There’s a lot more to bats than their spooky reputation
Welcome to From Florida, a podcast where you’ll learn how minds are connecting, great ideas are colliding and groundbreaking innovations become a reality because of the University of Florida.
Bats! Bats are the only mammals that power their own flight and the University of Florida has hundreds of thousands of them living in the world’s largest occupied bat houses. In this episode, From Florida host Nicci Brown talks with Verity Mathis, mammal collections manager at the Florida Museum of Natural History about the history of bats at UF, species found in our colony, the role bats play in the ecosystem and other fascinating facts about bats. Produced by Nicci Brown, Brooke Adams, Emily Cardinali and James L. Sullivan. Original music by Daniel Townsend, a doctoral candidate in music composition in the College of the Arts.
Nicci Brown: Welcome to From Florida where you'll learn how minds are connecting, great ideas are colliding and groundbreaking innovation is becoming a reality because of the University of Florida. I'm your host, Nicci Brown.
Now, Halloween is just around the corner and we thought we'd take a moment to learn about a creature often associated with this time of year — bats! Here's a fact many people may not know. The University of Florida is home to the world's largest occupied bat houses. There are two bat barns and a bat house just across from Lake Alice on Museum Road and they are home to hundreds of thousands of these flying mammals. Our guest today is Verity Mathis, mammal collections manager at the Florida Museum of Natural History. Verity, welcome!
Verity Mathis: Thank you so much for having me.
Nicci Brown: So how did we come to have three bat barns on our campus?
Verity Mathis: So, back in 1991, there was a colony of Brazilian free-tailed bats that were roosting in the stadiums, on the track stadium and the tennis stadium. And as you can imagine, when you have a large colony of bats, they make a lot of mess and smell. If you've ever gone past the bat houses, you know what I'm talking about. And so the Athletics Association decided to try to build a house to rehome those bats. So they built the house and, funnily enough, they transported all these bats into the new house, excluded them from the stadiums and then the night after they transported them, they all left and they didn't come back for three years. But then finally in 1995, the bats started recolonizing the bat houses on their own and they've made it a permanent home now. And so then in 2010, they built the bat barn to help give the bats some more space and then in 2017 they built the new bat house. And that was built with the intention of eventually tearing down the original bat house, which is becoming really deteriorated and getting to the point where it's probably going to have to come down. And so they're hoping the bats will colonize that new house.
Nicci Brown: So from what I understand, there are more than 1,400 species of bats. Would you tell us more about the ones that live here on the UF campus?
Verity Mathis: Yeah, so like I mentioned, the bat houses are primarily occupied by Brazilian free-tailed bats, which are one of the most common bat species in North America. They're definitely the most common one here in Florida. And that's the majority of bats that you see probably around town and just pretty much anywhere. And then there are also a couple other species that you might see coming out of the bat house. There's the Southeastern myotis, which is in smaller numbers. I think the estimates I read were maybe a hundred or so might colonize that house. And then you might also get a few evening bats as well, but by and large when you're seeing bats coming out of that house, it's going to be the Brazilian free-tailed.
Nicci Brown: I understand they're really quite amazing when it comes to flight.
Verity Mathis: They are! So, bat species, all of them are capable of different heights of flight and types of flight. But the Brazilian free-tailed bat that we have here is actually really remarkable. Not only is it capable of long-distance flight, so within a night it can go 30 miles or so foraging, looking for insects, but it's also capable of very high-altitude flight. So, the species out West that are migrating, they've been documented to migrate up to like 9,000 feet in the air, 10,000 feet in the air, which is really, really high. And in fact, when they're doing these migrations, sometimes if there was enough numbers of them, they actually show up on the weather radars and you could see these masses moving through the air. And they're also really fast flyers. So this particular species, normally it can maybe fly around 60 miles an hour is probably like maybe top speed, but they've actually been documented to go as fast as 100 miles an hour in like short bursts, which is just amazing to think about. This one species is just capable of so much.
Nicci Brown: As you can probably tell from my accent, I grew up in Australia and we have the flying fox there.
Verity Mathis: You're so lucky.
Nicci Brown: One of the largest bats, but how big are the bats here at UF in comparison?
Verity Mathis: They are really small in comparison. So the ones that you have over in Australia, which are the flying foxes, those are what we call mega bats. They're huge. They can have a six-foot wingspan. You compare that to the bats we have here in Florida, which are much, much smaller. They might have, I don't know . . . the wingspans vary depending on the species, but anywhere from maybe six inches or nine inches, something like that. They're maybe a little bit bigger, but they're small bats here. They call them microcystins, which is hard to say. But so, yeah, they're a lot smaller.
Nicci Brown: And then even when you look at their wings, the structure of what are called wings, but really they're like hands.
Verity Mathis: They are and they are our hands. They have the exact same bone structure in their wings that we have in our hands. So, the thin bones that are in the actual wing membranes are their fingers. They're the same fingers that we have. And in fact, the order of bats, the order is called Chiroptera and that literally translates to “hand wing.” So that's the same morphology, just like the flipper in a whale is our fingers. It's all homologous.
Nicci Brown: So can you tell us how many of them we actually have here?
Verity Mathis: So, the estimates vary and I don't know the last time anyone has done a real true estimate count, but we think we have around 400,000 to 500,000 of the free-tailed bats. And like I mentioned, maybe around a hundred or so of the Southeastern myotis. And so that's a pretty good size and the bat houses have the capacity . . . the two houses have the capacity to hold, I think, 750,000 bats and now that we have the third house, we have even more capacity.
Nicci Brown: Wow. So small bats, but large population.
Verity Mathis: Yes.
Nicci Brown: What's the typical behavior of these creatures?
Verity Mathis: When you see them emerging for the evening, they're going out to forage. And so they're going out to look for insects. So they come out and about 15 minutes after sunset is when you start to see the emergence. So that's a good time to go to the bat houses if you're trying to watch that. And then just throughout the night, they're going to be flying around looking for food. They might come back to the roost occasionally throughout the night. But the cool thing about the Brazilian free-tailed bat is it is capable of really long-distance flights for a bat its size. It can fly over 30 miles a night just looking for food. So they're going to be ranging pretty far. And they're feeding on insects. All the bats we have here in Florida are insect eaters. So they're going to be looking for mosquitoes, for moths, beetles, flies, anything that they can find.
Nicci Brown: Wow. So, they are the only mammal that flies, too, from what I understand?
Verity Mathis: That's true. Yeah. They're the only one capable of power flight. We have gliding squirrels or flying squirrels, which really don't fly. They just glide from tree-to-tree, but bats are the only ones that are actual true flyers.
Nicci Brown: So, when they are out flying at night, when do they generally come back to roost? Is it called roosting?
Verity Mathis: Yeah. It's roosting. Yeah. So, the bats are roosting in the bat houses or in trees or in caves, depending on the species. So, they'll forage frequently throughout the night. Sometimes they'll come back to the roost, like every three or four hours maybe. And then they usually start to really head back for the morning or we would say we're going home for the night and they're going home for the day. Maybe like around three, four, in the morning, they'll start making their way back. Although, I've seen them out still foraging at 5:30, 6:00, in the morning when I'm walking my dog when it's still dark outside. So, there's still some late . . . I don't know what you would call that — early morning bats?
Nicci Brown: Right? Yeah. Well, I guess it's all relative. Right?
Verity Mathis: Right, yeah.
Nicci Brown: One of the things that I think is really important for us to recognize is the part they play in our ecosystem. How is the bat population doing in our state and are the colonies decreasing or are they increasing?
Verity Mathis: Right. So bats are extremely important ecosystem service providers because they provide natural pest control. So, the ones that we have here on campus, the Brazilian free-tailed bats, seem to be doing really well. They tend to roost in large numbers. They seem to have a pretty steady population. We have 13 species of bats here in Florida. They're all insectivorous but we have two that are federally endangered. Those are the gray bat, which is found in north Florida. And then the bonneted bat, which is only found in south Florida and the bonneted bat is cool because it's the only bat that is only found in Florida. It's not found anywhere else in the world. So that's what makes it special. So those two bats are of conservation concern and are being monitored and FWC, which is the Florida Wildlife Commission, is actively looking at those populations. And they survey other bat populations as well. But by and large, I think the Florida bats are doing really well.
Nicci Brown: How does the weather affect their behavior?
Verity Mathis: So, they do tend to slow down on their emergence when it's cold outside, when it's rainy. The bats that we have here are active year-round. They don't hibernate like some bat species would up north because it just doesn't get cold enough for them to need to do that. You'll notice if you go out on a really cold night, you probably won't see the same emergence numbers that you would see in the summertime, but they are here year-round. So, the bats that we have here also don't migrate. So, the same species of bat that you find out West will be migrating to Mexico during the wintertime, but here they're just year-round residents.
Nicci Brown: And are there other bat houses in Alachua County?
Verity Mathis: There are, I mean, a lot of people have bat houses on their own properties, which is great and then some of the businesses are starting to put them up as well. So, if you go to Swamp Head Brewery here in town, they have a really nice big bat house out in their area. And then we're really lucky to have Lubee Bat Conservancy here in town. So not only are they doing really great conservation work for bats, like the flying foxes that you have in Australia, but they also are really active in building bat houses.
Nicci Brown: And it sounds to me like that is something that you encourage -- people setting up these bat houses in their yards.
Verity Mathis: Absolutely. Yeah. The one thing we do say is if you're interested in putting a bat house up in your yard, it's just to do your research and make sure that you're getting the right kind of house and putting it in the right kind of location because Florida does have a little bit more . . . maybe some more specific requirements just based on our temperature and just everything because Florida, you know, we’re special! So, there's some really good information out there on the web, especially if you go to the UF/IFAS website, which is the Institute for Food and Agricultural Services. They have a really good web page dedicated to bat houses in Florida and how to do it, what kind of design you want, how high you want it, the direction it needs to face, because the bats do have very specific requirements.
Nicci Brown: And what should you do if you encounter a bat?
Verity Mathis: Well, No. 1 is never handle it with your bare hands. Bats do carry rabies. So do almost all mammals. Maybe the exception could be made for the possum. But bats are a health risk. So, you want to be careful. What we usually tell people is if you find an injured bat on the ground and it doesn't look like it's capable of flying is to put on some nice thick gloves, get it into a container, maybe put a towel on there so it has something to hold onto and then call your local wildlife rehab. So here in Alachua County, we have Florida Wildlife Care and they're certified and trained on how to handle these bats. If you have a bat in your house and you're trying to figure out how to get it out of your house, you want to open up your windows, maybe open up your door, close any interior doors in your house to keep it in that room and then try to just stand back and stay out of the way and hopefully it'll get out on its own.
And then if for some reason it lands on your curtains or on furniture and it's just hanging out, put on those gloves again, get him into a container and then you can take it outside and very carefully put it up on a tree or some other vertical surface because bats really aren't great at taking off from the ground. They have to be up in a nice vertical service and then they can fly away. So, you just want to get them into a place where they can do that.
Nicci Brown: They have pretty amazing skills, though, in terms of not hitting people or running into people and, from what I understand, it's not likely that they will fly into you or anything like that.
Verity Mathis: Exactly. That is a huge myth that bats will get tangled up in your hair or attack you. They're just trying to avoid you. And so the other . . . like bats aren't blind. They have vision and they have echolocation, which is very . . . it’s not unique to bats because whales and dolphins also have it, but it is really cool because they can emit these sonar signals and that bounces off things and tells them information as to what they're looking for. So, it tells them if that's an insect they want to eat, that's a tree they want to avoid. So they're really good at navigating the environment around them and they're going to avoid you if they can.
Nicci Brown: Well, let's talk a little bit more about some of those myths, because we know that bats feature quite prominently in popular culture — everything from being characterized as blood-sucking vampires to being represented by one of our greatest superheroes, Batman, and even being the namesake of an operetta by Johann Strauss, “Die Fledermaus,” which translates directly, if I'm not wrong, to “flutter mouse,” which I have to admit I love. Why were you so fascinated with bats and are we being fair with these representations, especially the ones that we associate with evil things?
Verity Mathis: Yeah, bats, they get probably the worst rap of almost any mammal I can think of and it's very undeserved and a lot of that has to do with pop culture and their long association with blood-sucking and vampires. And the funny thing is, out of the 1,400 species of bats that there are in the world, only three of them are actual blood drinkers. And those are all found in South America, Central America. So, it's not even a problem for North America. And they, like I mentioned before, provide all these amazing ecosystem engineers of natural pest control. There are pollinator bats that are found in other places which help pollinate the plants around them, especially if you like tequila. Tequila is from agave and agave is a bat pollinator obligate. So, they have to be pollinated by bats.
There's bats in tropical countries that eat fruit and then they disperse the fruit and help the forest diversity that way. Their bat guano, the bat poop itself, is a really great fertilizer. So it's really helpful for gardens and things like that. So they do all these great things for us and then we turn around and we're scared of them. We want to be respectful of them and of their lifestyle and we don't want to encroach upon them and bother them because like I mentioned, there's always the possibility of handling a bat wrongly and getting bit by rabies, but that's actually not a very common thing that happens. I think as long as we continue these conversations about telling people how cool bats are then maybe eventually pop culture will catch up to that.
Nicci Brown: Catch up. And I understand there is a connection between our namesake Gatorade and bats.
Verity Mathis: Yeah. So, one of the things that we sometimes do is . . . well, sometimes we find bats on campus that maybe aren't doing so great or found on the ground in the middle of the day and they need to get rescued. And so what we sometimes do is we will get gloved up and get them into a box and then we'll get them Gatorade and just using a little dropper, give them some Gatorade just to give them some hydration, some sugar just to perk them up a little bit, and that helps them recover. And then we can then release them out into the woods here on campus and hopefully they can continue on their way. We used to have a container of Gatorade in our work fridge that was just labeled “bat juice.”
Nicci Brown: Oh, my goodness. Little bat athletes!
Verity Mathis: Yeah.
Nicci Brown: Are there any other interesting facts that you'd like to share with us?
Verity Mathis: Oh my gosh. I probably could talk for hours about bats. So, like you mentioned, there's 1,400 species of bats, which makes them a quarter of all mammalian diversity in the world. And they're the only ones that can fly so how cool is that? But some things that people maybe not might not know is bats are also extremely long lived for their size. So, when we think about small mammals like rats and other things like that, they only live maybe a year or two in the wild and bats can live decades. The oldest living bat that's known in the wild lived over 41 years and that was a small bat. That wasn't one of the big flying foxes, too. So it's pretty amazing that they can live for so long. And as a counterpoint to their long lives is they only give birth maybe once a year to maybe one pup, maybe two.
Sometimes if things are really great, they might give birth at twice year, but I think that's pretty rare. So they have very low reproductive rates, but very long lives, which I don't know, that's fascinating for such a small mammal because that's pretty opposite to everything we know about how size correlates to reproductive activity and how size correlates to age.
And yeah, they're not rodents. People want to call them rodents. They're more closely related to humans than they are to rodents.
Nicci Brown: I want to circle back. How did Verity get involved with bats? Was there a young Verity that was fascinated or was it something that came upon you when you were studying? How did you get so enthralled with bats?
Verity Mathis: Yeah, it just came upon me through my job and how I just came to Florida. My background is actually more in rodents. And then I was working for a time in Mississippi and I started helping out our bat biologist there and just going out and getting to net bats with her and learning more about them. I really just got into it. And then when I came here, I just, I don't know, it just happened that I started becoming more and more about bats. And then our curator of mammals, he had an active research program on bats in the Bahamas. So when I first started working here about seven years ago, I got to go on trips to the Bahamas where we were netting bats there. And that was just so much fun and really cool. And so just learning more about them just through life, I guess.
Nicci Brown: And if anyone who is listening wants to share that passion and learn more about UF bats and the bat barns, where can they go?
Verity Mathis: So, if you just go to your favorite search engine and just put in “UF Bat Houses” that should take you directly to the web site that we have. The museum hosts a web site about the bat houses and it gives all the information about them that I talked about today and some more information as well. I think that's probably the first hit you'll get when you search for it. So that's probably a good resource to start and then you can always just email or call me.
Nicci Brown: Verity, thank you so much for joining us today. It's been a real pleasure.
Verity Mathis: It was awesome. Thank you.
Nicci Brown: Listeners. Thank you for joining us for an episode of From Florida where we share the stories of faculty, researchers, students and administrators whose thought leadership is moving our state, our nation and our world forward. I hope you'll return for our next story of innovation From Florida.