Photo Credit: Roger Birkhead
SCIENTIFIC NAME: Didelphis virginiana
OTHER NAMES: Possum
DESCRIPTION: The opossum is North America’s only marsupial - an animal with a pouch, like a kangaroo or a koala. The possum has been around for at least 70 million years and is one of Earth’s oldest surviving mammals. The name ‘opossum’ was first used in western culture by Captain John Smith in 1608. It comes from the Algonquin name ‘apasum’, which means ‘white animal’. The opossum is about the size of a large house cat. It has a triangular head and long pointed nose. It has grayish fur everywhere but on its ears, feet and tail. Its prehensile tail is adapted for grasping and wrapping around things like tree limbs. The opossum can hang from its tail for a short time. Some people mistakenly think opossums hang from their tails and sleep, but their tails aren’t strong enough to hold them for that long. The opossum has an opposable thumb-like hallux on each rear foot. The hallux helps it grasp branches when it climbs. The opossum doesn’t hibernate in the winter. It will often hole up during very cold weather because it runs the risk of getting frostbite on its hairless ears, tail, and toes.
HABITAT: The opossum lives in a wide-variety of habitats including deciduous forest, open woods and farmland. It tends to prefer wet areas like marshes, swamps and stream and river bottoms. The opossum can be found in most of the United States east of the Rocky Mountains and on the West Coast. It is also found in Mexico, Central America and British Columbia, Canada.
FEEDING HABITS: The opossum is nocturnal and uses its keen sense of smell to locate food. It is omnivorous and eats just about anything, including lots of different plants, fruits, insects, and other small animals. Sometimes it eats garbage and carrion. Because so much carrion is roadkill, opossums are often killed by cars while looking for food on roadways.
LIFE HISTORY AND ECOLOGY: An opossum mother can have as many as 25 babies, but she will usually have seven or eight. The reason opossums have so many babies is to ensure that some of them survive. Like most marsupials, opossums are very small when they are born – about the size of a navy bean. They climb up the mother’s fur and into her pouch where they find a teat. Some babies do not find their way to the pouch and die. If they make it to the pouch, only babies who find one of the thirteen teats will survive. They will stay in the pouch and suckle for 55-60 days. Then they will move out of the pouch and spend another four to six weeks on their mother’s back. In some parts of their range, females will have three litters a year. The opossum uses many behavioral adaptations to survive. When threatened, opossums will exhibit behaviors like running, growling, belching, urinating and even defecating.
Sometimes they will “play possum” and roll over, become stiff, and their breathing will become slow and shallow. This coma-like state can last up to four hours. Some predators will think the opossum is dead and go away.
Opossum Society of the United States www.opossumsocietyus.org
National Opossum Society www.opossum.org
Novak, M., J.A. Baker, M. E. Obbard and B. Mallock. 1987. Wild Furbearer Management and Conservation in North America. Ontario Ministry of Natural Resources. pp. 246-261.
Author: Dave Nelson, Wildlife Biologist, May 2005