Opossums: A Gentle and Beneficial Wild Neighbor
Fun facts about opossums: 1) Opossums are the only marsupials native to North America; 2) despite their appearance, they are rarely any kind of threat to humans or chickens or other animals; 3) rabies is extremely rare in opossums; 4) they are beneficial to humans in many ways, eating slugs, snails, insects, ticks, and sometimes small rodents, and will even clean up spilled garbage!
Opossums are often accused of getting into garbage cans, doing damage to gardens, and even killing chickens, but they are usually the “clean up crew” stopping by to clean up the mess left by other food-seeking critters. It is very rare that opossums kill chickens.
Opossums are not aggressive. When frightened, their open-mouth, defensive hissing (“alligator mouth”) is merely a bluff to look vicious, a defense mechanism. Opossums may also drool, which causes a predator to think the opossum is sick and therefore unappetizing. Opossums may also release a greenish-colored, unpleasant-smelling anal fluid (note: opossums cannot “spray”). And if all that doesn’t work, they play dead (also known as “playing ‘possum”), lying in a comatose-like state, which makes predators uninterested in killing them, until the danger passes.
People often mistake the open-mouth hissing and drooling behavior of opossums as a sign of rabies. In fact, rabies is extremely rare in opossums. It is speculated that this is due to their naturally low body temperature compared to other warm-blooded animals.
Figure 1: Although their appearance is sometimes perceived as menacing, opossums are gentle beings, rarely posing a threat and have the distinction of rarely having rabies. Photo credit: The Humane Society of the United States.
Fig. 2: Joeys in mother’s pouch being helped by a certified wildlife rehabilitator. Opossums are often victims of car hits. Check the pouch, and if any babies are alive inside, call a wildlife rehabilitator immediately (https://cwrawildlife.org). Photo credit: The Humane Society of the United States.
If you want to keep opossums from denning under a deck or shed, make sure they cannot get there in the first place by keeping any holes filled. If you suspect a mother opossum has already moved in and you do not want to wait until she leaves (opossums are nomadic), wait until she leaves her den--two hours after dark is generally a safe time. Then, loosely close the opening with straw or other fibrous material. This will ensure that an animal trapped inside can clear the path to escape, but one outside will not disturb the blockage to get back in. Opossum mothers take their babies, called “joeys”, wherever they go, so there is not much chance that any babies will be left behind. But always check for youngsters before closing the opening. If the hole has not been disturbed for two or three nights, it’s safe to assume that no one is inside and the hole can be properly filled. For permanent exclusion, put in an L-shaped footer, which prevents digging under.
Every now and then, an opossum will get into a house through a pet door. Encourage them to leave by closing the doors to all rooms and opening the doors to the outside. Opossums are usually not aggressive, so you may be able to help them on their way by gently nudging them with a broom.
Instead of viewing our prehistoric-looking wild neighbors as a nuisance, consider seeing opossums a blessing, as their presence is often mutually beneficial.
Annie Hornish is Connecticut State Director for The Humane Society of the United States and a supporting member of Sierra Club.