What Does It Take To Photograph A Bat Cave?

Longtime cave photographer Stephen Alvarez goes underground to document an endangered bat species on the rebound

Just over a decade ago, photographer Stephen Alvarez documented a bat census in a Tennessee cave. At the time, he says, the bats seemed doomed by white-nose syndrome—a life-threatening fungal disease that affects bats in hibernation. The disease had rapidly spread across the eastern United States since it was first documented in New York in 2006. But, when Alvarez heard in 2022 that scientists expected the next local census to be quite a bit more promising, he knew he had to photograph it.

“You don’t often get good conservation news,” he says. “Instead of a tragedy—which is what we all thought a decade ago, that we were going to lose a class of animals—these bats are doing quite well.”

The story, published in a recent issue of Nature Conservancy magazine, tells how researchers are studying and tracking the endangered gray bat, using tiny transmitters that are attached to the bats. (The devices fall off after a couple of weeks.) The transmitters ping off of Motus wildlife tracking receivers allowing researchers to learn where bats go when they leave their caves.

To photograph the bats’ lifecycle and the conservationists trying to help them would require Alvarez to document both the installation of the receivers on high towers above the nearby forests and the researchers’ hands-on work in the caves themselves.

Alvarez has photographed caves for decades, so he knew the project would come with many challenges, not least among them the limited (if any) natural light. “Oftentimes, as a photographer, you simply show up and point your camera at the subject,” he says. “That doesn’t work when you’re working underground, because you’ve got to bring a bunch of lights in.”

There are also the pools of water, animals to avoid disturbing, and, in the case of at least one cave Alvarez photographed, literal tons of trash to step over and avoid. That’s all on top of the tight spaces and potential geologic hazards any cave explorer might encounter as well as the challenge of not just getting the photograph, but getting a good photograph that did the research justice.

But for Alvarez—who lives in Tennessee—the joy of photographing caves comes from illuminating a world many people forget exists.

“I’ve always loved the notion that there is a world under our feet that we don’t really know,” he says. “The mystery of that world continues to draw me back.”

A version of this story ran in the Fall 2023 issue of Nature Conservancy magazine. Below is a series of photographs Alvarez took in his reporting that did not make it into the print story.

people standing in a cave looking at bats with a flashlight
In the winter in Tennessee, bats hibernate in caves. During a semi-annual gray bat census in 2022, a 6-person crew counts the bats in Hubbard’s Cave, Tennessee. Stephen Alvarez first photographed a census in this cave a decade earlier. With an estimated half million bats on the cave’s 50-foot limestone walls, the cave houses the second largest gray bat hibernaculum in North America. © Stephen Alvarez
close upof bats huddled on cave wall
A close-up image of gray bats in Hubbard’s Cave that are showing signs of white-nose syndrome. When Alvarez photographed a bat census in the 2010s, white-nose was sweeping through the population. “It’s gone from being a fairly depressing subject,” he says, to something else entirely. “The gray bat, which we really thought was going to go extinct is on the rebound.” © Stephen Alvarez
bats flying out of a cave with trees in the background
In the summer, bats venture out into the Tennessee forests to feed. Alvarez has experienced the rush of the bats emerging from a cave many times. “For maybe 20 to 30 minutes there’s just a firehose of bats pouring out,” he says. “And it’s dark so you don’t see the bats, but you feel the air coming off of their wings.” © Stephen Alvarez
people standing on top of a building with equipment
To track bat movements in the summer, researchers installed a Motus wildlife tracking receiver on top of a tower at the University of the South. To photograph it, Alvarez used camera drones to capture the scale and height of the project. “There was a bat we caught one week that was tagged in Bellamy Cave, and that same night it flew 50 straight miles,” says Alvarez. “I had no idea that the animals move that much. There’s all this new information that the tagging and the Motus towers are providing that we just didn’t know before.” © Stephen Alvarez
view of a forest through the opening of a cave mouth
Alvarez lives in Tennessee, home to well over 10,000 caves, and has photographed caves for decades. Capturing the world underground comes with a slew of challenges not least of which is entering through small crevices or large came mouths like this one. Capturing the scale of a cave with little room to move can be its own feat. © Stephen Alvarez
people standing inside a cave with lights and photography equiptment
“The primary challenge in any cave photography is caves are dark, and there’s not enough light. So, you have to create all of your light,” Alvarez says. All the equipment Alvarez and the researchers need has to be carried into the cave. © Stephen Alvarez
people climbing inside a cave
Many caves come with dangers for photographers and visitors alike. Sometimes there’s hazardous trash, sometimes steep drops. Here Southeastern Cave Conservancy Incorporated’s preserve manager Kristen Bobo sits above the “Blue Hole,” a drop deep within Wolf River Cave. © Stephen Alvarez
two people lying in a narrow crevice in a cave
At times the caves allowed for little movement for Alvarez. Here two of the researchers examine a rock formation. © Stephen Alvarez
gloved hands holding a bat
Another challenge Alvarez faced was how quickly and precisely the researchers’ work with the bats had to be. During the project, the team would capture bats to install Motus transmitters on them. (The tiny devices track the animals’ movements for up to 21 days before falling off.) “It could be traumatic for the animal if they’re kept for more than just a few minutes so they have very strict protocols,” Alvarez says. But Alvarez had seen this type of work before and knew where to be to capture the shots he needed. He also went out with the researchers several times to capture enough images. © Stephen Alvarez
man with a head lamp holding a bat
Alvarez was struck by how thin the bats’ wings are and used carefully placed lighting to demonstrate the nearly translucent quality of this gray bat’s wing. “The body of a gray bat is about the size of my thumb and probably weighs less,” he says. “And yet this animal will fly 50, 60, 70 miles in a night.” Here TNC’s Cory Holiday holds a gray bat captured as part of the Motus tracking project. © Stephen Alvarez
footprints on a cave floor
“Caves often act as time capsules,” Alvarez says. In one cave, he found jaguar footprints. In another, hundreds of archaic era human footprints. They’re all part of a world underground that Alvarez wants to preserve. He has a nonprofit organization called Ancient Art Archive, which digitizes and advocates for the protection of cave art and rock art around the world. © Stephen Alvarez
fish underwater
In the cave systems of Tennessee, Alvarez saw numerous species that are foreign to the world above. Here the blind southern cavefish swims through an underground pool. “There are ecosystems that exist because of these underground spaces. And most of us don’t understand them because we don’t see them,” he says. “But through photography, I can go into those spaces and help people begin to understand why you might want to conserve something like that.” © Stephen Alvarez

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  1. Littlejohn Jacquie says:

    This is just so fabulous. Thank you.

  2. Sharon Chafin says:

    This is so interesting! Thank you. I now know a bit more about bats and what you are doing to protect them and the underground wonders of our world!

    Respectfully…Sharon Chafin
    Seattle, WA