Marsupials, are a class of mammals in which young are born at a very early stage of development and are reared in the mother's pouch until mature. Marsupials also differ from placental mammals in that they have two vaginas or a two-pronged penis, to facilitate their characteristic dual-compartment uterus. Their reproductive organs and their excretory orifices are contained within a single cloaca, or posterior opening. The young begin to develop in their mother's uterus gaining nutrients from a yolk-like sac, not a placenta. After birth they travel externally up the mother's belly, clinging to the fur, then enter the pouch and feed from the nipple. Because the tiny, underdeveloped newborn must make the climb externally, marsupials generally have strong grasping forelimbs and never hoofs or stiff paws. Like placental mammals, marsupials invest dearly in the rearing of their young. When mature enough, the young will leave the mother's pouch, but may return for protection or comfort. Although some theories suggest that marsupials are in fact primitive mammals, fossil evidence to this date demonstrate that marsupials and placental mammals evolved at nearly the same time. It is theorized that at one time marsupials were well distributed across the globe, and that continental shift and predation have isolated marsupials to their current habitats. Today they are mostly found in Australia and South America. Only one species, the Virginia Opossum, lives in North America and is native to this region.
Virginia Opossum Didelphis virginiana Click images for enlargements and license information Click here for alternate image. Click here for alternate image. Click here for alternate image.		AKA: Opossum, Possum, hillbilly steak Identifying characteristics: This small furry animal should be easy to identify with its grayish-brown fur (often appearing frosted) and white face. Their tails are void of fur, black to pinkish-gray in color, and are prehensile, meaning they can grasp tree branches or other objects with it. Their ears are also hairless and black. Their eyes are dark, but their nose is pink. Their rear limbs have clawless opposable thumbs (called a hallux). Their digits are pink. Size: Average body length of 15-20 inches, weighing roughly 10 pounds. Habitat: Deciduous forests, open woods, farmland, preferring wet areas. Food: Omnivorous. Various plants, animals, fruits insects, garbage, carrion. Because of carrion, primarily road kill, being a large part of their diet, opossums often become road kill themselves. Vocalization: Hissing, when threatened. Predators: Foxes, coyotes, large predatory birds, wild dogs, snakes and humans. Reproduction:  Litter size ranges between 7-9 with up to 2 litters per year. Young are weaned after about 100 days. Other Info.:  Nocturnal, solitary. Do not hibernate. When threatened, will often hiss, urinate, defecate and then may fall over limp and "play possum." Their breathing will be almost undetectable and they may remain in this state for up to 4 hours or until the trouble has passed.		Distribution Common in many areas of the state, but absent from the northern-most counties. They seem to be spreading further north as road kill becomes a more readily available food source. Status: Common. Tracks Look for opposable thumbs on the rear limbs. Prints measure about 2 inches with a 7-10 inch stride.