11 Intriguing Facts About Vampire Bats

Bats are deeply ingrained in Western vampire mythology, but only three species among the over 1100 in the Chiroptera order actually feed on blood. Vampire bats are unique among mammals for subsisting entirely on blood, and this unusual diet presents them with distinct challenges, making them some of the most specialized, captivating, and downright strange creatures in nature.

1. Each species of vampire bat targets different types of prey.

The common vampire bat (Desmodus rotundus), the hairy-legged vampire bat (Diphylla ecaudata), and the white-winged vampire bat (Diaemus youngi) are closely related and classified under the Desmodontinae subfamily. These species overlap in parts of Central and South America, and to avoid competition, they tend to target different prey. The common vampire bat mostly feeds on mammalian blood—from animals like tapirs and horses to the occasional human—and favors livestock. The hairy-legged vampire bat is primarily a bird-blood feeder, while the white-winged vampire bat is more adaptable, consuming both bird and mammal blood.

2. Europeans were initially mistaken about vampire bats.

European explorers in the Americas often misjudged other bat species that had more mundane diets. They had heard tales of blood-drinking bats and encountered Native people and livestock with mysterious night-time bites. Lacking any real understanding of the bats' feeding habits, the Europeans began indiscriminately calling different bats 'vampires,' particularly those that were larger or considered uglier. Bats that consumed insects or fruit were often labeled vampires based on their appearance, a misconception that persisted when they were scientifically named, as seen in species like Vampyrum spectrum and Pteropus vampyrus. Meanwhile, when a naturalist first described the true vampire bat, D. rotundus, his claims about its blood-drinking habits were met with disbelief, and he didn’t even mention it in his initial description.

3. Their teeth are razor-sharp, and they have grooved tongues.

When feeding, vampire bats use their sharp teeth to carefully trim away hair or feathers from a small area before cutting into their victim’s flesh with their incisors. (Zoologists at the Field Museum in Chicago note that even teeth on old, preserved bat skulls in museum collections are sharp enough to cut someone if they handle them carelessly.) Rather than sucking the blood like traditional vampires, these bats rely on the physics of capillary action. They lap up the blood, with specialized grooves on their lips, tongues, or the roof of their mouths, allowing them to suction it. A protein in their saliva, called a plasminogen activator, keeps the blood from clotting and ensures it flows freely while they drink.

4. White-winged vampire bats trick chickens to feed on their blood.

White-winged vampire bats have developed clever techniques to feed on domestic chickens without alarming them. At times, they approach a hen and mimic the behavior of a chick by nuzzling her brood patch. This featherless area on the hen’s belly is full of blood vessels and helps her warm her eggs or chicks during nesting. The bat can easily target these vessels, and if the hen thinks it's her baby, she remains still, allowing the bat to feed. On other occasions, the bats climb onto a hen’s back, imitating the weight and touch of a rooster, causing the hen to crouch as she would before mating. This gives the bat access to her neck for a bite, and she stays in that position until the bat moves away.

5. They also sneak up on birds perched in trees.

White-winged vampire bats also prefer to hunt in trees rather than the barnyard. While a bird rests on a branch, the bat quietly approaches from below, crawling along the underside of the branch to stay hidden. When it's directly beneath its prey, the bat bites the bird's large, rear-pointing toe and drinks its fill.

6. The hairy-legged vampire bat’s feet are specially adapted to cling to its prey.

D. ecaudata also feeds in trees, but it’s less subtle than its cousin. Often, they land directly on a bird and hang upside-down from its body with their feet while feeding near the bird’s cloaca, the shared opening for digestive, reproductive, and urinary systems. This ability is enhanced by the bat’s calcar, a bony spur that extends from the ankle. While some bats lack or have underdeveloped calcar spurs, the hairy-legged vampire’s calcar protrudes noticeably and functions like an extra digit to help it grip.

7. The common vampire bat feeds exclusively on the ground.

It has evolved to move as gracefully on the ground as it does in flight. Unlike most bats, which are clumsy crawlers, the common vampire is able to move quickly with a running gait or hop across the ground, using its hind legs to support its weight while its wings and elongated thumbs help steer and push off. This agility is useful for chasing moving prey and for leaping out of danger when necessary.

Feeding can be risky for common vampires, especially since their preferred prey, the domestic cow, is vastly larger than they are. They typically target the area just above and behind the cow's hoof, where the skin is thinner and the blood vessels are nearer the surface. A single misstep could lead to the bat being crushed, but its ability to run or leap up to three feet into the air helps it avoid such danger.

8. Vampire bats must drink about an ounce of blood at every feeding.

To meet their energy needs, vampire bats consume half their body weight during each 20- to 30-minute feeding session. Their bodies have adapted to this high demand by quickly absorbing the water content from the blood, sending it to the kidneys for excretion. They process their meal so efficiently that they may start urinating just minutes into feeding, often even before finishing their meal.

9. Vampire bats sometimes share meals with one another.

Mother bats regurgitate blood they've previously consumed to feed their young until the babies are old enough to hunt on their own. This behavior isn’t limited to mothers—other related bats, and even unrelated ones, have been observed sharing blood through regurgitation in a reciprocal manner. If one bat goes without food one night, a roost-mate may share part of its meal, and in return, the bat who was fed will likely reciprocate later. A bat that takes but never gives may find itself ignored the next time it needs help.

10. Vampire bats have sharp vision.

In addition to their sharp eyesight, vampire bats possess highly developed senses of smell and heat-detecting facial features. Their wrinkled, leaf-shaped noses are full of nerves and proteins that are sensitive to infrared radiation emitted by warm-blooded animals. They also have acute hearing and specialized neurons that respond specifically to the sound of breathing. Not only can they detect breathing, but they may also be able to recognize and remember the unique sound of a particular animal's breathing, enabling them to consistently return to the same source of blood night after night.

11. Vampire bats seem to have lost the ability to develop taste aversions.

Animals that are more experimental with their diet typically learn to avoid harmful foods through trial and error. They try new things, feel ill, and then avoid those particular flavors in the future, a process known as conditioned taste aversion. Vampire bats, however, don’t appear to learn from such experiences.

In experiments [PDF], scientists offered vampire bats and their fruit- and insect-eating relatives treats seasoned with unfamiliar flavors, followed by induced vomiting. The bats were then given a choice between their usual food and food flavored with the same seasonings they had associated with sickness. While the other bats steered clear of the flavors that made them ill, the vampires continued to consume both the flavored and unflavored blood.

Researchers believe that vampires may have either lost the ability to associate flavors with negative experiences because their diet lacks variety, or perhaps they had to lose it early in their evolution to sustain a blood-based diet.