Jennifer Redell with Tri-colored bat (photo by WDNR)
In this episode, we talk about White-nose Syndrome and how it affects our Wisconsin bats as well as what scientists are doing to help with our bat expert Jennifer Redell, a conservation biologist at the Wisconsin Department of Natural Resources (WDNR).
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Transcription
Part One
Hey, and welcome to Questions Asked by Curious Kids or QuACK, a podcast made by Southern Wisconsin Bird Alliance. This is a podcast where we gather questions about nature from kids to be answered with a local expert. My name is Mickenzee. I'm an educator, and I'll be the host for this series. This episode I'll be interviewing Jennifer Redell, a conservation biologist for the Wisconsin Department of Natural Resources, and she's going to be answering questions about bats and a disease they get called White-nose Syndrome.
This episode has so much to learn from that it's split into two parts. In the first part, we'll get to know Jennifer and talk about things like our Wisconsin bats and a little bit about White-nose Syndrome. And in part two, we'll dive even deeper into the problems faced with White-nose Syndrome and what scientists have done to help bats.
Okay. Let's get started with Jennifer.
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Mickenzee: Hello, Jennifer. Welcome to the show.
Jennifer: Thank you for having me.
Mickenzee: Before we get started with the questions from the kids, can you tell us a little bit about what you do at the Wisconsin DNR?
Jennifer: Sure. I am a bat biologist and also the cave and mine specialist for the bat program. We're in the Bureau of Natural Heritage Conservation, so we're the part of the DNR that takes care of our state natural areas, and we keep track of and study endangered and threatened species. And the rarest of Wisconsin’s plants and animals and bats are part of that group.
Mickenzee: That sounds like a really awesome job.
Jennfier: Yeah, it's one of the best jobs in the world. But I will say is, you know, I get to go underground in the caves and mines. I get to work out at night listening to bats and actually capturing them, and keeping track of where they are in the landscape and what they're doing.
And so it's really amazing.
Mickenzee: Wow. Well, that's really convenient because today's questions are all about bats. What first got you interested in these creatures of the night?
Little brown bat cluster (photo by USFWS)
Jennifer: Yeah. I started working at Cave of the Mounds when I was in college, and I thought I wanted to be a teacher. And I went underground into the cave and started guiding cave tours and fell head over heels in love with caves, and started caving and spent a lot of time and years doing that. And of course, what comes along with caves are the bats that are sometimes in them. Not all the time. But when you do see a bat underground in a cave, you're struck by the fact that it's one of the only animals in the wild that you can get inches away from and look at up close. And it sits there and doesn't move. And as a mammal, it lets you look at it. And that's a pretty incredible thing. So I found them really fascinating. And the fact that they conserve energy and spend more than half the year not moving underground in that cave habitat is incredible. And then once you start to learn a little bit about bats, you start to learn just how many unanswered questions we have about this group of animals, and specifically about the bats in Wisconsin. And because bats have sometimes been misunderstood in the past, they don't receive a lot of money, to be studied, and therefore we don't have a great understanding of them, even to this day.
Mickenzee: Yeah, well, I will say that myself and the listeners, we are a group of bat lovers. So you're with the right crowd today. All right. Today's questions were all submitted by fourth graders at Lincoln Elementary School. I work with these students, and we have a lesson that talks all about bats and the disease that affects them, called White-nose Syndrome. Would you mind telling the listeners what White-nose Syndrome is and what bats are most affected?
Jennifer: Okay, so in Wisconsin we have eight different bat species and four of them, when it comes time to, survive the winter, migrate just like some birds. And then four of those species, the other half of the group, hibernate. And so they go to caves and mines, and again, they're going to spend 6 or 7 months of the year with no insect food available. And in order to conserve energy during that period, they're using the cool, damp, dark cave environment to sort of shut down their body. So they're going to lower their body temperature to about the same temperature as the cave air. So about 50 degrees because we're in Wisconsin. And their heart rate is going to drop to only four beats per minute. And they're only going to take a breath every ten minutes or so. And they're going to kind of shut down their immune system, that part of our body that helps keep us healthy normally and fights off any body invaders. So when that happens, and if there happens to be a fungus in the environment in the cave called Pseudogymnoascus destructans.
Mickenzee: Whoa.
Little brown bat affected by White-nose Syndrome (photo by USFWS)
Jennifer: Which is the scientific name for the White-nose Syndrome. Yeah. So we call it P.d. as its initials for short. So if there's P.d. in the cave or the mine with the hibernating bat, P.d. is a cold loving fungus, and it starts to grow on the bats’ cold skin, and they're hibernating. And unlike certain other fungal pathogens, that's something that can cause disease. A type of mold or fungus that can cause a disease, like ringworm or athlete's foot in people are both, you know, problems caused by a mold or fungus on your skin. Unlike those, P.d. grows into the bats living skin tissue, and ultimately, it causes the bat to wake up from hibernation every few days. And when that happens, the bat has to warm its body up so it goes from 50 degrees as a body temperature, or close to that, up to nearly 100 degrees.
Mickenzee: Wow.
Jennifer: You know, just like you or I. And that's really energy expensive, bats burn a lot of calories doing that. So when this bat suddenly has to start waking up to try to fight off this fungal disease, it ends up burning through all its fat reserves before winter's over and either starves to death, or goes out of the cave and is eaten by a predator, or freezes up on the frozen landscape in wintertime, Wisconsin. So what happens is that within three years of P.d. arriving at a cave or a mine, we see most of the bats disappear. And that's if they're little brown bats or tri colored bats or northern long eared bats. And those are three of the four hibernating bats that we have in our state. After that three year initial die off, we in some cases see a few bats sticking around that are surviving with this disease. And if we're lucky, and this is the case at some of our biggest and most important bat mines in Wisconsin, the numbers start to grow again. And so we finally are at a point where we have good news. There's been a lot of bad news with White-nose Syndrome. And we're not completely out of the woods yet. Our bats are still threatened and still need our protection bats still need to stay quietly hibernating in the winter and not get disturbed because they are sick every winter, but they're coexisting or surviving with this fungus and with the disease. And, numbers are growing again at many of the important hibernation sites.
Mickenzee: Yeah, that's really great news. Yeah. You touched on this a little bit, but the students want to know, how did the bats in Asia, where White-nose Syndrome is thought to originate from, deal with White Nose Syndrome?
Jennifer: Okay, so in Europe and Asia, we know that the fungus has been in caves and with bats and causing the disease White-nose Syndrome for probably a very long time. And when we look at P.d. as a fungus and we look at it compared to its closest fungal cousins, it diverged or separated from the other related species about 20 million years ago.
Mickenzee: Wow.
Jennifer: So it's been around a long time. And there's this really interesting thing about the fungus. You know, it's sort of literally a vampire because it not only grows into the living skin tissue of bats, and it's sort of sucking moisture out of their skin. And that's probably one of the reasons it's doing that. But it has evolved and adapted to life in total darkness. And we know that because when we look at this fungus and compare it to its closest related fungal cousins, it completely lacks the repair mechanisms for ultraviolet light. The light from the sun. And normally when sunlight hits a fungus or a mold, it kills that fungus or mold. Or the fungus or mold responds by repairing its DNA from the UV light damage but P.d. can't do that. And so we would say it's Achilles heel. It's its point of weakness.
Jennifer: And there's probably a superhero analogy or something for this. But all it takes is a little bit of ultraviolet light exposure to kill this fungus. So we know it's been evolving with bats for a long time. Underground probably, or flying at dark of night for a long time along with the bats. So all of that is a long way of saying that the bats in Europe and Asia have probably had White-nose Syndrome for a long time. We know that they don't have as much fungus that grows on them when they hibernate, even though they do have the disease White nose Syndrome in Europe and Asia. And so they are surviving with it. And we don't see these massive die offs anywhere happening in Europe or Asia related to the fungus. So the bats have sort of normal hibernation patterns and everything seems normal. And they're surviving the winter along with the disease, even though they're sick. Now. There's some other differences though. So there's fewer bats in Europe and Asia and in each given hibernation site. And that means if you have less animals in a space and they're getting sick with this fungal disease, there's less fungus getting put back into the cave where they're hibernating. So the next year, when more bats come back, there's perhaps less fungus in the cave in Europe or Asia. When the disease first got to North America, all these bats were getting sick and dying, and all this fungus was getting shed or put into the cave. And there it lurked until bats returned the next winter to hibernate, and the fungus was just waiting for them, when they came back the next fall. So as more time goes by and there's fewer bats in a cave or a mine, there's actually less fungus in the environment. Less fungus is coming off of the bats. And additionally, there's all these other microbes, bacteria and other fungi living in the cave environment that are competing with the white nose fungus that's in the soil. They're competing for resources. And so we think there's some competition knocking back some of the P.d. fungus, I want to say bad, but of course, nothing in nature is good or bad, but it does have different effects, right? So our tendency is to say, you know, the P.d. fungus is bad, but I try to be careful. When I talk about that and not label it, it's a fascinating pathogen.
Mickenzee: Yeah.
Jennifer: And it's like perfectly adapted to be the perfect killer of bats. So it's fascinating in and of itself.
Mickenzee: Right. And we always talk about the animals that maybe are the predators. They're not doing it to be mean. They're doing it to survive.
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Okay. That's it for part one. If you are interested in learning more about bats or getting involved with our programs, please head to our website at swibirds.org.
From there you can find our free lessons, games and activities, as well as check out our event calendar or citizen science programs. Big thank you to Jennifer for providing us with lots of bat education materials. Be sure to come back to part two, where we're going to talk even more about these awesome creatures. If you have a big nature question that you'd like to have answered, please have your teacher or a grown up submit your question to info@swibirds.org with the title Questions for QuACK.
Make sure to include your grade in the school you attend so I can give you a shout out. Thanks for tuning in and I hope you join us next time on QuACK!
Part Two
Hey, and welcome to Questions Asked by Curious Kids or QuACK, a podcast made by Southern Wisconsin Bird Alliance. This is a podcast where we gather questions about nature from kids to be answered with a local expert. My name is Mickenzee. I'm an educator and I'll be the host for this series. This is part two to our Bats episode with Jennifer Redell.
If you haven't listened to part one, I recommend starting there. Okay, let's get bat to it.
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Mickenzee: This student would like to know, do bats ever recover from White-nose Syndrome on their own?
Jennifer: Yeah, they do. And you know, certainly we know they do because many are now surviving all around us in Wisconsin. They go into hibernation in the fall and they come out in the spring. And even though they've been sick with White-nose Syndrome, they're not sick enough that they died. So they're recovering as soon as they can get their body out of the cave and warmed up. And they're active and flying, because remember, when they hibernate, they've kind of turned off their immune system to save energy. And when they come out of the cave and are active again and there's insects to eat and the night is warm and they're roosting in an attic or a bat house or a tree, now they've got a warm body. So this cold, loving fungus can't grow on them. And any of the damage that the fungus caused to their skin can heal, and they can go about, you know, their batty business of eating insects every night. So it's been really challenging and frustrating because we knew this early on we knew that if you just could take a sick bat out of the cave and warm them up in the middle of winter, that they can heal and cure themself of the disease on their own. They just need to have warmth and an active immune system.
Mickenzee: They're also wondering if a bat catch White-nose Syndrome again. And it sounds like from our conversation they can. Because it's sitting there waiting.
Jennifer: Yeah. We have to assume that every cave and mine we go in now in most of the United States has White-nose Syndrome, fungus in it. And every bat that goes back into that cave or mine to try to hibernate is going to come in contact with the fungus. And so it's probably going to get sick again next winter. But what we do know is that the bats that have gotten through the worst of the disease the first three years, and they're still around and they're still surviving, they have less fungus growing on them, and they have resumed normal hibernation patterns. And normally a healthy bat would go into hibernation and they'd only wake up every 2 to 3 weeks. And they do that because they might want to groom themselves or they like a little bit of moisture off their fur. They get all dewy and sparkly looking in the cave because they've got little dewdrops all over their hairs. Or they might mate with other bats during that period and move around the cave or mine, but very quickly they'll go back into hibernation. They don't want to use up too much energy. So the bats, even that are sick and fighting, you know, to coexist with the disease today are resuming normal arousal patterns. They're only waking up in the same way that a healthy bat would wake up during the day.
Mickenzee: All right. We've learned that scientists have made a vaccine for White-nose Syndrome, which bats would get this vaccine, the sick bats or the healthy bats?
Jennifer: Yeah. Ideally, you would give the vaccine to the naive hosts is what we say in science, right. The healthy bats that have not come in contact yet with P.d. in a hibernation site. And so the fungus or excuse me, the vaccine was developed, right here in Wisconsin at the National Wildlife Health Center here in Madison and with UW Madison, and also with our work at DNR. And it's been a partnership where as DNR biologists, we help the lab scientists who are developing the vaccine, get that vaccine into wild bats. And so we can, we can trial and test it. And that's been a really long process. It took about ten years to get it to the point where it's at now, where there is a vaccine available. And it's being used now in western states like Utah. And one of the places in Utah that they're using it, is a cave called Minnetonka Cave. And they were able to go to that cave and vaccinate all of the bats before White-nose Syndrome got there.
Mickenzee: Wow.
Bat houses are structures made by humans that give bats a place to roost during the day (photo by USFWS)
Jennifer: So the disease, you know, is kind of getting spread from bat to bat and cave to caves and slowly marching its way across the country. So at Minnetonka Cave, the bats were vaccinated before the disease arrived. Then they started swabbing in the cave and testing for the presence to see if the P.d. fungus. They found it there, but none of the bats were getting sick. And so the vaccine is effective. It's now been several years that they're testing and finding P.d. in Minnetonka cave and the bats have not gotten sick. They don't show any clinical signs, and there has been no death from White-nose Syndrome at that cave. So it's really a success story. But the problem is that all the bats that are getting the vaccine are still at the point where we have to actually hand trap and capture a bat. So we use a special type of trap called a harp trap. When the bats are coming into hibernation, we can set it across the cave or mine entrance, and they land in this trap and we can pick them up, and then they get a little bit of vaccine dripped into their mouth. So that's all great, but it's not sustainable. It's not a way that we would consider delivering the vaccines, a huge number of bats. It's a lot of work, and it's stressful on the bat to get captured. So we and other scientists have been looking at different ways to deliver the vaccine, like maybe spraying it on the bats and then as they groom it off of themselves, they're ingesting it, and getting protected. We don't yet know if the vaccine needs to be given multiple times. That was part of the question. But all of this is very tricky. And bats are really difficult to work with. They're very sensitive to disturbance. So I can give one example. And here in Madison, when we were first trying to figure out how we would deliver the vaccine, we went to some different bat houses locally and smeared a gel up inside the bat house. And that gel had a dye, a red dye in it. And as the bats crawled over the gel, they got some of it on their fur. And as they groomed themselves and licked their fur, just like a cat or a dog would, they took up some of that red dye, and we can come back a few days later and trap the bats and see if they've ingested the dye. We actually pluck a couple of their hairs and we can see the dye in their hair follicles. And so that's a way to know if they've ingested this gel. And once the vaccine is developed, we would put the vaccine in the gel. Right. So the test was to get the dye into the bats and see if they were grooming it off of themselves. But we found a couple of challenges. One is that we were hoping that one bat would get gel on it and crawl up into the bat house and transfer that gel to other bats, and that they would all mutually groom and groom each other as they’re social animals. Well, it turns out they don't. Little brown bats don't mutually groom in the way that certain other bat species do. So it was becoming a little trickier. We were going to have to get gel on every bat. And we also learned that we can go out and do a test at a bat house and capture some bats, and maybe put gel directly on them. But when it comes to recapturing them a few days later, we can go out and be very quiet and set up our trap underneath the bat house and hope that the bats will fly out into it. But what we found is that sunset comes and goes and we wait 30 minutes, and that's the time when bats would usually come out. But they didn't on the second visit because they knew we were there.
Researcher with Big brown bat (photo by USFWS)
Mickenzee: They became wary.
Jennifer: Bats are smart and they want to avoid predators, and that's what they think we are. And so they just hung out and sat tight up in their bathhouse and did not emerge. So it became very tricky to continue those trials. And that tells us that, you know, maybe that's not the way to go is to have to hand capture bats and deliver the vaccine to them individually. So we need to look at other ways to do that.
Mickenzee: Yeah. Are there any new ways that scientists have thought of, or is it still a mystery?
Jennifer: Yeah. Well, they're looking at maybe spraying it on bats, but again, we have to we have to kind of be careful, because if you think of putting like a big, you know, spritz or bottle or spray fan or something at a cave or a main entrance, the bats come in in the fall and they're swarming around, or they're circling in and out of the cave or mine entrance all night long for about a month each fall. And that's called the Fall swarm. And that's one we would probably want to target, giving them the vaccine. But we don't want to scare them away from the hibernation site, because without that hibernation site, they don't have anywhere else to go. And that's a really critical need for them to be able to survive the winter is to get there, go inside and hibernate. So it's been very challenging. And we're looking at maybe doing the spray at a bat house in the summer months where maybe we have a little more flexibility, and won't be disturbing them as much. So it's really challenging. Bats are, like, really fun to work with and really amazing the more we work with them and understand, like, what works and what doesn't.
And as a conservation biologist and a bat biologist, that's the way that we help when it comes to bat diseases and working with people who are in the lab developing a vaccine or a medication.
Mickenzee: Totally. I feel like today has been full of good news and mysteries, and I've learned so much. Thank you to the students who've submitted their questions. And thank you so much, Jennifer, for teaching us today.
Jennifer: Yeah, bats are amazing, resilient. And I think, given that they've been around for 50 million years looking pretty much the way they do today, we know that they're very adaptable. And, probably going to be around a lot longer.
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If you're interested in learning more about bats or getting involved with our programs, please head to our website at swibirds.org.
From there you can find our free lessons, games and activities, as well as check out our event calendar or citizen science programs. Big thank you to Jennifer for providing us with lots of bat education materials. If you have a big nature question that you would like to have answered, please have a teacher or your grownup submit your question to info@swibirds.org with the title Questions for QuACK.
Make sure to include your grade in the school you attend so I can give you a shout out. Thanks for tuning in and I hope you join us next time on QuACK!
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Audio Editing and Transcription by Mickenzee Okon
Logo design by Carolyn Byers and Kaitlin Svabek
Music: “The Forest and the Trees” by Kevin MacLeod
