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Yesterday I drove home from a meeting. As often the case I decided to try a new route. Hurtling along the highway I noticed something down along the side of the road: a quickly approaching dot on the horizon. It was a fair size and as I passed it, my head swiveled to catch a fleeting glimpse of the object. In that instant, I caught the marbled coat and hairless prehensile tail of Didelphis marsupialis, and was deeply saddened. Another opossum had become a road kill statistic.

As North America's only marsupial, the opossum is a genetic throwback to an earlier age of mammals. Marsupials are mammals. As mammals they have fur, produce milk for their young and give birth to live offspring. The main difference is that the length of time spent in the womb for marsupials is shorter than it is in placental mammals. The placenta is what the fetus derives nourishment from, and is attached to through the umbilical cord while in the mother's womb. Placental mammals include: people, rodents, whales, dogs, cats, monkeys, and most other mammals with fully developed placentas. Marsupials also have a placenta, but it does not add to the nourishment of the fetus to the extent that it does in the placental mammals. Placental mammals give birth to live young that are fully developed or close to being so. Marsupials give birth to live young that require weeks and even months to develop. As with all marsupials, this second stage of development takes place inside of the female's marsupium or pouch. Didelphis, the first part of the opossum's Latin name translates to "double womb".

Upon leaving the birth canal, the young marsupial crawls up the belly of its mother and into the pouch, where it attaches itself to one of the mother's nipples. It is here in the pouch that the young will continue to develop. In the case of the opossum, it is about a half of an inch in length and weighs no more than a dime at birth. By comparison, the woodchuck, a mammal of similar size and proportion when fully mature, is 4-inches in length at birth and weighs slightly less then a pound. In the case of the opossum, as many as 14 young in a litter will remain in the pouch attached to one of the 17 nipples for 2-3 months. Leaving the pouch is not the end of development for the opossum as they remain in the care of their mother, riding on her back while away from the den for another 1-2 months.

The uniqueness of the opossum was not lost on early explorers of the New World. Vicente Yáñez Pinzó, returning from the New World in the early 1500's, presented an opossum to the Spanish Court. Captain John Smith, an early explorer of the Chesapeake Bay, described the opossum as a creature with "an head like a swine, and a taile like a rat, and is of the bignes of a cat." In regards to the female's pouch, he wrote "Under her belly she hath a bagge, wherein she lodgeth, carrieth, and sucketh her young." European naturalists were at a loss for how to classify this new creature. They explained the opossum as being half fox, half monkey and gave it the Latin name Simia vulpa (SimianMonkey, Vulpes-Fox).

These early explorers and naturalists were even more at a loss regarding the opossum's reproductive nature. The penis of the male opossum is bifurcated or forked. This, combined with the female opossum's prenatal habit of licking her belly, nipples and pouch area, led to the folktale that in reproducing, the male and female have sex through the female's nose and she then blows the young into her pouch. Later, it was discovered that the females have a bifurcated reproductive track and all the preening is done to create a moist warm pathway for the newborns to follow.

The tail of the opossum has also been the source of folklore and stories. The most popular tale being that opossums hang from their tails. Long, pink and hairless, the tail of the opossum serves many functions, but hanging from trees is not one of them. The Cherokee Tribe in the American Southeast tells a story that explains the reason for the opossum's naked tail, linking it to a punishment for hubris. Their tails are prehensile, which means to a certain extent, they have control over its movement. On occasion they are seen carrying nesting material with it and use it to provide balance while tree climbing, sometimes grasping branches with it. Adding to the uniqueness of the opossums are their interesting physical features. Their hind feet have clawless thumbs which stick out inwardly from the rest of the foot. The placement and shape of this toe aids in tree climbing. Also unique are the opossum's teeth. Numbering approximately fifty, the opossum has more than any other terrestrial mammal. The opossum is an omnivore (eats both plants and animals) and uses these teeth to eat worms, slugs, persimmons, pokeberries, crayfish, crabs and anything else it can get its claws on.

When threatened, the opossum has a few effective defense mechanisms. The act of "playing possum" is most widely known, and is not something the opossum can control; rather it is an involuntary reaction to threat. Some predators react to the stimulus of killing their prey and an inert opossum is less than appealing. Somehow, sensing when the threat is gone the opossum awakens and proceeds on its way. Before going into this inert state, an opossum will also growl and blow bubbles through their saliva, creating the appearance of a sick or dying animal.

North America's only Marsupial is both special and unique. Although marsupial populations across the world are decreasing, the opossum population is on the rise. Before European settlement, the range of the opossum was limited to Central America and the Southeastern United States. Since that time, their range has greatly increased. Now the main limiting factor to their range is climate, whether it is too cold in the north or too hot and dry in parts of the west. Today opossums are found on the pacific coast from California to British Columbia. Even as their numbers increase, opossums in the wild seldom live more than 1 year. While not a major carrier of rabies, opossums are highly susceptible to other diseases. Predation and human factors (hunting & road kill) also add to the numbers killed each year.

If you are interested in learning more about North America's only marsupial, Didelphis marsupialis, please contact Audubon Maryland-DC by calling (410) 745-9283.

Burt, William, Grossenheider, Richard; The Peterson Field Guide to Mammals, 1980, Houghton Mifflin Company.
The National Opossum Society web site.
Nebraska State Wildlife web site.
The Opossum Network web site.
The Opossum Society of the United States web site.
The Skunk and Opossum Website.
The University of California Berkley Museum of Paleontology web site.

An' jes' gits me out o' hitch, Twell I want to tek my coat off, So's to r'ar an' t'ar an' pitch, Hit's to see some ign'ant white man 'Mittin' dat owdacious sin-

W'y dey ain't no use in talkin', Hit jes' hu'ts me to de hea't Fu' to see dem foolish people Th'owin' 'way de fines' pa't.

Possum skin is jes' lak shoat skin; Jes' you swinge an' scrope it down, Tek a good sha'p knife an' sco' it, Den you bake it good an' brown.

Dat yo' thoughts is 'mos a sin When you's settin' dah a-chawin' On dat possums's cracklin' skin.

("Paul Laurence Dunbar, born in Dayton, Ohio, on June 27, 1872, was the first African-American poet and novelist to attain international recognition. Dunbar was known for his use of dialect, but was also an accomplished poet and novelist in standard English. At age seventeen he published his own newspaper, the Dayton Tattler, an African-American newspaper printed by his high school classmate and friend, Orville Wright. His first book of poems, Oak and Ivy, was published in 1893. The book contained Dunbar's first dialect poem, "A Banjo Song." Dunbar published numerous books of poetry, novels and music during his career. He died in Dayton on February 6, 1906." from www.libraries.wright.edu/dunbar/)

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