals. Their shining eyes when illuminated by flashlights or headlights distinguish them. They climb excellently and rapidly, but they are clumsy runners. Their night vision is excellent, but they can not see far, and the overall acuity of their vision is poor. Opossums are active throughout the year, and their activity may be extended to daylight hours of the winter season. When predators threaten them they urinate, belch, or defecate. They are known for their possum game where they lay on the side with eyes wide open and a fixed stare into space, tongue out. This makes them appear dead to the predators, and they can stay in this position for up to four hours.
Females mature at the age of one. The breeding season occurs from February to August. The gestation period of Virginia opossum is twelve to thirteen days, and the average number of litters a female can have in a year is three. The babies born are small, size of honey bees. They crawl up to the pouch after birth and attach to the nipples. An adult female has thirteen nipples. They swell in return providing a secure attachment to the babies where they feed on secretions from the mammary glands. Virginia opossums can have twenty five babies in one litter, but less than half survive. Some of them do not make it to the pouch and others die for lack of nipples to attach to. Babies stay in the pouch for about nine weeks then move out to the back of the mother for four weeks as they are weaned (McManus, 1974). They then leave to fend for themselves. An average opossum lives for eighteenth months in the wild with the oldest having lived three years and about six years if captured. Opossums are mostly killed by cars when feeding at night on carrion which provide protein to the animals.
Despite eating everything, Virginia opossums are also predated by foxes, hawks, coyotes, and large owls. Humans hunt them for food and fur though their fur is not valuable. They are used as research animals in laboratories. In the farmland, they control garden pests (Wilson & Ruff, 1999). Opossums transmit and carry such diseases as rabies. These mammals are the useful lots in the food chain.