Ask a Scientist

Dr. Nancy Simmons is a biologist from the American Museum of Natural History.

On April 4, 2006, students and teachers interviewed Dr. Nancy Simmons, a biologist at the American Museum of Natural History. To learn about how bats "see" with sound, who keeps bats as pets, and what bat skin feels like, read the transcript below.

What's your favorite kind of bat?
My favorite bats are New World Leaf Nosed Bats. They're really pretty and they do all sorts of different things. Some of them eat insects, some eat fruit, and some visit flowers to get nectar and pollen — even the vampire bats are members of this group. They are also pretty easy to catch, which is good when you're a bat biologist.

Where do you go to study bats?
I go to South America and Central America. There are a couple reasons for this. One is the tropics have the greatest diversity of bats because there's more food available all year round. And the other reason is I've done research there in the past and I know the animals well. From a scientific perspective it's important not to get spread too thin and do too many things, so I like to keep my fieldwork in the same geographic area.

What did you think of bats when you were a kid?
I've always thought bats were cool. They were more mysterious to me as a kid than they are now, but I've always liked them. I never actually saw or handled a bat up close until I was in college.

What's an exciting discovery you've made about bats?
The most exciting thing I've learned is how some fossil bats are related to living bats — no one knew this before. I used features of the fossil bats skeletons to put them in the bat family tree and show how they were related. What's really neat is some of the fossils that are very old don't come out on the bottom of the tree; they actually represent lineages that come out further up the tree. That means the diversification of the bat families happened a long, long time ago.

Are there female bats and male bats?
Yes. They have some of the same characteristics that male and female people do. Sometimes you catch female bats with their babies or pregnant. When they're pregnant, they're huge because female bats give birth to one large baby at a time like humans do. This is different than many other mammals like cats and dogs and mice that have litters of many, smaller babies.

I read that bats use echolocation so they know where to fly. What exactly does that mean?
Echolocation means using sound to identify obstacles rather than using vision. Bats make very high frequency calls and then they listen for the returning echoes. Their brains process the returning sounds in terms of how fast the echo comes back, the frequency of the returning echo, and they use this information to "see" what's around them in their environment. Some bats are so good at this that they can detect tiny flying insects and calculate their speed and direction. The bats use this information to catch and eat their prey.

Have you been bitten by a bat — or almost bitten by a bat? If so where and what did you do?
I have been bitten many, many, many times by bats. When you catch a bat in a net, it reacts like any other scared animal and it bites. I'm pretty good at handling bats without getting bitten, but sometimes I do mess up. Usually I get bit on the fingers. What's really interesting is that in all the many times I've been bitten by a bat, I've never gotten an infection. When I accidentally cut myself with a knife doing fieldwork, I seem to always get an infection. When I do get bitten by a bat, I just treat it like a regular cut.

What's a surprising fact about bats that most people don't know?
All bats can see, and many of them can have quite good vision including bats that use sonar.

Have you ever spent a lot of time with one bat? Why and what was it like?
I can't say that I have. Usually we collect data from one bat and release it as fast as possible to avoid causing it any more discomfort or stress than necessary.

Does anyone keep a bat as a pet?
Some people do. Mostly this happens in the Old World Tropics where people have Flying Foxes as pets. In some villages people get Flying Foxes as babies and raise them. There are people in the U.S. who keep bats to educate people, but they're not really pets.

How many bat species are there? Are any endangered?
There are 1,116 species of bats that we know about, and there are probably many more that are yet unknown to scientists. Many of these species are endangered, mostly due to loss of habitat.

What is one mystery about bats that you hope to solve?
I hope to eventually build a complete family tree of all bat species including fossil bats. I think within 10 years we'll have it.

Have you ever discovered a new species of bat? What was that like?
I have discovered and named new species of bats. It's very exciting. At first it's confusing because you expect to be able to identify what you've caught and it's confusing when you have a bat that doesn't fit into any preconceived notions of what species there are. Then, when you realize that you are seeing something really, truly new for the first time, it's really exciting.

Why do you think bats have such a bad reputation?
Because people don't understand them. They are small; they are nocturnal; they move fast; and they don't stand still for you to examine and look at them — so people don't understand them and make up stories about them.

What other animals do you find interesting and why?
I like lots of different kinds of animals. One of the animals is called a katydid, which is a big insect related to grasshoppers. They're fascinating. They're very diverse and they sing wonderful songs at night. I've seen many interesting katydids when I'm out catching bats.

What other subjects are you interested in besides bats — any hobbies?
I spend time with my kids. I also do tae kwon do and I run for fun.

What's a typical day like for you at the museum?
For every month that I spend in the field, I take at least another year to write up the results, so I spend a lot of time at my computer writing papers on my research findings. I have a microscope in my office and I also spend a lot of time looking at bat skulls and teeth and studying bat anatomy.

Do vampire bats suck human blood?
There are three species of vampire bats. Two of those species prefer to feed on birds. However, the Common Vampire Bat prefers mammal blood and it's not picky. So yes, they do feed on people sometimes, but they don't suck blood. They use their very sharp front teeth to make little, tiny cuts and then lick the cuts with their tongue to get the blood. The most common place for a person to get bitten is on their hands and feet that might stick out from a hammock while that person sleeps. Hammocks are common in the tropics. The chances of being bitten by a vampire bat in the United States are almost zero.

Are all bat species related back to one common bat ancestor?
Yes. All bats evolved from a single ancestor.

Are bats smart?
Yes. Bats are smart, they live a long time and they can learn a lot about where they live. They remember where their food resources are and where their roost sites are, and if things change within their home range, they can adapt — as long as things don't change too much.

Do bats ever fight with each other?
I wouldn't say that bats fight with each other. They compete with each other for resources, but they don't really fight.

Why do some bats eat one thing, like frogs, and others eat other things, like blood?
Different bat species have evolved to take advantage of the different resource in their environment. Some bats have evolved to only use one food source but most bats use multiple kinds of food sources. What I mean by that is they don't rely on just one thing. For example, an insect-eating bat will eat many different kinds of insects. Some bats are real generalists — they will eat insects, fruit, feed from flowers, all kinds of things depending on what's readily available at the time.

What does bat skin feel like?
Bat skin feels like your skin. It's warm and stretchy — so touching the wing of a bat feels like touching the skin on your arm. Of course, most of the bat is covered with fur, and it's very soft fur like on a kitten.

What is the average age that bats can live?
Nobody knows. We know that some bats live a very long time for such small animals. There are cases where a captive bat has lived 30 years. Considering that a mouse of a similar body size can live two years at the most, it's very impressive how long bats seem to live. Scientists who study aging are interested in bats because of this.

Do bats have bones? If so, what's their skeleton like?
Bats have bones. They have many of the same bones that a person does, but their bones are different shapes. The wing of a bat is supported by very long finger bones. So, it's the same bones as a person has but very elongated and that's what supports the wing membrane.

What kind of school did you go to in order to become a bat scientist?
To become a biologist, you need to go to college and usually to graduate school. I went to college in California, Pomona College, and I went to graduate school at the University of California, Berkeley, and that's where I got my PhD. But there are many different universities where you can do research on bats. What's important when choosing where to go is what kind of classes you can take and what kind of research is being done by the professors because you learn most from your advisors.

What kinds of subjects should kids study if they want to be scientists?
The most important thing is math because much of what we do in science is based on mathematics. It's also important to take science classes. It can be helpful to study foreign languages because if you want to do work outside the United States, it's good to know the local language. It's also good to take courses in writing because that's how scientists communicate with one another.

Who is your favorite scientist and why?
I really like Ed Wilson who spent his whole life studying ants. He generalized what he learned from ants to apply his ideas and help understand the evolution of life.

What do you think of superheroes like Batman and Batwoman?
I have a picture of Batwoman on my wall. One of my students gave it to me. I think they're fun, but they don't have much to do with bats.

How fast do bats grow?
Bats grow very fast in their first few weeks of life and reach adult size within a couple months of birth.

How can bats eat so much without getting fat?
They exercise a lot. Being a small mammal requires a great deal of energy to power your metabolism. And for bats, they need the added energy to fly, which takes up a lot. So, the problem for bats isn't getting fat but finding enough food to eat.

How can you observe bats when they're only out at night?
To observe bats you need to be active when they are. In the summertime in the U.S., bats come out before dark and you can see them in the twilight. But for a bat biologist, you need to work at night if you want to learn about them.

How many bats can live together at one time?
In a single place in the rainforests of South America, I have personally captured 78 species all living in the same area. And that was undoubtedly not all of the species living there. We think that there are over 100 species living together in some areas of the New World Tropics. In terms of individuals, there are caves with as many as 30 million bats living together in them.

Do you think bats might live near me, but I've just never seen them?
If you live in the U.S., bats live near you. You just haven't seen them.

Is it possible to get rabies if you get bitten by a vampire bat?
Yes. It's also possible to get rabies from a bat that's not a vampire bat, but it's a rare disease even among bats. The vast majority of living bats don't have it.

What would you say to kids who are afraid of bats?
Learn about them! They aren't scary. They're beautiful and fascinating.

What kind of studying or exploring do you think it's important for all kids to do?
It's really important for kids to get outside and explore the natural world. Look at everything and ask questions.

My cousin says there are bats in his attic. What should he do?
The best thing to do is to leave them alone unless they're causing trouble. If they are causing problems, he should call an exterminator.

Were you interested in science when you were a kid?
I've always been interested in science, particularly natural history and biology. I was always the kid with a jar full of tadpoles and a snake in my pocket.

About how many species of bats are there in Florida?
There are about 10 species of bats in Florida. If you want to know more about them, go to the library and get a field guide for North American mammals.

What's the best thing about being a biologist?
My job is to study animals and nature. What better job can there be than that?

How do bats care for their young?
Female bats look after their babies until they're old enough to find food on their own. When they're little, the mother leaves them in the roost while she goes out to find food. Bats are mammals, so the mother makes milk that the baby feeds on when it's very small. When the youngster gets big enough, the baby will follow the mother to learn how to find food. The relationship ends only when the mom is ready to have another baby.

There are so many different kinds of bats. Are they more diverse than other animals?
Bats are more diverse than any other kind of mammal. Only rodents are more diverse. But bats are not very diverse at all when compared to insects or fish. There are many, many more insect and fish species than bat species or other mammals.

Do you think you'll ever learn all you want to know about bats?
No, because every time you learn something new, it raises more questions. We are just beginning to learn about how bats live and how they evolved.