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Bats: Facts

bat in a cave
Photo: National Park Service

When you think of bats, what comes to your mind? A lot of people think bats are creepy because they only come out at night, roost in dark caves, and are associated with legends about vampires. But bats are not really scary at all. Despite the myths, bats are not blind, will not suck your blood, and won't become entangled in your hair. The truth is, bats are amazing creatures that benefit the earth in many ways. Let's find out more.

Bat Basics

little brown bat
Little brown bat
US Fish & Wildlife Service

Bats belong to an order of animals known as Chiroptera, meaning “wing hand.” Bats, although they can fly, are not birds. They are actually mammals, the group of warm-blooded animals that give birth to live babies, produce milk to feed their young, and have fur or hair. Bats are the fastest mammals on earth and the only mammals that can fly.

flying fox bat
Flying fox bat

Fossils of ancient bats have been found which indicate that bats have been on earth for at least 50 million years. Today, there are over 1,400 different species of bats. There are more species of bats than of any other mammals -- one-quarter of all mammals on Earth are bats! Bats are found on every continent except for Antarctica. Their many adaptations have allowed them to live and thrive almost everywhere.

Bats come in all different sizes. The tiny bumblebee bat, whose body is about the size of your thumb, weighs less than a penny and has a full wingspan of six inches. The largest bat, on the other hand, is the flying fox bat with a wingspan of six feet! Large bats, known as megabats, are long-nosed vegetarians found primarily in the tropics. Microbats are smaller insectivores found all over the world.

Bat Wings

Townsend's big-eared bat
Townsend's big-eared bat

Bats are the only mammal that can fly. They can accomplish this because of their powerful wings which are very similar to human hands. Their wings are formed by skin which is stretched over four extremely long finger-type bones. They even have thumbs. Besides flying, bats use their wings for grasping and holding on to food and their young.

Bat Habits

If you look up at the sky around the time the sun is going down, you might see bats flying. At first, you may think they are birds, but as you watch you may notice that they don't glide like birds; rather they fly in a more erratic pattern.

Roosting bats
Microbat roost, USFSW

Bats are nocturnal. During the day they sleep in roosts such as caves or trees. Depending on what is available in the area where they live, bats have been known to roost under bridges, in buildings or barns, under logs, within abandoned mines, inside hollow tree trunks, and even under large palm tree leaves. They hang upside down from claws on their feet, often in large groups called colonies. Some colonies can have thousands or even millions of bats!

Megabat roost
Megabat roost
Photo: Mike Lehman, CC-BY-3.0, Kiddle Ency.

Bats huddle together for warmth and safety, but colonies are also social communities. Sometimes, when a bat is injured or ill and cannot hunt for its own food, other bats will bring food back to it. Within the colonies, bats like to groom themselves and each other. Like cats, they lick themselves thoroughly to keep themselves clean, all while hanging upside down.

Hanging upside down in a high location puts bats in an ideal position for takeoff. From their elevated position, they drop straight into flight. It also helps them hide from danger. Bats are hunted by owls, hawks, snakes, and other carnivores. By roosting during the day in high, hidden locations, bats are safe from most daytime predators.

Flying bat

When dusk falls, bats awaken and leave the roost to search for food. A large colony of bats emerging from a roost is one of nature's amazing sights. Bats' flexible wings allow them to quickly maneuver through caves and trees in remarkable ways. In fact, bat flight is so acrobatic and complex that it provides a model for engineers who design aerial robots. Bats are the fastest of all mammals. They often fly at speeds of 60 miles per hour and at heights of 10,000 feet. The Mexican free-tail bat can fly 100 miles per hour over short distances.

During the winter when temperatures are low and food is scarce, some bats enter into a state of hibernation. Hibernating bats conserve energy by slowing their heart and breathing rates and lowering their body temperature. Other bat species follow an annual migration, traveling to cooler climates in the warm months and warmer climates in the cool months. Some tiny bats have been known to migrate as far as 1,500 miles!

Dinner!

insects flying at night

Different species of bats have different food tastes. The greatest number of bats feast on insects. A single bat typically eats over 3,000 mosquitoes in one night, while the little brown bat routinely consumes 1,200 mosquitoes in just one hour! Some bats, mostly in the tropics, eat fruit or sip nectar. Other kinds of bats eat small rodents, birds, frogs, lizards, and smaller bats. A few bat species fish for their dinner by flying over the water and snatching up fish. A very small number (only three species out of 1,400) feed off the blood of animals such as cows, horses and birds by puncturing their skin with their fangs and licking the blood from the wound. Known as vampire bats, they are found in Mexico and Central and South America.

Baby Bat Pups

Bat nursery colony
Bat nursery colony
Photo: Mnolf, CC-BY-SA-3.0, Kiddle Ency.

Most bat species give birth to only one baby per year. Although bats usually have only a single infant, occasionally twins are born. Infant bats are known as pups. Pups can be born weighing up to one-third of their mother's weight.

Infant bats are very small when born and require the care of their mother for food, warmth and protection. Like all mammals, the mother produces milk for the newborn pup. The pup clings to the mother during roosting and could die if it lets loose and falls. When the mother bats leave the nest to find food, they count on the fact that the pups from all the other mothers will huddle together for warmth and safety. Upon the return of the mothers, infants and mothers will quickly locate each other through smell and voice recognition. Baby bats grow quickly and can usually fly by the end of their first month.

Echolocation

echolocation

The expression “blind as a bat” is a myth; bats are not blind. Large megabats such as fruit bats search for food using sight and smell. However, microbats who hunt insects mainly find their way around in the dark through a system known as echolocation. They produce high-pitched squeaks, often not audible to human ears, which bounce off of objects like an echo. By hearing the echo as it returns, the bats can sense the location of objects. Echolocation works so well that bats can fly and find food in total darkness without hitting anything. They can also tell distance, size, texture, and speed of travel. Their huge outer ears help to gather this information more effectively than many other animals. This allows them to distinguish between prey and non-prey objects. If you were to stand in a room with flying bats, it is very unlikely that one would touch you. You are not a prey object!

In addition, bats have special cells in their ears that make them very sensitive to noise. They can hear the sounds made by their prey, such as faintly buzzing insects and croaking frogs. Some bats' hearing is so sharp that they can even detect the sound of a beetle walking on a leaf.

Benefits of Bats

farm crops

Bats provide several useful benefits to humans. They eat huge numbers of insects, which provides natural pest control that helps farm crops, humans and animals. Scientists estimate that bats save billions of dollars in reduced crop damage from insect pests every year. Also, as the primary predators of destructive night-flying insects like moths and beetles, bats help to keep our forests healthy.

The spread of fruit seeds is a natural benefit that comes from fruit-eating bats, as they eat the fruit and then deposit seeds in other areas through their waste. The seeds will then germinate and grow more of those plants. In the tropics, 95% of rainforest regrowth is due to seed dispersal from bats! Bats also help to pollinate plants in much the same way as bees and butterflies do by collecting pollen on their bodies when they eat.

Pollinator Bat
Pollinator Bat, USFWS

Bats are key pollinators for yummy foods such as mangos, avocados, bananas, dates, and cashews. In fact, over 300 species of fruit in tropical and desert climates depend on bats for pollination. In some areas of the world, bat excrement (known as guano) is gathered from caves and used as fertilizer for farms and gardens. Scientists study bats to further expand our understanding of flight, sound, and sonar. There are some areas of the world where bats are a huge tourist attraction, which helps local communities.

Bats have many potential uses in medicine and human health. Since the saliva of vampire bats contains a chemical that stops its victims' blood from clotting, scientists have used it to develop a medicine that helps patients who have had strokes or bleeding issues. Studying how bats use echolocation has helped scientists develop assistive devices for blind people. Research on bats has also led to advances in vaccines. In addition, about 80 medicines come from plants that rely on bats for their survival.

Bats can have some negative effects, as well. Like all mammals, bats can have rabies, which can be passed through their bite. This dangerous disease is especially concerning for herds of cattle or other livestock, but can also be passed to humans. Although most bats do not have rabies, it is important not to handle any bats you might find. Bat waste (guano) can become a problem when bats gather in buildings or public areas. Large colonies of bats roosting in warehouses or abandoned buildings can create a nuisance in city environments. However, scientists agree that bats' essential role in plant pollination, seed dispersal, and insect control makes up for the negative effects.

How You Can Help Bats

White-nose bat
Bat with white-nose syndrome, USFWS

Bats are essential to the health of natural ecosystems and to human economies as well. With all that bats do for us, you wouldn't want to live in a world without bats! But today, they are threatened from several sources, and bat numbers are declining across the globe. White-nose syndrome is a fungal disease that has caused the death of millions of hibernating North American bats. Habitat loss is a widespread problem for bats who depend on forests to roost and hunt. Wind turbines can pose risks to bats who may collide with them. In addition, some people fear and misunderstand the value of bats, and many bat colonies have been destroyed by humans.

Fortunately, there are things you and your family can do to help bats. You can avoid disturbing bats. You can share what you learn about bats to help other people learn how important they are. You can avoid the use of pesticides that can harm bats and reduce their food source. Remember, hungry bats provide natural bug control! Turning off outdoor lights and providing a dark nighttime environment can help improve conditions for bats. If you visit a cave, be sure to clean your clothing and shoes before entering so as not to spread disease.

Bat house
Bat house, USFWS

Building backyard habitats for bats has become a new conservation effort in many communities. Planting a garden helps attract pollinating insects that bats feed on. Bat houses, constructed in people's yards and natural areas, provide shelter for bats to roost. Providing bat houses also discourages bats from roosting in our houses, barns or attics. Find out more about what makes a good bat house and how to create one that bats will love to make their home.

Fun Facts About Bats

Bats flying out of cave
Bats emerging from Bracken Cave, USFWS

  • Bracken Cave in Texas is home to a colony of more than 20 million Mexican free-tailed bats. This colony of bats eats about 200 tons of insects in one night - approximately the weight of 55 elephants!

  • During the warmer months, the Congress Avenue Bridge in Austin,Texas is the roosting spot for 1.5 million free-tailed bats, the largest urban bat colony in the world. They eat up to 30,000 pounds of insects each night. Crowds of people gather at the bridge every evening at sunset to watch the bats fly out.

  • The tube-lipped nectar bat is a two-inch bat with a retractable three-inch tongue that it uses to get nectar from the inside of blossoms. It has the longest tongue compared to its body of any mammal in the world. If this bat were an adult human, its tongue would be almost nine feet in length!

vampire bat
Vampire bat, Wikimedia commons

  • Vampire bats can locate prey by sensing a large animal breathing. Unlike other bats, they can walk, run and jump, which helps them attach to their prey. The bat may spend about 30 minutes lapping up about one tablespoon of the animal's blood, but the animal often remains asleep and doesn't even know the bat has been there. Back at the roost, well-fed bats may vomit up the blood up to share with others.

  • Bats are unusual among small mammals in that they can live up to 20 or 30 years. The oldest bat on record was 41 years old.

  • Bats have distinctive prints on their wings, like human fingerprints. There's no mistaking one bat from another!

  • Every species of bat has its own special echolocation call, so scientists can identify what kind of bat is flying just by listening to echolocation calls.

Bats flying
Mexican free-tailed bats, USFWS

Remember: Go outside at dusk and look up! Watching bats fly over you is a great way to further understand and appreciate these amazing “heroes of the night” that help keep nature in balance.

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