
Bats
Bats are misunderstood animals. Because they
are nocturnal or
active at night, people think of them as spooky and dangerous. Bats are actually
fascinating animals that are very helpful to humans. In some cultures, bats
are symbols of good luck.
Bats are flying mammals that are found in most parts of the world. Many
eat insects but some eat fruit and even frogs and fish.
©M.Durham/GLOBIO.org
The bone structure of bat wings looks a lot like a hand with very long fingers.
Hold out your hand with your fingers spread apart. Can you see the similarity?
©M.Durham/GLOBIO.org
Bats are the only mammals that
can truly fly. Although some bat species look
like mice, bats are not closely related to rodents.
Bats have their own scientific group name, which comes from Greek words meaning “hand-wing.” Look
closely at the bat wing in the photo to see why the name fits.
Bats are Everywhere
There are more than 1,100 known species of
bats. That means nearly one out of four mammal species is a bat! There are
two main types, microbats and megabats. Scientists think microbats and megabats
may have evolved from
the same gliding, shrew-like ancestor.
Microbats are small. Most of them eat insects. They live almost everywhere
except the polar ice caps of the Arctic and Antarctic, the hottest deserts
and some islands.
Megabats are larger. They eat fruit. In fact, megabats are commonly called
fruit bats. They are found only in tropical regions of Africa, Southeast Asia,
India, the Pacific islands, and Australia.
Soft Skin and Hearing Aids
Like all mammals, bats have fur-covered bodies.
Their wings are a double layer of skin stretched over their arms and long fingers.
People think of a bat’s skin as tough and leathery, but it’s really
soft. (To find out how soft, touch your eyelid.)
Some microbats have strange “nose leaves” and projections on their
lips. They use these features to help them focus sounds as they echolocate.
Microbats have small eyes and large ears that are an adaptation for
excellent hearing. Fruit bats lack these features because most do not echolocate.
They have large eyes and short, rounded ears. Some fruit bats have faces that
resemble foxes or dogs. That’s why the largest fruit bats are called “flying
foxes.”
Is that a Bat or a Bumblebee?
Fruit bats like the one in this picture are sometimes called flying foxes.
Can you see why? This bat’s thin face and big eyes make it look like
a tiny fox with wings.
©Thomas Hawk
The smallest bat is the endangered Kitti’s
hog-nosed bat from Thailand, also known as the “bumblebee bat.” This
tiny bat weighs only 2
g and has a wingspan of 16
cm. It’s the smallest mammal on Earth! The large fruit bat from Malaysia
weighs about 1.5
kg and has a wing span of nearly 2
m. Life spans of bats are variable, but the little brown bat is known to
live more than 30 years.
Where Do Bats Hang Out?
Large groups of bats hanging out together are called camps. These fruit
bats hang around all day eating their favorite food, fruit.
©G.Ellis/GLOBIO.org
Microbats may roost alone
in hollow trees or live with many other bats in caves, mines, and old buildings.
Several million Mexican free-tailed bats live in the same colony!
Large groups of fruit bats gather to sleep in roosting trees. Females and their
young group together, while males may gather in separate groups. Large groups
are called “camps.”
Reproduction and Babies
Baby bats are tiny, hairless versions of their parents. Can you see the
baby bat in this picture? Try turning your head upside down for a bat-like
view.
©G.Ellis/GLOBIO.org
In some bat species one male mates with
many female bats. To attract mates, bats may vocalize, flap their wings, and
groom each other. After a two-month gestation,
most microbat species give birth to one pup. These babies can weigh up to one-third
as much as their mother. Some microbats form nursery colonies where mothers
drop off their babies when they fly out to feed. When they return, mothers
find their own baby using scent and sounds.
Fruit bats have one pup, following a gestation of four to five months. Pups
are weaned from
their mothers’ milk at 10-11 weeks. They are then old enough to begin
flying and looking for food.
Bat Habits and Survival Secrets
Bats are active at night, when the temperature
is cooler and the humidity higher.
This helps them save energy and prevent water loss. The darkness also helps
them avoid predators such
as certain kinds of hawks, snakes and toads. During the day bats lick their
fur and comb it with their feet to keep clean. They also groom their wings,
using oil from their glands to keep wings soft and in great flying condition.
When it’s hot, bats cool down by licking their fur and wings, then fanning
themselves. When it’s cool, they warm up by wrapping their wings around
themselves. Microbats and fruit bats are active year round in tropical areas,
where fruit and insects to
eat are available all year. Some microbats in colder places migrate to
where it’s warm. Others stay where they are and hibernate.
When hibernating, a bat’s heart rate slows and its body temperature drops
in a state called torpor.
Bring on the Bugs!
Some bats eat pollen and are important to the life cycle of plants. This
bat looks like it spent the night dipping its head into lots of flowers.
©C.Ziegler/GLOBIO.org
Microbats are the world’s most important
predators of night-flying insects. Little brown bats can eat 1,200 insects
an hour! But some microbats are meat-eaters. They feed on fish,
frogs, lizards, rodents, birds,
or other bats. Some small microbats eat fruit such as figs. Some eat nectar and pollen from plants.
Do Bats Drink Blood?
Vampire bats are a type of microbat. Yes, they do feed on the blood of birds
or mammals. But they don’t turn into Count Dracula. And there aren’t
very many of them. Of all the species of bats in the world only three are vampire
bats. These are found only in South and Central
America. These tiny bats (with a wingspan of 75
mm) don’t suck blood. Instead, they make a cut with their sharp teeth
and lap blood. An anticoagulant in their saliva keeps the blood flowing.
Vampire bats do drink blood but they do not suck it from an animal. Instead,
they make a tiny cut and lap up the blood that drips out.
©J.Clare/npl/Minden Pictures Bats as Planters
This hungry fruit bat is taking its lunch to go. Maybe the seeds from this
meal will become a new tree that will make even more food for bats.
©C.Ziegler/GLOBIO.org
Bats keep new plants growing by spreading
seeds. A fruit bat frequently carries fruit far from its tree, then chews and
crushes the fruit against the roof of its mouth. The bat swallows the juice
and soft pulp and spits out the tough parts. The fruit’s whole seeds
pass quickly through the bat’s digestive system and are dropped with
the animal’s poop. This disperses the
seeds far and wide. The seeds then germinate and
a new plant grows.
Bats as Pollinators
Nectar-feeding fruit bats take in protein-rich pollen as they sip the sugary
liquid.
Pollen sticks to the bat’s slender nose as it probes deeply into the
flower. The bat transfers the pollen to the next plant it visits. This allows
the plant to reproduce.
The flowers of bat-pollinated plants bloom at night. Their flowers are large,
creamy-white and easy for bats to find in the dark. They may send out strong,
bat-attracting odors.
Many plants that need bats to pollinate them are light, bright colors so
they can be easily found in the dark. Some even give off special bat attracting
odors.
©C.Ziegler/GLOBIO.org
All over the world, several species of plants and trees need bats in order
to reproduce. Bat-pollinated plants such as the baobab tree and the saguaro
cactus provide food, water, and shelter to many other animals.
Many of the foods people eat and the products we use depend on bats, too.
Bats in Trouble
Several species of bats, especially fruit
bats, are in trouble. Their forest habitat is
being cut down by loggers or being cleared for houses and farms. The bats are
threatened by mining, deadly plants that have invaded their habitat, and tropical
storms.
In some countries, fruit bats are eaten. Over-hunting has threatened several
bat populations to
near extinction.
Fruit bats are also killed by farmers who think of them as pests. Insect-eating
bats have been killed on purpose by people who are afraid of them. They have
also been killed by accident by explorers disturbing winter hibernation caves.
It is important to make sure bat populations are healthy. To do this, scientists
sometimes catch some of the bats and examine them. This information lets
scientists know how the bats are doing.
©M.Durham/GLOBIO.org
Protecting Bats
But it’s not all bad news for bats. Conservation groups have helped
protect large areas of forest land. Hunting has been banned in some areas.
Special gates have been installed across cave entrances to allow bats to enter
and leave, but to keep people out. Reducing the use of pesticides on
crops is one of the best ways to protect insect-eating bats.
Change Bad Bat Attitudes
The best way we can all help conserve bat populations is to change negative
attitudes. Share what you know about bats with your friends and family. Look
for bats and study their behavior. Bats are safe to be around. However, if
you can get close enough to touch any wild animal, it may be sick and could
spread diseases. If you find a bat, never touch it.
Build Your Own Bat Box
You can also help protect bats by asking your family to avoid using chemical
pesticides. To attract bats to your area, install a bat box. You can buy one
or build it yourself. Plans and directions are available from Bat Conservation
International. Bats may not move in right away, but be patient. Soon you may
be enjoying summer evenings of bat-watching, with no mosquito bites to scratch
the next day.