How big is the opossum?
Baby opossums at this size or smaller are too young to be by themselves. Between two and three months of age, baby opossums ride on their mother’s back and are dependent on her for care. Sometimes babies fall off their mother’s back and if she doesn’t notice, she will continue on without them. Mother opossums do not come back for their babies.
If you find a baby opossum of that size alone with no mother in sight, contact a wildlife rehabilitator.
If the opossum is bigger than 18 cm (7 inches) nose to bum (not including the tail)
Baby opossums larger than 7 inches may be independent – their behaviour should indicate whether or not they need help. What does the opossum do when you approach them? If they are alert, run away or act defensive (stand still holding their mouth open while drooling), they might be just fine. Virginia opossums leave the care of their mother at about 3 months of age. They may not be full-grown yet, but they can take care of themselves! Keep pets inside until the opossum leaves the area on their own.
If the opossum doesn’t act defensive, try to get away from you, or stays in a highly exposed area for several hours, there may be something wrong. Keep them contained in a dark, quiet place and contact a wildlife rehabilitator for advice.
Temporary Care
While you are waiting to hear back from a wildlife rehabilitator, keep the baby opossum contained in a dark, quiet place. Make sure they have a heat source. Don’t give them any food or water until you have spoken to a rehabilitator. Further temporary care instructions can be found here.