I’m in my third week of antibiotics after returning from a trip from New Hampshire with a textbook bullseye surrounding a tick bite. Which animal should I blame?

The New York Times let five biologists and entomologists debate the issue. The first guy out, Thomas Mather, professor of public health entomology, gave the answer that has become commonly lore: deer. The premise: Deer populations have risen along with lyme disease cases.

But then other scientists basically cast some reasonable doubt on the case against the deer. Ixodes scapularis, commonly known as deer ticks, bear ticks or black-legged ticks, can pick up the bacteria that causes lyme disease from a whole range of animals, not just its namesake. The American Lyme Disease Foundation calls deer this species’ “preferred host” but notes that mice are the primary carriers of the disease, which can also be spread via birds, dogs, cats, horses, squirrels and other small mammals.

Richard S. Ostfeld, of the Cary Institute of Ecosystem Studies, notes that the incidence of lyme disease and deer don’t correspond, but that acorn crops (which feed white-footed mice) do. William L. Krinsky, entomologist at Yale’s Peabody Museum, says we don’t have enough data to understand how much blame rodents and deer should get.

Interestingly, two species come out as heroes. Bard biology professor Felicia Keesing cites the Virginia opossum (Didelphis virginiana) as the under appreciated fighter of lyme disease; these guys attract and kill ticks by the thousands. Ostfeld gives some credit to owl,

Keep reading Which Animal to Blame for Lyme Disease? Not Deer