Expert Voices

Want to Be a Bat Hero This Halloween? Don't Visit the Batcave. (Op-Ed)

Bat Myotis evotis
Myotis evotis, a long-eared bat (Image credit: Sarah Olson/WCS)

It may sound like a thrilling adventure to visit caves full of hibernating bats — which, just like Batman's Batcave, are largely hidden from the public eye. But venturing inside of bats' dark homes is actually incredibly dangerous to the bats — especially those suffering from white-nose syndrome. 

Bats hibernate during the winter, and they need a cool, humid and relatively stable place where they can roost and rest.

Tourists hoping to catch a glimpse of these creatures during the wintertime may actually disturb them, waking them up and causing them to lose precious calories. Limiting public access can also prevent the spread of a deadly fungus that kills bats by causing white-nose syndrome, one of the most devastating diseases that has impacted any mammal species on the planet. [Flying Mammals: Gallery of Spooky Bats]

Roughly half of all North American bat species live in caves, mines or even abandoned buildings. Bats use these "hidden" habitats for mating, raising young, resting or hibernating.

When used for hibernation, these locations are called hibernacula. Hibernation is an energy-saving behavior that allows bats to rely on fat stored during the fall and then limit their energy usage through physiological changes, such as lowering their metabolic rate and body temperature. Contrary to public perception, bats are not "sleeping" during hibernation; rather, they alternate between periods of torpor, or low metabolic rate and temperature, and arousals, or periods when they bring their body temperature and metabolic rate back up to normal levels.

The team sets up mist nets early in the evening on a mountainside in central Montana. (Image credit: Sarah Olson/WCS)

Though arousals only make up about 5 percent of the entire hibernation period, these periods can use as much as 90 percent of the fat stored for winter hibernation. Therefore, too many arousals, due to human disturbance or other factors, can threaten bat survival.

Shhh, hibernating bats

Catherine Haase, a postdoctoral researcher of wildlife ecology at Montana State University and modeling lead with the Wildlife Conservation Society, carries bags filled with bats so she can transport them down to the mobile laboratory. (Image credit: Sarah Olson/WCS)

Awareness campaigns can help to keep people away from bat caves, but it's more challenging to stop white-nose syndrome, which has killed millions of bats across North America, likely by interrupting their hibernation. White-nose syndrome is caused by a fungus that grows well in cold and moist environments, like the caves and mines where bats roost. The fungus grows on the wings and body of the bat and causes the animal to arouse more frequently.

Although it's not immediately clear how white-nose syndrome instigates these additional arousals, many bat biologists think that the fungus may cause excess water loss, which makes the dehydrated bats arouse to drink water.

These extra arousals are devastating to bat survival; they lead to rapid fat loss, starvation and eventual death. White-nose syndrome has already infected bats from 11 species so far and has spread from its original discovery in New York to more than 30 U.S. states and seven Canadian providences. Millions of bats have perished due to this disease, threatening some species with local extinction.

Bat biologists are doing all they can to understand and stamp out the disease. Many disease ecologists are researching how they can prevent or slow down fungal growth or even kill the fungus through bio-control. (Bio-control is the process of using other organisms to control pests, such as the fungus that causes white-nose syndrome.) Immunologists are also trying to figure out if it's possible to prevent infection or the effects of the disease by using preventative measures, such as a vaccine.

Meanwhile, wildlife managers are researching whether they can change the habitat for bats to either slow the fungus from growing or alter temperatures to provide suitable roosts for hibernation. 

Ecologists like myself are using a combination of field data and mathematical models to predict the effects of white-nose syndrome in new bat populations and species across western North America. [In Photos: Rare Conjoined Bats]

Nate Fuller, the field lead and a postdoctoral researcher at Texas Tech University, inspects a bat. (Image credit: Sarah Olson/WCS)

During each fall swarming and winter hibernation season, we visit hibernacula to acquire body mass and physiological measurements from multiple bat species, including temperature and relative humidity. We can use these data to determine which species are highly susceptible to disease — and where in the world the disease may flourish.

For now, the biggest way to help bat species is prevention — by limiting access to hibernation habitats and decontaminating anything that comes in contact with the habitat or bat. This means avoiding caving in areas without professionals or other biologists. Many caves and mines are closed to the public, so we must trust the state and federal agencies that manage these areas in their decision to protect the bats. It is okay to enter caves with proper supervision on a tour, as these caves are managed to maintain the least disturbance for bats.  

But even scientists have to be careful in caves. If biologists unknowingly carry spores of the fungus on their clothing and then go into a cave where bats are present, they can inadvertently introduce the fungus into a clean cave. Therefore, we must follow decontamination protocols to clean our gear and clothing after every entrance to a bat habitat — even if the fungus has not been observed in that location.

It's worth noting that even bats with no obvious signs of the fungus (a white, powdery substance on the nose and torn wings) may still be infected. Behavioral changes, such as unusual flying during the day in near-freezing weather, can be another sign of infection. Because of this (and generally because bats can carry rabies), it is smart to play it safe and avoid contact with any bat.

What else can you do? Report bats that are flying during the day in the winter to your local wildlife officials. You can also be a hero for bats by leaving their habitats undisturbed; trust your local Batmen and Batwomen biologists to do what is best for your local bat population, even if that means keeping bat caves private during the winter.

The bats will thank you!

Catherine Haase is a postdoctoral researcher at Montana State University, working with the Wildlife Conservation Society (WCS) under funding from the Department of Defense Strategic Environmental Research and Development Program (SERDP) to study white-nose syndrome threats to western bats. Haase wrote this article for Live Science's Expert Voices: Op-Ed & Insights.

The views expressed are those of the authors and do not necessarily reflect the views of the publisher. This version of the article was originally published Live Science.

Wildlife Conservation Society