Are opossums “nature’s pest control” and “cleanup crew”?

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Some say opossums are unsung heroes with a bad reputation. In recent years, social media users and news publications have presented research that allegedly claims that marsupials have harmless bites for all their notorious hype. (That’s not true, their bites are vicious.) Another claim readers sent us was the meme below, which called the white-faced, pointy-nosed animals “the pest and pest control team.” cleansing of nature”.

To determine the accuracy of the above meme, we checked the four claims it made. (And just so we’re all clear, yes, opossum and opossum are the same animal.)

Statement: “I am naturally immune to rabies. »

❌ No. Any mammal can contract rabies, but some species are more prone to viral illness than others. In the United States, the Centers for Disease Control and Prevention report that the most infected animals are raccoons, skunks, bats and foxes.

Although it is possible for an opossum to be infected with rabies, it is extremely rare. In fact, a 2013 study published in the Journal of the American Veterinary Medical Association found that among documented cases of rabies across the country, there were only two recorded infected opossums, or 2.8% of the population. .

“People often mistake the open-mouth hissing and drooling behavior of opossums for a sign of rage. However, this is just a bluffing behavior that opossums use as a defense mechanism,” writes the Humane Society.

“In fact, rabies is extremely rare in opossums, possibly because they have a much lower body temperature compared to other warm-blooded animals.”

Claim: “Only one of me eats up to 5,000 ticks a year.”

❓ Not proven. We have classified this claim as “unproven” because while it is true that opossums are good groomers and have been known to eat ticks, it is not known exactly how many insects they are able to eat in a season.

The estimate of 5,000 was presented in a blog post published by the National Wildlife Federation that cited the Cary Institute of Ecosystem Studies, both based on a 2009 study.

As writer Ken Perrotte described in an article published in Field and Stream, this claim is largely based on a study published in the biological research journal, Proceedings of the Royal Society B. New York researchers have trapped six opossums in cages, inoculated each with 100 of the tick larvae and left the parasites attached for four days (the agreed time it takes a tick to feed). At the end of the study period, the researchers counted the ticks, either on the animal or on the floor of the cage, and assumed that those not counted had been consumed by their host. From this limited dataset, they concluded that the opossums, along with the squirrels included in the study, killed between 83% and 96.5% of ticks, a number that was extrapolated to 5,000 ticks each season. .

But this theory was tested in September 2021. Scientists publishing their work in the scientific journal Ticks and Tick-borne Diseases examined 23 papers describing opossum feeding behavior and analyzed the stomachs of 32 Virginia opossums (commonly called northern opossums). American) from Illinois and found no trace of ticks.

Why such a big difference? Perotte gives two explanations. For one thing, it’s possible there were ticks on the opossum even after four days, especially since temperature can affect how the parasites feed. In short, the 2009 researchers assumed that the ticks would feed and fall off, but they might just still be embedded in the animal.

“This set of memes turned out to be a hugely successful opossum advocacy campaign; allowing the oft-maligned scavenger to achieve cult status as a biocontrol for ticks,” the 2021 study concluded. “Unfortunately, these purported benefits are not supported by our findings or by previous diet analyses.” , adding that it’s still possible to appreciate opossums, even if they’re not the little tick-suckers they were meant to be.

Affirmation: “I can’t get or carry Lyme disease.”

❌ No. Lyme disease is a tick-borne bacterial infection that infects mammalian populations worldwide. When a tick bites an infected animal, the tick can become infected with the bacteria Borrelia burgdorferi and spread the bacterial infection to its next host, including opossums.

The Center for Food Security and Public Health at the Iowa State University College of Veterinary Medicine notes that possums can become infected with Lyme disease, but the Wildlife Habitat Council maintains that this is a rare occurrence (although that this may be due to other reasons, such as a lack of data on opossum populations). While it is true that opossums eat ticks and thus can inadvertently stop the spread of infected ticks, it is not true that they cannot catch or transmit Lyme disease.

Opossums are known carriers of fleas and ticks, both of which can infect pets and can carry diseases such as leptospirosis, tuberculosis, relapsing fever, tularemia, spotted fever, toxoplasmosis, coccidiosis , trichomoniasis and Chagas disease, according to the California University of Agriculture. and natural resources (UCIPM). The pest control program puts opossums on a par with skunks and raccoons, noting that once they’ve “taken over a neighborhood, they’re likely there to stay as long as food, l water and shelter are available”.

Affirmation: “I also eat bugs, spiders, small rodents and dead stuff!”

✅ True. Opossums are omnivorous and love insects, snails, slugs, frogs, birds and small mammals, but that’s not all. The Opossum Society notes that marsupials love overripe fruit, and most gardeners can attest to their love of compost, pet food, and garden vegetables.

“Possums that live near people may visit vegetable gardens, compost piles, garbage cans, or dog or cat food dishes. Having lost much of their natural fear of people, they will even enter a house through a cat flap in search of food. Fortunately, they are not aggressive unless cornered, when they can hiss, growl and show their teeth,” the UCIPM wrote.

In short, yes, opossums can feed on creatures that a person might not want in their garden. But their presence can cause more of an overall long-term harm than a benefit.

“Possums are considered a nuisance in gardens and near homes where they feed on berries, grapes, tree fruits and nuts, and defecate on garden paths and patios. They fight with dogs and cats and can inflict serious injury with their bite of sharp teeth,” the UCIPM wrote.

Unsung hero or overhyped nuisance?

While it’s true that opossums eat ticks, potentially preventing some spread of Lyme disease, their good traits may be overstated by some social media users. Possum control mechanisms vary by state, but most pest control experts recommend treating their removal the same way one would treat raccoons or skunks. After determining that an opossum has moved in, experts advise making the environment less appealing to them by clearing overgrown shrubs and trees they might use for hiding, cleaning up fallen fruit and hiding trash cans. , pet food containers or the like. food sources. Secure living areas so they cannot hide under stairs or other nooks and crannies.

Trapping or sending may also be suitable options for those with opossum invaders. Learn more about how to treat animals here.

If you enjoy reading about weird animal habits, you might also enjoy these stories from the Snopes Critter Country category:


Sources

In defense of the opossums. https://www.wildlifehc.org/in-defense-of-opossums/. Accessed March 23, 2022.

CDC. « Lyme Disease Home | CDC.” Centers for Disease Control and Prevention, January 19, 2022, https://www.cdc.gov/lyme/index.html.

Dyer, Jessie L., et al. “Rabies surveillance in the United States in 2013.” Journal of the American Veterinary Medical Association, vol. 245, no. 10, November 2014, p. 1111–23. PubMed Central, https://doi.org/10.2460/javma.245.10.1111.

Hennessy, Cecilia and Kaitlyn Hild. “Are Virginia opossums really ecological traps for ticks? Ground verification laboratory observations. Ticks and tick-borne diseases, vol. 12, no. 5, September 2021, p. 101780. ScienceDirect, https://doi.org/10.1016/j.ttbdis.2021.101780.

Keesing, F., et al. “Hosts as Ecological Traps for the Lyme Disease Vector.” Proceedings of the Royal Society B: Biological Sciences, vol. 276, no. 1675, November 2009, p. 3911–19. PubMed Central, https://doi.org/10.1098/rspb.2009.1159.

“A new study indicates that possums do not like to eat ticks.” Field & Stream, January 5, 2022, https://www.fieldandstream.com/conservation/possums-dont-eat-ticks/.

Possum Management Guidelines – UC IPM. http://ipm.ucanr.edu/PMG/PESTNOTES/pn74123.html. Accessed March 23, 2022.

http://ipm.ucanr.edu/PMG/PESTNOTES/pn74123.html. Accessed March 23, 2022.

“Opossum”, oh lovely “Opossum”. https://www.merriam-webster.com/words-at-play/possum-vs-opossum-difference-pronunciation. Accessed March 23, 2022.

“Possums: Unsung Heroes in the Fight Against Ticks and Lyme Disease • The National Wildlife Federation Blog.” National Wildlife Federation blog, June 13, 2017, https://blog.nwf.org/2017/06/opossums-unsung-heroes-in-the-fight-against-ticks-and-lyme-disease/.

Rabies | CDC. September 22, 2021, https://www.cdc.gov/rabies/index.html.

“Why you should brake for the opossums.” Cary Institute of Ecosystem Studies, https://www.caryinstitute.org/news-insights/podcast/why-you-should-brake-opossums. Accessed March 23, 2022.

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