Scientists have figured out that a fuzzy white fungus on bat wings may be the cause of bat deaths in the Northeast. The fungus, which spreads quickly because bats sleep in close quarters, appears to thrive in cold weather. It causes wing damage and may also be affecting bats' immune systems and metabolism, in part by disrupting the bats' hibernation cycle. Bat deaths are worrisome because they could make for many more insects in the air, so scientists are working on ways to combat the fatal fuzz. On a brighter note, the fungus does not appear to have affected Batman... yet.