The opossum is North America’s only marsupial. Marsupials develop in a unique manner: The young are born in an embryonic form and make their way into a pouch where they are nourished. At about 80 days of age, the young may leave the pouch for short periods of time, clinging to their mother’s side and back. Young are on their own when they are 8 to 9 inches in length from their nose to the base of their tail.
Opossums are nocturnal and live a mostly solitary life. They are not aggressive, and a common means of defense is faking death or “playing possum.” When frightened, they may show their teeth and hiss.
Living in Your Yard
Opossums prefer to live in wooded areas by streams. Cities and suburbs provide adequate food and shelter. Common den sites include abandoned woodchuck burrows, hollow logs, and wood or brush piles; openings under buildings, elevated sheds, concrete slabs and porches; and crawl spaces under houses. Inside the cavity, a nest is made of leaves and grass. Opossums are climbers and take shelter by day in trees or old squirrel nests. Most only use our homes during March through August to raise their young. If possible, consider “living with them” until the young are on their own at about five months of age.
- Do not encourage opossums by feeding them.
- Keep pet food and water dishes inside, especially at night.
- Do not allow spills to accumulate below bird feeders.
- Keep grills and barbecues clean. Even small food scraps may attract opossums.
- If possible, do not keep garbage cans outside.
- Use welded wire to prevent animals from accessing openings under decks, elevated sheds, concrete slabs and porches. Secure outside access to crawl spaces.
- Place lighting, such as bright flashlights, flood lamps or blinking strands of holiday lights, in the den. It is best to leave the lights on 24 hours a day. If this is not possible, the lights must be on during the day to disturb the animal’s sleep.
- Play a radio, portable alarm clock, noisy children’s toy or anything that makes noise repeatedly either in or near the den. It is best to have the sound on for 24 hours a day. If this is not possible, the sound must be on during the day to disturb the animal’s sleep.
- Place ammonia-soaked rags in the den for one week. (Ammonia has an irritating smell.) Over time, the ammonia will dissipate, so it is important to resoak the rags daily. Do not use ammonia-soaked rags March through August; they may injure infant wildlife too young to escape.
For deterrents to be successful, it is important to use all of the techniques at the same time. To determine if an animal has left a den site, wad up newspaper, and pack it into the den entrance. (This also helps to hold in ammonia fumes.) If the animal is still using the den, the newspaper will be pulled out. If after a few days the newspaper has not been disturbed, securely repair any openings. Failure to do so may result in another animal moving in.
The simplest way to keep animals out of garbage cans is to bring the cans inside where the animals cannot reach them. If this is not possible, pour 1 cup of ammonia inside the can, sprinkle black pepper on the top bag, or place ammonia-soaked rags on top of the lid and secure the lid with bungee cords. Use these techniques for five to seven days or when placing garbage on the curb for pick up.
The best way to keep opossums out of your garden is to build a 4-foot-high chicken-wire fence around it, leaving the top 12 to 18 inches bent outward and unattached to any support. The opossum’s weight will pull the top of the fence down, landing the animal back where it started.
Taste deterrents work, such as spraying a mixture of 1 gallon of water and 2 tablespoons of hot sauce or garlic puree onto the plant, but they need to be reapplied after a heavy dew or rain. Nurseries or home centers may carry commercial products as well.
Opossum in a Window Well
Place a roughed board at a 45 degree angle into the window well. Make sure the board is long enough to act as a ramp to the top. If you do not have a roughed board, wrap a towel or carpeting around the board to provide traction for the opossum. Place fish-scented cat food, Twinkies or cheese at the top of the ramp to entice the opossum. Opossums are active at night and may not leave the window well until then.
Attach a string or rope to a 5-gallon bucket handle. Place food inside the bucket to entice the opossum, and lower the bucket into the window well. Place the bucket on its side so that the opossum is able to walk inside. Once the opossum is inside, slowly raise the bucket to ground level, and place the bucket on its side with the opening away from you so that the opossum can walk out.
Public Health Concerns
Opossums have a lower body temperature than most mammals, which makes them fairly resistant to many diseases. Rabies is rare in opossums, and there have not been any reports in DuPage County in recent years.
Opossums are known carriers of leptospirosis, a bacteria carried in their urine that can cause disease in other animals. To be safe, always keep pets’ vaccinations current, and remove opossum urine or feces from your garage, window wells or other areas. Do not handle feces or urine with your bare hands; use gloves or a shovel. Then, disinfect the area with bleach.
What Not To Do
- Trapping and removing an animal is not always a solution to the problem. Removing the animal is illegal without the proper permits and only creates an open space for another animal. A trapped adult may also leave young behind to die of starvation in an inaccessible area. Focus on removing the attraction, not the animal.
- Never move young from a nest.
- Do not use poisons. They are inhumane and may be illegal. They can also result in secondary poisoning of raptors, wild scavengers and neighborhood pets.
- It is illegal to keep wild animals, even for a very short time. They have specialized nutritional, housing and handling needs that you are unlikely to be able to provide. Inexperienced individuals who attempt to raise or treat them inevitably produce unhealthy, tame animals that cannot survive in their natural habitats.
Willowbrook Wildlife Center
If you come across a wild animal and are concerned, leave it alone. Call Willowbrook Wildlife Center for advice at (630) 942-6200. The center is located at 525 S. Park Blvd. in Glen Ellyn and is open 9 a.m. to 5 p.m. every day except select holidays. Recorded messages provide general information for callers when the center is closed.