Monday, September 21, 2015

Virginia Opossum Didelphus virginiana: Only Marsupial of Canada and US


Summary: Virginia Opossum (Didelphus virginiana) is the only marsupial native to Canada and the U.S. The nocturnal scavenger's greatest threat is from cars.


North American Opossum carrying at least 8 joeys on her back: Specialjake, CC BY SA 3.0, via Wikimedia Commons

Didelphus virginiana is a New World mammal native to North America from southeastern Canada through Central America. Canadian native range occurs in a thin sliver across southern Ontario and southern Quebec. Mexican native range encompasses all states except for Baja California. Central American range includes all countries except for Panama. In the United States, Didelphus virginiana claims homelands east of the Rocky Mountains to the Gulf and Atlantic coasts.
Due to intentional introductions during the Great Depression (1929–ca. 1941), Didelphus virginiana successfully ranges along the Pacific coast, from California northward to Washington. From its base in the Pacific Northwest, Didelphus virginiana is expanding into southern British Columbia, Canada’s westernmost province.
Didelphus virginiana is known commonly in English as North American opossum or as Virginia opossum.
The word opossum derives from *wa˙p- aʔθemw, the name given to the native marsupial by the Powhatan tribe of Tidewater Virginia. Transcribed into English as apousom, *wa˙p- aʔθemw means "white animal or dog" (*wa˙p- "white" + *-aʔθemw- "dog, animal").
Versatility in habitat acceptance promotes the characteristic flexibility of Virginia Opossum’s range. When possible, the Virginia Opossum selects thicket and woodland habitats in proximity to streams and swamps as ideal sites for denning in abandoned burrows, hollow logs, and tree cavities.
Virginia Opossum claims unique status as the only marsupial native to Canada and the United States. Marsupials join monotremes (egg layers) and placentals as the three extant, or living, divisions of mammals. Marsupials characteristically carry their young, known as joeys, in pouches or pseudo-pouches of temporary skin folds.
As a medium-sized mammal, the Virginia Opossum generally is sized similarly to a housecat. Total length, from snout to base of tail, ranges from about 13 to 37 inches (35 to 94 centimeters). The long tail contributes an additional 8.5 to 18.5 inches (21.59 to 46.99 centimeters) to their silhouette.
A long white head extends into a snout with long whiskers and a pink nose. Large, leaf-shaped black ears lack fur or hair, rendering them, along with the long naked tail, susceptible to frostbite.
The coat gives a gray to black impression. Northern populations, which feature a much thicker underfur than southern populations, have black-tipped, white underfur covered with a protective coat of greyish guard hairs.
A prehensile tail wraps around branches and opposable thumbs on hind feet enable grasping, gripping, and holding.
As a nocturnal feeder, the Virginia Opossum scavenges for an omnivorous smorgasbord of aquatic and land animals, berries, fruits, garbage, and vegetation. The Virginia Opossum includes in its environmental cleanup diet a penchant for carrion, or dead animals. The Virginia Opossum fearlessly hunts snakes and exhibits immunity to venom.
“Playing possum” is the Virginia Opossum’s legendary strategy to fool predators. No nuance is missed in the Virginia Opossum’s believable, dramatic feigning of death, which may last for 6-plus hours. Eyes are glazed; tongue hangs out; a foul, green anal fluid is emitted; breathing and heart rate are virtually undetectable.
Nevertheless, predators strike at the Virginia Opossum primarily from both air and land. Air attacks are launched by such fearsome predators as Red-Tailed Hawk (Buteo jamaicensis), Barred Owl (Strix varia) and Great Horned Owl (Buteo virginianus). Land strikes are conducted by such wily mammals as coyotes (Canis latrans) and red foxes (Vulpes vulpes).
The greatest threat comes from humans, who have hunted Virginia Opossum as game animal and as fur. Poorly sighted, the Virginia Opossum suffers high mortality from humans in vehicles as accidental or intentional roadkill.
Especially the traditional cuisine of the southeastern United States has featured Virginia Opossum-based recipes for jerky, pie, roast, soup, and stew. The marsupial's meat is described as a sweet white meat.
Virginia opossums in my yard: Virginia Opossums often trek the north-to-south expanse of my yard, moving from the lush field on the northern border to the vast meadow to the south.
This year a female Virginia Opossum, her back mounded with half a dozen joeys, strolled carefully and determinedly southward across the lower terrace in front of my house’s front porch.
Happily the field, meadow and trees framing my yard meet the needs of the unobtrusive Virginia Opossum population so they never seem to venture near the busy rural-suburban highway that runs past my home.

Prehensile tail and opposable thumbs enable Virginia Opossum to be avid, skillful climbers ~ Virginia Opossum (Didelphis virginiana) in juniper tree in northeastern Ohio: Mark A. Wilson (Wilson44691), Public Domain, via Wikimedia Commons

Acknowledgment
My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:
Virginia Opossum (Didelphis virginiana) in juniper tree in northeastern Ohio: Mark A. Wilson (Wilson44691), Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Possum122708.JPG
North American Opossum carrying at least 8 joeys on her back: Specialjake, CC BY SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Didelphis_virginiana_with_young.JPG?uselang=fr


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