Bat

For other meanings see Bat (disambiguation)

Bats Fossil range: Upper Paleocene – Recent
Townsend's big-eared bat, Corynorhinus townsendii
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Infraclass: Eutheria Superorder: Laurasiatheria / Archonta Order: Chiroptera Blumenbach, 1779

Bats are mammals in the order Chiroptera. They are the only mammals that can fly. Other mammals like flying squirrels, or flying possum, can glide but not fly.

Bats are the second largest order of mammals: there are more than 1,100 species of bats. This means that 20% of all known mammal species – one in five – are bats.

About seventy percent of bats are insectivores. Most of the rest are frugivores (fruit bats). A few species suck blood (hematophagy), and some large ones are carnivorous.

Taxonomy

• Order Chiroptera
  • Megabats (Megachiroptera)
  • Microbats (Microchiroptera)

The phylogenetic relationships of the different groups of bats have been the subject of much debate. The traditional subdivision between Megachiroptera and Microchiroptera reflects the view that these groups of bats have evolved independently of each other for a long time, from a common ancestor which was already capable of flight.

The hypothesis was that flight only evolved once in mammals. Most molecular biological evidence supports the view that bats form a single or monophyletic group.

Adaptations

Echolocation

An interesting thing about bats is that even though they can see with their eyes, they also use their ears to help them 'see' in the dark. Because of this, they can fly into very dark places where no eye could see. This way of seeing is called echolocation. Basically, echolocation means they use echoes to find where things are.

Echolocation is a lot like sonar that submarines and ships use to find things underwater. This is how it works: when a bat flies, it makes lots of sounds. We can not hear these sounds (they are too high-pitched), but bats can hear them. Scientists have instruments to measure them.

When a bat makes its noises, the sound waves move away from the bat. If they hit something, they bounce back to the bat (this bounce is called an echo.) If nothing bounces back, the bat knows there it's okay to fly forward. They use this echolocation to catch their food, like butterflies or dragonflies. When a bat begins its nightly exploration, it usually sends out about 10 calls per second, but when they get an echo from something good to eat, the calls increase up to 200 calls per second. This increase of sounds is called a feeding buzz. The bat makes a feeding buzz to "see" all the quick moves of the insect it is trying to catch.

Hearing and understanding the echoes that go back to the bat must take a really big amount of complicated structures in the bat's brain. Because of this, many scientists, doctors, and even the U.S. army study bats carefully. The U.S. army spends hundreds of thousands of dollars every year to study echolocation in bats.

Bats also have quite good eyesight and can see their prey and where they are flying if it's not too dark. There are lots of stories about bats flying right into people, but this is not true. They can see in the light very well, and in the dark, they can see much better than us because they are nocturnal - that is, they are active during the night, dusk, or dawn. So the expression "blind as a bat" is not very scientific.

Bat wings

Bats fly with their hands. In fact, the order of bats, Chiropetera, means 'hand-wings' in Latin.

Bat and bird wings are different. Birds do not have long finger-like bones in their wings like bats. Birds can not move each of their fingers, but bats can. Because of this, bats can change their direction while flying or fly in any pattern they want: this makes it easier to catch their food. A bat flies as if they are "swimming" through the air – pushing both wings down and backward.

A bird's wing has lots of feathers, while a bat's wing is mostly a stretchy, thin skin called a patagium. This thin membrane of skin stretches between each finger bone, connects to the bat's ankle, and connects to the bat's tail (if it has one). When a bat folds its wings next to its body, the skin puckers up as if it's getting smaller.

Bats have one claw (sometimes called a bat thumb) that sticks out of the top of the wing. They use their "thumb" to climb and crawl. Interestingly, bats also use their thumbs to clean his ears out.

Bats' wings have a lot of maneuverability (it can change direction well) – more than a bird, in fact – but it does not have a lot of lift. Because of this, they usually have to climb up onto a tree or jump up into the air for the boost before they start flapping their wings.

Food

Megabats eat fruit, nectar or pollen. Most microbats (7 out of 10) are “insectivorous”, that is, they eat insects, but some microbats eat small vertebrate animals (small mammals or fish), blood, or even other bats.

Bats perform a very important role in ecology: They pollinate flowers and sometimes spread their seeds. Many tropical plants completely depend on bats.

Bats mostly live in caves or trees. In North America and in Europe they sometimes live in peoples houses without them knowing. People can be scared by this and sometimes hurt the bats, who mean no harm, unless they are Vampire bats. They eat blood.

Unusual bats

Fruit bats (Pteropodidae) are the largest of the bats. They eat fruit and can see well. There are 166 species, all found in the Old World.

Vampire bats live in Latin America. They are famous for only drinking blood.

The Fisherman bat Lives in Latin America and the Caribbean. It swoops low over water and grabs small fish with its claws.

The bumblebee bat, from Thailand, is the world's smallest bat, and is also one of the world's smallest mammals. Adults grow to a length of 29-33mm, and weigh 2 grams.

The biggest known bat is the Giant golden-crowned flying fox. It has a wing span of 1.5m and weighs approximately 1.2 kg.

Bats and people

In the United Kingdom all bats are protected by law, and even disturbing a bat or its roost can be punished with a heavy fine.

Austin, Texas is the summer home to North America's largest urban bat colony (under the Congress Avenue bridge), an estimated 1,500,000 Mexican free-tailed bats, who eat an estimated 10 to 30 tons of insects each night, and attract 100,000 tourists each year.

In Sarawak, Malaysia bats are protected species, but the large naked bat and greater nectar bat are eaten by the local communities.

Bats in folklore and fiction

In the West, Bats are associated with vampires, who are said to be able to change into bats. Bats are also a symbol of ghosts, death and disease. However bats are said to be lucky in some European countries, such as Poland.

The bat is used in fiction by both villains like dracula and heroes like Batman. Kenneth Oppel, wrote a series of novels , beginning with Silverwing, which feature bats as good characters.

An old wives' tale says that bats will entangle themselves in people's hair. This is untrue as bats can detect even a single hair, and fly around it.

Gallery

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  A Megabat.

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  A colony of Megabats.

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  A colony of Microbats.

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  A Microbat.

References

Look up Chiroptera in Wikispecies, a directory of species

Wikimedia Commons has media related to:

Chiroptera