Virginia opossum

Last updated

Contents

Virginia opossum [1]
Temporal range:
Middle Pleistocene – present (~600,000–0 YBP) [2]
Opossum 2.jpg
North American opossum in winter
Status TNC G5.svg
Secure  (NatureServe) [4]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Didelphimorphia
Family: Didelphidae
Genus: Didelphis
Species:
D. virginiana
Binomial name
Didelphis virginiana
(Kerr, 1792)
Virginia Opossum range.png
Range of habitat, showing both historic, native range and introductions in the west; these areas are currently expanding northward (e.g., into Wisconsin and Minnesota). [5]
Synonyms

Didelphis marsupialis virginiana [6]

The Virginia opossum (Didelphis virginiana), also known as the North American opossum, is the only opossum living north of Mexico, its range extending south into Central America. It is the northernmost marsupial in the world. In the United States and Canada, it is typically called a possum. [7] It is a solitary nocturnal animal about the size of a domestic cat, and a successful opportunist.

Opossums are familiar to many North Americans as they frequently inhabit settled areas near food sources like trash cans, pet food, compost piles, gardens or housemice. Their slow, nocturnal nature and their attraction to roadside carrion make opossums more likely to become roadkill.

Name

The Virginia opossum is the original animal named "opossum", a word which comes from Algonquian wapathemwa, meaning "white animal". Colloquially, the Virginia opossum is frequently just called a "possum". [8] The name opossum is applied more generally to any of the other marsupials of the families Didelphidae and Caenolestidae. The generic name (Didelphis) is derived from Ancient Greek: di, "two", and delphus, "womb". [9]

The possums of Australia, whose name derives from their similarity to the opossums of the Americas, are also marsupials, but of the order Diprotodontia.

The Virginia opossum is known in Mexico as tlacuache, tacuachi, and tlacuachi, from the Nahuatl word tlacuatzin.

Range

The Virginia opossum's ancestors evolved in South America, but spread into North America as part of the Great American Interchange, which occurred mainly after the formation of the Isthmus of Panama about 3 million years ago. Didelphis was apparently one of the later migrants, entering North America about 0.8 million years ago. [10] It is now found throughout Central America and North America from Costa Rica to southern Ontario and is expanding its range northward, northwesterly and northeasterly at a significant pace. [8]

Its pre-European settlement range was generally as far north as Maryland; southern Ohio, Indiana and Illinois; Missouri and Kansas. The clearing of dense forests in these areas and further north by settlers allowed the opossum to move northward. Elimination of the opossum's main predators in these areas also contributed to their expansion. Since 1900, it has expanded its range to include most of New England (including Maine); New York, extreme southwestern Quebec; most of southern and eastern Ontario; most of Michigan and Wisconsin; most of Minnesota, southeastern South Dakota and most of Nebraska.

Areas such as Rhode Island and Waterloo Region and Simcoe County in southern Ontario rarely had sightings of opossums in the 1960s, but now have them regularly; some speculate that this is likely due to global warming causing winters to be warmer. [11] Some people speculate the expansion into Ontario mostly occurred by opossums accidentally being transferred across the St. Lawrence, Niagara, Detroit and St. Clair rivers by motor vehicles or trains they may have climbed upon. As the opossum is not adapted to colder winters or heavy snow, its population may be significantly reduced if a colder winter with heavier snow occurs in a particular northern region.

The Virginia opossum was not originally native to the West Coast of the United States. It was intentionally introduced into the West [8] during the Great Depression, probably as a source of food, [12] and now occupies much of the Pacific coast. Its range has been expanding steadily northward into British Columbia, Canada.

Description

Skull of a Virginia opossum Opossum Skull.jpg
Skull of a Virginia opossum
The back foot has an opposable "thumb". Virginia opossum opposable thumb.jpg
The back foot has an opposable "thumb".

Virginia opossums can vary considerably in size, with larger specimens found to the north of the opossum's range and smaller specimens in the tropics. They measure 33–55 cm (13–22 in) long from their snout to the base of the tail, with the tail adding another 25–54 cm (9.8–21.3 in). Males are slightly larger, with an average body length of 40.8 cm (16.1 in) with an average tail length of 29.4 cm (11.6 in), while females are 40.6 cm (16.0 in) long with a 28.1 cm (11.1 in) tail. Weight for males ranges from 2.1–2.8 kg (4.6–6.2 lb) and for females from 1.9–2.1 kg (4.2–4.6 lb). [13]

Their coats are a dull grayish brown, other than on their faces, which are white. Opossums have long, hairless, prehensile tails, which can be used to grab branches and carry small objects. They also have hairless ears and a long, flat nose. Opossums have 50 teeth, more than any other North American land mammal, [14] and opposable, clawless thumbs on their rear limbs. Opossums have 13 nipples, arranged in a circle of 12 with one in the middle. [15] [16]

The dental formula of an opossum is 5.1.3.44.1.3.4. [17] No other mammal in North America has more than 6 upper incisors, but the Virginia opossum has 10.

Perhaps surprisingly for such a widespread and successful species, the Virginia opossum has one of the lowest encephalization quotients of any marsupial. [18] Its brain is one-fifth the size of a raccoon's. [19]

Tracks

Opossum tracks (photo center) in mud: Left-fore print appears on left center of photo, right-hind print appears right center. The small, circular tracks at bottom center of photo were made by a meadow vole. The yellow ruler (top) is in inches. Opossum and vole tracks in mud.JPG
Opossum tracks (photo center) in mud: Left-fore print appears on left center of photo, right-hind print appears right center. The small, circular tracks at bottom center of photo were made by a meadow vole. The yellow ruler (top) is in inches.
Pacing diagram for Virginia opossum - key: rectangles represent hind tracks, ellipses are fore tracks, left tracks are red, right are green. (a) the position of the four feet frozen in mid-pace. (b) the opossum brings right fore and hind feet forward. (c) the opossum brings left fore and hind feet forward. One grid square represents one square inch. Pacing diagram opossum.png
Pacing diagram for Virginia opossum - key: rectangles represent hind tracks, ellipses are fore tracks, left tracks are red, right are green. (a) the position of the four feet frozen in mid-pace. (b) the opossum brings right fore and hind feet forward. (c) the opossum brings left fore and hind feet forward. One grid square represents one square inch.

Virginia opossum tracks generally show five finger-like toes in both the fore and hind prints. [20] The hind tracks are unusual and distinctive due to the opossum's opposable thumb, which generally prints at an angle of 90° or greater to the other fingers (sometimes near 180°). Individual adult tracks generally measure 1.9 in long by 2.0 in wide (4.8 × 5.1 cm) for the fore prints and 2.5 in long by 2.3 in wide (6.4 × 5.7 cm) for the hind prints. Opossums have claws on all fingers fore and hind except on the two thumbs (in the photograph, claw marks show as small holes just beyond the tip of each finger); these generally show in the tracks. In a soft medium, such as the mud in this photograph, the foot pads clearly show (these are the deep, darker areas where the fingers and toes meet the rest of the hand or foot, which have been filled with plant debris by wind due to the advanced age of the tracks).

The tracks in the photograph were made while the opossum was walking with its typical pacing gait. The four aligned toes on the hind print show the approximate direction of travel.

In a pacing gait, the limbs on one side of the body are moved simultaneously, just prior to moving both limbs on the other side of the body. This is illustrated in the pacing diagram, which explains why the left-fore and right-hind tracks are generally found together (and vice versa). If the opossum was not walking (perhaps running), the prints would fall in a different pattern. Other animals that generally employ a pacing gait are raccoons, bears, skunks, badgers, woodchucks, porcupines, and beavers.

When pacing, the opossum's 'stride' generally measures from 7 to 10 in, or 18 to 25 cm (in the pacing diagram the stride is 8.5 in, where one grid square is equal to 1 in2). To determine the stride of a pacing gait, measure from the tip (just beyond the fingers or toes in the direction of travel, disregarding claw marks) of one set of fore/hind tracks to the tip of the next set. By taking careful stride and track-size measurements, one can usually determine what species of animal created a set of tracks, even when individual track details are vague or obscured.

Behavior

"Playing possum"

When injured or threatened (e.g., by a dog), the Virginia opossum is known to feign death or "play possum". PlayingPossum.jpg
When injured or threatened (e.g., by a dog), the Virginia opossum is known to feign death or "play possum".

If threatened, an opossum will either flee or take a stand. To appear threatening, an opossum will first bare its 50 teeth, snap its jaw, hiss, drool, and stand its fur on end to look bigger. [21] If this does not work, the Virginia opossum is noted for feigning death in response to extreme fear. [22] This is the genesis of the term "playing possum", which means pretending to be dead or injured with intent to deceive. [23]

In this inactive state it lies limp and motionless on its side, mouth and eyes open, tongue hanging out, and feet clenched. [21] Fear can also cause the opossum to release a green fluid from its anus with a putrid odor that repels predators. [22] [24] Heart rate drops by half, and breathing rate is so slow and shallow it is hardly detectable. [21] Death feigning normally stops when the threat withdraws, and it can last for several hours. [21] [24] Besides discouraging animals that eat live prey, playing possum also convinces some large animals that the opossum is no threat to their young. [22] "Playing possum" in response to threats from oncoming traffic often results in death. [25]

Diet

Night camera shows video of an opossum considering a bagel before walking away

Opossums are omnivorous (sometimes said to be insectivorous) and eat a wide range of plant-based food, as well as animal-based food like small invertebrates, carrion, eggs, fish, amphibians, reptiles, birds, small mammals, and other small animals. [26]

Insects such as grasshoppers, crickets, and beetles make up the bulk of the animal foods eaten by opossums. [27] It has been stated that opossums eat up to 95% of the ticks they encounter. [25] [28] and may eat up to 5,000 ticks per season, helping to prevent the spread of tick-born illnesses, including Lyme disease and Rocky Mountain spotted fever. [28] This interpretation has been challenged. [29] A widely publicized 2009 study by the Cary Institute indicated that Virginia opossums in a laboratory setting could eat thousands of ticks per week grooming. [30] [31] However, subsequent studies of the stomach contents of wild Virginia opossums have not found any ticks in their diet. [32]

Small animals include young rabbits, meadow voles, mice, rats, birds, snakes, lizards, frogs, fish, crayfish, gastropods, and earthworms. [33] [34] [35] [36] [37] The Virginia opossum has been found to be very resistant to snake venom. [38] [28] Attracted to carrion on the side of the highway, opossums are at an increased risk of being hit by motor vehicles. [24]

Plant foods are mainly eaten in late summer, autumn, and early winter. [27] These include raspberries, blackberries, apples, acorns, beechnuts, seeds, grains, bulbs, and vegetables. [27] [37] Persimmons are one of the opossum's favorite foods during the autumn. [39] Opossums in urban areas scavenge from bird feeders, vegetable gardens, compost piles, garbage cans, and food dishes intended for dogs and cats. [27] [33]

Virginia opossum in northeastern Ohio Possum122708.JPG
Virginia opossum in northeastern Ohio

Opossums in captivity are known to engage in cannibalism, though this is probably uncommon in the wild. [40] Because of this, placing an injured opossum in a confined space with its healthy counterparts is inadvisable.

Seasonality

The Virginia opossum is most active during the spring and summer. [27] It does not hibernate but reduces its activity during the winter. [26] [41] It may not leave its den for several days if the temperature drops below −7 to −4 °C (19 to 25 °F). [27] Both males and females are at greater risk of injury during breeding season. [42] Males extend their range in search of mates which puts them at greater risk of injury from motor vehicles and predators due to unknown territory. [42] Females carrying young are slower moving and have to forage earlier in the evening and later into the night, also increasing their risk of injury from motor vehicles and predation. [42]

Reproduction

Carrying its young Didelphis virginiana with young.JPG
Carrying its young

The breeding season for the Virginia opossum can begin as early as December and continue through October with most young born between February and June. [42] A female opossum may have one to three litters per year. [42] During the mating season, the male attracts the female by making clicking sounds with his mouth. [42] The female's estrus cycle is 28 days and lasts 36 hours. [42] Gestation lasts 11–13 days and the average litter size is 8–9 infants, although over 20 infants may be born. [42] Opossums have a very high mortality rate of their young; only one in ten offspring survive to reproductive adulthood. [43]

Newborns are the size of a honeybee. [27] Once delivered through the median vagina or central birth canal, newborn opossums climb up into the female opossum's pouch and latch onto one of her 13 teats. [42] The young remain latched for two months and in the pouch for 2+1⁄2 months. [42] The young then climb onto the mother's back, where she carries them for the remainder of their time together. [42] It is during this time that the young learn survival skills. [42] They leave their mother after about four or five months. [44]

Like all female marsupials, the female's reproductive system is bifid, with two lateral vaginae, uteri, and ovaries. [45] The male's penis is also bifid, with two heads, and as is common in New World marsupials, the sperm pair up in the testes and only separate as they come close to the egg. [45] Males have three pairs of Cowper's glands. [46]

Lifespan

Compared to other mammals, including most other marsupials except dasyuromorphians, opossums have unusually short lifespans for their size and metabolic rate. [47] [48] The Virginia opossum has a maximal lifespan in the wild of only about two years. [49] Even in captivity, opossums live only about four years. [50] The rapid senescence of opossums is thought to reflect the fact that they have few defenses against predators; given that they would have little prospect of living very long regardless, they are not under selective pressure to develop biochemical mechanisms to enable a long lifespan. [51] In support of this hypothesis, one population on Sapelo Island, 5 miles (8 km) off the coast of Georgia, which has been isolated for thousands of years without natural predators, was found by Dr. Steven Austad to have evolved lifespans up to 50% longer than those of mainland populations. [51] [52]

Historical references

An early description of the opossum comes from explorer John Smith, who wrote in Map of Virginia, with a Description of the Countrey, the Commodities, People, Government and Religion in 1608 that "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." [53] [54] The opossum was more formally described in 1698 in a published letter entitled "Carigueya, Seu Marsupiale Americanum Masculum. Or, The Anatomy of a Male Opossum: In a Letter to Dr Edward Tyson", from Mr William Cowper, Chirurgeon, and Fellow of the Royal Society, London, by Edward Tyson, M.D. Fellow of the College of Physicians and of the Royal Society. The letter suggests even earlier descriptions. [55]

Relationship with humans

Virginia opossum cornered in a piano in Houston, Texas, shortly before its release American opossum in baby grand piano.jpg
Virginia opossum cornered in a piano in Houston, Texas, shortly before its release

Opossums are not considered dangerous to humans. [56] Though their open-mouth hiss when frightened is often mistaken as rabid behavior, opossums are naturally resistant to rabies due to their low body temperature. Opossums can however host parasites and carry diseases such as tuberculosis, leptospirosis, and tularemia, among others. [57]

Like raccoons, opossums can be found in urban environments, where they eat pet food, rotten fruit, and human garbage. They also are considered a common predator of poultry farming in North America. [58] [59] Research suggests that proximity to humans causes an increase in body size for opossums living in or near urban environments. [60] Though sometimes mistakenly considered to be rats, opossums are not closely related to rodents or any other placental mammals.

The opossum was once a favorite game animal in the United States, particularly in the southern regions which have a large body of recipes and folklore relating to it. [61] Their past wide consumption in regions where present is evidenced by recipes available online [62] and in books such as older editions of The Joy of Cooking . [63] A traditional method of preparation is baking, sometimes in a pie or pastry, [64] though at present "possum pie" most often refers to a sweet confection containing no meat of any kind.

Around the turn of the 20th century, the opossum was the subject of numerous songs, including "Carve dat Possum", a minstrel song written in 1875 by Sam Lucas. [65]

Although it is widely distributed in the United States, the Virginia opossum's appearance in folklore and popularity as a food item has tied it closely to the American Southeast. In animation, it is often used to depict uncivilized characters or "hillbillies". Not surprisingly, then, the Virginia opossum is featured in several episodes of the hit TV show The Beverly Hillbillies , such as the "Possum Day" episode in 1965. [66] The title character in Walt Kelly's long-running comic strip Pogo was an opossum. In an attempt to create another icon like the teddy bear, President William Howard Taft was tied to the character Billy Possum. [67] [68] The character did not do well, as public perception of the opossum led to its downfall. In December 2010, a cross-eyed Virginia opossum in Germany's Leipzig Zoo named Heidi became an international celebrity. [69] She appeared on a TV talk show to predict the 2011 Oscar winners, similar to the World Cup predictions made previously by Paul the Octopus, also in Germany. [70]

The Perelman Building in Philadelphia, Pennsylvania, an annex of the Philadelphia Museum of Art, was formerly the Fidelity Mutual Life Insurance Company Building. Built in the late 1920s its facade is decorated with polychrome sculptures of animals symbolizing various attributes of insurance, including a possum to represent "protection".

Related Research Articles

<span class="mw-page-title-main">Marsupial</span> Infraclass of mammals in the clade Metatheria

Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are primarily found in Australasia, Wallacea, and the Americas. One of the defining features of marsupials is their unique reproductive strategy, where the young are born in a relatively undeveloped state and then nurtured within a pouch.

<span class="mw-page-title-main">Tasmanian devil</span> Australian carnivorous marsupial

The Tasmanian devil is a carnivorous marsupial of the family Dasyuridae. It was formerly present across mainland Australia, but became extinct there around 3,500 years ago. The size of a small dog, the Tasmanian devil became the largest carnivorous marsupial in the world following the extinction of the thylacine in 1936. It is related to quolls, and distantly related to the thylacine. It is characterised by its stocky and muscular build, black fur, pungent odour, extremely loud and disturbing screech, keen sense of smell, and ferocity when feeding. The Tasmanian devil's large head and neck allow it to generate among the strongest bites per unit body mass of any extant predatory land mammal. It hunts prey and scavenges on carrion.

<span class="mw-page-title-main">Sugar glider</span> Species of Australian marsupial

The sugar glider is a small, omnivorous, arboreal, and nocturnal gliding possum. The common name refers to its predilection for sugary foods such as sap and nectar and its ability to glide through the air, much like a flying squirrel. They have very similar habits and appearance to the flying squirrel, despite not being closely related—an example of convergent evolution. The scientific name, Petaurus breviceps, translates from Latin as "short-headed rope-dancer", a reference to their canopy acrobatics.

<span class="mw-page-title-main">Opossum</span> Family of mammals

Opossums are members of the marsupial order Didelphimorphia endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North America in the Great American Interchange following the connection of North and South America.

<span class="mw-page-title-main">Common brushtail possum</span> Species of marsupial

The common brushtail possum is a nocturnal, semiarboreal marsupial of the family Phalangeridae, native to Australia and invasive in New Zealand, and the second-largest of the possums.

<span class="mw-page-title-main">Squirrel glider</span> Species of marsupial

The squirrel glider is a nocturnal gliding possum. The squirrel glider is one of the wrist-winged gliders of the genus Petaurus.

<span class="mw-page-title-main">Eastern cottontail</span> Species of mammal

The eastern cottontail is a New World cottontail rabbit, a member of the family Leporidae. It is the most common rabbit species in North America.

<i>Didelphis</i> Genus of marsupials

Didelphis is a genus of New World marsupials. The six species in the genus Didelphis, commonly known as Large American opossums, are members of the opossum order, Didelphimorphia.

<span class="mw-page-title-main">Bare-tailed woolly opossum</span> Species of marsupial

The bare-tailed woolly opossum is an opossum from South America. It was first described by Swedish zoologist Carl Linnaeus in 1758. The bare-tailed woolly opossum is characterized by a gray head, brown to gray coat, orange to gray underside and a partially naked tail. It is nocturnal and solitary; there is hardly any social interaction except between mother and juveniles and in mating pairs. The opossum constructs nests in tree cavities, and its litter size ranges from one to seven. Gestation lasts 25 days, and the juveniles exit the pouch after three months; weaning occurs a month later. The bare-tailed woolly opossum inhabits subtropical forests, rainforests, secondary forests, and plantations; its range extends from northern Venezuela to northeastern and southcentral Brazil. The IUCN classifies this opossum as least concern.

<span class="mw-page-title-main">Common opossum</span> Species of marsupial

The common opossum, also called the southern or black-eared opossum or gambá, and sometimes called a possum, is a marsupial species living from the northeast of Mexico to Bolivia, including Trinidad and Tobago and the Windwards in the Caribbean, where it is called manicou. It prefers the woods, but can also live in fields and cities.

<span class="mw-page-title-main">Gray short-tailed opossum</span> Species of marsupial

The gray short-tailed opossum is a small South American member of the family Didelphidae. Unlike most other marsupials, the gray short-tailed opossum does not have a true pouch. The scientific name Monodelphis is derived from Greek and means "single womb" and the Latin word domestica which means "domestic". It was the first marsupial to have its genome sequenced. The gray short-tailed opossum is used as a research model in science, and is also frequently found in the exotic pet trade. It is also known as the Brazilian opossum, rainforest opossum and in a research setting the laboratory opossum.

<span class="mw-page-title-main">Southern brown bandicoot</span> Species of marsupial

The southern brown bandicoot is a short-nosed bandicoot, a type of marsupial, found mostly in southern Australia. A subspecies in Western Australia was also known as the quenda in South Western Australia. This subspecies was elevated to species in 2018.

<span class="mw-page-title-main">Eastern pygmy possum</span> Species of marsupial

The eastern pygmy possum is a diprotodont marsupial of south-eastern Australia. Occurring from southern Queensland to eastern South Australia and also Tasmania, it is found in a range of habitats, including rainforest, sclerophyll forest, woodland and heath.

<span class="mw-page-title-main">Boodie</span> Species of marsupial

The boodie, also known as the burrowing bettong or Lesueur's rat-kangaroo, is a small, furry, rat-like mammal native to Australia. Once common throughout the continent, it is now restricted to a few coastal islands. A member of the rat-kangaroo family (Potoroidae), it lives in burrows and is active at night when it forages for fungi, roots, and other plant matter. It is about the size of a rabbit and, like most marsupials, carries its young in a pouch.

<span class="mw-page-title-main">Western pygmy possum</span> Species of marsupial

The western pygmy possum, also known as the southwestern pygmy possum or the mundarda, is a small marsupial found in Australia. Genetic studies indicate its closest relative is probably the eastern pygmy possum, from which its ancestors diverged around eight million years ago.

<span class="mw-page-title-main">Red-legged pademelon</span> Species of marsupial

The red-legged pademelon is a species of small macropod found on the northeastern coast of Australia and in New Guinea. In Australia it has a scattered distribution from the tip of Cape York Peninsula in Queensland to around Tamworth in New South Wales. In New Guinea it is found in south central lowlands.

<span class="mw-page-title-main">Elegant fat-tailed mouse opossum</span> Species of marsupial

The elegant fat-tailed mouse opossum, also known as the Chilean mouse opossum, is an opossum from central Chile. The type species of Thylamys, it was first described by English naturalist George Robert Waterhouse in 1839. This medium-sized opossum is characterized by black rings around the eyes, white limbs, gray to light brown coat, lighter flanks and underbelly and a thick 12.7–14.6 centimetres (5.0–5.7 in) long tail covered with hairs. It is crepuscular and lives in nests in tree hollows or under rocks and roots. This opossum feeds mainly on arthropods and larvae apart from fruits. Litter size is typically between 11 and 13. The elegant fat-tailed opossum can occur in a variety of habitats – from cloud forests to chaparrals. The IUCN classifies the opossum as least concern.

<span class="mw-page-title-main">Woodlark cuscus</span> Species of marsupial

The Woodlark cuscus is a species of marsupial in the family Phalangeridae endemic to Papua New Guinea, specifically on Madau and Woodlark Island, a part of the Milne Bay Province of Papua New Guinea. It happens to be the largest mammal living on Woodlark Island but it is also found on the neighboring island of Alcester, 70 kilometers south of Woodlark Island.

References

  1. ↑ Gardner, A.L. (2005). "Order Didelphimorphia". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 6. ISBN   978-0-8018-8221-0. OCLC   62265494.
  2. ↑ Harrington, Arianna (12 May 2015) [28 April 2015]. Hulbert Jr., Richard C.; Valdes, Natali (eds.). "Didelphis virginiana - Florida Vertebrate Fossils". Florida Museum. University of Florida. Retrieved 17 April 2024.
  3. ↑ Pérez-Hernandez, R.; Lew, D.; Solari, S. (2016). "Didelphis virginiana". IUCN Red List of Threatened Species . 2016: e.T40502A22176259. doi: 10.2305/IUCN.UK.2016-1.RLTS.T40502A22176259.en . Retrieved 19 November 2021.
  4. ↑ "Didelphis virginiana". NatureServe Explorer. Retrieved 17 April 2024.
  5. ↑ Gardner, A.L.; Sunquist, M.E. (2003). "Opossum: Didelphis virginiana". In Feldhamer, G.A.; Thompson, B.C.; Chapman, J.A. (eds.). Wild Mammals of North America: Biology, Management, and Conservation. JHU Press. pp. 3–29. ISBN   978-0-8018-7416-1.
  6. ↑ John J. McManus (July 1970), "Behavior of Captive Opossums, Didelphis marsupialis virginiana", American Midland Naturalist, 84 (1): 144–169, doi:10.2307/2423733, JSTOR   2423733
  7. ↑ "Possum vs. Opossum: Is There a Difference?". Merriam-Webster. Retrieved 2023-11-12. Textbooks, encyclopedias, and science publications favor opossum, but when it comes to general speech and writing, possum is and has been the far more common choice.
  8. 1 2 3 Gingerich, Jerry Lee (1994). Florida's Fabulous Mammals. Tampa, FL: World Publications. p. 2. ISBN   978-0-911977-13-4.
  9. ↑ Day, Leslie (10 May 2013). Field Guide to the Natural World of New York City. JHU Press. p. 225. ISBN   978-1-4214-1149-1.
  10. ↑ Woodburne, M.O. (2010-07-14). "The Great American Biotic Interchange: Dispersals, Tectonics, Climate, Sea Level and Holding Pens". Journal of Mammalian Evolution. 17 (4): 245–264. doi:10.1007/s10914-010-9144-8. PMC   2987556 . PMID   21125025.
  11. ↑ Walsh, L. L.; Tucker, P. K. (2017). "Contemporary range expansion of the Virginia opossum (Didelphis virginiana) impacted by humans and snow cover". Canadian Journal of Zoology. 96 (2): 107–115. doi:10.1139/cjz-2017-0071. hdl: 1807/81311 .
  12. ↑ The Opossum: Its Amazing Story, William J. Krause and Winifred A. Krause, University of Missouri-Columbia, 2006, p. 23, ISBN   0-9785999-0-X, 9780978599904.
  13. ↑ "ADW: Didelphis virginiana: Information (1974-05-02)". animaldiversity.ummz.umich.edu. Retrieved 2011-09-15.
  14. ↑ Wildlife Directory: Virginia Opossum — Living with Wildlife — University of Illinois Extension Archived 2018-05-13 at the Wayback Machine . Web.extension.illinois.edu. Retrieved on 2011-09-15.
  15. ↑ With the Wild Things - Transcripts Archived 2013-03-23 at the Wayback Machine . Digitalcollections.fiu.edu. Retrieved on 2011-09-15.
  16. ↑ Mary Stockard, AWRC Mammal Supervisor (2001) Raising Orphaned Baby Opossums. AWRC.org
  17. ↑ "Virginia Opossum (Didelphis virginiana)". www.nsrl.ttu.edu. Retrieved 2018-11-11.
  18. ↑ Ashwell, K.w.s. (April 2008). "Encephalization of Australian and New Guinean Marsupials". Brain, Behavior and Evolution. 71 (3): 181–199. doi:10.1159/000114406. ISSN   0006-8977. PMID   18230970. S2CID   7544968.
  19. ↑ "Virginia Opossum". Mass Audubon. Archived from the original on December 29, 2010. Retrieved May 11, 2011. Opossums are frequently encountered as corpses along highways. Some biologists believe that many die as they feed on road-killed animals – a favorite food. Others believe that the opossums' small brain (5 times smaller than that of a raccoon[sic - erroneous logic]) suggests that they may just be too dumb to get out of the way of vehicles!
  20. ↑ Krause, William J.; Krause, Winifred A. (2006).The Opossum: Its Amazing Story Archived 2012-12-11 at the Wayback Machine . Department of Pathology and Anatomical Sciences, School of Medicine, University of Missouri, Columbia, Missouri. 80 pages.
  21. 1 2 3 4 "Virginia Opossum". www.psu.edu. Archived from the original on 2010-06-01. Retrieved 2020-09-28.
  22. 1 2 3 "Opossum Defense Mechanisms | Opossum Society of the United States" . Retrieved 2020-09-28.
  23. ↑ "PLAY POSSUM | definition in the Cambridge English Dictionary". dictionary.cambridge.org. Retrieved 2020-09-28.
  24. 1 2 3 "Give opossums a break". Cary Institute of Ecosystem Studies. 30 March 2015. Retrieved 2020-09-30.
  25. 1 2 "Why you should brake for opossums". Cary Institute of Ecosystem Studies. 23 July 2012. Retrieved 2020-09-28.
  26. 1 2 "Virginia opossum". Smithsonian's National Zoo. 2018-01-05. Retrieved 2020-09-28.
  27. 1 2 3 4 5 6 7 "Opossum | Adirondack Ecological Center | SUNY ESF | College of Environmental Science and Forestry". www.esf.edu. Retrieved 2020-09-28.
  28. 1 2 3 Maurer, Steph. "The Helpful Opossum | Wildlife Medical Clinic at Illinois". Archived from the original on 2021-07-16. Retrieved 2022-04-24.
  29. ↑ Hennessy, C.; Hild, K. (September 2021). "Are Virginia opossums really ecological traps for ticks? Groundtruthing laboratory observations". Ticks and Tick-Borne Diseases. 12 (5): 101780. doi:10.1016/j.ttbdis.2021.101780. PMID   34298355 . Retrieved 2022-04-20.
  30. ↑ Kirchner, Jane (13 June 2017). "Opossums: Unsung Heroes in the Fight Against Ticks and Lyme Disease". National Wildlife Federation. Retrieved 26 August 2019.
  31. ↑ Bayly, Julia (24 March 2022). "Turns out, opossums may not actually like eating ticks". Bangor Daily News. Retrieved 27 October 2022.
  32. ↑ Hennessy, Cecilia; Hild, Kaitlyn (15 July 2021). "Are Virginia opossums really ecological traps for ticks? Groundtruthing laboratory observations". Ticks and Tick-Borne Diseases. 12 (5): 101780. doi:10.1016/j.ttbdis.2021.101780. PMID   34298355 . Retrieved 18 January 2021.
  33. 1 2 "Opossum Management Guidelines--UC IPM". ipm.ucanr.edu. Retrieved 2020-09-28.
  34. ↑ "Virginia Opossum | Chesapeake Bay Program". www.chesapeakebay.net.
  35. ↑ "Basic Information Sheet: Virginia Opossum". June 11, 2018.
  36. ↑ "Virginia opossum". September 11, 2020.
  37. 1 2 Martina, Leila Siciliano. "Didelphis virginiana (Virginia opossum)". Animal Diversity Web.
  38. ↑ Sharon A. Jansa; Robert S. Voss (2011). "Adaptive evolution of the venom-targeted vWF protein in opossums that eat pitvipers". PLOS ONE. 6 (6): e20997. Bibcode:2011PLoSO...620997J. doi: 10.1371/journal.pone.0020997 . PMC   3120824 . PMID   21731638.
  39. ↑ Sparano, Vin T. 2000. The Complete outdoors encyclopedia. St. Martin's Press. ISBN   0-312-26722-3
  40. ↑ Cannibalism in the Opossum. Opossum Society. Accessed May 7, 2007.
  41. ↑ "Virginia Opossum Didelphis virginiana". eNature.com. Shearwater Marketing Group. Archived from the original on 2011-05-17. Retrieved 2009-03-24.
  42. 1 2 3 4 5 6 7 8 9 10 11 12 "Reproduction – Life Cycle | Opossum Society of the United States" . Retrieved 2020-09-30.
  43. ↑ Tyndale-Biscoe, Hugh (2008). Life of marsupials ([New.] ed.). Collingwood: CSIRO. pp. 105–138. ISBN   9780643092204.
  44. ↑ "Reproduction – Life Cycle - Opossum Society of the United States". opossumsocietyus.org.
  45. 1 2 Krause, William J. (2005). The Opossum: Its Amazing Story. Department of Pathology and Anatomical Sciences, School of Medicine, University of Missouri, Columbia, Missouri. ISBN   0-9785999-0-X.
  46. ↑ Martan, Jan. "The genital tract of the male opossum Didelphis marsupialis virginiana and other marsupials." Trans. I 11 (1983): 3-28.
  47. ↑ Krause, William J.; Krause, Winifred A. (2006).The Opossum: Its Amazing Story Archived 2012-12-11 at the Wayback Machine . Department of Pathology and Anatomical Sciences, School of Medicine, University of Missouri, Columbia, Missouri. 80 pages.
  48. ↑ Fisher, Diana O.; Owens, Ian P. F.; Johnson, Christopher N. (2001). "The ecological basis of life history variation in marsupials" (PDF). Ecology. 82 (12): 3531–3540. doi:10.1890/0012-9658(2001)082[3531:TEBOLH]2.0.CO;2. Archived (PDF) from the original on 2017-08-24.
  49. ↑ Virginia Opossum. Didelphis virginiana Archived 2007-10-24 at the Wayback Machine . Great Plains Nature Center. accessed Oct. 15, 2007
  50. ↑ The Life Span of Animals Accessed Oct. 15, 2007
  51. 1 2 Karen Wright Staying Alive. Discover Magazine. November 6, 2003 Accessed Oct 15, 2007.
  52. ↑ "State Of Tomorrow™ - Rising Challenges. Higher Education Solutions". www.stateoftomorrow.com.
  53. ↑ Chrysti the Wordsmith > Radio Scripts > Opossum. Retrieved 2009-12-29.
  54. ↑ Possum History Archived 2011-07-15 at the Wayback Machine . Retrieved 2009-12-29.
  55. ↑ Langworthy, Orthello R. (1932). "The Panniculus Carnosus and Pouch Musculature of the Opossum, a Marsupial". Journal of Mammalogy. 13 (3): 241–251. doi:10.2307/1373999. JSTOR   1373999.
  56. ↑ "Are opossums dangerous? They can be, but they're also good for your backyard". USA TODAY. Retrieved 2023-12-25.
  57. ↑ Weinberger, Dawn (2023-10-19). "Are Opossums Dangerous To Humans, Pets And Property?". Forbes Home. Retrieved 2023-12-25.
  58. ↑ "Predators of Poultry". Ohioline Ohio State University . 2018-12-20. Retrieved 2022-04-21.
  59. ↑ "Predator Management for Small and Backyard Poultry Flocks". Cooperative Extension Poultry. Retrieved 2022-04-21.
  60. ↑ Wright (2012). "Influences of an Urban Environment on Home Range and Body Mass of Virginia Opossums (Didelphis virginiana)". Northeastern Naturalist. 19 (1): 77–86. doi:10.1656/045.019.0106. JSTOR   41429417. S2CID   86663111.
  61. ↑ Keith Sutton. Possum days gone by. ESPN Outdoors. January 12, 2009. Retrieved 2009-12-29.
  62. ↑ Wild Game Recipes online. Retrieved 2009-12-29.
  63. ↑ The joy of the ‘Joy of Cooking,’ circa 1962 Archived 2006-10-30 at the Wayback Machine . Retrieved 2009-12-29.
  64. ↑ opossum pie Archived 2011-07-18 at the Wayback Machine . Retrieved 2009-12-29.
  65. ↑ "Carve dat possum". Library of Congress. Retrieved 2020-11-09.
  66. ↑ "Possum Day". October 13, 1965 – via IMDb.
  67. ↑ Possum Politics Archived 2006-12-16 at the Wayback Machine . 'Possum Network. Last accessed November 19, 2006.
  68. ↑ Political Postcards. Cyberbee learning. Last accessed November 19, 2006.
  69. ↑ Kelsey, Eric. (January 11, 2011). "Cross-eyed opossum capturing hearts". Reuters. Retrieved January 12, 2011.
  70. ↑ Kelsey, Eric. (28 February 2011). "German celebrity opossum misses one Oscar pick". Reuters. Retrieved 6 March 2011.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.