ST. GEORGE — In a cave system shaped by tectonic forces cracking ancient limestone, conditions are ideal to host one of the largest known bat colonies in Southern Utah.
But just because biologists know there are plenty of bats in Bloomington Cave from year to year, that doesn’t mean it’s an easy task to catch and catalog them during annual surveys.
One such checkup was recently completed April 25 by a crew with the Utah Division of Wildlife Resources. This year, as in years past, the primary goal was to screen for one of the deadliest threats to bats in the entire United States: white-nose syndrome.
“We have quite a few species of bats out here where there’s no understanding at all how they’re going to respond to white-nose (syndrome), if they do at all,” said Keith Day, native species biologist with the state wildlife agency. “We don’t exactly know what’s going to happen – I’d really rather say ‘if’ – but probably when it gets out here.”
Caused by an invasive species of fungus (Pseudogymnoascus destructans) that thrives in the cold, damp conditions typical of caves, white-nose syndrome is estimated to have killed millions of bats since it was first detected in North America in 2006.
The disease has spread across the continent from east to west, carried by migrating bats and unwitting spelunkers transporting the fungus on boots, clothing and climbing gear. Utah is among the last Western states without a confirmed case, along with Arizona, Nevada, Idaho and Oregon.
Catching crafty cave dwellers
At the Bloomington Cave survey, biologists set out to determine whether local bat colonies remain uncontaminated – deploying several fine mesh nets over major cave entrances to catch the bats as they emerged in the hours just after sunset.
“Success is no positive samples,” Day said. “We may be getting bats from other areas, so if we get positive bats it may mean that bats are coming in and bringing it from somewhere else.”
After carefully disentangling the winged mammals from the nets and placing them in a soft cotton bag to weigh, biologists swabbed the bats’ wings and noses, took down key body measurements and identified each bat’s sex and species.
None of the seven bats caught during the evening survey showed signs of white-nose syndrome, though Day said they planned to return for additional testing bats to get a larger sample size.
Earlier surveys completed during the winter at Mammoth Cave and Bower’s Cave in Garfield County also showed no signs of the deadly fungus, which means it’s likely the disease hasn’t reached Utah’s bats.
Surveys are conducted each year at Bloomington Cave, Mammoth and Bower’s Cave because of the relatively large bat colonies they house. However, colonies like these are likely the exception and not the rule in Southern Utah.
Even large caves in the West do not support massive colonies like those often found in the Eastern United States, Day said.
“A lot of our bats are probably just roosting in ones, twos and fives in the cracks and crevices of the cliffs,” he said. “I know of a few colonies that may have a couple hundred bats, but nothing like the numbers you see in the rest of the country.”
What Utah lacks in population it makes up for in variety: the Beehive state is home to at least 18 of the country’s 47 bat species.
Several species of the myotis genus (meaning mouse-eared) are commonly found in Southern Utah, including the myotis thysanodes, or fringed myotis. Day and his team caught fringed myotis and Townsend’s big-eared bats that apparently share use of Bloomington Cave’s mile and a half of caverns and corridors.
Why fuss over these furry flyers?
Researchers are still working to piece together the whole picture of bat health and their relationship with their local environment. Bats’ behavior, preferred habitat and size make them difficult research subjects, but there are some clear patterns that have emerged that Day and his colleagues would like more people to be aware of.
First, individual bats pose little danger to humans. Since all the bats in Utah are insectivores, if a bat ever swoops close to a person traveling at night it’s certainly not out for blood.
“Bats aren’t afraid of humans at all,” Day said. “As far as I can tell, being around humans doesn’t bother them. They’re curious animals, so they might fly around and check you out but then go away.”
While much has been said about the risk of infection from interacting with a live or dead bat, the truth is that most bats do not carry rabies – though you should contact the Utah Division of Wildlife Resources to remove any nuisance bats rather than dealing with them yourself.
Kyle Voyles, outdoor recreation manager and cave coordinator for the Bureau of Land Management, has certainly seen his fair share of the animals while exploring caves across the world. Voyles joined the crew at Bloomington Cave for their evening survey and shared his views on the role bats play in the animal community.
“Bats definitely play a very important role in the micro-ecosystem of caves,” he said. “Many of the invertebrates that live in cave systems are detritivores, meaning they eat whatever falls on the ground. A lot of times that’s bat guano or lepidoptera (butterfly or moth) wings – that’s what actually feeds a lot of insects.”
The nutrients bats bring into the cave environment support a very unique microcosm at Bloomington Cave: researchers identified six new species of invertebrates there in 2011. These newly described creatures were connected to the bats through the larger food web of the cave.
Finally, when it comes to helping people, the most direct benefit of local bats is their voracious appetite. A single bat can eat hundreds of insects in a night – keeping mosquito, moth and beetle populations under control.
These benefits also translate to agriculture, where bats serve as a free and natural form of pest control. An economic analysis of the value bats provide to North American agriculture estimated that bats may contribute anywhere from approximately $4 billion to $53 billion in pesticide savings.
So, protecting bat health ensures that their contributions in the form of pest control and their role in the food web are preserved. Continuing surveys provide more data to better understand how bats and humans interact and to possibly find a solution for threats like white-nose syndrome.
“I just would like the public to know that bats are friends, not enemies,” Voyles said. “They’re not the flying rats that people say they are. We share the same territory: people go in caves where bats live, but they will respect us if we respect them.
Photo Gallery
A satellite view of Southern Utah with the location of Bloomington Cave marked by a red pin | Image courtesy of Google Maps, St. George News Keith Day with the Utah Division of Wildlife Resources sets a net for an annual survey testing the health of Southern Utah bats, Washington County, Utah, April 25, 2022 | Photo by Ammon Teare, St. George News Kyle Voyles (left), cave specialist and outdoor recreation manager with the Bureau of Land Management, assists Day and Anderson with setting nets at the north entrance to Bloomington Cave, Washington County, Utah, April 25, 2022 | Photo by Ammon Teare, St. George News Day and Anderson work together to remove a particularly tangled big-eared bat captured during the overnight survey, Washington County, Utah, April 25, 2022 | Photo by Ammon Teare, St. George News Biologist Patrick Anderson works to carefully remove a bat tangled in the nets set outside the south entrance to Bloomington Cave, Washington County, Utah, April 25, 2022 | Photo by Ammon Teare, St. George News Native Species Biologist Keith Day and Wildlife Manager Theresa Griffin prepare to record data from bats captured during the survey at Bloomington Cave, Washington County, Utah, April 25, 2022 | Photo by Ammon Teare, St. George News Townsend's big-eared bat, like this specimen captured during the survey, are identified by their disproportionately large ears that can appear like ram's horns, Washington County, Utah, April 25, 2022 | Photo by Ammon Teare, St. George News Theresa Griffin swabs the wing of a fringed myotis, testing the bat for a fungal disease commonly called "white-nose syndrome," Washington County, Utah, April 25, 2022 | Photo by Ammon Teare, St. George News A little brown bat showing the characteristic white crust indicating white-nose syndrome, Greeley Mine, Vermont, March 26, 2009 | Photo courtesy of Marvin Moriarty/USFWS via Flickr, St. George News
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