Forest Preserve District of Cook County (Illinois)
Nature Bulletin No. 296-A March 2, 1968
Forest Preserve District of Cook County
Richard B. Ogilvie, President
Roland F. Eisenbeis, Supt. of Conservation
****:THE OPOSSUM
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.
NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators.
Argonne National Laboratory, Division of Educational Programs, Harold Myron, Ph.D., Division Director.