Facts About Opossums.
Opossums measure 2 to 3 feet in length, a third of which is a round, scaly, sparsely haired tail. The head is conical, tapering to a slender, elongated snout tipped by a pink-colored nose. The face is light gray to white, whereas the general color of the fur from neck to rump is grayish white. Because of its body shape, a small opossum is sometimes mistaken for a large rat. Prior to European settlement of North America, the Virginia opossum was found only in Central America and the southeastern United States. During the 1900s, its range expanded northward and westward.
Virginia opossums, also known as “possums,” first arrived in Washington in the early 1900s as pets and novelties. Some of these animals, or their offspring, later escaped from captivity or were intentionally released. With few natural predators, the absence of hunting, and an abundance of food and shelter, opossums have adapted well to living close to people in urban and suburban environments. Except for higher elevations, opossums now occupy most human-occupied habitats in western Washington. Opossums are marsupials (mammals with a pouch in which they carry their young), a primitive group of mammals found most commonly in Australia. Kangaroos, koalas, and wombats are other well known marsupials. Opossums are the only marsupials in North America. All other mammals are placentals, which means their young develop within a saclike membrane called the placenta inside the mother’s uterus, rather than in an exterior pouch. In Australia and elsewhere, many species of marsupial have been out-competed and even driven to extinction by more modern mammals. Yet, the opossum has adapted to the changing environment in the Western Hemisphere, and continues to thrive. Opossums are inhibited animals, especially in daylight or under artificial light, but are by no means stupid. Results from some learning and discrimination tests rank opossums above dogs and more or less on a par with pigs in intelligence.
Food and Feeding Habitats
Den Sites
Virginia opossums, also known as “possums,” first arrived in Washington in the early 1900s as pets and novelties. Some of these animals, or their offspring, later escaped from captivity or were intentionally released. With few natural predators, the absence of hunting, and an abundance of food and shelter, opossums have adapted well to living close to people in urban and suburban environments. Except for higher elevations, opossums now occupy most human-occupied habitats in western Washington. Opossums are marsupials (mammals with a pouch in which they carry their young), a primitive group of mammals found most commonly in Australia. Kangaroos, koalas, and wombats are other well known marsupials. Opossums are the only marsupials in North America. All other mammals are placentals, which means their young develop within a saclike membrane called the placenta inside the mother’s uterus, rather than in an exterior pouch. In Australia and elsewhere, many species of marsupial have been out-competed and even driven to extinction by more modern mammals. Yet, the opossum has adapted to the changing environment in the Western Hemisphere, and continues to thrive. Opossums are inhibited animals, especially in daylight or under artificial light, but are by no means stupid. Results from some learning and discrimination tests rank opossums above dogs and more or less on a par with pigs in intelligence.
Food and Feeding Habitats
- Opossums lived during the time of the dinosaurs and one reason for their continued survival is their ability to eat nearly anything.
- Foods include fruits, nuts, grains, insects, slugs, snakes, frogs, birds, bird eggs, shellfish, mice, and carrion (dead animals).
- Around human habitation, opossums also eat garbage, pet food, birdseed, poultry, and handouts.
- A study of Portland Oregon’s opossum population found that small mammals (dead and alive) were the most important food in winter and spring, slugs in summer, and fruits in fall.
- Because opossums eat many road-killed animals, including other opossums, they often become road kill themselves.
- Because opossums accumulate little body fat for winter and don’t store food, they must forage year-round.
Den Sites
- Opossums will den nearly anywhere that is dry, sheltered, and safe. Den sites include burrows dug by other mammals, rock crevices, hollow stumps, logs and trees, woodpiles, and spaces in or under buildings.
- Their fur doesn’t provide much insulation, so opossums fill their dens with dried leaves, grass, and other available soft material to form well-insulated nests. Nest materials are carried in their coiled tail.
- To avoid predators, opossums move to a different den every few days. (A male opossum followed by radio tracking used 19 different dens in five months.)
- A female with young or an opossum “holed up” during a cold spell will use the same den for a greater length of time.
- Opossums are successful as a species due in part to the size and frequency of litters.
- The breeding season begins as early as January and may continue to mid-November.
- Being marsupials, opossums give birth to undeveloped young. Only 12 days following breeding, five to ten bumblebee-sized pups crawl into their mother’s pouch, where each firmly attaches to a teat.
- Opossum pups find nourishment, warmth, and safety in the pouch. When closed, it is so well sealed that if the female swims, the pups remain dry.
- At 60 to 70 days old, the house mouse-size young begin to leave the pouch for brief periods, returning to suckle.
- At 80 to 90 days old, the young begin to ride on their mother’s back with their feet and tail firmly attached to her fur. (Contrary to myth, a female opossum never carries her young on her tail.)
- At 3½ months of age, the young begin to leave the den to feed on their own, and soon disperse to establish their own territories.
- Opossums have high mortality rates at all ages. They are killed by dogs, coyotes, foxes, raccoons, bobcats, eagles, hawks, and owls, with young opossums being the most vulnerable.
- Car kills in the fall and in winter conditions account for many opossum deaths.
- Opossums rarely live a full two years in the wild.
This information Was provided by the Washington State Department of Fish and Wildlife, Russell Link, and Michael Holmquist
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