The estimate, drawn from surveys by wildlife officials mostly in Northeastern states and announced by the U.S. Fish and Wildlife Service Tuesday, has conservationists worried about the long-term survival of the little brown bat, the northern long-eared bat and the tricolored bat.
"We're watching a potential extinction event on the order of what we experienced with bison and passenger pigeons for this group of mammals," Mylea Bayless, conservation programs manager for Bat Conservation International in Austin, Texas, said.
"Unlike some of the extinction events or population depletion events we've seen in the past, we're looking at a whole group of animals here, not just one species," she told The Washington Post. "We don't know what that means, but it could be catastrophic."
White-nose syndrome, caused by a fungus called Geomyces destructans that eats through the skin and membranes of bats, was first detected in a cave near Albany, N.Y., in 2006.
Since then, biologists in multiple states examining caves and mines during the annual winter hibernation of bats have found alarming numbers of dead animals.
The bats' decline could begin to affect the general public if their disappearance results in an explosion of the insects they normally feed on and higher food prices if crops are invaded by those swarms of insects, biologists said.