Amid Mass Die-Offs, Pockets of Brown Bats Survive

White nose syndrome has killed millions of bats over the past five years, decimating the little brown bat population by more than 90% in some areas, but scientists have found reason to hope: In Vermont and Pennsylvania, there are surviving colonies of the threatened species. “I’m cautiously hopeful that eventually these animals can be recovered,” says one conservationist. But the crisis isn’t over yet: Though “bats haven’t entirely fallen off the cliff yet,” they’re hanging on by just “a tiny little fingernail,” she says.

The colonies found in about a dozen sites in Vermont appear to be made up of bats who are resistant to the disease, which is caused by a fungus, but a biologist for the state’s Fish and Wildlife Department says they need to be evaluated further to see if they’ve been exposed. “It’s just a ray of hope that there are bats that have survived over three years of white nose syndrome, and we want to know how they survived, or if they will continue to survive, and if this is enough bats to ... recover a population,” he adds. Several other species have been affected by the disease as well, the Washington Post notes. (More white nose syndrome stories.)