Does my nose look white to you? A mysterious nasal fungus has been linked to bat deaths.

RODALE NEWS, EMMAUS, PA—Scientists are racing to find out what is killing tens of thousands of bats in the Northeast. Most suffer from white-nose syndrome. Now the condition has spread into hibernating bat populations in New Jersey and Pennsylvania, according to the U.S. Fish & Wildlife agency.

THE DETAILS: Researchers from the Pennsylvania Game Commission and Bucknell University in Lewisburg, PA, confirmed that several hundred little brown bats were found dead in the snow outside caves. In the last several weeks, Pennsylvania and New Jersey joined a list of states seeing massive bat die-offs. Most of the animals have a fuzzy white growth on their noses; the previously undiscovered, cold-loving fungus was only identified last October. New York, Connecticut, Vermont, and Massachusetts have also seen devastating die-offs; in some caves and abandoned mines affected, 90% of bat populations have been wiped out. It’s not clear whether the phantom fungus found on the animals is a symptom or a cause of death. “Researchers are studying how the fungus may be causing the reduction of body fat in the hibernating bats,” explains biologist Rob Mies, director of the Organization for Bat Conservation. “Other theories exist.” The killer may be an unknown virus or bacteria, or the bats may be failing to put on enough body fat because of a decline in numbers of the insects they feed on. “And finally,” Mies says, “global warming may be causing problems with consistent hibernation.”

WHAT IT MEANS: Bats are invaluable. They are voracious mosquito-eaters, protecting us from annoying bites and even West Nile virus. During the warm months, one bat can consume thousands of insects in one night. “Bats also eat large amounts of moths and beetles that destroy farmers’ crops, including corn earworm moths, spotted cucumber beetles, and leafhoppers,” Mies says. “Without bats, far more pesticides will have to be used to control insect populations.” And that’s not safe for the environment or us.

They also are also important to the economy and food production—they work for free, pollinating crops, just like bees.