BATS   Leave a comment

Because they fly, bats are often mistaken for birds. Bats are mammals, however, not birds. They have soft fur and large ears. The young are born alive and get milk from their mothers.

Bats are completely specialized for flying. The bones in a bat’s wings are similar to those in a humans arms and hands. A bat holds objects with its mouth and with the hooks on its wings. It cannot walk or run. Its legs and feet are only strong enough to hold on when it hangs upside down from a perch, which is how bats rest or sleep. To start flying a bat drops from its perch. If it is on the ground it usually crawls to some height, using its wing hooks and feeble legs, until it can drop into the air. It can, however, take off from a position on the ground if necessary.

Bats can chase insects through thick forests on the darkest night without striking a branch or twig. To learn how they do so, experimenters sealed the eyes of several bats with gum and released them in a large room where many ropes hung from the ceiling. The bats flew about with their usual bullet speed without once hitting a rope.

When their ears and mouths were sealed, however, they blundered about helplessly. Further study showed that a flying bat gives a continuous cry, so high-pitched that people cannot hear it. The high-frequency waves of the cry, like radar waves, are reflected by all obstacles in the bat’s path and echo back to its sensitive ears. The animal instantly responds to the signals and avoids the obstacles.

Habits of Brown and Red Bats

About 900 kinds of bats are known, more than any other kind of mammal except rodents. One kind or another can be found in all but the coldest climates. In North America the little brown bat is the most abundant. It ranges from Alaska southward. (There is also a big brown bat in the United States.)

The little brown bat is only 3 1/2 inches (9 centimetres) long and weighs about 1/2 ounce (15 grams). It hunts insects in the air, and it may catch beetles, crickets, and other insects while crawling on the ground. It spends its daylight hours in caves and hollow trees, under eaves and roofs, and in attics.

Between May and July the female brown bats gather in dark hiding places in colonies of a hundred or more. They drive away all the males, and each one gives birth to a single, naked, pink, blind baby. There is no nest. When the mother goes out she hangs the baby up by its feet. The young reach full size and can fly when they are three weeks old.

The red bat is common from Canada southward. It is thought by many to be a beautiful little animal, about 4 1/2 inches (11.5 centimetres) long, with soft, fluffy fur. Males are orange red, frosted with white; females are a delicate chestnut.

Red bats live in forests and spend the daylight hours hidden among the leaves. Females bear from one to four young. For a few days the babies cling to the mother’s breast as she flies about seeking food.

Bats may live ten years or longer. Owls are among their few enemies. During the winter the little brown bats hibernate in caves. Red bats migrate in winter to the southern limits of their range.

Harmful and Helpful Bats

In the tropics some bats are huge. The flying foxes of the Malay region may have a wingspread of 5 feet (1.5 meters). These and other large tropical bats are fruit eaters and do great damage to crops. Flying foxes are found in Madagascar, tropical Asia, eastern Australia, and on South Pacific islands. If fruit is lacking they live by fishing. They skim over the surface of bodies of water and catch fish with their feet. Many other bats also catch fish. All bats skim the surface of water to scoop up drinks.

Vampire bats are common in parts of Central and South America but are never found in the United States. They puncture the skins of animals and sleeping humans and lap up blood as it oozes out. For some unknown reason this process is painless, and the victim is usually unaware of it.

Some vampire bats spread disease among cattle and horses. These bats get their name from the legendary vampires, which were believed to come out of their graves at night to suck blood from the living.

Insect-eating bats are extremely useful to humans. A brown bat may eat half its weight in insects in one night. In some parts of the southern United States, huge roosts, or shelters, have been erected for them to get their help in fighting insects.

The guano, or droppings, that bats deposit year after year while occupying a roost is a valuable material for fertilizer. One deposit in Carlsbad Caverns is more than a quarter of a mile (half a kilometre) long, 100 feet (30 meters) wide, and 100 feet deep. Some deposits are mined and sold.

It is not true that bats carry common lice or bedbugs. Bat parasites are peculiar to bats and will not attack humans. It is also not true that bats willingly entangle themselves in women’s hair.

The insect-eating bats of the United States and Canada usually do their best to avoid humans. On rare occasions, however, a bat suffering from rabies, or hydrophobia, will bite a human. Any person bitten by a bat should consult a doctor immediately for tests and for treatment if needed.

If a bat flies into a room through an opening, it may be easily caught and removed. Shut the door so it cannot get into the rest of the house. Soon it will be fluttering in a corner of the ceiling, trying to escape. Then toss up a large piece of soft cloth. The bat will become entangled in it and will fall with it to the floor. Open the cloth outdoors to release the bat.

Bats belong to the order Chiroptera, a name that comes from Greek words meaning “hand-winged.” They are divided into two suborders: Megachiroptera and Microchiroptera. Megachiroptera, including fruit bats and flying foxes, are fruit- or flower-eating natives of the Old World tropics. Most of this suborder depend heavily on vision to avoid obstacles.

The suborder Microchiroptera is comprised of small bats that generally prey on insects, but a number of them feed on fruit, flowers, blood, and small animals. They orient themselves by sound.

The scientific name of the little brown bat is Myotis lucifugus; the big brown bat is named Eptesicus fuscus; the red bat is named Lasiurus borealis. The common vampire bat is Desmodus rotundus.


Posted 2011/11/20 by Stelios in Education

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