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Vampires: The Legend Continues

BY STEVE WING,

General Curator

I am a person who loves and respects all creatures on our planet. I think
warthogs are beautiful, goats donít smell, and the bray of a donkey is music to my ears. I even think there is a place for leeches and mosquitoes (where that is I havenít found out yet!)

But, other than making a good horror story, what good can I say about the lowly vampire bat (Desmodus rotundus) Vampires have long been the stuff that legends are made of. While some folklore is based in reality, many myths surround this diminutive creature.

Vampire bats do not come from or live in Romania. And they are NOT found in the United States. They are a New World tropical species ranging from Mexico south to Argentina. They mainly inhabit caves, but are also found in hollow trees, mine shafts and abandoned buildings.

And unlike the giant vampire bats we see in movies, true vampires are very small, about the size of your thumb. The grayishbrown bats have a wingspan of 8 inches and they weigh about 40 grams. In the wild they live to be 9-12 years old, but can easily live to be 20 years or older in zoos. They generally have one pup a year after a gestation of about 7 months. They live in colonies of 20-100 individuals, but can number as low as 6 or as many as 2000!

The common vampire bat is the only bat that can walk and hop on the ground and take off vertically.

It is true that vampire bats drink blood. No, they donít suck blood like in the movies, but they do make a small, sharp incision in an area of the skin where blood vessels are near the surface. Most of the time the animal being bitten does not even feel the bite. An anticoagulant in the vampiresí saliva delays the blood from clotting, allowing the bat to lap up the blood. The amount of blood taken by a single bat is not great and generally does not affect the sleeping animal. The real danger of vampire bites lies in the diseases and infections that may result. Rabies is a common disease transmitted by vampire bats. This occasionally has a detrimental effect on the cattle and horses that cohabitate with us. And yes, vampires do occasionally feed upon human beings.

Think that vampire bats have no redeeming value? Think again! Scientists have isolated an enzyme from the saliva of the vampire bat. This enzyme, named desmoteplase after the vampireís scientific name, has been developed into a bloodthinning drug that helps prevent strokes and heart attacks in humans. Clinical studies have indicated that desmoteplase could improve blood flow in the damaged area of the brain if it was given within nine hours after the onset of stroke symptoms. Although the drug is now made synthetically, we would not have discovered it without the vampire bat!

Steve Wing is the chair of the AZA Bat Advisory Group, which directs breeding programs and in-situ conservation efforts worldwide. He also maintains the North American studbook for the Rodrigues fruit bat.

photos courtesy of Houston Zoo, Inc.

This article was originally published in the Spring 2006 issue of Trunkline magazine.