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Today on Animal Fact Files we’re discussing vampire bats. If the idea of a blood eating mammal freaks you out, then I can imagine three blood eating mammals would be three times worse. There are, in fact, three living vampire bat species: the common vampire bat, the hairy-legged vampire bat, and the white-winged vampire bat. All three of these species are part of a larger group known as the leaf nosed bats, however, they stand apart from their family members because they are hematophagous: they eat blood! This should come as no surprise; vampire bats are, after all, named after some of the most iconic blood eaters in human mythos. We, however, like to think there's more to these furry little critters than their unsettling dining habits.

There are other, much larger bats known as false vampire bats, but they don't drink blood. They just look a little freaky with their oversized canine teeth. Vampire bats are much smaller. On average, they only weigh about 40 grams (1.4oz), which is less than the weight of a C battery. Their weight changes depending on when they last ate. Vampire bats average just under three and a half inches (89mm) in length, and they don't have a tail! During the day, these mammals roost in caves, hollow trees, and places like abandoned buildings. They live in forests and agricultural areas throughout Central and South America, though vagrants have been seen in parts of Texas. Depending on the species they may live alone or in family groups with hundreds to thousands of members. They may also roost with other bats, though hairy-legged vampire bats are a lot less social!

Family is important to these little mammals. If a vampire bat goes more than two days without eating it will starve. Luckily for them, other members of their group will regurgitate a meal to feed the individuals who haven't eaten. Grooming is often part of this ritual with the bat receiving the food offering a groom to the bat giving the food. Mother vampire bats also groom their babies. These bats are reproductive once they reach a year old and can give birth any time throughout the year. Most births, however, occur in April and May or October and November. Despite their small size, vampire bats have a lengthy gestation period averaging seven months. Babies are nursed for at least a month before they're introduced to blood meals, but they're still dependent on their mother for almost half a year after. In fact, other female vampire bats help to raise the young in their families. If a mother dies, another female will often take up responsibility for the baby. Predators to vampire bats include snakes and birds of prey, but they're known to reach about ten years of age in the wild. 

Vampire bats do not suck blood. Instead, they use their extremely sharp incisors to make an incision in another animal's skin and lap up the blood with their tongue. They have special organs for detecting temperature. The warmest spot indicates where blood is flowing closer to the animal's skin. The bat crawls up to the animal, licks and chews away any hair or feathers, then makes an incision. The animal is usually asleep during this process and often doesn't feel it happening. In a single thirty minute feeding, a vampire bat consumes up to half its body weight! That's a lot of extra weight to carry around for flight, so these bats urinate a lot after a meal to make themselves lighter. Common vampire bats are the most agile on the ground and can actually fly from a stand still jump. They can also walk, run, and hop - something most other bats are unable to do.

While this is rare, vampire bats are able to transmit the rabies virus to other mammals they bite, including humans. However, it's important to note that vampire bats affected with the virus are often unstable and some aren't even able to fly, so it limits them, as well. While the incisions they make and the blood they take don't often cause harm initially, the open wounds can become infected which can lead to complications. Still, white-winged vampire bats and hairy-legged vampire bats much prefer birds for their meal sources, meaning they're even less likely to transmit rabies (which is a virus that only affects mammals). Plus, vampire bats have helped humans! The anticoagulant in their saliva, what keeps the blood from clotting while they eat, has been used by humans to help victims of heart attacks and strokes!

Vampires are often depicted with sharp, elongated canine teeth, but vampire bats rely more heavily on their incisors for feeding, or their front teeth. These teeth are so sharp, even vampire bat skulls with incisors still intact can cut through skin! Hairy-legged vampire bats have the most teeth of all the vampire bats with 26 teeth in total. They have rounded ears and a pug-like nose. They're also slightly smaller than the other two species. White-winged vampire bats have a pug-like nose, small, pointed ears, and wings outlined in white, hence their common name. Common vampire bats are the largest of the three species. They have large, pointed ears. 

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