They consume garbage and carrion, including animals killed on highways. Sometimes opossums forage by day, but they are mostly nocturnal. They shelter in hollow logs, woodchuck burrows, rock crevices, tree cavities, the abandoned leaf nests of squirrels and beneath porches and old buildings. They seldom spend two successive nights in the same den. Opossums do not dig their burrows, but they will occupy abandoned burrows.
Opossums are solitary.
Females and unweaned offspring stay together, and the sexes come in contact during breeding season, late February and March in Pennsylvania. After mating, the female drives off the male. The male plays no part in raising young. Newborn young are hairless, pink-skinned, blind and scarcely past the embryonic stage. They are about one-half inch in length and weigh 0.005 ounces.