By Melody Bell Wilkes
For the Salisbury Post
If you are in the baby boomer generation, this time of year brings back memories of Bela Lugosi starring in his infamous role of Dracula.
In this black-and-white movie classic, there is a young brunette poised sheepishly in her white gown lying on the bed in the evening hours. A small and inconspicuous bat flies onto the veranda, turns into the shape shifter vampire form, enters the portal and bites the dream-stricken girl on the neck for his next bloody meal.
It is no surprise people are still enthralled with the fictitious image of vampires. Just note the huge success at the movie box office. With the movie blockbuster Twilight, the sequel New Moon still to come and TV’s new Vampire Diaries, it is obvious vampires still capture our attention and imagination.
In Hollywood, vampires are making a comeback. In the real world, vampire bats are not. The truth is vampire bats have never earned people’s respect or understanding.
Many people are convinced all bats are rabid vampire bats that drink blood and get entangled in people’s hair. This is far from the truth. In fact, only half of 1 percent of bats actually carry rabies. Seventy percent of bats eat insects, and tropical species feed exclusively on fruit or nectar. There are a few carnivorous bats that eat fish, frogs, mice and even other bats.
Of the nearly 1,100 bat species found worldwide, only 3 species are vampire bats, and they live in Latin America. In North America, all of our bats eat insects. Bats make up one quarter of all mammal species on earth.
What captivates many of us about vampire bats is their diet. Protein-rich blood is all the nutrition a vampire bat needs. In areas where vampire bats live, land that once was forest has turned into pastures holding livestock. Finding food for a vampire bat can be as easy as locating a penned cow, donkey, horse or chicken.
Unlike other bats that gather their food in flight or rest on a branch to eat, vampire bats can crawl on the ground and jump on an animal. This gives them the advantage to quietly approach an animal when it is asleep. Specialized leg tendons allow them the ability to jump.
Once on the animal, the vampire bat starts to sniff. Their noses have specialized heat sensors that can detect a vein close to the surface of the skin. To begin feeding, the bat uses its front teeth to make a small incision. An anticoagulant in the vampire’s saliva causes the blood to flow without clotting.
Vampire bats do not actually suck blood but lick it up just like a dog drinking from a bowl of water. While the host animal continues to sleep, the vampire bat will drink up to 2 tablespoons of blood.
Once the blood reaches the stomach lining, the blood plasma is rapidly absorbed and transported to the kidneys and finally to the bladder for excretion. The bat needs to facilitate its absorption quickly so its full stomach doesn’t weigh it down. If the bat is too heavy, it cannot fly. To help relieve it of extra fluid, a common vampire bat can expel urine within two minutes of feeding.
Once the bat has returned to its roost such as a cave, old wells, tree hollows or buildings, it will mingle with its colony. The colony will typically have one reproducing male and about twenty females with offspring. Each member of the family will need to feed once every few days. If by chance one of the bats has not been able to gather food on its own, then another member of the colony will regurgitate a portion of its meal to the hungry bat. This strengthens family bonds and makes sure everyone has had food to eat.
Vampire bats are small bats that weigh about 40 grams with an 8-inch wingspan. They can live up to 9 years in the wild and 19 years in captivity. They produce only one young or “pup” per year. It has been documented that they will adopt an orphaned bat, and adoption is unusual for any wild animal.
So how can vampire bats help humans? The answer lies in their saliva, which contains anticoagulants that inhibit blood clotting and compounds that prevent the constriction of blood vessels. The anticoagulant from vampire bats saliva has been synthesized and is now used in medication for human heart patients and has been shown to increase blood flow in stroke patients. Even vampire bats can be helpful to humans.
Vampire bats are one of the few bat species that are considered a pest. In Latin America, raising cattle is a growing business, and sleeping cattle attract vampire bats. In ranching areas, control programs are killing the bats by poisoning them. However, millions of beneficial bats are destroyed by people who mistake them for vampires.
This is unfortunate since bats are the slowest reproducing mammals on earth for their size. When populations of bats are poisoned or exterminated, it is hard for them to rebound in number.
Educational programs have been helpful to dispel myths and misconceptions about bats. For more fascinating facts about bats, please attend A Walk in the Woods program and learn how they can reduce mosquitoes and garden pests in your own neighborhood. Get out of the dark and into the light about bats.
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Melody Wilkes is owner of A Walk in the Woods, an environmental education company that provides outreach wildlife programs. Contact her at 704-436-9048 or visit www.awalkinthewoods.us.