The bat population in Maine has been hit hard by white nose syndrome. But there are signs things could be turning around. Credit: Julia Bayly / BDN

When it comes to bats surviving white nose syndrome, size matters, according to a bat expert at University of Maine.

And it could be one of the reasons you may have seen more bats this summer.

Over the last decade white nose syndrome has wiped out 95 percent of the state’s bat population, and hit little brown bats particularly hard. But for the first time in years, the numbers may be increasing as people are sharing information about seeing more bats this summer than in past years.

Named for the white fungus that appears on the muzzle of infected bats, white nose syndrome kills bats as they hibernate during the winter.

Bats could be starting to get an upper hand on the disease, according to Dr. Erik Blomberg.

The more that is learned about how populations of bat species respond to the long term presence of white nose syndrome, the more it appears it is not always fatal, said Blomberg, an associate professor who chairs UMaine’s department of wildlife, fisheries and conservation biology.

“We are learning that even where white nose syndrome has been found and killed bats, there are some segments of the remaining bat population that better withstand the disease,” Blomberg said. “Those bats are surviving.”

It has also been observed that larger bats are less susceptible to white nose syndrome, and Blomberg said that could be sparking an accelerated evolutionary response.

“We could be seeing a rapid selection process for larger bats,” he said.

New discoveries about bat hibernation could also help explain why some bats are surviving white nose syndrome.

“Bats hibernate in caves, or mines or any subterranean spot,” Blomberg said. “There is some evidence that the bats choosing the colder parts of those locations are a bit more insulated against white nose syndrome since the fungus is not as virulent in certain microclimates.”

In ongoing research in his lab, Blomberg said there is new evidence that bat hibernation areas have been historically overlooked.

“There are places we have not always appreciated as bat hibernacula and we are now finding them,” he said. “We are finding them hibernating in human dwellings and in tallus slopes below cliff faces.”

Blomberg said these smaller, lesser known hibernating locations may be playing a large role in protecting the bats from white nose syndrome and preserving those small populations.

While it’s not time to break out the champagne to celebrate a recovery of the bat population in Maine, there is cause for cautious optimism.

“There is no confirmation yet that yes, there are more bats,” Blomberg said. “But there is growing evidence that is consistent with more sightings.”

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Julia Bayly

Julia Bayly is a reporter at the Bangor Daily News with a regular bi-weekly column. Julia has been a freelance travel writer/photographer since 2000.