Vampire bats. They strike fear in even the manliest of men. Mention them, and people walk around with shoulders hiked up to cover their necks.
It's Halloween, so it's only natural to think about vampire bats. They're part of the holiday's lore. But they are a misunderstood animal, say the people who work with them.
In fact, researchers and curators at Iowa State University and Omaha's Henry Doorly Zoo and Aquarium think about vampire bats all year long, not just in October. And one of the things they think about is how best to feed them.
Their diet is simple: fresh blood. Each one of these sanguivores laps up about two tablespoons of blood a day.
Yes, that's right, contrary to myth, vampire bats don't suck blood. They lap it, like a dog or cat laps water. But first, they make a small cut with their razor-sharp teeth, so sharp, that they can make tiny incisions in even tough cattle hides and the food source rarely feels anything.
Vampire bats, especially those in captivity, seem to like beef blood the best, said Christie Eddie, the zoo's curator of small mammals.
The zoo doesn't require them to find their own food, of course. They put specific amounts in petri dishes around the exhibit.
The blood used to be supplied by Omaha packing houses, but as that source has dried up, other arrangements have been made.
Cheryl Morris, an assistant professor of animal science at Iowa State and nutrition director for Omaha's zoo, said finding good beef blood isn't as easy as it would seem. Fresh blood from a USDA-inspected beef processing facilities presents a challenge.
Recently she has been providing blood from the university's meat lab, she said, but now she will be coordinating studies on feeding the zoo's vampire bats.
The study results can be important for other zoos with vampire bat colonies, she said. What the researchers want to know is:
» Will the bats accept beef blood mixed with that of other animals, such as goat, sheep or pig? Morris will supply various combinations in the trials. And, no, human blood isn't an option.
» Do the bats like freeze-dried blood? In an experiment conducted by a high school student last year in the Zoo Academy, Morris said, the bats accepted blood that had been freeze-dried. But they didn't seem to like it much. Morris would like to try the freeze-drying process again and see how to make the blood more appealing to the bats. That could be important if there is a shortage of fresh blood for food and zoos need to store food for the animals.
» And there is the really interesting question: Some day could anything be substituted for blood in the vampire bats diet? Could vampire bats survive on a synthetic formula concocted in the lab?
Until last year, Eddie said, the zoo's 25 to 30 vampire bats were housed in a Lied Jungle enclosure. Now they are in a larger exhibit in the Kingdoms of the Night below the Desert Dome.
It's dark down there, but she urges visitors to not hurry by the exhibit. “Stand long enough and you'll see activity.”
She was right. On a recent afternoon, the vampire bats were hanging from vines, including one with a baby clinging to her. They flew around the exhibit, climbed walls and ate from the petri dishes of blood.
When blood is given to vampire bats at the zoo, the keepers add an anticoagulant to keep it from clotting or drying up. The bats have an anticoagulant in their saliva that works fine when they feed in the wild. Draculin (named after Count Dracula, of course) is made up of 411 amino acids.
Medical researchers are exploring draculin as a treatment for strokes or heart attacks in humans, or as a blood thinner to prevent heart attacks and blood clots.
One other thing. You're not likely to meet a wild vampire bat in Nebraska. They are native to tropical areas and couldn't survive in this climate, Eddie said.
And if they can't survive here, they certainly couldn't survive in dreary Transylvania.
Still, there's no getting around the vampire bat's tie to Dracula. Eddie doesn't like it. Rather than fearing vampire bats, she wants people to get to know and like them.
“They're very cool,” she said. “I'm not going to lie. I think they're fascinating.”
* * * * *
More about vampire bats...
The legend of the vampire, someone who returns from the dead and seeks the blood of living people, has been around since the biblical story of Lilith.
That's far longer than vampire bats have been known to man. The bats actually owe their name to the human vampire because explorers in the 18th and 19th centuries returned to Europe with tales of a bat that sucked blood. So it must be a vampire bat, right?
Writers were thrilled about the explorers' tales of vampire bats and combined the stories with the myths of human vampires. One such writer was Bram Stoker, author of “Dracula,” a book that has been in print since 1897, influencing all the vampire lore of film and books since its publication.
Vampire legends often are based on Vlad the Impaler (c. 1431-1476), who liked to dip bread into the blood of his enemies and eat it. His name, Vlad, means son of the dragon, or Dracula. Though Vlad the Impaler was murdered in 1476, his tomb is reportedly empty, according to J. Gordon Melton's “The Vampire Book: The Encyclopedia of the Dead.”
Some random facts with which to impress your friends:
• Bats are the only mammals that can fly, and vampire bats are the only mammals that feed entirely on blood.
• Vampire bats are native to South and Central America and Mexico — not eastern Europe.
• In addition to flying, vampire bats can walk, run and jump.
• Vampire bats need about 2 tablespoons of blood a day, and if they go longer than two days without blood, they die.
• In the wild, they feed mostly on cattle, but vampire bats have been known to settle for goat, sheep or hogs — even humans — in a pinch.
• Vampire bats' teeth are razor sharp. They can pierce an animals skin without the animal knowing it.
• They don't suck blood, they lick or lap it.
• Their noses have special sensors that aid them in locating an area where a food source's blood flows close to the skin.
• Vampire bats are not blind. They have excellent eyesight.
• Vampire bats help fellow bats. If one has no food, another will feed it by regurgitating some of its most recent blood meal.
• Female vampire bats will care for each other's babies or non-nursing female bats will feed a mother bat who has a baby.
• Vampire bats are clean animals; they groom themselves and others in their colony.
• Twenty is considered an old age for vampire bats.
• The only time a vampire bat's bite is harmful is if it is carrying rabies.
Sources: NationalGeographic.com and other websites.