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Bats fly in a cave by the river Danube near Bazias, some 480 kilometers west of Bucharest on Oct. 9, 2010. Bats in the United States have been affected by a fungus that's leaving scientists stumped.

Bats are a popular decoration at this time of year, but the real animals are getting harder and harder to find. A mysterious fungus is infecting them across the country – and so far more than 1 million bats have died from it. It's called white nose syndrome and scientists are at a loss for how to stop it.

Guest:

DeeAnn Reeder, expert on bats; professor of biology at Bucknell University in Pennsylvania.