Virginia opossum

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The Virginia opossum (Didelphis virginiana), informally called possum, is a solitary, nocturnal marsupial omnivore, common in urbanized areas. It ranges across Central America and North America, east of the Rocky Mountains, and on the west coast. It is the only native marsupial in the United States.

The word "opossum" is a borrowing from the Algonquian wapathemwa meaning "white animal", a description of the pale fur on their faces. Their body fur varies from light gray to gray-brown, and their ears and tails are hairless. Their back feet have opposable "thumbs" which aid in climbing. Adults vary widely in size, from 13 to 37 inches long from snout to rump, and from 1 to 14 pounds in weight. Typically larger animals are found in colder climates, or where food sources are plentiful. Opossums have large mouths with 50 teeth. Their brain cavities are relatively small, approximately a fifth the volume of a comparatively-sized raccoon.

Opossums are omnivorous and opportunistic eaters. They consume a wide variety of plants and animals, including fruits, grains, insects, snails, works, carrion, snakes, birds, and mice. They are well-known as tick eaters, and are largely immune to snake venom. Their low body temperature does not sustain rabies infections. They thrive in urban environments where they enjoy access to garbage, ornamental fruit and pet food.

Opossum reproductive organs are bifid (paired). Female opossums can have up to three litters per year, with up to 20-50 joeys born. Of those, only 13 can suckle and typically only 8 or 9 will survive. Once weaned, they emerge from the mother's pouch and climb onto her back until they reach maturity. The opossum's life span is short: approximately two years in the wild and rarely more than four years in captivity.

An opossum under extreme stress can enter a state of feigned death, popularly known as "playing possum", by dropping motionlessly to its side, baring its teeth, slowing its breathing and emitting a strong putrid-smelling fluid from its anal glands. In other circumstances possums can display ferocity, including hissing, screeching and teeth-baring.

Opossums were described in 1608 by explorer John Smith, who wrote, "An Opassom hath an head like a Swine, and a taile like a Rat, and is of the bignes of a Cat. Under her belly she hath a bagge, wherein she lodgeth, carrieth, and sucketh her young." London anatomist William Cowper contributed the first known scientific description of a Virginia opossum to the Royal Society. Jefferson County's Opossum Valley is named for the animal.

Opossums have long been pursued as game animals. The west coast population of Virginia opossums was introduced intentionally during the Great Depression as a food source.

Notable opossums