Since it was first observed in New York in 2006, a bat-killing infection known as white-nose syndrome has spread across the eastern seaboard. More than a million bats of six different species have perished so far and infected caverns continue to be discovered. That's bad news since the fungus kills at least 90 percent of the bats it infects.
Even worse, the fungus may not be the culprit, but merely an opportunistic invader breaking out among bats already weakened by some other unknown factor.
Check out the fungus and efforts to fight the bat killer in this video: