Bats are the only mammals capable of sustained flight. Comprising nearly 1000 species, bats are found on every continent except Antarctica; with the possible exception of the rodents they are the most successful mammals on earth.
In recent years, knowledge of bats has replaced much of the superstition and fear that has been associated with them; they are now recognized as beneficial to man by pollenating crops and consuming insect pests.
Bats are divided into two suborders:
- Megachiroptera, which comprises the larger fruit bats and flying foxes of the Old World;
- Microchiroptera, the smaller bats with a wider distribution, and which feed on insects, fish, and small animals.
The chief characteristic of bats are the wings, which are two layers of skin (the membrane) stretched over the modified and elongated finger bones of the hand (hence the order name Chiroptera, "hand wing"). Six muscles per wing produce the strokes needed to propel the bat through the air, and unlike birds, bats can dramatically alter the shape and curvature of their wings in flight, resulting in extreme manuverability. When at rest, the only digit not attached to the membrane, the thumb, is used to help the bat cling to its roost.
Microchiroptera has the ability to echolocate via sonar. Rapid clicks are uttered by bats at high frequencies well above human hearing, bounce off objects, and return as echoes; bats are apparently able to tell speed, distance, direction, and the size of surrounding objects, as well as knowing the difference between a food item, such as a flying insect, and a pebble tossed in the air.
By contrast, many species of Megachiroptera do not use sonar, instead relying on sight.
The majority of bat species feed on insects; many of these can consume their entire weight in insects in a single night of feeding. Several hunt small reptiles and mammals ; one species (Nyctalus lasiopterus) hunts and kills birds on the wing , another (Noctilio leporinus) bears long claws on its feet and specializes in catching fish . The legendary vampire bat (Desmodus rotundus) of South America is the only species of mammal that subsists exclusively on a diet of blood, and is considered a serious pest to the livestock industry there.
Bats in the Bible
And these [are they which] ye shall have in abomination among the fowls; they shall not be eaten, they [are] an abomination: the eagle, and the ossifrage, and the ospray, And the vulture, and the kite after his kind; Every raven after his kind; And the owl, and the night hawk, and the cuckow, and the hawk after his kind, And the little owl, and the cormorant, and the great owl, And the swan, and the pelican, and the gier eagle, And the stork, the heron after her kind, and the lapwing, and the bat. Leviticus 11:13-19 (KJV)
[Of] all clean birds ye shall eat. But these [are they] of which ye shall not eat: the eagle, and the ossifrage, and the ospray, And the glede, and the kite, and the vulture after his kind, And every raven after his kind, And the owl, and the night hawk, and the cuckow, and the hawk after his kind, The little owl, and the great owl, and the swan, And the pelican, and the gier eagle, and the cormorant, And the stork, and the heron after her kind, and the lapwing, and the bat. Deuteronomy 14:11-18 (KJV)