Disease devastates UP’s bats, but new hope for one species
Little brown bat begins to show a genetic immunity
NORWAY — Steve Smith has explored old caves ever since he was kid — usually illegally.
Now he does it legally.
“Listen to the water dripping, and bats, and you can smell the timbers and almost visualize what the miners were going through. I have a passion for this,” Smith said.
In 1992, when Smith was 37, he stood above the abandoned Millie Mine in Iron Mountain. It was rumored to be “bottomless,” so he took that as a challenge.
Armed with 200 feet of rope and a couple of old flashlights strapped to motorcycle helmets, he and a friend made their descent. They found the bottom about 100 feet down, and were greeted by a hissing sound — bats.
It was a hibernation spot for up to 250,000 of them. He knows because he helped count them.
“There were all these bats flying, like just dozens of bats, hundreds of bats would be flying by the time we were through.”
Later, he heard the city of Iron Mountain planned to fill in the mine with the bats still inside. So, he called Bat Conservation International, an organization dedicated to protecting bats and their ecosystems. Together, they saved the mine and its bats.
Soon afterwards, the Michigan Department of Natural Resources offered Smith a job as a mine inspector, and “what I had been doing since I was a little kid, illegally sneaking into mines, turned into a 26-year career.”
He had worked closely with bat biologists throughout his career and grew fond of bats. He even thought they were cute.
But then something happened that neither he nor biologists could protect bats from: white-nose syndrome.
White-nose arrived in New York from Europe in 2006. It has spread to 33 states and seven Canadian provinces.
Smith and his colleagues were the first to discover white-nose in Michigan in 2014.
Six years later, 90% of the Upper Peninsula’s bats have died. That includes little brown bats, northern long eared bats, big brown bats, tri-colored bats and Indiana bats.
“That’s a lot of years of work putting into this, and then to have it all end because of a fungus, it’s just horrible,” Smith said.
White-nose syndrome grows on bats while they hibernate in the winter, but it doesn’t kill them. Rather, the fungus irritates their skin, causing them to wake up in the middle of winter and burn up their fat reserves. As a result, bats either starve or freeze to death when they leave the cave in search of food.
Smith now owns his own mine in Norway in Dickinson County.
Bats don’t live in caves during the summer, but he took this reporter inside his mine to show where thousands of bats used to spend winters.
Much of the fungus’s spread can be attributed to people visiting caves without protection. The fungus spores stick to everything from boots to nose hair, so disposable suits and gloves are important when entering a cave, Smith said.
Especially since once the fungus reaches an area, there’s no getting rid of it.
In Wisconsin, bat biologists tried stopping its spread by stripping down, showering and leaving the site with new clothes after entering an infected mine, but it was no use.
“It didn’t matter because when a bat leaves carrying white-nose and goes to another mine, it dumps the spores in the mine. The bats themselves are carrying it,” Smith said.
In 2000, before he got his mine, an advertising campaign used pictures of it to promote protection of bat habitats.
“This mine had (bat) clusters of like 2,500 to 5,000, clusters that were 5 feet long, and those are gone. We’ll never see them again because the bats are decimated by this white-nose.”
He once found 5,000 bats floating dead in a pool of water in a mine he called “The Death Chamber.” He watched another mine’s population drop from 18,000 to 100 in just two years.
“We were in another mine, and when we got down into it there was like wind blowing pine needles all over, like piles of pine needles,” Smith said. “It turns out they were bat bones, thousands of bat bones in piles. There were so many dead bats that you couldn’t walk anywhere without seeing carcasses.”
There is no known cure for white-nose syndrome.
Experts have tried everything from an oral vaccine to installing air conditioning in mines to slow down the growth of the fungus. They’ve gassed mines to kill the fungus but ended up killing everything else in the mine, too.
No matter what, bats always reintroduce the fungus when they return in the winter.
Even if by some miracle, all bats received a vaccine tomorrow, Smith says there’s no way to reverse the fact that 90% of them are gone.
And he warns it may get worse. They’re expected to reach a 93-95% mortality rate before the population stabilizes.
Some species will likely die off entirely. “The northern long-eared bat — it’s rare that we even find one — so they’re on the verge of extinction right now,” he said. “And then the tri-colored bat, they’re almost gone, too.”
But a new study by Giorgia Auteri and L. Lacey Knowles of the University of Michigan shows a glimmer of hope for one species.
The researchers found that the little brown bat has begun to show a genetic immunity to white-nose.
“It means that the ones that are surviving the disease seem to have genes that make them less susceptible to the disease,” Auteri said. “And they’re probably going to pass some of those genes on to their offspring, so their offspring will also be less susceptible to the disease.”
This means little brown bats should eventually repopulate. But with most bats having only one or two babies per year, Smith isn’t optimistic.
“It’s going to be a long-term thing. This isn’t going to happen like next year or next decade,” he said. “I think we’re looking at a long-term thing, like centuries.”
In the meantime, he says Michigan residents should prepare because their loss will have a negative impact on both people and the environment.
“They’re extremely beneficial. They consume insects, especially pest insects, including mosquitoes, gypsy moths, forest tent caterpillars and corn borers,” he said. “The more bats eat these insects, the less insecticides we have to use.”
Bats also eat disease-spreading insects, and some even pollinate plants.
“I just don’t see where you can eradicate one entire population and not have drastic effects across the board, to all the animals,” he said.
Cassidy Hough reports for Interlochen Public Radio and Great Lakes Echo.