The Bat vampirul

The only mammal capable of sustained flight.

Bats are divided into two suborders-larger bats or megabats, and smaller bats or microbats-and 17 families. One of these families includes all megabats (more than 150 species); the other 16 families are microbats.

In all, there are 850 to 900 species of bats, far more than in any other mammalian order except for rodents-and bats probably exceed even rodents in total abundance.

Bats occur throughout the world, except in the Arctic Zone and certain remote oceanic islands. All megabats and some families of microbats are confined to the eastern hemisphere; other microbats are confined to the western hemisphere, and a few families have worldwide distribution. Bats are believed to have originated in a warm climate, probably in the early Eocene Epoch (the oldest known fossil bat is about 60 million years old), and the centre of their distribution and abundance remains the tropical and subtropical areas. Members of only four families-all of them microbats-live in temperate regions, and the number of resident species diminishes towards the poles. Members of only two families reach subarctic regions, and then only in the summer.

The megabats include the largest bats, the giant flying foxes of Africa, India, and Australo-Malaysia. They are so called because of their long, fox-like muzzles. The biggest, a megabat inhabiting Java, achieves a wingspan of 1. 7 m (5. 6 ft) and a body length of 42 cm (16. 7 in). Many species of megabats are smaller than the largest microbats, however, the distinction between the suborders being based on tooth form and major skeletal differences rather than size alone. The smallest microbat, Kittis hog-nosed bat of western Thailand, is only 2. 9 to 3. 3 cm (1. 1 to 1. 3 in) long and weighs only about 2 g (0. 07 oz), making it one of the tiniest of mammals. The differences between microbats and megabats are sufficient, in fact, to suggest that they are of different evolutionary origin, with the megabats appearing much more recently than the microbats.

Among living vertebrates, true flight is limited to bats and birds. Unlike most birds, however, bats are able to fly at relatively low speeds with extreme manoeuverability. The wing is a thin, fleshy membrane supported near its leading edge by the greatly elongated bones of the forelimb and second finger, and towards the tip and rear by the even more attenuated third, fourth, and fifth fingers. It is attached along the midline of the trunk and outward-directed limbs, and in various species it extends between highlimbs and tail. Only the first finger, or thumb, is free, and in most bats it alone is clawed, together with the toes. This structure enables bats to vary the convexity of the wings dramatically and thus vary their aerodynamic lift.

All microbats navigate-and most insectivorous species also target their prey-by echolocation.

This is the pulsed emission of high-frequency sounds that are reflected back as echos to a bats ears ...