Answer: Opossums

When it comes to protecting ourselves from Lyme disease, we have an unlikely ally: the humble opossum. Opossums are generally disliked due to their rat-like appearance, bare tail, and the chance that we’ll come across them outside the garage while taking the trash out and be startled out of our wits.

Despite the poor opossum’s lackluster reputation, however, we should be thankful they’re around: they attract and destroy thousands of ticks every season. The opossum’s physiology makes them very poor hosts for Lyme disease and their aggressive grooming habits kill most of the ticks trying to feed on them. Researchers at the Cary Institute of Ecosystem Studies, who uncovered the link between opossums and a decrease in Lyme-carrying ticks, estimate that each opossum could kill as many as 4,000 ticks per week and that the general population of ticks is lowered by roughly 90 percent in areas with opossums roaming about.