Vampire bats are the only known mammals that survive solely on blood.

 There are three different types of vampire bats: Desmodus rotundus, Diaemus youngi, and Diphylla ecaudata.The common vampire bat species is Desmodus rotundus.Two of the three vampire bat species—Diaemus youngi and Diphylla ecaudata—feed primarily on the blood of birdsEach night, vampire bats drink about half their body weight in blood.

 A special substance in vampire bat saliva keeps blood from clotting.

Vampire bats have fewer teeth than other kinds of bats.

Vampire bats have special teeth for making small cuts in their prey.

The wingspan of a common vampire bat is about 8 inches (20 centimeters), but its body is only about the size of a human thumb.

Common vampire bats roost alone, in small groups, or in colonies of thousands.

 Vampire bats are nocturnal and most active in the early night.

Vampire bats, which weigh between .5 and 1.7 ounces (15 and 50 grams), often feed on animals 10,000 times their size in weight, such as a cow. After feeding, the common vampire bat has added so much body weight that it needs additional help from its long thumbs to propel its body off the ground to fly.

 Scientists have observed that female bats form associations with one another that can last for many years.

 After feeding, the common vampire bat has added so much body weight that it needs additional help from its long thumbs to propel its body off the ground to fly.

Vampire bats find their prey by using smell, sound, and a process called echolocation.

 Using echolocation, bats emit high-pitched sounds and interpret the sounds' echoes to locate objects

Keeping low to the ground, vampire bats generally fly about three feet (one meter) off the ground.

Vampire bats can live about 20 years in captivity.

While much of the world sleeps, vampire bats emerge from dark caves, mines, tree hollows, and abandoned buildings in Mexico and Central and South America. They glide stealthily through the night air as they search for food.

Like the legendary monster from which they get their name, these small mammals drink the blood of other animals for survival. They feed on blood from cows, pigs, horses, and birds. Though uncommon, vampire bats even occasionally bite humans for blood.

Rather than sucking blood, vampire bats make a small cut with their teeth and then lap up the flowing blood with their tongues. These bats are so light and agile that they are sometimes able to drink blood from an animal for more than 30 minutes without waking it up. The blood sucking does not hurt the animal.

Vampire bats have special adaptations to help them with their unique feeding needs. Unlike some other species of bats, vampire bats can walk, run, and jump. They have very strong hind legs and a special thumb that helps them take off after feeding. Also, heat sensors on their noses help them find a good spot on an animal’s body to feed.

What happens if vampire bats don’t get their nightly meal? If they can’t find blood for two nights in a row, they will die. Luckily, female bats can be generous. Well-fed bats will often regurgitate blood to share with others, in exchange for grooming. Female bats in captivity seem especially friendly toward new mothers. After a baby is born, other bats have been observed feeding the mother for about two weeks after the birth.

Are vampire bats really that scary? Even though bat bites themselves aren’t harmful, vampire bats can spread a disease called rabies. This disease hurts farmers’ livestock, especially cattle herds. However, vampire bats can actually be quite tame, and even friendly to humans. In fact, one researcher reported that he had vampire bats that would come to him when he called their names.

Text by Monique Duwell