A little brown bat with white-nose syndrome. The disease gets its name from the white fungus that looks like confectioner's sugar found around the noses (and ears, wings, and other exposed skin) of infected bats, though not all affected bats show signs. Researchers strongly suspect but have not proved that the sickness is caused by a cold-thriving soil fungus. Other key questions that remain unanswered: how exactly the disease kills the animals and how it spreads to other bats.
Photograph by Susi von Oettingen, USFWS