The Misunderstood Marsupial
By Jo Ann Abell | Jul 30, 2019
Photo by Getty Images/quadxeon
My first up-close encounter with an opossum took place years ago, when I went to get feed for our horses one evening. I was used to seeing these hairy, grayish animals flattened on the road, their lives abruptly and unceremoniously ended while out on a nightly prowl, but I was not expecting to see an 18-inch-long freeloader wedged under the feed bin. I walked over for a closer look, which prompted a couple of low hisses, but it didn’t move. The poor animal was probably as surprised to see me as I was to see it. I’d unknowingly put out the opossum welcome mat when I forgot to close the feed room door that morning.
About the size of a large house cat, the Virginia opossum (Didelphis virginiana) is North America’s only marsupial — a mammal that carries and nurses its young in a pouch. One of Earth’s oldest surviving mammals, the opossum has been around for at least 65 million years, having first appeared in North America about the time dinosaurs went extinct. With little need to evolve in order to survive, the modern-day opossum is somewhat of a living fossil, having retained many of the features of the earliest known marsupials.
The critter received its unusual name in 1608 from Captain John Smith, one of the British settlers of Jamestown, Virginia. The colonists traded with the Algonquin tribes, and the opossum got its name from their word apasum, meaning “white animal.” These mammals are found in the United States east of the Rocky Mountains and along the West Coast, as well as in Mexico, Central America, and British Columbia. In North America, they’re typically referred to as the North American opossum, or merely “possum.”
These habitat generalists can live in a wide range of settings, including wooded areas, open fields, farmland, parks, and even in suburbs and cities, most often near water. They take shelter in the abandoned burrows of other animals, as well as in hollow trees, in brush and rock piles, under porches and storage sheds, in crawl spaces, and occasionally in attics and garages, if they can gain access.
They’re excellent climbers because of their opposable “thumbs,” which are actually clawless digits on their rear feet (so, technically, they’re toes). This adaptation helps them flee up trees, and also allows them to scale wood or wire fences, gutters, and more. Their prehensile tails are similar to a monkey’s, and they use them to grasp and wrap around things, such as tree limbs.
Nomadic opossums tend to stay in an area only as long as food and water are available. Females may remain in a small area while they care for their young, and families will sometimes group together in ready-made bur-rows or even under houses until their young go out on their own. They favor dark, secure areas, both aboveground and belowground.
Not true hibernators, opossums simply take long naps in winter. These semihibernators, a group that also includes bears, skunks, and raccoons, go into a state of torpor. This means that their breathing slows down and their body temperature lowers a few degrees while sleeping to conserve energy, but they wake up to forage between winter snows.
Female opossums have 1 to 3 litters per year, giving birth to up to 20 underdeveloped offspring, called “joeys.” Born just 12 to 13 days after mating, the newborns are about the size of a jelly bean. Like kangaroos and koalas, the infants crawl into the mother’s fur-lined pouch, where they’ll live and nurse for the first two months of their lives. If they don’t find the pouch, they won’t survive. As they grow and the pouch becomes full, they venture out, spending another 4 to 6 weeks riding on their mother’s back until they’re old enough to go out on their own. The male opossum plays no role in raising the joeys.
Photo by Adobe Stock/geoffkuchera
Virtues of the Lowly Opossum
The opossum is a fascinating creature that suffers from an image problem. Frequently perceived as a dimwitted, rat-like scavenger whose most impressive trick is playing dead, the opossum has some lesser known virtues that just might transform the aversion of some for this odd, waddling mammal into, at least, tolerance.
Turns out opossums are the unsung heroes in the fight against Lyme disease. Ticks that carry the Lyme disease bacteria are found on mice, shrews, squirrels, and chipmunks, but not so with the opossum. Research by scientists at the Cary Institute of Ecosystem Studies in Millbrook, New York, showed why. Several opossums were placed in cages and covered with ticks. The researchers waited for the biting ticks to jump off, and counted how many escaped the mammal’s voracious appetite. The opossums ended up grooming off and eating more than 95 percent of the ticks that landed on them. It was estimated that a single opossum could eat as many as 5,000 ticks in one season.
These solitary scavengers will eat almost anything. Besides eating ticks, the opossum’s diet includes snails, slugs, and beetles, so they’re a welcome addition to the garden. They’ll also catch and eat unwelcome pests, such as mice, rats, and cockroaches, and they’re one of the few animals that prey upon shrews and moles. Immune to snake venom, they actually kill and eat snakes, even venomous rattlesnakes, copperheads, and cottonmouths. They like overripe fruit, berries, and grapes, which they eat off the ground. They also eat roadkill, even skeletons, making them an important part of nature’s cleanup crew.
Photo by Getty Images/mtruchon
Opossums are nonaggressive, reclusive animals that just want to be left alone. Unfortunately, they often fall victim to misinformation, and the results can be disastrous for them. Not the cutest animal, they’re further burdened by the popular misconception that they’re rabid when they drool and hiss, which is actually a bluff tactic to scare off predators. In fact, opossums tend to be resistant to rabies. This resistance is thought to have something to do with the opossum’s low body temperature (94 to 97 degrees Fahrenheit), which doesn’t provide a suitable environment for the virus to live.
Having no defenses, they’re often the target of inhumane acts to get rid of them, especially in urban areas where they’re trapped and poisoned. Opossums have a life expectancy of only 1 to 4 years due to their many predators, which include foxes, bobcats, coyotes, owls, and dogs. However, their No. 1 predator is humans. Their habit of eating roadkill results in far more opossums being struck and killed by automobiles than by any other predator.
Perhaps the opossum’s most curious characteristic is its ability to feign death when confronted by danger. When threatened, the opossum can use several defense tactics, including running, climbing a tree, growling, baring its 50 sharp teeth, and hissing. If these tactics fail, the opossum has one last trick up its sleeve — “playing ‘possum.” In an involuntary response similar to fainting, the opossum rolls over on its side, with lips drawn back, teeth bared, and tongue hanging to the side, mimicking a dead animal. In this unconscious state, they also secrete a foul-smelling liquid like that of a rotting carcass. Because most predators prefer live prey, the opossum’s foe will take these traits as a sign that the opossum is dead and lose interest.
Photo by Getty Images/mtruchon
Opossums are increasing in number and expanding their range throughout North America. A better knowledge and understanding of all wild animals and the role they play in the greater ecological scheme are essential to a peaceful coexistence with humans.
That couldn’t be truer in the case of the opossum. These harmless creatures pose absolutely no threat to people, and they provide benefits in the places they occupy. They’re far more beneficial than they are harmful. The good news is, if you can keep them from where you don’t want them, opossums are actually pretty amazing creatures to have around.
Typically, they go about their business so quietly that you won’t even know they’re around. If you happen to encounter an opossum, do nothing! Opossums seldom stay in one place for more than a few nights. Just watch from a distance and enjoy one of nature’s most unusual and beneficial wildlife species
10 Ways to Discourage Opossums from Hanging Around
If there’s an opossum in your area, it’ll most likely move on in a day or two. If not, there are simple, nonlethal ways to encourage them to leave. The easiest way to eliminate opossums is to prevent them from becoming a problem in the first place.
- Eliminate all food sources. Keep in mind that they hunt at night, relying chiefly on
their sense of smell to find food.
- Feed pets indoors or bring in any leftover pet food before dark, when opossums are most active.
- Keep compost containers secure, and use tight fitting lids on garbage cans.
- Clean barbecue grills and grease traps after use.
- Harvest fruit and garden crops when they’re ripe, and pick up any fruit that drops from trees or bushes. Also clean up spilled birdseed.
- Remove brush piles, dilapidated buildings, and holes under concrete slabs to eliminate opossum hiding places.
- Keep your yard well lit at night. Opossums favor darkness and won’t consider your property welcoming.
- If gutters or other vertical surfaces are being climbed, cover them with an 18-inch piece of sheet metal, or apply vegetable shortening up to a height of 18 inches.
- Motion-activated sprinkler systems are an effective deterrent. Place them near the trouble spot, such as your garden or porch. The system will activate when an animal comes within its reach, teaching it to steer clear of the area.
- Should you have to remove an opossum, use a live-catch trap baited with a can of cat food, but first check to ensure that trapping is legal in your area. You can also call your local animal control office for help with removing “nuisance” wildlife.
Jo Ann Abell lives on a small farm in southwestern Virginia, where she enjoys watching and writing about nature and wildlife.
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