Opossums are marsupials, carrying their babies in a pouch during gestation. Once slightly mobile, baby opossums cling onto their mother’s back as she forages at night. During the daytime they will sleep in her pouch and nurse. A mother opossum may seek a temporary den for her young for a period of about 2 weeks, when the babies are a bit too big to cling onto her back, and not fall off her back as she traverses shrubbery in search of food at night.
If there are baby opossums under a house, allow the babies to mature until they are old enough to join the mother outside, then close the opening when they have left. (Always sprinkle white flour outside a hole before closing it. If the flour is undisturbed, you can close the hole. If it is disturbed, you may trap an animal in. Repeat the process until the flour is undisturbed the next day to be sure no animal went inside to sleep there.)
Opossums that are 6 inches nose to butt, minus their tail, are generally self-sufficient. If the opossum appears thin, is lethargic, or has sunken eyes, indicating dehydration, the opossum should come into care.
Opossums that have bright eyes, display defensive behavior — open mouth and growl, and or run away — should be left alone.
Any opossum attacked by a pet should come into care. Opossums may “play dead” when startled or confronted; and may take up to an hour before coming to and scurrying away. Don’t assume an opossum is dead within this time frame!
Mother opossums hit by cars may have babies in her pouch that can survive with care. Young ones, too small to survive on their own, may crawl into nearby shrubbery, and should be kept warm during transport to a licensed wildlife rehabilitator. Hypothermia is the biggest risk of death to these small animals, aside from predators. Do not attempt to remove baby opossums from a mother’s pouch because this can harm the babies.
Ask about volunteering if you think you have the time and desire to care for wildlife. Most centers never have enough help, and will train new volunteers to provide the specialized care that wildlife require, and permit people to legally possess wildlife for the purpose of rehabilitating wildlife for release back to the wild.