Vampire bats own two distinctions: they are the only mammals that can fly, and they are the only animals that feed entirely on blood. These creatures have given rise to tales of terror for centuries. As with most legends, the myths of stalking vampires have been greatly embellished.
Vampire Bats are Small but Possibly Deadly
Desmodus rotundus – genus and species – is ugly enough for any horror movie, with a face maybe even a mother couldn’t love, but he is very small. The average body length is a mere four inches with a wing span of eight inches. Normally rotundus tips the scales at only two or three ounces, but he can weigh twice that after a blood meal. Vampire bats are not birds and do not have feathers, but hair, which is typical of other mammals.
The bats live in colonies of up to 1,000. Although a colony of 100 bats could drain 25 cows in a year, they don’t kill their victim, at least not by blood-letting. The main danger vampire bats bring is disease. Since they feed by opening a small wound in their host, they can spread germs as they move from one animal to another. Rabies is the most dreaded disease spread by the bat.
Farm Animals are a Favorite Source of Blood
The domestication of farm animals has provided a perfect food source for vampire bats. They are not particular about which animal they will attack, although it helps if the selected victim has short hair to allow easy access to the skin. The bats have been known to feed on chickens and even humans. Wild animals provide other options, but farm animals are convenient and plentiful.
Typically, rotundus lands on the ground near his victim, not swooping from above as the movies might depict. They walk to the victim and fly up to a convenient spot where they use their razor-like front teeth to make a small puncture – perhaps four mm long and one mm deep. The attack is generally too minor to be detected by a sleeping animal.
The bat feeds for perhaps half an hour from the wound, consuming merely a half an ounce of blood. Their saliva contains a chemical that prevents clotting while the vampire laps up the blood with its tongue. Rotundus has special nerves on his nose that can detect a good spot to bite. The nerves are sensitive to the heat of blood flowing through vessels close to the victim’s skin.
A Thirst for Blood
Adult vampire bats feed only on blood and must feed often. They have a very high metabolism and cannot live more than two or three days without a blood meal. Their throats are narrow and do not allow the consumption of solid food. However, newborn vampire bats nurse on milk until they are perhaps nine months old.
When not feeding, vampire bats prefer the darkness of cave ceilings for a home, where they wait for the dark of the next night to hunt out their next victim.
Vampire bats are tiny mammals that feed entirely on blood. The fact that they feed on the blood of living animals has given them a macabre reputation and provided inspiration for countless horror tales. The main danger of the vampire bat is its ability to spread disease.
Sources
“The Common Vampire Bat” conservationcentre.org Accessed January 24, 2010
Harvey Craft - I am a retired educator with diverse experience. I read anything science, education, and history. I write to share what I learn.
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