Forest Preserve District of Cook County, Illinois
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The Opossum

Nature Bulletin No. 296-A   March 2, 1968
Forest Preserve District of Cook County
Richard B. Ogilvie, President
Roland F. Eisenbeis, Supt. of Conservation

Several times, in the past few years, newspapers have reported the discovery of Opossums gorging themselves on garbage in the alleys of downtown Chicago. They are numerous in our forest preserves and frequently found in adjacent suburbs but it seems impossible that an animal so stupid, with such a slow shambling gait, could travel 10 miles or more through a great city. Opossums seem to have the wanderlust and many are killed on the highways as they prowl around at night. A hundred years ago, although plentiful in our southern states and much hunted for their meat and fur, they were uncommon in central Illinois and Indiana. As they increased in numbers they gradually spread northward as far as central Wisconsin and Michigan, southern Ontario and Vermont.

Br'er Possum is a queer beast. He is a living fossil. Near the end of the Age of Reptiles, about sixty million years ago, peculiar little animals appeared on earth. Most of these had small heads with long snouts, walked on the soles of their five-toed feet, and the females carried their young in abdominal pouches. In ancient rocks of Wyoming and Montana -- in one instance, near the remains of a huge dinosaur -- fossils of an animal little different from our modern opossum have been found.

It is the one animal of its kind -- a marsupial -- in North America. There are several in Central and South America but most marsupials are native only in Australia and neighboring islands: about 30 kinds of kangaroos and wallabies, the wombats, the sloth-like koala "bear", the Tasmanian wolf, the Tasmanian devil, and-many other pouched mammals resembling moles, mice, rats, cats, and flying squirrels.

How has the possum managed to survive and thrive during these millions of years with tremendous changes in the earth's surface and climate, and in spite of modern civilization, when so many other animals have become extinct ? Because it eats anything, plant or animal, alive or dead; because it is very prolific; and because it has a peculiar way of carrying its young until they are able to fend for themselves, Further, it has remarkable vitality and ability to take punishment.

The young, from 5 to 15 or more in number, are born after a gestation period of less than two weeks. Each is a naked pink embryo-like creature, smaller than a honeybee, with no eyes, no ears, and a tiny round mouth. The front legs are well developed with sharp hooked claws but the hind legs are mere buds. Somehow it manages to crawl into the pouch on its mother's belly, where it fastens onto a teat and hangs for a month or more. After that, they come out and ride on her back, clinging to her shaggy fur. When about 3 months old, and the size of a half-grown rat, they leave her. In the meantime, in our southern states, she may be carrying a new litter within her pouch.

The possum's off-white head has a long sharp muzzle with an unusually large number of teeth -- fifty; naked black ears; and a very small brain. Its outer fur is long, coarse and grizzled gray. The long, naked tail is very muscular and used for carrying leaves and grass to its den, or for clinging to the branch of a tree. Unlike the front feet, the first toe on each hind foot has no claw and is like a human thumb, which makes the possum a good climber as much at home in trees as on the ground. It eats all kinds of insects, worms, snails, snakes, birds, eggs, mice, vegetables, corn, chickens, any dead animal, berries and fruit -- especially persimmons. When attacked, it feigns death-- "plays possum" -- with closed eyes, lolling tongue and a limp, apparently lifeless body, regardless of how much it is abused.

A possum, roasted with sweet 'taters, is heaps better than his I.Q.

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