11 Bloody Facts About Vampire Bats

iStock / through-my-lens
iStock / through-my-lens

Bats are firmly rooted in Western vampire lore, but only three species, out of some 1100 in the order Chiroptera, actually have a taste for blood. The vampire bats are the only mammals in the world that live on blood alone, and the unique challenges of that diet make them some of the most specialized, fascinating and downright weird animals that nature has to offer.

1. The three vampire bat species—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 grouped together in the subfamily Desmodontinae. Their ranges overlap in parts of Central and South America, so, in what might be an effort to avoid competition with each other, the species specialize in different prey. The common vampire feeds primarily on the blood of mammals —ranging from tapirs to horses to the occasional human—and seems to have a preference for livestock animals. The hairy-legged vampire, meanwhile, lives almost exclusively on bird blood, while the white-winged vampire is more versatile and drinks from both birds and mammals.

2. Other bats with less grisly diets got a bad rap from European explorers in the Americas. The Europeans had heard stories about blood-drinking bats and encountered native people and livestock that had been bitten in the night and, without any real knowledge of the animals’ diets, began labeling different bats as vampires willy nilly, usually applying the term to bigger and/or uglier ones. Bats that lived on insects or even fruit were assumed to be vampires thanks to their appearance, and the association stuck when they were scientifically described and saddled with names like Vampyrum spectrum and Pteropus vampyrus. Meanwhile, when a naturalist finally got his hands on an actual vampire, D. rotundus, no one one believed his assertions that it drank blood, and he made no mention of it in his description.

3. When the bats feed, they use their teeth to shear away hair or feathers from a small spot and then cut into their victim’s flesh with their sharp incisors. (According to zoologists at Chicago’s Field Museum, even the teeth on old, preserved bat skulls in museum collections are sharp enough to cut someone handling them carelessly.) Rather than actively suck the blood from the wound like their namesakes, the bats let the physics of capillary action do the work. They lap at the blood and specialized grooves on their lips, tongues, and/or roof or their mouths suction it up. A protein in the bats’ saliva called a plasminogen activator prevents the blood from clotting and keeps it flowing freely while they drink.

4. White-winged vampires have a few tricks for feeding on domestic chickens without startling the birds. Sometimes, they’ll approach a hen and mimic a chick by nuzzling up to her brood patch. This featherless section of skin on the hen’s underside is densely packed with blood vessels and is used to transfer heat to her eggs or chicks during nesting. The vessels make an easy target for the bat, and if the hen thinks it's her baby cuddling up to her, she’ll sit on the bat to give it access to drink. Other times, the bats will climb up on a hen’s back, mimicking the touch and weight of a mounting rooster and sending the hen into the crouching stance they take before mating. The bat can then shimmy up to the hen’s neck for a bite and she’ll stay in that position until the bat hops off.

5. White-winged vampires will also take their meals in the trees instead of the barnyard. While a bird roosts on a branch, the bat sneaks up on it from below, crawling along the underside of the branch and staying out of sight. Once it’s directly underneath its prey, the bat bites the bird’s big rear-pointing toe and drinks its fill.

6. The hairy-legged vampire also feeds in the trees, but doesn’t bother with subtlety like its cousin. They’ll often land directly on a bird and hang from its body upside-down with their feet while biting around the bird’s cloaca, the all-purpose entrance and exit for the intestinal, reproductive, and urinary tracts. The maneuver is helped by the bat’s calcar, a bony spur that comes off the ankle bone. It’s absent in some bats and underdeveloped in others, but the hairy-legged vampire’s protrudes noticeably and is used by the bat like an extra digit to help it hang on.

7. Unlike its cousins, the common vampire bat eats solely on the ground, and it has evolved to be as nimble there as it is in flight. While most other bats are awkward crawlers, the common vampire can move with a quick run-like gait or hop along the ground, supporting its weight on its hind legs and using its wings and elongated thumbs to steer and push off of the ground. This comes in handy for chasing after prey on the move and for jumping out of the way if it needs to.

Feeding for common vampires is often risky, given that their preferred victim, the domestic cow, is several thousand times larger than they are. They usually bite cows on the area of the leg just above and behind the hoof, since the skin is relatively thin and the blood vessels run close to the surface. One step backwards, and a bat could be squashed if it hadn’t figured out how to run or make impressive three-foot leaps into the air.

8. To meet their energy needs, vampire bats need to drink about an ounce of blood at every meal, meaning they consume half their body weight during each 20 to 30 minute feeding session. Their bodies have adapted to lighten that load, and their stomach lining rapidly absorbs much of the blood’s water content and sends it to the kidneys so it can be excreted. The bats can process their meal so quickly that they may begin disposing of it before they’re even finished with it, and start urinating just a few minutes into the feeding.

9. Vampires are known to share meals with each other. Mother bats regurgitate previously-drunk blood for their offspring until the babies are old enough to hunt on their own. Other related bats and even unrelated ones have also been observed puking blood up for one another in a reciprocal arrangement. If a bat can’t find a meal one night, one of its roost-mates may share some of its meal. In the future, the bat who was fed is highly likely to return the favor. If it cheats, or takes a blood donation without ever giving back, it may find that it gets the cold shoulder the next time it needs help.

10. Vampire bats have a few different tools for finding their food. They have well-developed senses of smell and, despite bats’ reputation, keen eyesight. They’ve also got heat-seeking faces—their wrinkly, leaf shaped noses are loaded with nerves that are, in turn, loaded with proteins that are sensitive to the infrared radiation given off by warm-blooded animals. They also have finely-tuned hearing and specialized neurons that react only to the sound of breathing. They can even distinguish the breathing sounds made by different individuals, and may be able to remember the unique sonic components of an individual animal’s breathing, allowing them to return to the same reliable source of blood night after night.

11. Animals that are adventurous eaters learn to avoid potentially toxic foods through trial and error. They try something new, get sick, and then avoid those flavors in the future. Vampire bats appear to have lost their sense of taste aversion, though. In experiments, biologists have given vampire bats and their fruit- and insect-eating cousins treats seasoned with different, unfamiliar flavors, and then induced vomiting. At their next few meals, the bats were given the choice between normal food and food flavored with the same seasonings from before. While the other bats avoided the flavors they associated with getting sick after the first meal, the vampires dug in to both flavored and unflavored blood. The researchers think that the vampires either lost the ability to make these associations because their diet doesn’t present a variety of flavors and it wasn’t needed, or maybe that they had to lose it early on in their blood-drinking history to make the diet viable.

5 Ways You Can Help the Jaguar Rescue Center Save Costa Rica’s Wildlife

A curious sloth says hello after members of the Jaguar Rescue Center reunited her with her baby.
A curious sloth says hello after members of the Jaguar Rescue Center reunited her with her baby.
Jaguar Rescue Center

In 2005, Catalonian primatologist Encar Garcia and her husband, Italian herpetologist Sandro Alviani, were living in southwestern Costa Rica when locals began to bring them injured animals in hopes that the two experts could save them. As word spread and more animals arrived, their property slowly transformed into a full-fledged rescue center. So they purchased the surrounding land and named their new organization the Jaguar Rescue Center (JRC), after one of their early rescues: a young, orphaned jaguar whose mother had been killed by farmers.

Today, the center covers nearly 5.5 acres of land near Puerto Viejo de Talamanca in Costa Rica’s Limón province. It can accommodate around 160 animals at a time, and is home to everything from spider monkeys to sea turtles (though, by law, staff members aren’t allowed to accept domesticated animals like cats and dogs).

While locals still bring injured and orphaned animals to the JRC, others are brought by tourists, the Ministry of Environment and Energy, the National Animal Health Service, and even the police, who confiscate animals that have been poached or illegally kept as pets.

howler monkey at jaguar rescue center
Skye, a young howler monkey who recovered from electrocution.
Jaguar Rescue Center

The rescues are often victims of road accidents, animal attacks, environmental destruction, human interaction, or electrocution from exposed power lines. After the animals are rehabilitated, they’re released into La Ceiba Natural Reserve, a human-free (except for JRC workers) part of the forest where they can safely reacclimate to living in the wild. The JRC has cameras installed in the area to monitor the animals after their release and make sure they’re finding enough food.

Unfortunately, not all the creatures brought to the JRC recover from their injuries—in 2019, for example, 311 of the 749 rescues died [PDF]—so JRC staff members and volunteers understand just how remarkable it is to watch an animal regain its health and be successfully returned to its natural environment.

“There are so many amazing things about working for the JRC, but I think we all can agree that seeing a rescued animal make it through rehabilitation and be released is the best and most rewarding part of the job,” Torey, a JRC tour guide, tells Mental Floss.

Some thought-to-be-orphaned sloths are even released right back into the arms of their mothers. After recording the cries of a baby sloth, JRC staff will take the sloth back to wherever it was first found, play the recording, and wait for the mother to recognize the cries and (slowly) climb down from her leafy abode to reunite with her child.

Despite its partnerships with government agencies, the JRC doesn’t receive government funding. Instead, it relies on public donations and revenue from its visitor services. Find out more about how you can help below.

1. Donate money.

You can make a one-time or monthly donation that will go toward food, medical care, and supplies for the animals, or you can donate specifically to the JRC’s “Shock Free Zone” program, which insulates power lines and transformers that run through forests to prevent them from electrocuting wildlife.

2. Donate items.

Check out the JRC’s Amazon wish list to see which items are most needed—and what they’ll be used for, too. Examples include Pampers diapers for baby monkeys, snake hooks for safely rescuing snakes, and cans of worms to feed birds, opossums, and bats.

One of the most important products on the list is powdered goat’s milk, which staff members use to feed orphans of many mammalian species at the JRC.

“It has the most universally digestible enzyme compared to other milk,” Torey says. “Unfortunately, we do not have sloth milk, monkey milk, etc. readily available for the baby animals.”

3. “Adopt” an animal.

diavolino, a margay at the jaguar rescue center
Diavolino, the Jaguar Rescue Center's "feisty little margay."
Jaguar Rescue Center

For $105, you can virtually “adopt” an animal at the JRC. Choices range from Diavolino, a “feisty little margay” rescued from the illegal pet trade, to Floqui, a whitish two-fingered sloth who was born with only one digit on each hand and foot.

4. Visit the Jaguar Rescue Center.

You can stay overnight at the JRC in one of its three visitor residences—La Ceiba House, Ilán Ilán House, or one of the Jaguar Inn bungalows—which offer a variety of amenities, restaurant service, and access to nearby beaches.

Whether or not you’re staying there, you can book a tour of the JRC, where you’ll get to explore the premises and even meet some of the animals. There are private, public, nighttime, and VIP tours, and you can find out more here.

5. Volunteer at the Jaguar Rescue Center.

If you’re looking for a more hands-on, potentially life-changing way to help Costa Rica’s wildlife, you can apply for the JRC’s four-week volunteer program or a position at La Ceiba Natural Reserve that lasts three to six months.

According to the website, JRC volunteers are housed in the Jaguar Inn and help with “a broad range of tasks, from doing the dishes and cleaning up after the animals ... to building and remodeling enclosures, or babysitting a new arrival to ease the stress of their new environment.”

La Ceiba volunteers, on the other hand, stay right on the reserve and do everything from monitoring captive and recently released animals to keeping the trails clear.

Find out more about becoming a volunteer here.

YouTube Star Coyote Peterson Brings 'Misunderstood' Animals to His New Animal Planet Series

Animal Planet
Animal Planet

As host of the popular YouTube series Brave Wilderness, Coyote Peterson is no stranger to going face-to-face with creatures many deem terrifying—think great white sharks and pit vipers—but that he says are simply "misunderstood."

Animals have always been a big part of Peterson's life, even before he made a career out of being stung and bitten by ferocious critters. The Ohio native studied video production and directing at Ohio State University, and then decided to combine his two passions—film and all things wild—to teach viewers about wildlife and the importance of conservation. His YouTube channel currently has more than 15 million subscribers.

Now Peterson is embarking on a new adventure with Animal Planet in the show Brave the Wild. He'll travel all over the world with wildlife biologist Mario Aldecoa and his crew, sharing creatures that aren't often in the spotlight and that viewers may find a little frightening. He recently chatted with Mental Floss about the importance of conservation, his thing for snapping turtles, and his close encounter with a jaguar and her three cubs.

You’ve said your love of animals started with snapping turtles. Can you talk about the first time you saw one and what about them fascinated you so much?

The first snapping turtle I caught was when I was only 8 years old. I was always fascinated with turtles, because at first glance they look prehistoric, almost dinosaur-like. Growing up in Ohio, I never got to see any "exotic" animals. My favorite thing to watch on TV was Steve Irwin. Watching him wrestle crocs is what inspired me to catch my first snapping turtle, the most dangerous animal Ohio has to offer.

Coyote Peterson with a gigantic snapping turtle
Animal Planet

In Brave the Wild, you introduce animals that are often feared or misunderstood. What's the importance in exposing viewers to these creatures?

One of my goals through this series was to inspire people to overcome their fears of these seemingly dangerous animals and learn to admire them from a safe distance. The more you understand these creatures, the less you are afraid of them. One of the messages I try to convey in every episode is the importance of conservation.

What’s the most "misunderstood" creature you've encountered?

The most misunderstood creature that comes to mind is the carpet shark, which we filmed in season one. As I always say, people’s biggest fears are the three S’s (sharks, snakes and spiders). The carpet shark is found off the coast of Australia. They only bite humans in the case of mistaken identity. To some of these sharks a person’s foot might look like a fish. Any time you enter a new environment you need to be aware of what you need to look for, not only to keep yourself safe, but the animal as well.

What goes into preparing for each encounter to make sure you and the animals come out alive?

With any new expedition, you need to come into the environment knowing exactly what to expect. When encountering a new animal, I try to stay as calm as I can and have no hesitation. If I stay calm, the animal stays calm, [and] I'm creating a safer interaction for myself. I use different tactics when I encounter different animals. It also depends on whether the environment is land or in water.

How do you keep your composure on camera when you're in a potentially dangerous situation?

Any situation I find myself in, I look at it as my job. For example, I would be afraid operating a crane, because that is something I don't do. If it's part of your job, it's something that you get used to. When I do my job, I make sure I'm focused and never hesitate. Before I encounter any animal, I know what I'm going to say to the camera. I say that, for the best show, we always need to have the camera rolling so the audience can see what is happening.

Coyote Peterson with a kangaroo
Animal Planet

You were in Australia filming Brave the Wild during bushfire season. What was that like?

Visiting Australia was one of the best experiences I had filming the show. Australia is a fascinating country that has so many unique environments. We spent over 50 days in Australia and encountered more than 35 different species. We were there right before all these devastating fires started, and we got to witness the severity of the drought and all the different animals it impacted.

What was your favorite animal encounter in upcoming series?

Each encounter I have in the wild is special. I would have to say that the most exciting moment for me was when we were filming in Brazil and I saw a jaguar and three of her cubs up close. Not only did I get to see this in real life, but my amazing team was able to capture this special moment on tape. It is just so amazing seeing these animals survive and thrive in the wild while dealing with not only the dangers of the wild but human encroachment as well. Hands down, this was my favorite episode that we got to film.

Catch new episodes of Brave the Wild on Animal Planet, Sundays at 9 p.m. ET/PT.

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