Vertebrate Zoology - V. M. Konstantinov 2011

Chordates
Terrestrial or tetrapod vertebrates — Amniotes
Class Mammalia — Subclass Theria — Infraclass Placentalia — Order Chiroptera

Bats are taxonomically close to insectivores. They are distributed worldwide, except for the Arctic and Antarctic. The total number of species is about 1,000. The order includes two suborders: Megabats (flying foxes) and Microbats.

They are the only group of mammals adapted to true powered flight. Their wings are leathery membranes stretched between the greatly elongated fingers of the forelimbs, the sides of the body, the hindlimbs, and the tail (Fig. 193). Only the first digit of the forelimb remains free and does not take part in forming the wing. Much like birds, the Sternum features a keel to which the pectoral Muscles responsible for wing movement are attached.

Flight is highly maneuverable and controlled almost exclusively by wing movements. Contrary to popular belief, bats can take off not only from elevated perches (such as a cave ceiling or tree trunk), but also from flat ground and even from the Water's surface. In the latter case, takeoff begins with an upward leap driven by a powerful, abrupt stroke of the forelimbs.

They are crepuscular and nocturnal in habit. In addition to standard tactile corpuscles and vibrissae, their sense of Touch is mediated by numerous fine hairs scattered across The surface of the flight membranes and pinnae. Vision is poor and plays a minor role in navigation. Hearing, however, is exceptionally acute. Their hearing range is immense, spanning from 12 to 190,000 Hz (whereas the human hearing range lies between 40 and 20,000 Hz).

Class="center">

Fig. 193. Skeleton of a bat:

1 — clavicle; 2 — humerus; 3 — ulna; 4 — radius; 5 — thumb (digit I); 6 — digit II; 7 — digit III (metacarpal); 8 — Phalanges of digit III; 9, 10 — digits IV and V; 11 — Femur; 12 — calcar; 13 — interfemoral membrane

A specialized form of echolocation plays a decisive role in their orientation. Bats emit intermittent ultrasonic pulses at frequencies ranging from 30,000 to 70,000 Hz, with a pulse duration of 0.01 to 0.005 s. The pulse repetition rate depends on the distance between the animal and an obstacle. When preparing for flight, a bat emits 5 to 10 pulses per second, increasing to up to 60 pulses per second in flight just before encountering an obstacle. Ultrasounds reflected from obstacles are perceived by the animal's auditory system, enabling nocturnal flight navigation and the capture of flying insects.

Their diet is diverse, though the vast majority of species feed on insects (such as beetles and moths). During active periods, their METABOLISM is intensely high, and bats frequently consume an amount of food equivalent to roughly their own body weight within a 24-hour period.