All You Need To Know About Bats – Science Trek (Transcript)

“Bats play an important role in our ecosystem. They help pollinate plants so we have food. They eat insects so bugs do not overwhelm us. But 25% of all bat species are threatened with extinction. Find out more about bats on this month’s Science Trek. Host Joan Cartan-Hansen and her guests, Rita Dixon and Jesse Barber, answer students’ questions about bats.”

Joan Cartan-Hansen

Bats are the only mammals that fly, and they play a very important role in our ecosystem. Find out more. We’re here to answer your questions about bats.

Join us for science trek.

Hi, I’m Joan Cartan-Hansen, and welcome to Science Trek, and welcome to Boise State University’s sensory ecology lab. We’re here to answer your questions about bats.

But, before we do, let’s learn a little bit more.

Bats are mammals. They have furry bodies. Their wings are really webbed hands with thin skin stretched from their long fingers to their back legs. Bats are the only mammals that fly. A few other mammals can glide, but bats are true flapping fliers. The fastest bat can fly at more than 30 miles per hour.

One of the biggest bats is the golden-capped fruit bat. It’s a fruit-eating bat with a wingspan of more than 5 feet. The smallest bat, and indeed, the world’s smallest mammal, is the hog-nosed or bumblebee bat. It weighs less than 2 grams and is the size of a bumblebee.

Worldwide, there are more than 1200 different kinds of bats. Bats sleep during the day and feed at night. Most bats find their food using echolocation. They make rapid high-frequency sounds. These sound waves bounce off their prey and travel back to the bats’ ears. The bats hear the echo and find their dinner.

Some bats eat things like fruit or frogs or small birds, but most bats eat insects. Little brown bats can catch 250 mosquito-size insects in 15 minutes. A bat eats about half its own weight in insects each night. If you weighed 100 pounds, that would be like eating 50 one-pound pizzas every day.

Many bats live in colonies. Their homes are called roosts. Just like you and me, bats need shelter from the weather, protection from enemies, and a place to rest. Some live in caves or trees, but others live under bridges or inside old buildings. Pups, or baby bats, are born in the summer. In the winter, some bats migrate to warmer climates. Others hibernate.

Scientists study bats because a lot of these small flying mammals are threatened. Many bats are in trouble because people disturb them while they’re roosting or remove them from their homes. So, if you find a bat, it’s important to leave it alone.

Bats are also in trouble from a new disease called white-nose syndrome. So, if you go into a cave, change your clothes and clean your shoes and gear so you don’t spread disease from one cave to another.

Little girl: But bats can be scary.

Joan Cartan-Hansen: Ell, movies and TV shows haven’t been very nice to bats. But in china, bats are symbols of good luck. Bats are a really important part of our ecosystem. They eat lots of insects and help pollinate crops and spread seeds. Humans need bats, and sadly, about 25% of the world’s bats are threatened with extinction, so we need to do more to protect these amazing animals.

Question-and-answer Session

And joining me now to answer your questions about bats are Rita Dixon, State Wildlife Action Plan Coordinator for the Idaho Department of Fish and Game, and Jesse Barber, Assistant Professor of Biology here at Boise State University. Thank you both for joining us.

Rita Dixon: Thank you.

Jesse Barber: It’s a pleasure.

Joan Cartan-Hansen: All right. Let’s go to your questions.

Katherine: Hi. My name is Katherine. I go to Pioneer Elementary School of The Arts, and my question is, what do bats eat?

Rita Dixon: Well, bats eat a lot of different things, including blood. Some bats actually eat fish. Some eat frogs. Even some bats eat birds. But most bats eat either fruit or some kind of plant material, nectar, for example, or insects. In Idaho, all of our bats are what we call insectivorous, which means they eat insects. And some eat insects on the wing, and some eat insects that are feeding, foraging on plants or on the ground.

April: Hi. My name is April, and I go to Dalton Elementary, and my question is, why do bats hang upside down?

Jesse Barber: Well, bats hang upside down because being up high is safe from predators, and it’s a really good place for bats to be able to take off from. Bats don’t have very strong feet like birds, so hanging from the ceiling allows them to take flight really easily.

Katelyn: Hi. My name is Katelyn. I go to Prospect Elementary, and my question is, how do bats fly?

Rita Dixon: Well, bats fly because their wings are especially developed for flight. Their wing membranes have two layers and they are tight, and so bats’ flight comes from what we call lift, thrust and drag. So, the bat wing creates something we call an airfoil which allows the bats to go up and then maintain their flight through air circulating around their wings.

Joan Cartan-Hansen: Cooper would like to know, how many fingers do bats have?

Jesse Barber: Bats have five fingers. And, in fact, the scientific name for bats, chiroptera means hand wing.

Joey: Hi. My name is Joey, and I go to Dalton Elementary School, and my question is, how many species of bats are there?

Rita Dixon: There over 1200 species of bats, and we keep discovering new species of bats, so the number continues to grow.

Dominic: Hi. My name is Dominic, and I go to Dalton Elementary School, and my question is, where do bats live?

Jesse Barber: Many bats live in caves in large numbers, but there are lots of bats that live in trees. They can live under the bark in small groups or underneath giant leaves in the tropics that they modify to make tents. And some even live all by themselves at the very top of trees hanging by one foot, and they wrap their tail around themselves to look like a pine-cone.

Rita Dixon: And I’ll add to that in terms of around the world where bats live. Bats occur everywhere except the most extreme arctic regions of the world. So, bats go as far as Alaska to the north and Argentina in the south.

Ashley: Hi. My name is Ashley. I go to Lewis and Clark, and my question is, what is echolocation?

Jesse Barber: Echolocation is how bats see in the dark. They scream out and then listen for the returning echoes from the world around them.

Rita Dixon: And to add to that, interestingly, with bats, they’re producing the sound from their larynx just like we do, but the sounds they’re putting out, unlike what we’re putting out, is what we call ultrasonic high frequency that typically we can’t hear with the human ear.

Kenzie: Hi. My name is Kenzie, and I go to Cole Valley Christian School, and my question is, why do bats like the dark?

Rita Dixon: Bats were developed – they’re pretty much the ecological equivalent of birds except they switch shifts. And so bats have vision and they can see, but their vision is adapted more toward dim light instead of bright light. And because they use echolocation in the dark, that’s why they’re active at night.

Aurora: Hello. My name is Aurora from Dalton Elementary, and my question is, do bats have night vision?

Rita Dixon: Bats can see to some extent in the dark, and bats’ eyes are developed to illuminate things, so they’re a little different from our eyes. Our eyes are equipped more to have higher resolution, but bats’ eyes are equipped to have higher illumination in the night.

Jesse Barber: And remember that there are 1200 species of bats that make their living in all kinds of different ways. So, those that use echolocation to hunt as their dominant sense often have very tiny eyes and don’t use them very much. And other bats, that might not use echolocation to localize the insects but instead use the footstep sounds that these bugs make, also use their eyes for hunting.

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Dorin: My name is Dorin, and I go to Dalton Elementary in Dalton Gardens, Idaho. My question is, what are mega and microbats?

Rita Dixon: Mega and microbats – so, when we think about bats, Jesse talked about the order of bats, which is called chiroptera or hand wing. And that’s divided into two, what we call, suborders: megabats and microbats. Megabats means large. So, the megabats are much larger bats, often with a 6-foot wingspan, whereas the microbats are much smaller, and their eyes are very different, too.

The megabats use their vision for getting around foraging and typically don’t echolocate, whereas the microbats depend almost exclusively on echolocation.

 

Joan Cartan-Hansen: Blind as a bat? That’s not true. Bats have good eyesight, and some bats see better than humans in the dark, and not every bat uses echolocation to find food. Megabats find fruit with their strong sense of smell.

Ashley: Hi. My name is Ashley. I go to Dalton Elementary. My question is, why do bats live in large groups?

Rita Dixon: Bats live in large groups for different reasons. In one case, bats live in large groups because there’s safety in numbers. For example, if you have lots of bats watching for predators, it’s safer for the bats because it’s like a warning system.

Bats also live in large groups because they’re often – some species are very social, and they enjoy being with other bats. Another reason bats live in large colonies is to conserve body heat, and that can be true when they’re hibernating in the winter and when they have maternity colonies where female bats give birth to their pups.

Jada: Hi. My name is Jada. I go to Spalding Elementary School, and my question is, how far do bats travel in one hour?

Jesse Barber: Some bats fly so fast that they can travel tens of miles in an hour, 30 or 40 miles in an hour.

Mason: Hello. My name is Mason. I go to Dalton Elementary, and my question is, is there a maximum number for how many babies a female bat can have?

Jesse Barber: Most bats have one or two pups at a time, and only one genus of bats, lasiurus, have more than that, and they have four pups.

Blake: Hi. My name is Blake, and I go to Dalton Elementary School, and my question is, what would happen if a bat bit you?

Rita Dixon: First of all, I would say a bat is not going to bite you unless you’re handling it. So, I would say to all of you kids, you should never handle a bat or any wild animal with your bare hands. But if you get bitten by a bat, you need to get an adult for help and have the adult carefully get the bat, put it in a safe container, box, where it can breathe, and then call your doctor and the public health department.

The reason bat bites are a concern is because bats can get a disease we call rabies. And although most bats do not have rabies, some bats can get sick. It’s just like we can catch a cold or the flu. Some bats can get rabies and usually from other bats. Rabies, if treated, you’re fine. So, as long as you get vaccinations, if the bat is — tests positive for rabies, if you get vaccinated, which is a series of shots – you’ve all had shots, and it’s no different than getting a tetanus shot or a flu shot or anything like that, and that protects you from getting rabies if the bat tests positive for rabies.

Lilly: Hi. My name is Lilly, and I go to Dalton Elementary. My question is, how do bats pick where they nest?

Jesse Barber: So, the first thing is that bats roost. They don’t make nests like birds. And they pick where they roost very carefully, because the temperature and the safety of where they decide to spend the day and night is very important. So, they pick a spot that’s high and away from predators and is also just the right temperature.

Rita Dixon: And bats have – I’ll just add, bats have different kinds of roosts that they need. So, when they’re hibernating, they have a particular roost that’s going to be different than if it was female bats needing a maternity colony. And bats have what we call night roosts where they’re just temporary roosts at night, and some bats have day roosts where they sleep all day.

Olivia: Hi. My name is Olivia. I go to Dalton Elementary, and my question is, how long do bats live in their lifetime?

Jesse Barber: Bats live a long time. Decades. There are some records of bats living into their thirties, and the oldest known record is a bat that lived to be 41 years old, at least. So, while we don’t know how long bats live for sure, we know they live a long time.

Jackson: Hi. My name is Jackson. I go to Dalton Elementary. My question is, why do the wrinkle-faced bats have wrinkled faces?

Jesse Barber: Those wrinkles on the males also have scent glands inside the folds, and so it’s thought that the male communicates with these scent glands. And another really interesting thing that these bats can do, both the male and the female, is they can pull the skin all the way over their face so that you can’t see their head, and this might be a way for the bats to hide from predators when they’re in plain sight during the day.

Joan Cartan-Hansen: Al asks, how far would a bat in Idaho have to fly to find food?

Rita Dixon: Well, I’ll just have to say, that depends. I mean, some bats travel miles to find food and from – like, there are hoary bats, for example, that might roost on a ridge top but will fly out over – to forage over grasslands or agricultural fields. So, it really varies from species to species.

 

Joan Cartan-Hansen: The underground chamber of the Old Swan Falls power plant is home to a colony of little brown bats. There are only a handful of known bat colonies of this size in Idaho. State wildlife veterinarian, Mark Drew, and wildlife coordinator, Rita Dixon, are here on a mission. They’re here to try to save the bats.

Rita Dixon: There is a disease called white-nose syndrome, and it showed up in the eastern United States and has since spread to half the country.

Mark Drew: White-nose is one of those things that kind of came on the scene a decade or more ago. Never seen the fungus before. All of a sudden, it’s here, and it’s killing millions of bats. In fact, some bat species are almost endangered or almost extinct because of the fungus.

Joan Cartan-Hansen: It’s called white-nose syndrome because the disease leaves a white fungus on the infected bat’s nose and wings.

Rita Dixon: And you’ve got the clipboard, right?

Joan Cartan-Hansen: The fungus usually infects the bats as they hibernate in the winter.

Mark Drew: The fungus disrupts the hibernation because it makes them sick. It’s a very tight balance between I’ve got enough fat to get through the winter or I don’t. And anything that disrupts that balance is going to potentially cause mortality.

Joan Cartan-Hansen: Drew and Dixon start their investigation by recording the chamber’s temperature and humidity.

Rita Dixon: Temperature and humidity is really an important indicator of the conditions for the bats, as well as white-nose syndrome. Okay. This dry reading is 65, and the wet reading is 57.

Joan Cartan-Hansen: Next, the scientists collect samples from the bats.

Rita Dixon: Swabbing bats is basically taking a sterile swab, dipping it in a solution, and then rolling the swab back and forth across the bat’s forearm three times and then across the bat’s muzzle.

And what that does is, if there were any fungus from white-nose, we would probably pick it up on the swab. And then it gets broken off, put back in the little tube, and then we will be shipping that to the National Wildlife Health Center so that they can examine it and see if they find any fungus.

Mark Drew: The critical thing for us in Idaho, because we don’t have the fungus, is we need to know if and when it arrives.

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Rita Dixon: Okay. Sandy, you said there was one over here by the light.

Mark Drew: We want to be able to find this fungus really, really early so that we can respond to it in a colony like this where we can do something.

 

Joan Cartan-Hansen: The team collects samples from 25 bats. Everything needs to be done quickly and quietly.

Mark Drew: Most of them tolerated what we did. Some of them got a little irritated and flew around. That’s to be expected.

Joan Cartan-Hansen: Drew says humans are the biggest cause for the spread of white-nose syndrome.

Mark Drew: People move, and cavers and people that like to go into caves, they can transport the fungus in the debris and the mud and things like that that they have on their shoes and on their clothes.

Joan Cartan-Hansen: For the bats’ protection, these chambers aren’t open to the public, and the scientists wear protective clothing to make sure that they don’t spread any disease.

Before leaving, scientists take a last look around for any sick or dead bats, another sign of possible infection. Then the samples are sent off for testing. Fortunately, the National Wildlife Health Center found no trace of the fungus that causes white-nose syndrome in this colony, but the scientists will be back to make sure these bats stay healthy.

It’s important to remember that you shouldn’t disturb bats if you find them in the wild. And if you’re doing some caving, be sure to decontaminate your clothes and your shoes so you don’t spread the fungus.

Okay. Let’s go back to your questions.

 

Joshua: Hi my name is Joshua. I go to North Star Elementary, and my question is, how high can a bat fly?

Rita Dixon: Bats can fly up to 10,000 feet in the air. Brazilian free-tailed bats have been found to fly that high. And so bats will easily fly over the foliage, the canopy of the forest, but we do have high flying bats.

Pete: Hi. My name is Pete. I go to Dalton Elementary. My question is, why aren’t bats considered birds?

Jesse Barber: Well, bats aren’t birds because they don’t lay eggs. Bats are mammals because they give birth to their young just like us, just like any other mammal.

Rita Dixon: And I’ll just add that bats are the nocturnal counterpart to birds.

Joan Cartan-Hansen: Gunter would like to know, will bats become extinct by the white-nose syndrome in the future?

Rita Dixon: White-nose syndrome is a disease that’s killing bats in North America. And right now, it’s mostly – it’s in half the country and also in Canada. And there are some bat species that are particularly susceptible to the disease, and we’ve lost over five-and-a-half-million bats. So, we’re concerned about the possibility that some bats could go extinct, and already we have some bats that are no longer in the northeast region. They’ve almost been eliminated from that region, so we’re really concerned about white-nose syndrome.

Isaac: Hi. My name is Isaac from Dalton Elementary in Dalton Gardens, and my question is, do bats hate the light?

Rita Dixon: Bats don’t hate the light. They just are adapted to living mostly in the dark. They can see in the light just fine, but they do better in dim light instead of bright light.

Jesse Barber: And I’ll add that some bats do really well around street lights in cities because they attract a lot of insects. But other bats don’t like to be that exposed to predators. The light makes them easy to see, as well, where an owl could grab them, for instance, and so they avoid streetlights.

Rita Dixon: And to add to that, that’s one reason, when it’s a full moon, bats – some bats might not be as active when the moon is really bright because it makes them more vulnerable to predators.

Colby: Hi I’m Colby. I go to Dalton Elementary, and my question is, why do some bats migrate and others don’t?

Rita Dixon: Bats migrate because there’s no food for them in the winter. And so animals, including, you know, other animals besides bats, like birds also, they have two basic choices. They can either migrate or hibernate. And so we have some bats that hibernate for the winter and other bats that migrate where they can find food all winter long.

Joan Cartan-Hansen: Hank would like to know, what’s the most endangered bat in North America?

Rita Dixon: Well, right now, some of the bat species that are affected by white-nose syndrome we’re really concerned about, and some of them have been petitioned to be listed under the Endangered Species Act like the little brown bat, for example, the northern long-eared bat. We have other bats that are endangered; the Indiana bat, the gray bat, some of the nectar-feeding bats in the southwest, and so those are primarily the most endangered bats in North America.

Jake: Hi. My name is Jake. I go to Shadow Hills, and my question is, do bats have friends with other species of animals?

Rita Dixon: Well, first of all, many bats are social, and they form colonies, and, you know, they cuddle up next to other bats and talk to other bats, communicate with them. But, typically, bats do not socialize with other animal species. However, bats in captivity also readily interact with humans.

Jack: Hi my name is Jack. I go to White Pine Elementary, and my question is, how many hours a night do bats sleep?

Jesse Barber: Well, first off, bats sleep during the day, not at night. So, when they’re sleeping during the day, they can go into a form of hibernation called torpor, which is a much deeper sleep than you and I go into, and they’ll go into this torpor for three to six hours a night.

Joan Cartan-Hansen: Sam asks, what can we do to protect bats?

Rita Dixon: There are lots of things we can do to protect bats. One of the most important ways we can protect bats is to – when we find bats, leave the bats alone and not handle live bats so you don’t get bitten, because, when you get bitten, it means that bat has to die.

Other ways we can protect bats is to use fewer pesticides on our food because bats are affected by pesticides, and it’s very dangerous to them. We also need to survey abandoned mines before closing them so 1that we don’t trap bats. And one – another really important thing we can do to protect bats is, when bats are in buildings, we need to make sure that if you don’t want the bats living in your attic or your house that you wait until the pups are grown and can fly before you evict the bats from your home.

And other important ways of protecting bats is just to raise your awareness about bats and tell your friends, your family, your teachers, that bats are important in the environment.

Joan Cartan-Hansen: Rita, before we run out of time, why did you decide to pick a job that deals with bats?

Rita Dixon: Well, actually, I didn’t originally pick the job for bats. I originally worked on birds. But the job that I ended up doing brought bats to me, and I’ve been working on bats ever since, and I’m really grateful for it.

Joan Cartan-Hansen: And Jesse, if someone is interested in doing this as a job, what should he or she study in school?

Jesse Barber: Well, if you want to be a bat biologist, the first thing to do is get an undergraduate degree in biology, and then you usually have to go to graduate school and get an advanced degree; a master’s or a PhD in biology.

Joan Cartan-Hansen: I’m sorry. We have run out of time. Thank you both for being here. I appreciate it.

Rita Dixon: Thank you.

Jesse Barber: Great to be here.

Joan Cartan-Hansen: And thanks, too, to the folks at Boise State University for hosting us.

 

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