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From Wikipedia, the free encyclopedia

Didelphimorphia[1]
Fossil range: Late Cretaceous–Recent
Virginia Opossum Didelphis virginiana
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Didelphimorphia
Gill, 1872
Family: Didelphidae
Gray, 1821
Genera

Several; see text

Didelphimorphia (pronounced /daɪˌdɛlfɨˈmɔrfi.ə/) is the order of common opossums of the Western Hemisphere. They are commonly also called possums, though that term is also applied to Australian fauna of the suborder Phalangeriformes. The Virginia Opossum is the original animal named opossum. The word comes from Algonquian wapathemwa meaning "white dog". Opossums probably diverged from the basic South American marsupials in the late Cretaceous or early Paleocene. A sister group is Paucituberculata (shrew opossums).

Their unspecialized biology, flexible diet and reproductive strategy make them successful colonizers and survivors in diverse locations and conditions. Originally native to the eastern United States, the Virginia Opossum was intentionally introduced into the West during the Great Depression, probably as a source of food.[2] Its range has been expanding steadily northwards, thanks in part to more plentiful, man-made sources of freshwater, increased shelter due to urban encroachment, and milder winters. Its range has extended into Ontario, Canada, and it has been found farther north than Toronto.

Contents

Characteristics

Didelphimorphs are small to medium-sized marsupials, with the largest about the size of a large house cat, and the smallest the size of a mouse. They tend to be semi-arboreal omnivores, although there are many exceptions. Most members of this taxon have long snouts, a narrow braincase, and a prominent sagittal crest. The dental formula is: Upper: 5.1.3.4, lower: 4.1.3.4 By mammalian standards, this is a very full jaw. Opossums have more teeth than any other land mammal; only aquatic mammals have more.[citation needed] The incisors are very small, the canines large, and the molars are tricuspid.

Didelphimorphs have a plantigrade stance (feet flat on the ground) and the hind feet have an opposable digit with no claw. Like some New World monkeys, opossums have prehensile tails. Like in all marsupials, the fur consists of awn hair only. The tail and parts of the feet bear scutes. The stomach is simple, with a small cecum.

Opossums have a remarkably robust immune system, and show partial or total immunity to the venom of rattlesnakes, cottonmouths, and other pit vipers.[3][4] Opossums are about eight times less likely to carry rabies than wild dogs, and about one in eight hundred opossums are infected with this virus.[5]

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Reproduction and life cycle

Sleeping Virginia opossum with babies in her relaxed pouch

As a marsupial, the opossum has a reproductive system that is composed of a placenta and a marsupium, which is the pouch.[6] The young are born at a very early stage, although the gestation period is similar to many other small marsupials, at only 12 to 14 days.[7] Once born, the offspring must find their way into the marsupium to hold onto and nurse from a teat. The species are moderately sexually dimorphic with males usually being slightly larger, much heavier, and having larger canines than females.[8] The largest difference between the opossum and other mammals is the bifurcated penis of the male and bifurcated vagina of the female (the source of the Latin "didelphis," meaning double-wombed). Male opossum spermatozoa exhibit cooperative methods of ensuring the survival of genotypically similar sperm by forming conjugate pairs before fertilization.[9] Such measures come into place particularly when females copulate with multiple males. These conjugate pairs increase motility and enhance the likelihood of fertilization. Conjugate pairs dissociate into separate spermatozoa before fertilization. The opossum is one of many species that employ sperm cooperation in its reproductive life cycle.

Female opossums often give birth to very large numbers of young, most of which fail to attach to a teat, although as many as thirteen young can attach,[8] and therefore survive, depending on species. The young are weaned between 70 and 125 days, when they detach from the teat and leave the pouch. The opossum lifespan is unusually short for a mammal of its size, usually only two to four years. Senescence is rapid.[10]

Diet

Didelphimorphs are opportunistic omnivores with a very broad diet. Their diet mainly consists of carrion and many individual opossums are killed on the highway when scavenging for roadkill. They are also known to eat insects, frogs, birds, snakes, small mammals, and earthworms. Some of their favorite foods are fruits, and they are known to eat apples and persimmons. Their broad diet allows them to take advantage of many sources of food provided by human habitation such as unsecured food waste (garbage) and pet food.

Opossum fur is quite soft.

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 may be below ground or above.

Didelphis marsupialis: intrusion in human dwelling (French Guiana)
"Playing possum"

When threatened or harmed, they will "play possum", mimicking the appearance and smell of a sick or dead animal. The lips are drawn back, teeth are bared, saliva foams around the mouth, and a foul-smelling fluid is secreted from the anal glands. The physiological response is involuntary, rather than a conscious act. Their stiff, curled form can be prodded, turned over, and even carried away. The animal will regain consciousness after a period of minutes or hours and escape.

Adult opossums do not hang from trees by their tails, though babies may dangle temporarily. Their semi-prehensile tails are not strong enough to support a mature adult's weight. Instead, the opossum uses its tail as a brace and a fifth limb when climbing. The tail is occasionally used as a grip to carry bunches of leaves or bedding materials to the nest. A mother will sometimes carry her young upon her back, where they will cling tightly even when she is climbing or running.

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.

The Virginia opposum is the only North American marsupial.

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."[11][12] 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.[13]

In hunting and foodways

The opossum was once a favorite game animal in the United States, and in particular the southern regions which have a large body of recipes and folklore relating to the opossum.[14] Opossum was once widely consumed in the United States where available, as evidenced by recipes available online[15] and in books such as older editions of The Joy of Cooking.[16] A traditional method of preparation is baking, sometimes in a pie or pastry,[17] though at present "possum pie" most often refers to a sweet confection containing no meat of any kind. In Dominica and Trinidad opossum or "manicou" is popular and can only be hunted during certain times of the year owing to overhunting; the meat is traditionally prepared by smoking then stewing. The meat is light and fine-grained, but the musk glands must be removed as part of preparation. The meat can be used in place of rabbit and chicken in recipes. The cousin of the opossum, the possum, found in Australia (and introduced to New Zealand) is consumed in a similar manner.[18]

Historically, hunters in the Caribbean would place a barrel with fresh or rotten fruit to attract opossums who would feed on the fruit or insects. Cubans growing up in the mid-twentieth century tell of brushing the maggots out of the mouths of "manicou" caught in this manner to prepare them for consumption.

In Mexico, opossums are known as "tlacuache" or "tlaquatzin". Their tails are eaten as a folk remedy to improve fertility.

Opossum oil (Possum grease) is high in essential fatty acids and has been used as a chest rub and a carrier for arthritis remedies given as topical salves.

Opossum pelts have long been part of the fur trade.

Classification

See also

References

  1. ^ a b Gardner, Alfred (2005-11-16). Wilson, D. E., and Reeder, D. M.. ed. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. pp. 3-18. ISBN 0-801-88221-4. http://www.bucknell.edu/msw3. 
  2. ^ "The Opossum: Its Amazing Story" William J. Krause and Winifred A. Krause, University of Missouri-Columbia, 2006, p. 23, ISBN 097859990X, 9780978599904.
  3. ^ "The Opossum: Our Marvelous Marsupial, The Social Loner". Wildlife Rescue League. http://www.wildliferescueleague.org/report/opossum.html. 
  4. ^ Journal Of Venomous Animals And Toxins - Anti-Lethal Factor From Opossum Serum Is A Potent Antidote For Animal, Plant And Bacterial Toxins. Retrieved 2009-12-29.
  5. ^ Cantor SB, Clover RD, Thompson RF (07/01/1994). "A decision-analytic approach to postexposure rabies prophylaxis". Am J Public Health 84 (7): 1144–8. doi:10.2105/AJPH.84.7.1144. PMID 8017541. http://www.ajph.org/cgi/pmidlookup?view=long&pmid=8017541. Retrieved 2009-12-29. 
  6. ^ Campbell, N. & Reece, J. (2005)BiologyPearson Education Inc.
  7. ^ O'Connell, Margaret A. (1984). Macdonald, D.. ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 830–837. ISBN 0-87196-871-1. 
  8. ^ a b North American Mammals: Didelphis virginiana. Retrieved 2009-12-29.
  9. ^ Moore, H.D. (1996). "Gamete biology of the new world marsupial, the grey short-tailed opossum, monodelphis domestica". Reproduction, fertility, and development 8: 605–15. doi:10.1071/RD9960605. 
  10. ^ Opossum Facts. Retrieved 2009-12-29.
  11. ^ Chrysti the Wordsmith > Radio Scripts > Opossum. Retrieved 2009-12-29.
  12. ^ Possum History. Retrieved 2009-12-29.
  13. ^ Langworthy, Orthello R. (August 1932). "The Panniculus Carnosus and Pouch Musculature of the Opossum, a Marsupial". Journal of Mammalogy 13 (3): 241–251. doi:10.2307/1373999. http://links.jstor.org/sici?sici=0022-2372%28193208%2913%3A3%3C241%3ATPCAPM%3E2.0.CO%3B2-0. Retrieved 2009-12-29. 
  14. ^ Keith Sutton. Possum days gone by. ESPN Outdoors. January 12, 2009. Retrieved 2009-12-29.
  15. ^ Wild Game Recipes online. Retrieved 2009-12-29.
  16. ^ The joy of the ‘Joy of Cooking,’ circa 1962. Retrieved 2009-12-29.
  17. ^ opossum pie. Retrieved 2009-12-29.
  18. ^ Davidson, 1999.
  19. ^ Lew, Daniel; Roger Pérez-Hernández, Jacint Ventura (2006). "Two new species of Philander (Didelphimorphia, Didelphidae) from northern South America". Journal of Mammalogy 87 (2): 224–237. doi:10.1644/05-MAMM-A-065R2.1. 
  20. ^ David A. Flores, DA, Barqueza, RM, and Díaza, MM (2008). "A new species of Philander Brisson, 1762 (Didelphimorphia, Didelphidae)". Mammalian Biology 73 (1): 14–24. doi:10.1016/j.mambio.2007.04.002. 

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

OPOSSUM, an American Indian name properly belonging to the American marsupials (other than Caenolestes), but in Australia applied to the phalangers (see Phalanger). True opossums are found throughout the greater part of America from the United States to Patagonia, the number of species being largest in the more tropical parts (see Marsupialia). They form the family Didelphyidae, distinguished from other marsupial families by the equally developed hind-toes, the nailless but fully opposable first hind-toe, and by the dentition, of which the formula is i. -, c. i, p. 1, m. 1-; total 50. The peculiarity in the mode of succession of these teeth is explained in the article referred to. Opossums are small animals, varying from the size of a mouse to that of a large cat, with long noses, ears and tails, the latter being as a rule naked and prehensile, and with the first toe in the hind-foot so fully opposable to the other digits as to constitute a functionally perfect posterior "hand." These opposable first toes are without nail or claw, but their tips are expanded into broad flat pads, which are of great use to these climbing animals. On the anterior limbs all the five digits are provided with long sharp claws, and the first toe is but little opposable. The numerous cheek-teeth are crowned with minute sharply-pointed cusps, with which to crush the insects on which these creatures feed, for the opossums seem to take in South America the place in the economy of nature filled in other countries by hedgehogs, moles, shrews, &c. The true opossums are typically represented by Didelphys marsupialis, a species, with several local races, ranging over the greater part of North America (except the extreme north). It is of large size, and extremely common, being even found living in towns, where it acts as a scavenger by night, retiring for shelter by day upon the roofs or into the sewers. It produces in the spring from six to sixteen young ones, which are placed by the mother in her pouch immediately after birth, and remain there until able to take care of themselves; the period of gestation being from fourteen to seventeen days. A local race found in Central and tropical South America is known as the crab-eating opossum (D. marsupialis cancrivora). The second sub-genus, or genus, Metachirus contains a considerable number of species found all over the tropical parts of the New World. They are of medium size, with short, close fur, very long, scaly and naked tails, and have less developed ridges on their skulls. They have, as a rule, no pouch in which to carry their young, and the latter therefore commonly ride on their mother's back, holding on by winding their prehensile tails round hers, as in the figure of the woolly opossum. The latter belongs to the sub-genus Philander, which is nearly allied to the last; its full title being Didelphy (Philander) lanigera. The philander (D. [P.] philander) is closely related.

The fourth sub-genus (or genus) is Marmosa (Micoureus, or Grymaeomys), differing from the two last by the smaller size of its members and by certain slight differences in the shape of their teeth. Its best-known species is the murine opossum (D. murina), no larger than a mouse, of a bright-red colour, found as far north as central Mexico, and extending thence to the south of Brazil. A second well-known species is D. cinerea, which ranges from Central America to western Brazil, Peru and Bolivia. Yet another group (Peramys) is represented by numerous shrew-like species, of very small size, with short, hairy and non-prehensile tails, not half the length of the trunk, and unridged skulls. The most striking member of the group The Woolly Opossum (Didelphys lanigera) and young.

is the Three-striped Opossum (D. americana) from Brazil, which is of a reddish grey colour, with three clearly-defined deep-black bands down its back, as in some of the striped mice of Africa. D. dimidiata, D. nudicaudata, D. domestics, D. unistriata and several other South American species belong to this group. Lastly we have the Chiloe Island opossum (D. gliroides), alone representing the sub-genus Dromiciops, which is most nearly allied to Marmosa, but differs from all other opossums by the short furry ears, thick hairy tail, doubly swollen auditory bulla, short canines and peculiarly formed and situated incisors.

Whatever difference of opinion there may be as to the right of the above-mentioned groups to generic separation from the typical Didelphys, there can be none as to the distinctness of the water-opossum (Chironectes minimus), which differs from all the other members of the family by its fully webbed feet, and the dark-brown transverse bands across the body (see Water Opossum).

See O. Thomas, Catalogue of Marsupialia and Monotremata (British Museum, 1888); "On Micoureus griseus, with the Description of a New Genus and Species of Didelphyidae," Ann. Mag. Nat. Hist. ser. 6, vol. xiv. p. 184, and later papers in the same and other serials. (R. L.*)


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Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

See also opossum

German

Noun

Opossum n (pl Opossums)

  1. opossum

Synonyms


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