Virginia Opossum

The Virginia opossum is a solitary, nocturnal marsupial about the size of a domestic cat, found from southern Canada to northern Costa Rica, which makes it the northernmost marsupial in the world. It is omnivorous, eating plants, small invertebrates, carrion, eggs and small animals, and it often lives near settled areas where trash, pet food and gardens offer easy meals. The coat is dull grayish brown with a white face, and the long, hairless tail is prehensile. Newborns are about the size of a honeybee and climb into the mother's pouch to latch onto one of her 13 teats.

About the Virginia opossum

The Virginia opossum is a member of the opossum family found from southern Canada down to northern Costa Rica, which makes it the northernmost marsupial in the world. About the size of a domestic cat, it is a solitary, nocturnal animal and, by most measures, a highly successful opportunist. Its name traces back to the Algonquian word wapathemwa, meaning "white animal," and it was the original animal called an "opossum" — a term now used more broadly for other marsupials in the Didelphidae and Caenolestidae families. The genus name Didelphis comes from the Ancient Greek for "two wombs."

The species varies considerably in size across its range, with the largest individuals found in the north and the smallest in the tropics. Body length runs from 33 to 55 cm (13–22 in), with the tail adding another 25 to 54 cm (9.8–21.3 in). Males average a body length of 40.8 cm (16.1 in) with a 29.4 cm (11.6 in) tail, while females average 40.6 cm (16.0 in) with a 28.1 cm (11.1 in) tail. Males typically weigh 2.1–2.8 kg (4.6–6.2 lb) and females 1.9–2.1 kg (4.2–4.6 lb). The coat is a dull grayish brown, with a white face, long hairless ears, a long flat nose, and a long, hairless, prehensile tail used for grabbing branches and carrying small objects. Opossums have 50 teeth — more than any other North American land mammal — and opposable, clawless thumbs on their hind feet. They also carry 13 nipples, arranged as a ring of 12 around a single central one.

Its ancestors evolved in South America and spread north as part of the Great American Interchange after the Isthmus of Panama formed roughly 3 million years ago, with Didelphis itself entering North America about 0.8 million years ago.

Behavior and diet

The Virginia opossum's best-known trait is "playing possum." If threatened, it will first try to look intimidating — baring its 50 teeth, snapping its jaw, hissing, drooling, and puffing up its fur. If that fails, it feigns death: the animal goes limp on its side with mouth and eyes open, tongue out, and feet clenched, while its heart rate drops by half and its breathing becomes shallow and hard to detect. It may also release a putrid green fluid from its anus to repel predators. This death-feigning state can last several hours and normally ends only once the threat has moved on.

Opossums are omnivorous, eating a wide range of plant and animal food. Insects such as grasshoppers, crickets, and beetles make up the bulk of their animal diet, alongside young rabbits, meadow voles, mice, rats, birds, snakes, lizards, frogs, fish, crayfish, gastropods, and earthworms. They are notably resistant to snake venom thanks to unique blood proteins. Plant food — raspberries, blackberries, apples, acorns, beechnuts, seeds, grains, bulbs, and vegetables, with persimmons a particular favorite — is eaten mainly in late summer, autumn, and early winter. In cities, opossums readily scavenge bird feeders, gardens, compost piles, garbage cans, and pet food left outdoors.

Breeding can start as early as December and run through October, with most young born between February and June; a female may have one to three litters a year. Gestation lasts just 11–13 days, and the average litter is 8–9 infants, though more than 20 can be born at once. Newborns, each about the size of a honeybee, crawl into the mother's pouch and attach to a teat for about two months, then ride on her back for several more weeks while they learn to survive on their own. Mortality among young is high — only about one in ten reaches reproductive adulthood — and young opossums typically leave their mother after four or five months.

Range and habitat

The Virginia opossum's original range before European settlement extended roughly as far north as Maryland, southern Ohio, Indiana, and Illinois, and Missouri and Kansas. Clearing of dense forest and the loss of the opossum's main predators in these areas let the species push northward, and since 1900 it has expanded into most of New England, New York, southern Ontario, Michigan, Wisconsin, Minnesota, southeastern South Dakota, and most of Nebraska. It was not originally native to the West Coast — it was intentionally introduced there during the Great Depression, likely as a food source, and now occupies much of the Pacific coast, with its range still creeping north into British Columbia. Small, possibly introduced populations also occur in eastern New Mexico and parts of southern and central Arizona.

The species does not hibernate, but it becomes far less active in winter and may stay in its den for several days when temperatures drop below about −7 to −4 °C (19 to 25 °F), since it is not well adapted to cold or heavy snow.

Conservation status

The Virginia opossum is listed as Least Concern, and its range has been expanding rather than shrinking. No major conservation threats are noted for the species, though individual animals are frequently killed on roads: their slow, nocturnal habits and attraction to roadside carrion make them especially likely to become roadkill, and both breeding-season males (which range farther searching for mates) and females carrying young (which forage longer and later) face elevated risk. Opossums are not considered dangerous to humans and are naturally resistant to rabies, though they can carry other diseases and parasites, including tuberculosis, leptospirosis, and tularemia.