Bats are mammals. Sometimes they are mistakenly called "flying rodents" or "flying rats", and they can also be mistaken for insects and birds.
Bats use echolocation to see. Bat echolocation is a perceptual system where ultrasonic sounds are emitted specifically to produce echoes. By comparing the outgoing pulse with the returning echoes the brain and auditory nervous system can produce detailed images of the bat's surroundings. This allows bats to detect, localize and even classify their prey in complete darkness. At 130 decibels in intensity, bat calls are some of the most intense airborne animal sounds.
To clearly distinguish returning information, bats must be able to separate their calls from the echoes they receive. Microbats use two distinct approaches.
1.Low Duty Cycle Echolocation: Bats can separate their calls and returning echos in time. Bats that use this approach time their short calls to finish before echoes return. This is also important because these bats contract their middle ear muscles when emitting a call to avoid deafening themselves. The time interval between call and echo allows them to relax these muscles so they can clearly hear the returning echo.
2. High Duty Cycle Echolocation: Bats emit a continuous call and separate pulse and echo in frequency. The ears of these bats are sharply tuned to a specific frequency range. They emit calls outside of this range to avoid self-deafening. They then receive echoes back at the finely tuned frequency range by taking advantage of the Doppler shift of their motion in flight. These bats must deal with changes in the Doppler shift due to changes in their flight speed. They have adapted to change their pulse emission frequency in relation to their flight speed so echoes still return in the optimal hearing range.
Although the eyes of most microbat species are small and poorly developed, leading to poor visual acuity, none of them are blind. Vision is used to navigate microbats especially for long distances when beyond the range of echolocation. It has even been discovered that some species are able to detect ultraviolet light. They also have a high quality sense of smell and hearing. Bats hunt at night to avoid competition with birds, and travel large distances at most 800 km, in their search for food.
Most microbats are nocturnal and are active at twilight. A large portion of bats migrate hundreds of kilometres to winter hibernation dens, some pass into torpor in cold weather, rousing and feeding when warm weather allows for insects to be active. Others retreat to caves for winter and hibernate for six months. Bats rarely fly in rain as the rain interferes with their echo location, and they are unable to locate their food.
The social structure of bats varies, with some bats leading a solitary life and others living in caves colonized by more than a million bats. The fission-fusion social structure is seen among several species of bats. The term "fusion" refers to a large numbers of bats that congregate together in one roosting area and "fission" refers to breaking up and the mixing of subgroups, where individual bats switching roosts with others and often ending up in different trees and with different roostmates.
Studies also show that bats make all kinds of sounds to communicate with others. Scientists in the field have listened to bats and have been able to identify some sounds with some behaviour bats will make after the sounds are made.
70% of bat species are insectivorous, locating their prey by means of echolocation. Of the remainder, most feed on fruits. Only three species sustain themselves with blood. Some species even prey on vertebrates: these are the bat">leaf-nosed bats (Phyllostomidae) of America">Central America and South America, and the two bulldog bat (Noctilionidae) species, which feed on fish. At least two species of bat are known to feed on bats: the Spectral Bat, also known as the American False Vampire bat, and the Ghost Bat of Australia. One species, the Noctule bat">Greater Noctule bat, catches and eats small birds in the air.
Predators of bats include Bat Hawks and Bat Falcons.