In a climate-controlled room at the University of Central Oklahoma, Lynda Loucks swung open a drawer akin to that of a filing cabinet. Inside were not manila folders and documents, but rows of dead bats attached to handwritten paper tags.
Loucks, who teaches biology, manages tens of thousands of dead animals, plants, fungi and lichens at the university’s Natural History Museum. The specimens total 90,000 and are used for research and teaching.
But after dedicating a career to studying the natural world’s only flying mammal, the museum’s bat section is a favorite of Loucks. A large bat known as a flying fox, Mexican free-tailed bats, big brown bats and others have been donated or picked up by researchers.
The cave myotis, a small hibernating bat found in Oklahoma, is among the most familiar to Loucks. It’s also the subject of a recent study she co-authored in the Journal of North American Bat Research.
The paper measures the species’ winter population in five gypsum caves, before and after the presence of a deadly fungus.
The organism is called Pseudogymnoascus destructans, or Pd. It triggers a disease researchers say is responsible for the decline of several bat species. White-nose syndrome causes hibernating bats to wake up frequently and burn critical fat stores before spring.
Since being detected in North America in the 2000s, the disease is estimated to have killed millions of bats. Its mortality rate can be as high as 90 to 100%, according to the Cornell University College of Veterinary Medicine.
The disease affects more than the planet’s biodiversity. With billions of dollars of estimated savings in agriculture from bug-eating North American bats, scientists and conservationists worry the decline could disrupt human lives.
But according to the recent UCO study, along with one on the tricolored bat last year, Oklahoma has yet to see a significant decline. The fungus was detected in the state in 2015 and has been found in a small percentage of both tricolored and cave myotis bats.
“There's so many aspects of it, and there's still a lot that we maybe don't know, but my theory is that maybe they have built up a little bit of resistance, maybe the body size is a helpful tool,” Loucks said. “But not to say that I don’t, every year we go in, hold my breath and think, ‘I hope this isn't the year that we have a die off or an event.’”
So far, there haven’t been die-offs like some bat colonies in eastern states have experienced. Loucks said there could be several reasons why Oklahoma’s bat population is faring better. With millions of years spent coexisting with viruses and other illnesses on Earth, the animals may be well-equipped to build up a resistance to the disease, she said.
Exposure to Oklahoma’s unique weather systems could also be a factor.
“We joke about maybe the bats being hearty species because they have to fluctuate and adapt in that environment, but maybe that gives them kind of a leg up or a wing up on other species,” Loucks said.
With warming temperatures and more extreme weather from climate change, researchers say the disease could become more unpredictable. A 2022 study in the journal Climate Change Ecology found that although a hotter environment might help some hibernating species stave off the disease, the benefits would likely come too late. It also said rising temperatures wouldn’t shield all species or regions.
Daniel Becker, assistant professor of biology at the University of Oklahoma, said it’s unlikely that climate change would benefit bat species overall.
“ Even though maybe slightly warmer winters might mean more insect prey, more fat, I think the idea with climate change would be, just, there's less predictability, less stability, and so it's just as a whole harder for the bats to get the food they need,” Becker, who did not work on the 2021 study, said. “And if you're not fat enough going into hibernation, that can definitely then affect that progression.”
One conservation group has experimented with a project to attract more insects to sites where bats are entering hibernation. Texas-based Bat Conservation International (BCI) scientists set up ultraviolet lights in Michigan to create “prey patches.” The project resulted in little brown bats eating three to eight times more than normal before hibernation, potentially helping them survive white-nose syndrome.
For those interested in at-home conservation, Becker said installing bat boxes outside is an easy action to take.
“In some cases, these will offer a more thermally suitable habitat for bats,” he said. “So kind of a nice warm place for them to roost. You also get the benefit, then, of them eating your mosquitoes and stuff that you don't want around in your backyard.”
“Especially in areas where there aren't that many natural habitats for bats, this can sort of serve as a nice kind of refuge for them,” he said.
Supporting state wildlife conservation efforts is also critical, Becker said. The Oklahoma Department of Wildlife Conservation advises people to avoid disturbing hibernating bats in caves.
“ I think the more we can support our local departments, the more that they can do kind of the on-the-ground work that's really needed to understand where the fungus is and how it's spreading and what it's doing to bats.”
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