Fossils of opossums have been dated at 70 million years, making the opossum a North American resident during the time of dinosaurs. A marsupial, opossums have pouches in which they incubate newborn offspring. The nearly hairless tail of the opossum is prehensile, making the opossum the only native furbearer with the ability to grasp things with its tail. Opossums appear to have little intelligence, and they are commonly caught by novice and experienced trappers alike.
Opossums are grayish animals with naked ears and nearly naked tails. Males are usually larger than females. The males may measure up to 36 inches in length, including the tail of 12-14 inches. Weights average around 7 pounds for males and 5 pounds for females. An occasional male might weigh as much as 10 pounds or a little more.
Ears are soft, leathery, and white-tipped around the outer edge. Ragged ears are common in the northern parts of the opossums's range and usually the result of frost damage.
Male opossums have a gland under their chin that secretes fluids that often stain their chests a yellow color.
There are five toes on each foot, and the hind feet have a toe that resembles a thumb. All toes have toenails except the thumbs of the hind feet.
Opossums have 50 teeth, more than any other American mammal. Four canine teeth are present.
A opossum brain is small in comparison to its body size, and opossums are thought to be less intelligent than many other species.
Color variations do occur in the wild, and some opossums are darker in color. Rarely, opossums may be reddish or reddish-brown in color.
Opossums have two annual litters over much of their range. In far northern areas, one litter per year is typical. The two peak breeding times are February and June in much of the opossum range.
Birth is just 13 days after conception. After, the newborn are cleaned by the mother opossum, and they climb in a hand-over-hand fashion to the mother's pouch where they attach themselves to a nipple. The newborn young are very tiny — smaller than honeybees. It takes 22-24 newborn opossums to equal the weight of a common penny.
The newborn young appear to be only partially developed except for the front feet, which are needed to help the newborn travel the several inches to the pouch.
Once secured to the nipple, the newborn opossum does not let go for six to seven weeks. After 80 days in the pouch, young opossums begin to venture outside of the pouch. They begin climbing on the mother's fur, occasionally riding there as the mother travels.
Young opossums grow rapidly, and the first litter of the year is weaned and off on their own by mid-May. The second litter is usually born about four weeks later.
Average litter sizes are about seven or eight in southern states and 10 in northern states.
Six years of age is considered old for a opossum.
Opossums have an ability to feign death, called "playing possum." In this condition, the animal appears unconscious, the mouth opens slightly, drooling occurs, the feet clutch together, and the entire body becomes limp. Not all opossums "play possum," and the condition is induced by fear or other stresses. Whether this condition is voluntary or involuntary is not known or fully understood. One theory is that the opossum suffers a short circuiting of the nervous system known as catatonic shock. The condition is much more apt to happen during daylight hours, which suggests the animal might be able to trigger the response deliberately as a defense mechanism.
Weight: 10 pounds
Birth is 13 days after conception
Young stay in the pouch for 80 days
The only North American marsupial
Life span: up to 6 years
Opossums are clean animals and spend time grooming themselves.
Underground dens are favored by opossums, and the species commonly rakes piles of leaves or grass for bedding, which they transport into the dens by grasping the pile with their tails and carrying the bedding aloft to the nest.
Opossums are good tree climbers, and they seem to prefer to climb smaller trees where they can use their tails as an aid for grasping. If suitable, underground den sites are not available, a opossum will often use a larger hollow tree for a temporary daytime den.
The use of dens is sporadic except when young are being reared, and it appears that opossums use any convenient den site, as their nighttime activities are interrupted by dawn. Natal dens are an exception, and the female regularly uses the same den as the offspring are being reared.
Opossums do not hibernate, but they do store up layers of fat in northern ranges to sustain them during periods of severe cold and deep snow. When cold periods last for more than two weeks, the opossums do have to travel to seek more food, and ear tips freezing and tail end freezing does occur at these times. These frozen appendages do separate, leaving many northern opossums with rather ragged ears and stubby tails.
The sense of smell is well developed in opossums and helpful in the search for food. Insects are a most important food, as are worms, eggs of ground nesting birds, and young mice or rabbits. Fruits are eaten when available, and opossums frequently scavenge any dead animals found. Roads serve as an important source of food, as traffic-killed insects, birds, and small mammals are found regularly.
The home range of a opossum is about 50 acres. They are not territorial to the extent that they defend their ranges from other opossums. Many opossum ranges overlap, and good-quality habitats may support 20 opossums to the square mile.
Opossums do frequent the edges of water for food, and they are rarely found more than 750 yards away from water.
The opossum is found as far north as New York and occasionally in Maine. They do not thrive in arid regions or the Rocky Mountains.
Opossums are not serious predators upon any species, and they are more of a threat to ground nesting birds and their eggs than they are to other wildlife. The species does provide a service by cleaning up carrion.
Although opossum fur doesn't command a high price, annual harvests by man exceed 1 million animals, and the fur value does bring $2 million or $3 million to hunters and trappers in many states.
The meat of opossum is edible and appreciated in some areas of America.