Bats - Flying Mammals
Bats are the only mammals that can fly. Like all mammals they feed their young ones milk. We don’t see bats very often because they usually fly around only at night. During the daytime they hang in dark rooms of buildings, caves, hollow trees and other dark places.
There are about 900 types of bats. They live all over the world except in colder regions. You can often find them in groups, called colonies. If you see one bat flying around there are probably others nearby.
Bats can grow to be big or small. The largest ones have a wingspan of up to 1.5 metres; others are only 15 cm wide. The mouth of a bat is similar to the one of a rat or fox. They have large, pointed ears and grey or brown fur.
Bats have long arms and hands with especially long fingers. These are connected to the legs with membranes, which form their wings. The muscles in them make it easy for a bat to fly. When taking a rest a bat usually hangs upside down with its claws connected to a hard surface.
How bats live
Bats are creatures that are only active at night. They sleep during the daytime and come out at night in search of food. Flying around at night means meeting fewer enemies and being able to catch more insects than during the day because they don’t have to compete with birds for food. Some bats eat insects, fruit and pollen ; others are meat eaters that feed on birds and smaller bats.
In some regions bats are very important. They eat away insects that damage crops and they also pollinate plants, especially in tropical regions. By flying around they help plants disperse their seeds. However , people often harm bats by destroying their caves and roosting places.
Depending on the type, female bats are pregnant for up to five or six months and have their babies one at a time. They are usually born in late spring or early summer. Babies hang on to their mother’s fur with their own sharp teeth and claws . Baby bats grow to their full size after about a month. Bats can live up to 30 years, but many of them die shortly after birth.
Bats have been around for about 50 million years. During this time they have not changed that much. Scientists think that bats may have evolved from mammals that could climb trees and then jump to catch insects. Over the years wings may have evolved from their limbs .
The most famous bats are the vampires of South and Central America. The legends and stories about them are mostly wrong. Although they do bite other animals and maybe even humans, they suck only a small amount of blood and then fly away. These bats are dangerous, not because their victims die of blood loss but because they spread infections like rabies.
Bats cannot live in extremely cold surroundings . Some fly to warmer climates while others spend the winter months roosting in dark caves . Bats can hang with their heads down for many weeks. They have a layer of fat that stores food so that they can survive during the cold period.
How bats see
For a long time people have been wondering about how bats can fly in the dark. Today we know that bats depend on a technique called echolocation. In 1920 a Cambridge university professor found out that bats send out ultrasonic signals that humans cannot hear. These signals bounce off anything that is in a bat’s flight path . Bats use these echoes to locate objects in the dark. It is similar to the radar that planes and the sonar that submarines use.
Downloadable PDF Text- and Worksheets
- although = while
- amount =how much of something
- blood loss = if you lose a lot of blood
- bounce off = to jump back from an object
- cave = a natural hole in a hill or mountain
- claw = sharp curved nail of an animal or a bird
- compete = to fight for
- connect = fix to, tie to
- creature = living thing
- crops = plants like wheat or rice that farmers produce to make food
- damage = destroy
- depend on = here: the different species carry babies for a different length of time
- destroy =to damage so badly that you cannot use something any more
- disperse = to spread in different directions
- enemy = someone or something that is not your friend
- especially =above all, mainly
- evolve = to change slowly over a longer period of time
- except =apart from , not including
- feed = give food to
- female =relating to a woman
- flight path = the course that a bat or a bird is flying
- fur = the thick soft hair of an animal
- harm = damage , hurt
- hollow = empty inside
- however = but
- layer =here: material between two parts
- limb = an arm or a leg
- locate = find
- mammal = type of animal that drinks milk from its mother when it is young
- membrane = a very thin piece of skin that covers or connects parts of your body
- pointed = very sharp at the end
- pollen = the fine powder that a flower produces. It is carried away by the wind or by insects to other flowers which then produce seeds
- pollinate = to give a flower or a plant pollen so that it can produce seeds
- pregnant = to have an unborn baby in your body
- rabies = a very dangerous animal disease . You can catch it if you get bitten by an infected animal
- radar = a machine that uses radio waves to find out where things are
- roost = to rest or sleep somewhere
- scientist = someone who works or is trained in science
- similar = like
- size = how big something is
- sonar = a machine that uses sound waves to find out where things are
- spread =to move from one place to another
- store = to keep so that you can use later on
- submarine = a ship that can stay and travel under water
- suck = to pull out with your mouth
- surface = the top layer of an object
- surroundings = the world or place around you
- survive = to stay alive
- ultrasonic = sound that is too high for a human to hear
- upside down = the top is at the bottom and the bottom at the top
- victim =here: the people or animals that they bite
- wingspan = the distance from one end of the wing to the other