What is it like to be inside one of the wildest places on Earth? In a remote area of the Grand Canyon, explorers discovered two caves previously untouched by human beings, with thousands of ancient bats — some older than carbon dating can measure. We hear the latest findings and stories from the research team.
Over a decade ago, an explorer conducting surveys at Grand Canyon National Park noticed what appeared to be an opening in a red rock cliff face high above him in the park’s remote backcountry. His team discovered a cave that appeared, by all accounts, to have been completely untouched by people. Researchers found a series of passageways with gypsum formations and a variety of wildlife, including thousands and thousands of mummified bats.
In episode 4 of the podcast, we talked with several experts about this remarkable cave and its ancient remains. Since then, researchers have returned and ventured into a second cave, even more difficult to explore than the first, and made more exciting discoveries.
This episode, host Jennifer Errick speaks Carol Chambers, professor of wildlife ecology at Northern Arizona University; Shawn Thomas, volunteer caver and bat expert; and Stephen Eginoire, photojournalist. We learn about the implications for science, the extreme lengths the team takes to preserve the cave, and profound feeling of being the first person to set foot in an unmapped place.
The Secret Lives of Parks is a production of the National Parks Conservation Association.
Episode 43, Return to the Bat Cave, was produced by Jennifer Errick, with help from Todd Christopher, Bev Stanton and Linda Coutant.
Special thanks to Vincent Santucci.
Original theme music by Chad Fischer.
Read the Grand Canyon research team’s most recent paper at: parks.berkeley.edu/psf/wp-content/uploads/2024/01/psf_401_chambers_web.pdf
Read Stephen Eginoire’s story for the Grand Canyon Trust at: www.grandcanyontrust.org/wp-content/uploads/2025/01/AdvocateMagFall2024Digital.pdf
Learn more about this podcast and listen to the rest of our stories at thesecretlivesofparks.org
For more than a century, the National Parks Conservation Association has been protecting and enhancing America’s national parks for present and future generations.
And we’re proud of it, too.
You can join the fight to preserve our national parks. Learn more and join us at npca.org
Episode 43
Return to the Bat Cave
Jennifer Errick: In a remote area of the Grand Canyon, explorers discovered a cave previously untouched by human beings with thousands of ancient bat mummies unlike anything known to science. Since I first talked with members of this team in 2021, researchers have ventured to a second cave with even more fossils — some older than carbon dating can measure. We hear the latest from the field — and what it’s like to be inside one of the wildest places on Earth.
I’m Jennifer Errick, and this is the Secret Lives of Parks.
[Break with nature sounds]
Over a decade ago, an explorer conducting surveys at Grand Canyon National Park noticed what appeared to be an opening in a red rock cliff face high above him in the park’s remote backcountry. This experienced caver, named Jason Ballensky, applied for a permit to investigate. He gathered a team and bushwhacked, climbed and rappelled his way to a cave that appeared, by all accounts, to have never been set foot in by another person before him. There were no footprints or human artifacts, just a dark series of passageways with elaborate gypsum mineral formations and a variety of living and preserved wildlife, including thousands and thousands of mummified bats.
Back in 2021, I talked with several experts about this remarkable cave and its ancient remains. Bat fossils are relatively rare, because their small bodies and delicate bones break down more easily than those of other animals, so fewer specimens survive the ravages of time. The Grand Canyon, however, is an ideal environment for bat research, because the dry air preserves their bodies well. In the cave Ballensky discovered, researchers found fossils with intact fur and tissues that looked stunningly similar to living bats. In some cases, only their sunken eyes gave away that they had been dead for hundreds, if not thousands, of years.
Vincent Santucci: It seems as though treasures that we found in this remote cave in Grand Canyon National Park collectively exceed all of the known total of other bats together from North America.
Jennifer Errick: That’s Vincent Santucci, Senior Paleontologist and Paleontology Program Coordinator for the National Park Service, speaking about the significance of the team’s findings on episode 4 of the podcast. He described both the quantity and the quality of these bats as unprecedented and said at the time that it was the only example of a collection of research animals with DNA spanning 30,000 years.
Vincent Santucci:For a paleontologist that studies bones all their life, if they have an animal that has all the soft tissues, the fur, the skin, the internal organs so you can see what's in the gut contents, what was their last meal? All the aspects of the tissues that inform us more about what these animals look like and perhaps aspects of their physiology or behavior. Really, this was an exciting opportunity.
Jennifer Errick: That was four years ago. The research team has since returned to the cave and has also begun exploring a second cave that is relatively close to the first, but even more difficult to get to. The lead scientist studying the bat samples was happy to hop on a call with me to talk about what she’s been up to.
Carol Chambers: It's always fun talking about bats.
Jennifer Errick: That’s Dr. Carol Chambers, a professor of wildlife ecology at Northern Arizona University who has been working with the team to analyze the samples that these cavers have carefully collected. But before getting into the latest discoveries, I ask her to share what she finds so interesting about bats.
Carol Chambers: They are the only mammal capable of true flight. Other mammals can glide, but bats fly. And they're so diverse. If you name it, a bat is probably doing it. At this point, there are probably close to 1,500 bat species in the world that are known today, and we're finding more and more as we continue to look. And that's because bats have been very difficult to study until the last 30-40 years, and now we're doing a much better job of figuring out how they are moving, how they are echolocating, or how they're using vision to find things. Many people may not be familiar with the fact that bats are very long-lived — or can be. The oldest known bat is around 42 years old.
Jennifer Errick: Oh, wow.
Carol Chambers: Yeah. They aren't rodents. They don't have a short lifespan. And that means they can learn more from their environment. Their wing shapes and morphology differ, so that some are better at flying in very open spaces, and they can fly very fast, but they're not very agile. And some bats are very agile because they have a wing morphology that allows them to dip and turn and weave in very tight spaces. So, you know, those are just a few of the cool things.
Jennifer Errick: Very, very cool. So, the last time that we spoke, I believe it was in the summertime in 2021, you had gotten back the first dozen or so bat samples that you had sent for carbon dating of the bats from the Grand Canyon cave and discovered that these first dozen or so bats were just extraordinarily old. Can you share a little more about what's happened since then?
Carol Chambers: It's gotten even more incredible. So, there are two caves in the Grand Canyon. Both are very inaccessible. We have now sampled both caves, and by we — it's got nothing to do with me. I work with the cavers and wildlife ecologists who are doing this.
Jennifer Errick: So, you don't go rappelling into the cave yourself.
Carol Chambers: I do not. I would be a liability. So, this very well-trained and just incredible team go in, and they're surveying the cave. We have had at least two visits, and we're planning another one now. We have carbon dated 155 individuals, so it's a huge number.
Jennifer Errick: Oh, much more than I thought.
Carol Chambers: Yeah. The only problem is, some are so old we can't carbon date them. So, the limits of carbon dating go to about 48,000 years. So, we're looking at bats that range from 600 years before present to 48,000 years or older. It just blows me away. So, our four oldest bats were over 42,000 years old. That's all pretty amazing to me. And there's another method to try to carbon date some of these very, very, very old bats and see if we can get the ages of those preserved specimens that are in the caves.
Jennifer Errick: I ask Dr. Chambers if these are the oldest bats that have ever been discovered, and she tells me that she spent significant time studying research on bats and working with a librarian to try to discover any studies with bats that were this ancient, and she was unable to come up with anything close to what the team found at Grand Canyon.
Carol Chambers: Nothing compares to the level of preservation of these animals in these two caves in the Grand Canyon and the quantity of animals. I mean, we might be able to look at diet in these animals. We’re going to be able to, with these CT scans, we hope, to look at the structure of the ear, because these are echolocating bats. Does it look any different from a modern bat? And granted, we only have a sample size of one for each of these four species that we can look at, but it'll at least tell us if this animal is still in the range of what we see today. I'm still floored by the data that we have and the amount that we have and this incredible resource. I don't think there's anything like it known on the planet right now.
Jennifer Errick: What kinds of things can we learn from this much bat DNA across so much time?
Carol Chambers: So, looking to to predict, would they have been here 20,000, 40,000, 100,000 years ago, or was climate so different that the habitat differed, and they were not adapted to being here? So, we've taken these 155 samples that are carbon dated and we've plotted them across time by species, and we're comparing them to some metrics of climate, and we kind of feel we need more data, so that might be the next trip, is to go in and try to gather more samples to carbon date and still continue to look and see if we have all species represented throughout time, or do we have periods where the animals, some of these species didn't occur in the Southwest because the climate had changed so much that the habitat was no longer suitable for them?
The ancient DNA is also, you know, just fascinating to think — are these the same types of animals occurring today as occurred 50,000 years ago? Has there been very little change in the species? And they certainly look the same, you know, when you're looking at these preserved specimens and compare them to modern bats. But were there adaptations that might have been represented in their genetics that we don't know about?
Jennifer Errick: Shawn Thomas is one of the cavers who has been part of the expeditions since 2009 and has visited both caves. When he started, the team had only mapped about a mile of the first cave. Now, he and his team have mapped more than 40 miles, plus another 10 miles of the second cave.
Shawn Thomas: It's not like every trip is the exact same thing over and over again, and that's the exciting thing and what draws people to go back year after year, is we're literally walking into new cave passages. Sometimes it's not walking, we might be crawling or climbing into new areas, but yeah, we're seeing new things.
Jennifer Errick: Thomas helped carefully measure and sketch each section of the cave. He’s also an expert on bats, and over the years, he’s become the point person coordinating with Dr. Chambers on the field studies and leading the inventories of both sites. When I spoke with Thomas four years ago, he described why it’s so difficult to get to this area of the park.
Shawn Thomas: First of all, you have to do a really scary rappel. This was one of the longest rappels I'd done in broad daylight on the surface. So, you back over the red wall limestone, where it goes vertical into a cliff, and you can see down hundreds and hundreds of feet, far beyond where we're going to actually get into the cave. And it's definitely pretty alarming. So, you kind of have to get over that, that moment of panic and then rappel down the wall. The wall kind of vanishes away where it turns into the overhanging cave entrance. And then you land actually down below the cave. At that point, you have to climb up a big pile of rocks and breakdown and scramble up into the entrance.
Jennifer Errick: Thomas tells me that his team uses the same dramatic rappel to get to both caves, but the second cave is even more difficult to explore because it has no water source, and they have to carry all of their water in heavy packs on their backs. Despite the demanding physical challenges, the team has been able to examine the differences between the two environments. The first cave has narrow, twisting passages, whereas the second has much larger open areas. Thomas explains that the bat populations also differed significantly, to the team’s surprise.
Shawn Thomas: One cave is dominated by the Townsend's big-eared bat. This bat species is very common throughout the western US. It's the bat that we actually expect to see in caves. This other cave, we did find a few of these Townsends big-eared bats, as expected, but the big surprise over there is that the dominant species is the silver haired bat. This is traditionally considered a tree bat. So, it's really puzzling and fascinating. Why is this the dominant species? We're finding hundreds of silver haired bats in this cave. It outnumbers all other bats in that cave combined. So, what is going on there?
We don't know the answer to that. However, deep within that cave, over a mile from the entrance, there used to be a water source, and we know that because when water accumulates in caves as that water drains out and dries, it leaves behind mineral deposits that are easily identifiable as what used to be a cave pool. In that dried-out pool basin are many of these bats representing all the different species we found in that cave, including many of these silver haired bats. So, one idea we have right now is that the bats were using that cave as a water source. It's an easy, safe place to fly into and get a drink of water, and perhaps because that cave such big, open cave passages, something that's not used to spending time in caves, like a silver haired bat, had an easier time navigating and flying through those big open passes.
Jennifer Errick: Do you think there could be implications for bats today? I mean, there are so many bat species that are threatened or endangered, and habitat is changing as the climate changes. And I wonder if it's a kind of, you know, testament to how bats might be more adaptable, that a bat that's considered a tree bat could adapt to a different type of environment if it needs to?
Shawn Thomas: Certainly, wildlife are incredibly resilient, to a point. Large-scale habitat change and climate change are going to really test that. But yes, I think if there are opportunities out there for animals to find shelter and find water, they're curious, especially bats. They are constantly investigating the landscape and poking into things that are new or that have changed, and so I think part of our role as conservationists is to provide opportunities in lieu of the fact that many of their opportunities have been taken away through habitat loss. So, providing water sources on the landscape — many conservationists are doing that kind of work now. And yeah, with bats and other critters, if you put something out there and they can make use of it, they'll find it, and they'll exploit it.
Jennifer Errick: Are there aspects of what you've seen that for you, as an experienced caver, are really exciting now that you've gone multiple times and made new discoveries?
Shawn Thomas: Yeah, I think most of us who were involved early on were certainly struck by the bats. Honestly, we don’t know of anything on that scale anywhere in the world. But even setting that aside, these caves are just incredible on their own. They're these maze cave layouts. It's almost like a grid pattern of streets and avenues, but the connections are a little obscure at times, and you can be walking down a really nice cave passage, and suddenly it turns into a little crawl or a climb, and that might lead you into an even bigger passage that's kind of paralleling what you were just in. So they're really exciting and fun in that way, that it's a mystery of what's going to be around the next corner.
Jennifer Errick: What are you hoping that people will take away from your research?
Shawn Thomas: I think it's really important for people to understand that our lives are really short in scale, right. And anybody who's been through a geology class and has pondered the age of our planet starts to get a sense of deep time. And there are places like this out there that have been on our landscape for hundreds of thousands, millions of years. And for that time, at least a good portion of that time, it served as a very important habitat for bats. It continues to be habitat for bats today. It's not just dead bats we see in there. Bats are also still actively using these caves. There's no way to replace places like this. Habitat protection is more important now than it's ever been for all of these critters out there who need these places.
These caves have been on the landscape for potentially a couple of million years. So, I think we have a great responsibility to maintain them. I kind of think of these as, like, nature's perfect museum. It's a very special experience. We're all just fascinated and honored to be a part of it.
Jennifer Errick: Coming up after the break, I speak with another member of the expeditions who published a story last year about his experiences, and I ask him what it’s like to be in one of the wildest places on Earth.
Stephen Eginoire: There's no footprints ahead of you. And it's all wilderness, a hundred percent. And you think, once I step forward and leave this next footprint, it totally leaves that realm of what true wilderness is and comes onto our maps and into our photographs, and that place is changed forever right then and there.
Jennifer Errick: That’s next. Stay with us.
[Music break]
I love getting to share this story from one of the most secret, remote parts of the Grand Canyon — a place I know that I’ll never get to see. For me, this piece showcases so much of what makes our national parks special — their mystery, their ecological significance, their beauty, and their importance to research and our understanding of the world. As I’m recording this episode, I’m mindful that Congress is in the middle of debating budget legislation that would be disastrous for national parks and the people who care about them. The president has proposed cutting a billion dollars from the National Park Service budget. Enough already. National parks are a nonpartisan issue, and they always have been. Defunding places that preserve our lands, waters, wildlife and history is as un-American as it gets. Go to npca.org/voteno and tell your members of Congress not to gut the National Park Service. NPCA will continue to fight these unconscionable actions, and you can join us in saying this is unethical and unacceptable.
[Music break]
Part of what fascinates me about these Grand Canyon caves is that they are among the most hidden and delicate environments on Earth. I was especially curious about what it was like to be in this incredibly hard-to-get-to corner of one of the country’s most popular parks.
Stephen Eginoire is a photojournalist who has been a member of these research explorations since 2015. Both he and Shawn have been on enough expeditions that neither could remember exactly how many they’d been on. Last year, the Grand Canyon Trust published a comprehensive, beautifully written story by Eginoire with extensive photos from inside the caves. We’ll include a link to the story in the show notes. I was eager to talk with Eginoire and ask him to share more about his experiences.
Jennifer Errick: What is it like to be in these caves, surrounded by cool-looking dead things?
Stephen Eginoire: Man. Well, I think one of the first things that you would notice is it's totally dark, , blacker than you could possibly imagine. And totally still. As still as you could possibly imagine. And also quiet. And like, these things just kind of exist in this space that is so delicate, not only to like human entry and, you know, people bashing around, but also to sound. And you really just kind of sit in these places with your lights off and know that these bats are around you and let the stillness and the quietness and everything just kind of like come down on top of you.
Jennifer Errick: I can't tell if that's meditative and peaceful or downright spooky.
Stephen Eginoire: I think it's probably a little bit of everything.
Jennifer Errick: So, it’s a rather breathtaking rappel that you have to take down to the opening of this cave. Now, the professional photographers I know love their gear. It seems like a situation where you've got to pack very carefully. And once you get there, you can’t go setting up a ton of stuff, right?
Stephen Eginoire: So, I have, like, remote flashes that I can set up, and then I can change the amount of light being emitted from each flash. So, there's quite a bit of control, and what I really love about shooting in caves in general is they're a hundred percent dark, they're totally black. So, you bring your own light down. And you're able to just work in a studio, basically, like, this natural studio, which is really cool, whereas where you're working above ground, there's things to take into consideration, like where the sun is and time of day and blah, blah, blah. But underground, it’s 24/7/365, you can just be as creative as you want and splash a little light over there and put a little light on that, turn up the light over here and get everything just right, and hours go by, and everybody's like, Oh my God, what's taking so long?
Jennifer Errick: So, you bring your own golden hour.
Stephen Eginoire: Exactly. Yep.
Jennifer Errick: I also just really love talking about writers about their writing process. Because you’re not just taking photos. You put together this beautiful story. Where did you start? When you had the blank page in front of you, what was the first thing that you really wanted to capture?
Stephen Eginoire: Just the sense of space, I guess, and time and the utter just complete delicate space that these caves exist in and how fresh and untrammeled and unknown and unrealized they are. It's a horizon beyond a horizon beyond a horizon. It’s pretty amazing. It's been kind of like a fine line, I guess, wanting to share these places that I've been really inspired by, while also not wanting to shed too much light on something that's utterly delicate and incredibly fragile.
Jennifer Errick: That's really well said, because that's kind of the tension that's at the center of all national park sites, right? You want people to be able to enjoy and explore them, but you don't want that visitation or that enjoyment to actually harm the parks and why they're protected. But caving is its own very special contained environment where just breathing in a cave can harm it, right?
Stephen Eginoire: It can, in some places for sure. It's, like, a constant learning process about how to move through these places without damaging them and how to photograph them without damaging them. And it's important to have an intention and a reason to go into a cave in the first place, more than just, like, I wanna see it. If I'm gonna go in here and leave my footprints behind, I gotta be able to have something to show for it.
Of course, our camps would be very well-managed. Everything that goes in comes out, and you know, even the hair that falls off your body gets collected where you're sleeping and eating. All that stuff gets, like, folded up into like a wad and carried back out of the cave.
Jennifer Errick: See, that's the kind of detail that I love.
Stephen Eginoire: Yeah, you have to like, live your whole world over like a white tarp, and you see how that stuff collects on top of it over like the span of a week, it's intense. Like, yeah, that's a lot of hair.
Jennifer Errick: Have there been moments of discovery for you that really stand out, where you were just like, wow?
Stephen Eginoire: Yeah, so many times, almost every time, actually. One expedition really stands out. I had a few really amazing days with Shawn. We were surveying this, like, area that had just recently been discovered on that trip. And so, there's this whole realm that is completely delicate, and no human being has ever been to these places before. At that point, I had never experienced anything like that. This was a vast area that was pretty special and extensive, and we were walking past huge chambers — one over here, one over there — and we just had to stay focused. And the survey process is pretty slow. I was helping to set survey stations and helping to measure the passage while Shawn was sketching the passage, which takes time, because you’re trying to represent this three-dimensional space on this two-dimensional piece of paper. Meanwhile, I'm like running around kind of going bonkers with my camera. And Shawn’s like, you gotta rein it in, you know. Like, you can't go too far ahead.
It's definitely kind of a trip to think about when you're standing at the edge of this — it's a literal frontier, and there's no footprints ahead of you. And it's all wilderness, a hundred percent. And you think, once I step forward and leave this next footprint, it totally leaves that realm of what true wilderness is and comes onto our maps and into our photographs, and that place is changed forever right then and there. You know, we're not going to hurt it, but it's going to literally go from being something that nobody ever knew about, existed in total darkness. Now we're going to come out of it with a map and photos.
Jennifer Errick: Now that researchers at the Grand Canyon have documented some of the critical differences between the two hidden caves, mapped over 50 miles of terrain and analyzed more than 150 samples of these remarkable bats, I asked Dr. Chambers what some of the next steps are for the team.
Carol Chambers: We are looking for funding to do ancient DNA analysis of about 50 to 75 samples we brought out of the caves. If we are going to do some comparisons of modern and these old bats in terms of their flight and echolocation capabilities. And something that is of great interest is diseases. I'd be interested in diet, what they were eating at the time. Any parasites they might have had, those sorts of things. So, we're talking about another cave exploration this year, in 2025. We’re still honing what we want to do. I think a big part of that would probably be to survey as many more bats as possible and carbon date them just so we can try to get a better idea of the bat community across time with respect to changing climate. We're also trying right now to get range maps of the species that we find in the caves to see which species would have occurred and how might they have changed across time.
Jennifer Errick: Like Shawn Thomas, Dr. Chambers hopes her research contributes to the importance of cave conservation.
Carol Chambers: About half of the bats that we know of use caves to some extent, and some require caves to live in. And you have more and more disturbance of caves, and there are more people on the planet and less habitat, you're likely to have more bats put at risk because they can no longer use something that has been in good condition for a long time. And sometimes people change the cave structure in a way that changes the flow of air, the humidity, the microclimate, and sometimes that microclimate is so critical for an animal to hibernate or go into torpor or use that it changes the conditions, and the bats can't use it anymore.
Jennifer Errick: Is there an increasing issue with threats to caves, or is it sort of an ongoing threat?
Carol Chambers: Oh, I'd say it's both. It's ongoing and increasing. There are more people on the planet, more people want to go out and do things. Exciting things, explore caves, and it only takes one person finding a cave to share that location. And some are very accessible. Some you can drive right up to. And so, I think we're at greater and greater risk with cave protections.
Jennifer Errick: When I first had the opportunity to interview members of this research team four years ago, it was one of our earliest stories, and it’s still one of our most popular episodes. It’s special to learn about a hidden place on the map where bats have outnumbered people for thousands of years and to understand the care people have taken to study and protect it. And Dr. Chambers agree on an important point.
Carol Chambers: It's always fun talking about bats.
[Music break]
Jennifer Errick: The Secret Lives of Parks is a production of the National Parks Conservation Association.
Episode 43, Return to the Bat Cave, was produced by me, Jennifer Errick, with help from Todd Christopher, Bev Stanton and Linda Coutant.
Special thanks to Vincent Santucci.
Original theme music by Chad Fischer.
Learn more about this podcast and listen to the rest of our stories at thesecretlivesofparks.org
For more than a century, the National Parks Conservation Association has been protecting and enhancing America’s national parks for present and future generations. With more than 1.6 million members and supporters, NPCA is the nation’s only independent, nonpartisan advocacy organization dedicated to protecting national parks.
And we’re proud of it, too.
You can join the fight to preserve our national parks. Learn more and join us at npca.org