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PRI's Environmental News Magazine

Bats

Air Date: Week of October 26, 2001

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Bats blind and suck the blood of animals and humans. These are just some of the myths that follow these nocturnal creatures. WNPR's Diane Orson went out with a team of scientists one evening and discovered that bats are valuable in more ways than one.

Transcript

CURWOOD: It's Living on Earth. I'm Steve Curwood. Bats are some of the most misunderstood animals. Throughout history they've been linked to witchcraft and magic, and these days we mostly find bats in Halloween decorations and horror movies. But dig a little deeper, and you'll find that the truth about bats is more astonishing than the myth. WNPR's Diane Orson has our report.

MOVIE CLIP: Oh God, there's too many...What do you mean? Come on, let's go!

ORSON: Almost every reviewer agreed that the 1999 horror movie "Bats" was pretty absurd. It featured swarms of genetically altered bats terrorizing a sleepy Texas town. Bats, however, have been big-screen villains for a long time.

MOVIE CLIP: I see castles. There are empires. Dracula and his wives, they take the form of wolves and bats. They leave their coffins at night and they feed on the blood of the living.

ORSON: The 1931 film "Dracula" forever cemented in people's minds a connection between bats and that grand-daddy of all fiendish blood sucking vampires.

MOVIE CLIP: Over there!

ORSON: But what about this Pokemon movie, the kind kids love to watch on tv?

MOVIE CLIP: It's a bunch of zoo bats...They're attacking that guy...Dexter, analyze...Zoo bats. Blind Pokemon with supersonic powers. Zoo bats live in caves and hate to fly outside in daylight.

ORSON: Uh, could we hear that again, please?

MOVIE CLIP: Zoo bats, blind Pokemon with super sonic powers.

ORSON: Movies are filled with misconceptions about bats. Myth number one: Bats are blind. Wrong. All bats can see. They also have a kind of second sight, echolocation. Similar to dolphins, bats have sophisticated sonar systems so they can hunt for prey in total darkness. Myth number two --

MOVIE CLIP: They feed on the blood of the living.

ORSON: Unlike many movie images of bats as predatory carnivores, most bats feed on insects. They can eat more than 50% of their body weight each night: that's about 3,000 bugs. Other bats eat fruit. Vampire bats live in Central and South America. They're the only bats to lap animal blood from tiny incisions. They don't suck blood. And vampire bats almost never feed on humans. Here are a few more bat facts. Bats make up one-fourth of all mammals on the planet, with almost 1,000 different species. They're the only mammal that can truly fly.

[SOUNDS OF RESEARCHERS SETTING UP]

ORSON: On an October evening, biologists are taking advantage of bats in flight. Jenny Dixon is a wildlife biologist with the Department of Environmental Protection and Connecticut's resident bat expert. She and her colleagues are setting up very fine mist nets, in front of an old barn in Litchfield, Connecticut.

DIXON: One of the things that we're doing on some of the bats that we've been collecting as part of this study is we're putting wing bands on them. That will help give us an idea of the age where the bat has moved.

ORSON: Dixon tracks bat populations, surveying roosting sites and hibernating locations. She's involved in projects to protect endangered bat species. She says one reason bats frighten us is that they're so good at doing something we're not good at: maneuvering through darkness. She says she tries to think like a bat when she chooses where to place a net.

DIXON: What you try and do is set them up in places where the bats are not expecting them, so that they accidentally fly into the nets. If they're actively echolocating, they can go right past them every time, over and under them, through holes in the nets.

ORSON: Tonight she's working with scientists studying West Nile virus. They want to find out how many bats have been exposed or infected with the virus. Dr. Richard French is a veterinary pathologist at the University of Connecticut.

FRENCH: What we want to do is understand the dynamics of West Nile virus in North America since it's newly arrived here. And though it does kill birds and it affects other species, one of the things we want to know are the reservoirs for the virus. In other words, what animals carry that virus through the winter months?

ORSON: In preliminary studies, several bats tested positive for West Nile, and research shows that bats act as reservoirs for related viruses, like Japanese encephalitis and St. Louis encephalitis. Bats cannot pass West Nile directly to humans but, like birds, they can act like a canary in a coal mine to tell us where the virus has spread. On this evening, four bats are trapped in the net. Another ten or so have cleverly managed to maneuver around it, zig-zagging through tiny openings. Research assistant J.T. Stokowski is trying to untangle one caught in a string.

STOKOWSKI: They're making their echolocation sounds, which usually are inaudible to us, but since we are disturbing them they'll make them a little more audible. They're usually at a frequency that we can't hear.

[ECHO LOCATING BATS]

ORSON: Stokowski begins collecting data on the bats.

STOKOWSKI: The first one's a little brown, forearm length of 39.35. And this is a female.

ORSON: Next the pathologists collect blood samples which will be taken back to the university's bio safety area for testing.

DIXON: Come on. We've got a little drop coming off the back here. Yeah, all set.

ORSON: After a couple of hours in the field, the researchers are ready to pack up and leave. The University of Connecticut's pathologists will finish the testing during the fall, and expect results from the study later this year. Jenny Dixon says that, whatever the outcome, she hopes people won't jump to quick conclusions about bats and West Nile. She points to the 1960's, when it was believed that most bats carried rabies, a misconception since, according to Bat Conservation International, only one-half of one percent of wild bats are rabid. Jenny Dixon.

DIXON: I'm trying to prevent that whole let's-have-another-reason-to-be-afraid-of-bats-thing from happening. Because there certainly has been some talk, early on about the possibility of bats being an over wintering host for the virus, and before that proliferates, I really think it's important that we get the research information to back it up.

ORSON: In addition to her lab work, Dixon educates people year round about the benefits of bats. She says she hopes her work will help dispel some of popular culture's age-old superstitions about the winged creatures.

MOVIE CLIP We live in a most enlightened era. Superstitions such as you mentioned have been refuted by science...Faith, Dr. Von Helzing. Faith is the amazing faculty of man which enables us to believe things which we know to be untrue.

ORSON: For Living on Earth, I'm Diane Orson, in Litchfield, Connecticut.

 

Links

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