Virginia Opossum

Didelphis virginiana

Physical Characteristics

The opossum is about the size of a house cat, has coarse grayish fur, a pointed face, and hairless, rounded ears. With its long hairless prehensile tail, the opossum can carry things such as nesting materials and even hang upside down from a tree branch. Opossum are about 2 to 3 feet long, including the tail, and weigh up to 15 pounds. Males are usually larger than females. Their feet resemble small hands with 5 widely spread fingers. All of the toes have a claw except for the opposable thumb on the rear foot. Opossum are well adapted for climbing. The opposable toe on the hind feet assists in holding on to small branches or similar structures.

Habitat

While their natural habitats are diverse, ranging from arid to moist and wooded to open fields, opossum prefer environments near streams or wetlands. They take shelter in abandoned burrows of other animals, in tree cavities and brush piles, and beneath other dense cover. In urban and suburban settings they may den under steps, porches, decks, garden tool sheds, and if accessible, in attics, garages, and beneath houses, where they make an untidy nest of sticks and whatever else may be available. The nest components appear piled together rather than woven or stacked. The old belief that opossum are nomadic without well-developed home ranges had been disproved. They have complex but flexible social relationships, with overlapping home ranges that allow high populations to develop when food is plentiful.

Diet

In its foraging, the nocturnal opossum is a true omnivore, feeding on fruits, nuts, green plants, insects, snails, frogs, birds and their eggs, and small mammals such as meadow voles, mice, and rats. It eats both fresh meat and carrion and is often seen feeding on road kills, a habit that makes it vulnerable to also being killed. Opossum that live near people may visit vegetable gardens, compost piles, garbage cans, or food dishes intended for dogs and cats. Having lost much of their natural fear of people, they will even enter a home through a pet door in search of food. Fortunately, they are not aggressive unless cornered, when they may hiss, growl, and show their teeth.

Behavior

Opossums are usually solitary and nomadic, staying in one area as long as food and water are easily available. Some families will group together in ready-made burrows or even under houses.Though they will temporarily occupy abandoned burrows, they do not dig or put much effort into building their own. As nocturnal animals, they favor dark, secure areas. These areas mey be below ground or above.

Threatened opossums (especially males) will growl deeply, raising their pitch as the threat becomes more urgent. Males make a clicking “smack” noise out of the side of their mouths as they wander in search of a mate, and females will sometimes repeat the sound in return. When separated or distressed, baby opossums will make a sneezing noise to signal their mother. If threatened, the baby will open its mouth and quietly hiss until the threat is gone.

Hissing and squawking is a defensive process that helps the opossum deter other animals from approaching it.

Breeding

The mating season extends from January to July; 2 litters are produced averaging about seven young each. After a short 13 day gestation period, the tiny, hairless young are born. Like other marsupials, the blind, helpless young find their way into the mother’s pouch where they each attach to one of the 13 teats. No bigger than 1/2” and weighing less than 0.13 gram they do not let go for about 8 weeks, during which time they continue their development and growth. At approximately 11 weeks of age they can leave the pouch for short periods. When the young become too large for all of them to fit inside the pouch at one time, some will ride along by hanging on to the mother’s back. The young are weaned at about 14 weeks, at which time they are about 9” long, not including the tail. Females mate again after the first litter of the season is able to live on their own. The second litter will be sufficiently grown to leave the mother by fall. Mortality in the young is high; most will perish before they are a year old. Those that survive will breed the following spring. Few opossum live beyond 3 years.

 Predators and survival techniques

Opossum have atop running speed of only 7 mph, so they have developed strategies to escape enemies. They readily enter burrows and climb trees in an attempt to elude danger. When threatened, an opossum may bare its teeth, growl, or hiss.  “Playing possum” is another characteristic reaction; the animal rolls over on its side, the animal’s lips are drawn back, the teeth are bared, saliva forms around the mouth, the eyes close or half-closed, and a foul smelling fluid is secreted from the anal glands. The stiff, curled form can be prodded, turned over, and even carried away without reaction. The animal will typically regain consciousness after a period of between 40 minutes and 4 hours, a process which begins with slight twitching of the ears. When surprised during daylight, opossum appear bewildered and sluggish.

References

Virginia Opossum, From Wikipedia, the free encyclopedia

www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74123.html