This spring, nestled under the bark of ponderosa trees in eastern Wyoming, northern long-eared bat females will give birth to their pups. They usually only have one each year, a tiny creature weighing no more than a nickel.

A mother will move her pup to different trees every night or two until it’s old enough to fly on its own, which will mark the start of its lifetime quest to eat as many insects as possible. 

These bats, along with dozens of other North American species, eat so many insects that experts estimate they save U.S. agriculture more than $3 billion each year in pest control. And they’re disappearing.

The U.S. Fish and Wildlife Service on March 22 proposed upgrading the status of the northern long-eared bat from threatened, which means it’s seriously struggling, to endangered, which means it’s on the path to extinction.

A northern long-eared bat hangs from a rock wall. (US Fish and Wildlife Service/Natural Diversity Database Wyoming Field Guide)

“White-nose syndrome is devastating northern long-eared bats at unprecedented rates,” U.S. Fish and Wildlife Service Regional Director Charlie Wooley said in the federal release. And by “devastating,” he means white-nose syndrome, a disease caused by an invasive fungus, has killed 97-100% of affected northern long-eared bat populations.

As white-nose continues to spread west across the country, biologists say it’s inevitable it will continue spreading across Wyoming. The impact on at least a dozen species of bats in the state, however, is a little more uncertain.

Inevitable spread

Cavers exploring underground near Albany, New York, first documented white-nose syndrome on bats in 2006. They didn’t know what it was, but they photographed bats with a strange white powder on their noses, according to the White-Nose Syndrome Response Team.

The next year, biologists noticed bats were dying from the condition in the same area. Experts believe it likely traveled from Europe or Asia, where its effects on bats appear less severe. No one knows exactly how it arrived in North America. 

The syndrome is technically the presence of a fungus called Pseudogymnoascus destructans, or Pd. The fungus itself is not necessarily fatal. But it irritates their noses and bodies, waking them from hibernation, forcing them to burn precious calories and sometimes even leave their caves during the day in the winter.

All that extra effort ends up killing them. Millions of them. Up to 100% of bats in some hibernacula have died from white-nose.

A spotted bat captured in Wyoming. (Shelly Johnson, Wyoming Game and Fish Department/Natural Diversity Database Wyoming Field Guide)

It has also spread widely, often from nose-to-nose contact, and sometimes from cavers unwittingly carrying it from one place to another. The fungus can now be found in 38 states and seven Canadian provinces, mostly on the eastern half of the continent, though cases have cropped up in Washington and California.

The fungus remained undocumented in Wyoming until 2018 when the spores were discovered on a little brown bat at the Fort Laramie National Historic Site in the state’s southeast. The actual syndrome was recorded on a northern long-eared bat and a fringed bat in early May 2021 at Devils Tower National Monument.

White-nose syndrome is not the only threat to the nation‘s bats. Wind development has been particularly hard on species such as hoary bats and silver-haired bats, said Ian Abernethy, Invertebrate Zoology Program Manager for the Wyoming Natural Diversity Database. The Fish and Wildlife Service acknowledges in its listing proposal the impact of wind and transportation projects on bats and says it has habitat conservation plans in place. Timber harvest and other development have also chipped away at habitat for tree-dwelling species like the northern long-eared bat and the long-legged bat.

Destruction but possible hope

Wyoming is home to 18 species of bats, from the migratory hoary bat, with its glossy salt-and-pepper fur that prompted Bat Conservation International to dub it “the George Clooney of the bat world,” to the spotted bat with ears reminiscent of satellite dishes.

The little brown bat is arguably the most populous of all of Wyoming‘s bats, and, unlike the rest of the country, still seems to be faring well here. The little brown bat and tricolored bat have been so impacted by white-nose syndrome that they were petitioned for listing in 2010, said Zack Walker, non-game supervisor for the Wyoming Game and Fish Department.

A researcher holds a little brown bat. (Jessica Grant, Wyoming Game and Fish Department)

What biologists don’t know is exactly how populations of the northern long-eared bat are doing in Wyoming where they live exclusively in the state’s eastern mountains. For Wyoming bats, the biggest issue is lack of data, said Abernethy.

“There is a lot of really basic life history things for most species we don’t know,” he said. “We don’t know where they hibernate for the most part. During the maternity season, we don’t know [exactly] where they’re roosting, where they raise their pups.”

The eventual spread of white-nose throughout the state seems to be inevitable, Walker said. Even though cavers are generally much more responsible now, and many often provide critical assistance with soil samples and other data collection from caves, the fungus still spreads through bat-to-bat contact.

The bright spot for Wyoming, however, is that few of our bats hibernate in massive colonies as they do, and did, farther east. A large hibernacula for Wyoming would be 100 to 150 bats, Abernethy said, compared to colonies in the eastern U.S. which could reach hundreds of thousands. Instead of large groups, most Wyoming bats likely hibernate in rock crevices or boulder fields, though researchers still aren’t sure.

Fewer large colonies potentially means fewer opportunities to spread the disease. 

Another bit of hope comes from populations of little brown bats in the East that appear to be rebounding after massive die offs. It’s possible, Abernethy said, that some bats may be building natural immunity to the fungus. The question then becomes whether these protections can provide enough help before species like the northern long-eared bat blink out. 

Christine Peterson has covered science, the environment and outdoor recreation in Wyoming for more than a decade for various publications including the Casper Star-Tribune, National Geographic and Outdoor...

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  1. Great question Melodie, and thanks for supporting bats!! I’m studying northern long-eared bats for my master’s degree. The best way you can support healthy bats on your property is to 1) plant native flowering plants to attract insects, 2) not spray pesticides, 3) keep outdoor lights to a minimum/at least pointed downward to maintain dark skies that bats need to safely forage. You can also put up bat boxes as artificial roosts (google the Rocket Box style, it’s best!), but northern long-eared bats don’t use them as often as other species. Northerns mainly need your help when it comes to voting and forest policies–they are forest-dwelling bats that need old snags that often get removed. Write to your local representatives and weigh in on public comments for the Black Hills NF! 🙂

  2. Is there a way that us citizens can help build the population back up? I would be interested in building a habitat on my property for instance.