Bat Species Face Extinction in North America From Devastating Fungal Pandemic

by Jennifer Shea

A deadly fungus has been decimating North American bats in recent years. The fungus, dubbed “Pseudogymnoascus destructans,” causes white-nose syndrome in multiple bat species. And that disease has killed off over 90 percent of regional bat populations in the U.S. and Canada.

In total, more than 6 million bats have died from the disease caused by the fungus since the fungus was first found in an upstate New York cave in 2006, National Geographic reports. Some bat species – for example, the northern long-eared bat – face possible extinction.

The fungus can live in a cave for over a decade without a host. And white-nose syndrome has resulted in skyrocketing mortality among bats.

“White-nose is so much worse for bats than coronaviruses are to humans,” Kate Langwig, a conservation biologist at Virginia Tech, told National Geographic.

Some Bat Species Have Evolved Resistance to Fungus

The fungus came from Eurasia. It does infect some bats there. But it doesn’t cause the destruction of entire bat colonies as it has across the ocean. Scientists believe Eurasian bats evolved to resist the fungal growth. And in fact, research has shown Asian bats carry lower fungal loads than American ones do.

The way the fungus kills bats is by making them come out of hibernation mid-winter. They venture out to search for food and die of starvation, finding no insects and having used up their fat reserves.

In America, the fungus is at its worst in the East and Midwest. However, it has spread to the Mountain West. And there have been confirmed infections in Washington and California, as well. At least 12 bat species in North America have been infected with white-nose syndrome.

Bat experts fear some species of bats will go extinct. But others, such as little brown bats, appear to be evolving to resist the fungus.

Little Brown Bats Appear to Be Developing Resistance

According to National Geographic, little brown bats have seen the most significant population declines from the syndrome. But it is among this species that scientists see some potential good news.

The little brown bat population appears to be stabilizing in parts of the East coast, like New York and New England. And survivors of the fungal pandemic have different DNA than bats who died. Specifically, there are differences in the genes that control metabolism and hibernation.

Recent research shows that most of the changes in survivors were linked to metabolism and hibernation, not immunity. Some bats now store a lot more fat when they enter hibernation than was the case before the fungus invaded America’s shores.

Unfortunately, the population rebound appears to be limited to little brown bats so far. And more clarity is needed on how exactly those bats are evolving.

In the meantime, scientists are looking into conservation methods including vaccines, spraying caves with fungicide, habitat tweaks and even “bug buffets,” luring extra insects to caves right before hibernation season. That follows earlier efforts to combat human transport of the fungus, which may be how it spread in the first place.