10/09/2026
You may have seen posts on social media claiming that opossums eat thousands of ticks per week. But is it true? This claim came out of a 2009 study that went viral in the press and on social media before anyone looked very closely at the methodology. Alas, the opossum’s reputation for hoovering up ticks was shattered by a 2021 study by Cecelia Hennessy at Eureka College in Illinois. She and her apparently very committed team analyzed opossum s**t and the stomach contents of road killed possums. They found crickets, worms, fleas, and pretty much everything else…except ticks. So what went wrong with the original study? It turned out that the 2009 study assumed that ticks that disappeared from the lab had been eaten, and the “5500 ticks per week” number was extrapolated, which is a fancy word for taking a very small finding (in this case 5 animals in lab conditions) and multiplying it out in a way that isn’t guaranteed to happen in real life.
So sadly, the opossum’s reputation as a voracious tick slayer did not hold up. But they’re still really interesting animals! They’re the only marsupial (animals that carry newborns in a pouch like kangaroos) native to the US and Canada. And “playing possum” is a real thing. When threatened, opossums may flop over, drool, and emit a foul odor, pretending to be dead to ward off predators. And because they have a very low body temperature for a mammal, they are very unlikely to catch and spread rabies. So the next time you see one of these odd-looking critters waddling through your neighborhood, don’t thank them for cleaning up ticks. But give them a wave for being a fascinating part of our ecosystem.
