Bats are the only mammals that can fly. They usually sleep during the day and become active at night. There are more than a thousand different species of bats worldwide and they can be found on every continent on Earth, except Antarctica.
Bats range in size from the Kitti's hog-nosed bat, which is 1.14 to 1.34 inches (29 to 34 millimeters) long with a wingspan of 5.91 inches (15 centimeters), to the giant golden-crowned flying fox, which is 13.23 to 13.5 inches (33.6 to 34.3 centimeters) long with a wingspan of 4 feet 11 inches (1 meter 50 centimeters).
More than three quarters of all known bat species live on a diet of insects. Most of the rest eat fruit but there are some exceptions, such as the fish-eating bat, which lives around the Gulf of California, and the South American vampire bat, which is the only mammal that acts as a parasite by feeding off the blood of other living mammals.
In mythology, folklore and fiction
People from many different cultures have long been frightened by bats. Like owls and other nocturnal animals, bats have been associated with death, ghosts and witchcraft. The witches in William Shakespeare's play Macbeth use bats' body parts as ingredients in the potion that they brew. Bats are sometimes depicted as witches' familiars.
It was once widely believed that bats enjoyed tangling themselves up in women's hair. The origin of this idea may have come from bats sometimes diving dramatically towards people in order to catch and eat the mosquitoes and gnats that humans attract.
The idea that vampires have the abiltiy to change themselves into bats is a common theme in dozens of different novels, movies and other scary stories. In Bram Stoker's novel Dracula, Count Dracula has the power to take on the shape of a bat, a wolf and a mist.
In the origin story of Batman, as told in Detective Comics #33 from November 1939, Bruce Wayne wonders what new identity he should take on as a crimefighter. He thinks to himself, "Criminals are a superstitious and cowardly lot so my disguise must be able to strike terror into their hearts." At that moment a bat flies through the window of Wayne Manor, providing the hero with the perfect symbol of darkness and fear.
As a result of these associations, bat decorations, made of rubber, foil or paper, are often displayed at Halloween parties. People sometimes dress in bat costumes on Halloween and often carry rubber bats as props to go with other Halloween costumes, such as a witch costume or a vampire costume.
Bats do not have negative associations in every culture, however. For example, the bat is a traditional Chinese symbol of long life and happiness.