- The opossum is very similar to its ancestors, which roamed the giant fern forests with the dinosaurs 50 million years ago.
- The ability of the opossum to eat almost anything has helped it adapt to a changing environment. It has survived for eons and is likely to be around for a long time to come.
- The hind foot is hand-like with a "thumb" that lacks a claw.
- The opossum is a marsupial. This means the young are born very early. After birth, up to 20 bean-size young climb into the fur-lined pouch on the female's belly. Here, they attach themselves to one of the teats for about two months. Any that do not become attached do not live. At about three months of age, they begin to leave the pouch and ride on the female's back, grasping her fur. When 100 days old, they leave the mother.
- This "grinning" marsupial would rather run than fight and can climb trees easily. Even if cornered, fighting is the last resort. A cornered opossum usually will roll on its side, open its mouth, and "play dead." Still, with 50 teeth, it can inflict a severe wound.
- The opossum nests in any place where it can keep dry and hide from enemies, such as in deserted animal dens, brush piles, tree holes, or openings under old buildings. The preferred habitat is a wooded area near a source of water (stream, pond, lake, or swamp).
- In the past 20 years, the opossum has extended its range east to the Atlantic coast, north into Canada, and west to Colorado. It may have reached its northernmost limit; in northern areas, it is common to find opossums with frostbitten ears.
- Mating: believed to be monogamous.
- Breeding period: February, and again in May when the first litter is weaned.
- Gestation period: 12 to 13 days.
- Litters per year: usually 2; occasionally 3.
- Number of young: 5 to 14 per litter; as many as 20 are born, but the number that survive is limited by the number of teats (11 to 14) in the mother's pouch.
- Adult weight: 4 to 15 pounds.
- Life expectancy: 2 years.
- Feeding time: usually nocturnal.
- Movement: random, with no fixed home range; some spend their lives within 40 acres, while others may wander more than 2 miles in one night.
- Typical foods: major food is carrion; other foods include insects, fruits, reptiles, amphibians, fish, and bird eggs.