Opossums are primarily inhabitants of deciduous woodlands but are often found in prairies, marshes, and farmlands. In the western part of their native range they generally keep to the woody vegetation along streams and rivers, a habit which permits them to penetrate the otherwise treeless grasslands and deserts of west Texas. Hollow trees and logs are preferred sites, but opossums will den in woodpiles, rock piles, crevices in cliffs, under buildings, in attics, and in underground burrows. Since they are not adept at digging burrows for themselves they make use of those excavated by other mammals. Movements of opossums monitored in East Texas showed that these animals typically frequent a home range approximately 4.6 ha in size, although the minimum size of home ranges may vary from 0.12 ha to 23.4 ha.
Home ranges tend to overlap considerably.
The opossum is more or less solitary and strictly nocturnal, venturing forth to feed shortly after dark. It feeds on a variety of foods, including rats, mice, young rabbits, birds, insects, crustaceans, frogs, fruits, and vegetables. In June the food for four opossums was about the same except that fruits and berries were added and birds were lacking. Their mating season extends from January or February to June or July. Females, which are in heat for about 30 days, breed the first season following birth.