It's National Bat Week. We visit with NDSU Professor Erin Gillam about the roles bats play in a healthy ecosystem, as well as the threats they're facing. ~~~ Matthew Batt is the author of "The Last Supper Club, A Waiter's Requiem" It's a memoir that recounts the ups and downs of his workday at a new Minnesota supper club. It's called "A witty and humble tribute to the sometimes profane, sometimes profound world of waiting tables."
National Bat Week (transcript)
Ashley Thornberg: This is Main Street on Prairie Public. I'm Ashley Thornberg. We are going to start today with a couple of questions. How many of you want more mosquitoes? Or less tequila in this world.
Those could both happen if bats continue to face the same threats that they are under. October 24th through the 31st is National Bat Week. And here to help us understand the roles that bats play in a healthy ecosystem is Dr. Erin Gillam. She is a professor in the Department of Biological Sciences at North Dakota State University and has a heavy focus.
On bat research. Dr. Gillam, thanks so much for joining us today.
Dr. Erin Gillam: Yeah, I'm happy to be here. Thanks for having me.
Ashley Thornberg:
I wanna start, Erin, with that first thing I said, more mosquitoes, less tequila. how accurate of statements are those?
Dr. Erin Gillam: Bats do eat mosquitoes. They don't tend to eat a lot of mosquitoes. Because if you think about what is a mosquito, it's like that crunchy exoskeleton and then maybe whatever blood it's eaten.
And so there's not like any good fat in there or anything. So they're not really like a great prey source compared to something like a juicy fat moth or a beetle. So they do eat some mosquitoes, but it's not like the primary thing they eat. They are the only natural pollinator of agave, which is what tequila is made from.
Although nowadays most, agave is hand pollinated. There are some tequilas that are like bat friendly tequilas, where they leave some of their agave crop open so that the bats can pollinate it. And yeah, bats play a role in some, but yeah, humans have taken a bigger hand in that.
Ashley Thornberg: What would happen, Erin if all of the world's bats disappeared overnight?
Dr. Erin Gillam: I think the biggest impact would probably be around agriculture and crop pests. This is something that there has been some work done on, we don't have a really very specific and quantifiable idea of how much do bats do for agriculture because bats eat a lot of moths and beetles, which happen, a lot of them are crop pests.
In some areas, like in Texas, where there are these caves with millions of bats, it's easier to be like, okay, if each bat is eating this many moths a night and there's this number of bats, you can scale it up to understand the agro economic benefit of bats. It's a little bit harder in a place like North Dakota, where The bats aren't all in one big cave, and they're spread across the landscape, and it's hard to know the numbers.
But I suspect if that bats were to just disappear, we would see our ability to effectively produce crops and the cost associated with that in terms of the point where it might be not viable in certain places anymore.
Ashley Thornberg: How are bats doing in North Dakota?
Dr. Erin Gillam: We know some about this, and the biggest issue in North Dakota is that in 2019, we had the arrival of the fungal disease, white nose syndrome. We have already been seeing some drop offs in our little brown bat population.
Little brown bats are a species that, was previously one of the most common bat species in North America, and its populations have really declined very rapidly because of this fungal disease that's been going on for about, It was since 2006, so a little bit less than 20 years and populations have been decimated and they're slowly recovering.
But in North Dakota, we have seen this, that the populations are starting to go down. We saw it a couple years before it got to North Dakota because a lot of our bats overwinter in other states like Minnesota and South Dakota. Dakota. And then they come to North Dakota for the summer. We started to see drops in the number of bats who were catching specifically those little brown bats, and that has just continued since then.
Ashley Thornberg: What would be the change in climate sufficient enough from just North Dakota to South Dakota and Minnesota? I'm surprised you didn't say they went to Arizona.
Dr. Erin Gillam: Yeah, there are some bats here. if yeah. Red bats and hoary bats are species that are more long distance migrators and they can go to Texas and Mexico and further most of our bats are more like moderate distance migrators And they're going to places where they can hibernate for the winter and North Dakota, you know We have a lot to offer but we don't have a lot of caves to offer, necessarily.
And there are some caves out in the Badlands. And we have done some work out there that there are some bats that do overwinter there. But as far as we know, it seems like a lot of bats are leaving, especially those maybe on our side of the state, they're not so close to those caves in Western North Dakota that they're going elsewhere. But in reality, this is just something we think we don't have a lot of great data, because bats are very small. And the GPS technology to put a little GPS tag on a bat, it's still just getting there to the point where it can be light enough to not weigh the bat down.
Ashley Thornberg: Because a lot of them weigh, there's a species of bat that weighs about the same as just a couple of coins.
Dr. Erin Gillam: Yeah. So three to four grams is the smallest size. And, we have a bat in Western North Dakota that is, that four grams, I think we have it in Minnesota as well. So yeah, really small. And then they could be very big, too. But here, usually in our region, the bats are usually somewhere in the range of yeah, this kind of five grams to like 25 grams or something like that. There's no commercially purchasable GPS tags that are that small that you could really track the animals. When they can migrate far, we are just making guesses, which yeah, I wish we had better data about that. We're just not at that point yet.
Ashley Thornberg: We're visiting today with NDSU professor Dr. Erin Gillam, who is heavily focused on researching bats, has published or worked on such papers as Influences of Landscape Features on Bat Activity in North Dakota; Bats Flying at High Altitudes, 50 Years of Bat Research; and Contributions of Women and Creating a Culture of Inclusivity at the North American Society for Bat Research.
Erin, how many female colleagues do you have?
Dr. Erin Gillam: I have a lot of female colleagues. So yeah, that was something for our society had for its 50th anniversary. And so we did an analysis where we went back and looked how the number of women that have been involved in bat research has changed over the years.
And it is definitely in terms of like participation broadly in terms of research is much better. There still is some lack of parity in terms of once you get to some higher levels in terms of who's on the board of directors and who is the, who's chairing different committees or sessions within the conference.
And so trying to understand how the society has changed overall, and I think that maps pretty well with. biology over overall.
Ashley Thornberg: What do you think might be some of the main reasons there have been more women in this field over the past what three, five decades?
Dr. Erin Gillam: I don't know. Part of it is as just more women have been pursuing STEM careers that has grown and biology overall tends to be a field where there are a lot of. As a professor at NDSU for sure at least 50 percent of my students are female.
And It's, it's a discipline that has just, over the years seems to enroll more women into it. And so then the type of research that you get involved in is biological based. It's certainly not perfect still. But when you look at something like physics or mathematics or engineering, you tend to still see a lot more of these.
a classroom that's mostly full of males and only has a couple of females in it. but yeah, biology seems to have gotten to parity on that a little bit better.
Ashley Thornberg: 23 bat species are critically endangered, meaning they're facing imminent risk of extinction. 85 bat species are endangered. Another 113 considered vulnerable. These facts are from batcon. org. Erin, what are some of the biggest threats facing bat species and maybe most specifically in this area?
Dr. Erin Gillam: There's some really general threats that have to do with loss of habitat. Especially there are some species like the federally endangered northern long eared bat that is like a forest specialist.
That loss of habitat will lead to declines in populations. More specific to bats, because that's like an all wildlife thing, the big risks are this continuing like epidemic. Basically this white nose syndrome, this fungal disease that continues to spread throughout North America, and populations are beginning to come back from it. We're starting to see little bits of rebounds. But one thing with bats is that they reproduce very slowly.
A bat is roughly the size of a mouse, right? And a mouse can produce dozens of babies in a year and a bat produces one. So they have very low reproductive rates, which means that when they're hit with something like this disease, their populations recover extremely slowly, like to the point where,we're looking at like hundreds of years until the populations are going to get back to where they previously were in some of these areas.
Maybe something will change and that will do better than that. But just based on their reproductive rate, the recovery is going to be very slow for these populations.
Ashley Thornberg: Do you see any bright spots or find hope anywhere in recovery efforts?
Dr. Erin Gillam:
Where the hope is that it seems maybe like the worst of it is over. The disease continues to spread. It's slower than it used to be. But in these areas where it was hit hardest in the beginning, particularly the northeastern U.S. and eastern Canada. We're starting to see the numbers begin to creep up. So there's hope there. The other threat to bats that continues to be and is definitely in our area, but other areas as well, has to do with wind energy in that, there are, there can be pretty high fatality rates for bats at wind turbines.
There are some solutions that have been developed, but it's certainly not perfect, and, that specifically tends to kill those red bats and those hoary bats during the migration season when they're undergoing those long distance migrations. And so that has also a different reason that a different set of bats have gone into decline, because of that.
Ashley Thornberg: When you say bat researchers and the wind energy companies working together, can you give us some examples?
Dr. Erin Gillam: Part of it is like government mandated.If a company wants to put up a wind energy facility, they are, if they have any level of federal funding, they need to do like an environmental impact statement.
And it's known that bats are negatively affected. And so they have to work with biologists to gather data about what bat species are there. But I think the wind energy companies, they're selling a type of green energy. And having their facilities killing large numbers of wildlife isn't great for that brand.
And so that has been, I think, part of the drive that they have put a lot of money themselves into trying to fix this problem
Ashley Thornberg: What can homeowners do if anything?
Dr. Erin Gillam: Bats in your home are usually problematic because they poop everywhere.
And so that's a mess. And then also,they get into the main house. I would say in terms of if you have bats in your home, it's always a good idea to work with a professional. There are a couple in town that can exclude the bats rather than maybe just killing them.
Bats are like fields of dreams. If you make it, they will come, right? If there's an opening in your house, you can kill all the bats and more will just keep coming in, So I always recommend that people work with excluders because then they don't kill the bats.
They seal up the holes so the bats can't get back into your house. They can get out, but then they can't get back in. And in terms of just wanting to help with bat conservation,so much of it is just about. knowing something about bats and trying to tell others when it comes up in conversation.
That website you mentioned, batcon.org is Bat Conservation International. They're an amazing resource to just learn about bats. That's one of the best tools. You can also do things like put up bat houses in your, put up a bat house on your property, and it might take a while for bats to come into it.
It's hit or miss whether they do, but a bat house is just like an artificial roost that the bats can go into and maybe you'll get some bats in there.. A lot of it is just about being friends to bats, because there's a lot of people who don't like bats
Ashley Thornberg: There are a lot of scary thoughts when it comes to bats. They gave rise to the vampire myth. What are some other misconceptions? And I'll point out here that only three of 1, 400 bat species feed on blood if they're all in Latin America.
Dr. Erin Gillam:
Yeah, that's right. There are three vampire bat species and yeah, some of the myths have to do with the idea that bats are attacking you. And part of it is, if you have a bat in your house or something like that, there's not that much space for it to fly. And so it can feel like, oh, it's dive bombing me and trying to attack me. And that doesn't really have to do with is that there's limited space to fly in a house, and bats are meant to fly out in the open, and especially depending upon the species, some of them are quite bad at flying in tight spaces and so they can maybe feel like they're, trying to attack you or something like that.
Same thing can happen if you're out at a park at night in the summer. You might feel like a bat is swooping at you or something. One thing that you don't necessarily realize is that you lose a lot of heat from your head, and that heat attracts insects. Sometimes, you have a little pool of insects above your head, and so the bats can sometimes come down to get those insects, that kind of, concentrated set of insects, and that would very much feel like a bat was, you might feel the whoosh of the wings or something, and it would feel like it was attacking you. I have never heard of an account where a bat was actively attacking a person, usually they're just trying to get away.
Ashley Thornberg: You mentioned bat researchers working with the wind energy companies. Are you aware of any collaborations with either real estate developers or big farmers unions or even cities to talk about bat friendly policies?
Dr. Erin Gillam: I'm sure some of that exists, especially more in these areas in the southern U.S. like in Texas, where there's lots of these large concentrations of bats. Batcon.org also works globally, because sometimes, some of the biggest threats to bat conservation are happening outside of the U.S.
You have different countries, different governments, the way things are handled, what resources are protected, what are not. And so a lot of their work has to do with working with both local and whole, country governments to figure out how to protect bats.
Ashley Thornberg:
Do bats spread disease?
Dr. Erin Gillam:
In terms of spreading to humans, the biggest risk with that is rabies, right? And rabies is something that any mammal can carry. And it's thought that a very small percentage of bats actually have rabies. but the issue is that If you were to encounter a bat on the ground, anytime you can, touch wildlife, nah, something's wrong here, if you see a bat on the ground in a park, it might be like, oh, I'm gonna pick it up and move it, and, if it bites you, it's probably sick in some way, and it may be sick with rabies,bats can have rabies, it's very uncommon, but, the bats that are most likely to interact with people are the ones that are most likely to be sick because they're on the ground.
You do sometimes get bats, especially this time of year, it's in between seasons and they end up roosting in weird places, but that's still like on the side of the building. If you see an animal that's like on the ground, like a bat that's on the ground, something is wrong.
Yeah, so that's the biggest risk in terms of that in terms of other diseases overall. This is something we're still learning a lot about and there's kind of early theoretical work trying to understand why is it that bats seem to harbor a lot of diseases because there's a lot of examples of diseases that have jumped from bats into humans.
Now often there's an intermediate species in between, but, Nipah virus, Hendra virus, Ebola, COVID 19, SARS. MERS right? There's a variety of these viruses, right? When they've been traced back, they often originate in bats, right? and this is, this is not great because it again gives people a reason to hate bats and maybe kill them.
But also biologically, it's bizarre, right? And so one of the reasons that it's thought that bats may harbor these diseases, first of all, they harbor diseases, but they don't generally get sick from them, right? It's like they just, they're a reservoir of these viruses, but they don't sicken from them. But then they can spread them to other species, including humans who then do get sick. So one hypothesis is that because bats fly, flying is like the most energetically expensive mode of movement, right? It takes the most energy. And so a flying bat has a pretty high body temperature, like higher than we do when we have a fever.
And so the idea is that maybe because they're regularly engaging in this activity that brings their body temperature to such high levels that like viruses can never quite get a foothold because like they get to that high temp and so it's thought that maybe that's why bats can be reservoirs for disease. And also they also have a bunch of like other adaptations with having to do with having so much flying and so they have a bunch of stuff to deal with, okay, so when the bats are flying and they get really hot, their body goes into something called like reactive oxidative stress, which is something that happens to us too.
Bats have mechanisms for getting rid of those bad molecules that we don't necessarily have. and that may also be part of why they're able to handle these pathogens as well. It's potentially part of it. We're still figuring it out.
But so they seem to be able to harbor these diseases and then they often jump into a species that is related like it. So like cows or pigs or horses or something like that, like an intermediary, and then from that animal, it jumps into humans. And yeah, that's where the disease piece comes from.
A lot of the reason, I have certainly heard people say,bats are bad because they're gonna give us, The next covid, and things like that. And it's hard because okay, yes, a lot of these diseases are coming from these bat reservoirs. But why? Why are they spilling over into human populations now?
We are destroying their their homes, their land, the natural forest around the world where these bats live, you knock it down and you turn it into agriculture. And then you put a bunch of pigs and horses there. And then the bats are, they're still living there.
And this gives much more opportunities for the diseases from the bats to jump into these domestic species that we have on farms and things like that. There are also places where people eat bats. And that is also another way for disease to get into the to spill over into humans.
It's complex, right? Because it all ties into these really big things like global climate change and like habitat loss and these big problems for lots of species. And this is why we're seeing more of the spillover. That's the main hypothesis.
Ashley Thornberg:
How did you get into bats?
Dr. Erin Gillam:
When I was an undergraduate at the University of Maryland, I wanted to get a little experience doing research.
And I asked one of my professors if I could work in his lab and he was like, yeah, sure. And there was a little miscommunication. I thought he had said yes and he said we'll see and so like I signed up for research credits and then in the fall I came back and I was like, Okay, I'm ready to work in your lab.
And then he was like, Oh, I didn't think we'd decided on that. But he let me in anyway. I studied the behavior of bats. And like specifically the social calls that bats make in that lab. Ooh, can you imitate one? Oh, God, they're too high frequency, they have a lot of interesting social calls. And that was what I started with as an undergrad.
That's still a big thing that I'm interested in is the way that bats communicate with each other. In my lab, we do a lot of more ecology and conservation based research on bats in this region. But I've also done work in Costa Rica and Madagascar and other places like that, trying to understand the social communication of bats, what they're saying to each other and why.
Ashley Thornberg: Dr. Erin Gillam, a professor at NDSU on National Bat Week. Thanks so much for joining us today.
Yeah, thanks for having me.
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