The Good. The Bad. The Ugly.


Consider this. The opossum (Didelphis virginiana) eats approximately 5,000 ticks a season, helping to save humans and their pets from Lyme disease and other tick-borne diseases. This is the claim that has been widely reported and shared on websites, publications and on social media, earning the much-maligned opossum a well-deserved reprieve from its haters … until now.

The opossum has been getting some negative press lately after a recent study reported that they did not eat ticks. In the study by Dr. Cecelia Hennessy and Kaitlyn Hild of Eureka College’s Division of Science and Mathematics, looked at the stomach contents of 32 opossums. They also reviewed 23 scientific papers on opossum foraging, stomach contents and scat and found no evidence that opossums ingested ticks. The findings concluded that ticks were not a “preferred diet item for opossums.” But it also recommended that “lab-based studies of wildlife behavior be ground-truthed with studies based in natural conditions.” Hard to know what to believe, but tick eating or not, the opossum is still a valuable and vital part of our ecosystem.

Opossum Sergey Yarmolyuk
Photo by Sergey Yarmolyuk

Nicknamed the “little sanitation engineer” opossums are opportunistic feeders and eat a wide variety of foods, including insects, slugs, snails, rats, mice, birds, eggs, rotten fruit, bird seed, vegetation, garbage, carrion and so on. They also eat amphibians and snakes, including venomous ones. Interestingly, they have been found to be immune to pit viper venom and honeybee and scorpion stings.

Misunderstood and reviled for what some consider their repugnant rat-like appearance, their detractors consider them an ugly pest and dangerous. The opossum gets a bad rap because of its appearance. White-grey-to black in color, it has a pointy head, tiny eyes, naked ears and a scaly prehensile tail and scaly feet, both back feet have a thumblike opposable innermost toe.

A shy docile animal about the size of a house cat, its only defenses are to hiss, growl and show their many teeth, 50 to be exact, more than any other North American land mammal. They also try to run away but are very slow. So rather than rely on running from predators they have adapted an involuntary act of playing dead when threatened and might defecate and emit a foul odor while doing so. They remain in this “dead unconscious” state for several hours. Sadly, these defenses are not very successful against many predators (including humans, cars and dogs) and lead to a life span of only a year or two.

North America’s only marsupial, opossums rear their young in fur-lined pouches. Like kangaroos, baby opossums are called joeys. The gestation period is about 12 days, the blind, hairless newborns crawl to the mother’s pouch and nurse for approximately 100 days. Opossums are transient and den in just about anywhere that is dry sheltered and safe including, crawl spaces and attics, which usually gets them into trouble with homeowners.

Photo Credit: Mike’s Birds from Riverside

Eliminating access to possible den sites around your garden or home by blocking or sealing entry points is usually all that’s needed to dissuade wayward opossums from trying to move in. Keeping outdoor garbage cans inside a garage or shed or when outside tightly securing lids will reduce any mess caused by possible overturning by opossums (or any other creature). Feeding pets indoors and cleaning up around barbecue sites and using a securely covered compost structure will all aid in keeping nuisance behaviors to a minimum. Trapping and relocating opossums is never an option as it is illegal. The Washington State Department of Fish and Wildlife has some helpful tips and further info on trapping on their website.

Judging by how often the tick-eating opossum memes have been shared on social media and how many news outlets and websites have reported it, the successful campaign of the last few years to raise the opossum’s lowly status, in the public eye, has gone a long way to meeting that goal. Hopefully, that continues to be the case whether they eat ticks or not. Fossil records show that opossums existed at the time of dinosaurs, putting them among the world’s oldest land mammals. They have their detractors and they have their advocates. Either way, they are here to stay.

–Lucienne Miodonski, SWS class of 2021
Photos used with permission

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