By GAGE WILSON
for Glasgow News 1
In the stillness of a winter cave, the remains of a lost colony scatter the floor—tiny bones and fragile wings dusted in the pale fungus that has wiped out millions. Yet, from the darkness, a few survivors stir.
Against the odds, some bats are defying White-nose Syndrome, and their silent endurance has captivated researchers and conservationists alike.
Since the discovery of the fungus in 2006, its spread has decimated bat populations across the country, with mortality rates reported as high as 90 percent.
“Since the arrival of White-nose Syndrome in the park around 2012, researchers have seen a large decline in the numbers of some of the most visible species of bats, such as the federally endangered northern long-eared bat,” wrote Mammoth Cave National Park Ranger Molly Schroer. “Some of the numbers have gotten so low that the benefits they once provided—such as eating pesky insects like mosquitoes—are essentially no longer there.”
The species’ appetite for these pests cannot be overstated, as some bats can consume up to 1,000 insects in just one hour.
Like many fungi, the spores responsible for the syndrome thrive in dark, cool environments, making cave systems an ideal habitat for their development. Once a bat is infected, the spores spread across its skin, causing irritation that leads to increased activity when the animal should be hibernating.
This disruption is what makes the fungus so deadly—affected bats burn through their fat reserves, which are critical for surviving the winter. In most cases, they ultimately starve to death. Infected bats may also exhibit unusual behavior, such as flying during the day in freezing temperatures, further increasing their risk of harm.
Curiously, researchers have found that certain species are asymptomatic or even resistant to the disease.
“As some bat species have dipped to all-time lows, other species that were once rarely noticed have seen their numbers rise, possibly filling the niche left behind,” Schroer explained. “These include the tree bats (red, evening, and hoary) and some cave bats, like Rafinesque’s big-eared bats.”
The success of tree bats may be due to their more solitary nature and their preference for habitats outside caves. The resilience of Rafinesque’s big-eared bats, however, is more puzzling, as they share many of the same environments as affected species.
This species is also native to Kentucky. As described by the U.S. Fish and Wildlife Service, “This species is a year-round resident in Kentucky, probably moving only short distances between summer and winter roosting sites. The species occurs locally across the state but is most common along the western edge of the Cumberland Plateau and in the Mammoth Cave region.”
Since 2016, no cases of White-nose Syndrome have been observed to cause adverse effects in Rafinesque’s big-eared bats, though some individuals have tested positive for the fungus. Cave-dwelling gray bats, which are endemic to the park, have also been able to withstand mass mortality within their colonies. Their smaller colony sizes may help mitigate the severity of infection. While Mammoth Cave is fortunate to be home to these resilient species, Schroer notes that such resistance is not unique to the park.
“Bats that do not get the disease are not limited to Mammoth Cave National Park, though,” Schroer said. “They are found everywhere.”
In both tree and gray bats, genetic factors may also play a role in their survival. With research ongoing worldwide, Mammoth Cave is one of only a few sites dedicating resources to studying the fungus. The U.S. Fish and Wildlife Service has awarded nearly $5 million in grants since 2017 and is expecting to award another $1.5 million this year to combat the ecological damage caused by the disease.
While the future of nature’s favorite flying squeaker may still look bleak, new research into resistant species may offer a light at the end of the tunnel—or, in this case, the cave.
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