Lyme disease, which used to be a rare occurrence in the Catskill Mountains, is unfortunately becoming more common. As owners of cats and dogs will confirm, there has been a substantial increase in ticks over the last few summers… and ticks transmit Lyme. The consequences of misdiagnosed or untreated Lyme disease are so scary that a simple hike merits long sleeves, long pants and tube socks to cover bare skin, as well as a post-hike search for the tiny black specks that can ruin your life. Wouldn’t it be wonderful if ticks had a natural foe that would keep their numbers in check?
Enter the opossum: the scruffy creature with the sweet face, sharp teeth and unappealing tail. Although possums have a reputation as filthy critters, they in fact are compulsive groomers—who just happen to have a taste for garbage, carrion… and ticks.
In a study published in the Royal Society’s journal Proceedings B, opossums were found to be veritable tick magnets that devour over 96% of the blood-hungry parasites.
The study’s team of researchers, which included biologists, ecologists and foresters, were able to determine that the average possum is infested by as many as 5500 larval ticks each week. About 5300 ticks become snacks, while only 200 successfully feed and drop to the forest floor. That makes the opossum a very effective ecological trap for the removal of ticks.
Other species that have a positive effect on tick removal are squirrels (over 80% of ticks eaten), and chipmunks and birds (over 70% consumed). Mice only ingest about half the larval ticks they harbor, which allows the other 50% to feed and go forth to make mischief.
When preferred species aren’t available, ticks simply hitch a ride on whoever walks by. The research study claims that a forest’s loss of one opossum would result in at least a 15% rise in the number of ticks dispersed to other animals. An area that has plenty of mice—but few chipmunks and squirrels and no possums—could become a breeding ground for Lyme disease.
We often hear about how the loss of diversity will come back to haunt us, and this study proves that point. Lyme disease already affects about 300,000 Americans each year, and the numbers are on the rise.
Many people fear opossums because they wrongly believe the critters carry rabies. In fact, possums are resistant to viral diseases, including Lyme. They’re not aggressive and will only use their daunting teeth when cornered. Their usual defense is to play dead, which doesn’t work out too well for them when the predator is an automobile. Opossums would much prefer to climb a tree than stand and fight, and can easily be persuaded to move on. In addition to opossums’ ability to decimate populations of Lyme-bearing ticks, they’re also quite good at controlling mice, slugs, snails, and cleaning up carrion.
So the next time a possum steals your chicken eggs, hijacks vegetables from your garden, ransacks your compost pile or takes a snooze in your tool shed—be kind. And if you see one caught in the headlights—swerve.
The life you save could be your own.