The young opossums weigh about 0.16 grams at birth. They are fixed to the nipple for the first 50 to 65 days of their lives. By 95 to 105 days, the young no longer depend on their mother. There is no maternal bond between the mother and young after they are weaned. Behavior Opossums are nocturnal animals and have very poor social development.
Females tend to live in groups, but the males fight when confined together.
Groups of opossums are composed primarily of young because of the short life span of the opossums. Opossums, both male and female, are very aggressive. They use various forms of intimidation to defend themselves but usually play dead when they encounter a more powerful opponent. Opossums usually travel across the land but will swim in some cases to escape danger. For grooming, opossums use their hind feet to clean their fur and wash their faces with their fore feet.