Didelphimorphia

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(Redirected from Opossum)

{{Taxobox | color = pink | name = Didelphimorphia | image = AwesomePossum-AmericanOpossum.jpg | image_caption = Virginia Opossum Didelphis virginiana | image_width = 250px | regnum = Animalia | phylum = Chordata | classis = Mammalia | subclassis = Marsupialia | ordo = Didelphimorphia | ordo_authority = Gill, 1872 | familia = Didelphidae | familia_authority = Gray, 1821 | subdivision_ranks = Genera | subdivision = Several; see text }} Image:Opossum fur.jpg The order Didelphimorphia contains the common opossums of the western hemisphere. Opossums probably diverged from the basic South American marsupials in the late Cretaceous or early Paleocene. A sister group is the Paucituberculata, or shrew opossums.

Didelphimorphs are small to medium-sized marsupials, about the size of a large house cat. 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 (one side of one jaw) includes 5 incisors (four on the lower jaw), 1 canine, 3 premolars and 4 tricuspid molars. By mammal standards, this is a very full jaw. The incisors are very small, the canines large.

Didelphimorphs have a plantigrade stance (feet flat on the ground) and the hind feet have an opposable digit with no claw. Like some primates, opossums have prehensile tails. The stomach is simple, with a small cecum. Opossum reproductive systems are extremely basic, with a reduced marsupium. This means that the young are born at a very early stage. The species are moderately sexually dimorphic with males usually being somewhat larger than females.

Didelphimorphs are opportunistic omnivores with a very broad range of diet. Their unspecialized biology, flexible diet and reproductive strategy make them successful colonizers and survivors in unsettled times. Originally native to the Eastern United States, opossums were intentionally introduced into the West during the Great Depression, probably as a source of food. Their range has been expanding steadily northwards, thanks in part to more plentiful, manmade sources of fresh water, and milder winters. Since 1990, their range has extended into Ontario, Canada, and they have been found as far north as Toronto.

Opossums are usually nomadic, staying in one area as long as food and water are easily available. Though they will temporarily occupy abandoned burrows, they do not dig or put much effort into building their own. They favor dark, secure areas, below ground or above.

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. Many injured opossums have been killed by well-meaning people who find a catatonic animal and assume the worst. If you find an injured or apparently dead opossum, the best thing to do is leave it in a quiet place with a clear exit path. In minutes or hours, the animal will regain consciousness and escape quietly on its own.

Adult oppossums do not hang from trees by their tails, though babies may dangle temporarily. Their prehensile tails are not strong enough to support a mature adult's weight, though they often serve as a brace and a fifth limb when climbing. There are also confirmed accounts of the tail being used as a grip to carry bunches of leaves or bedding materials to the nest.

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Use as food

The opossum was a favorite game animal in the United States in particular, the southern regions which have a large body of recipes and folklore relating to the opossum. Opossum was once widely consumed in the United States where available as evidenced by recipes in older editions of the Joy of Cooking. A favorite recipe from the southeast is "'possum and taters" which is parboiled opossum, roasted with sweet potatoes. In Dominica and Trinidad opossum is popular and can only be hunted during certain times of the year due to over-hunting; the meat is traditionally prepared by smoking then stewing. The meat is light and fine grained and 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 New Zealand is consumed in a similar manner as its cousin. (Davidson, 1999)

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Classification

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References

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External links

Mammals
Monotremata

Marsupialia: Didelphimorphia | Paucituberculata | Microbiotheria | Notoryctemorphia | Dasyuromorphia | Peramelemorphia | Diprotodontia

Placentalia: Afrosoricida | Macroscelidea | Tubulidentata | Hyracoidea | Proboscidea | Sirenia | Cingulata | Pilosa | Scandentia | Dermoptera | Primates | Rodentia | Lagomorpha | Insectivora | Chiroptera | Pholidota | Carnivora | Perissodactyla | Artiodactyla | Cetacea

bg:Опосуми

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