Opossums are the only marsupial found in North America, where they live in urban settings, woodlands, and open fields. They are perhaps best known for "playing dead," a defense mechanism used to appear less appealing to predators. Opossums are nocturnal and omnivorous, taking advantage of any food source they come across. Their diet consists of insects, small rodents, amphibians, fruits, berries, garbage, and even untended pet food.
Quite large, opossums grow around 16 inches (41 cm) long and weigh anywhere from 6 pounds (3 kg) to 12 pounds (6 kg). Including their tails, opossums can reach up to 3 feet (90 cm) long. They are identifiable by their gray fur, white, pointed faces, and the long tails they use to help them climb. Opossum feet look like small hands with five fingers each. Their back feet contain opposable thumb digits that also help with climbing.
Though they are found throughout the country, opossums cannot survive in areas of extreme cold, like the Rocky Mountains. The marsupials prefer wooded areas near sources of water like streams, wetlands, swamps, and thickets. Highly adaptable, opossums survive easily in urban environments.
Opossums can indeed find their way into homes, though it is usually by accident. The animal may enter through pet doors in search of food or shelter. More commonly, though, they will take up residence under porches, sheds, decks, and brush piles. When searching for food, they target garbage cans, gardens, pet foods, and compost piles.
As is the case with most wild animals, opossums become aggressive when they are cornered. They will bite, scratch, bare their teeth, and hiss in order to escape. Pets and people alike may be harmed in the presence of aggressive opossums and are then susceptible to the diseases they carry, such as tuberculosis, tularemia, and Chagas disease. Additionally, the marsupials can be infested with parasites such as fleas, ticks, mites, and lice.