Scientists call such high-pitched sounds ultrasonic. Ultra means beyond, and the word sonic refers to sound. These are sounds beyond the human ability to hear. While the human ear can hear sounds up to 20,000 hertz, bats make sounds at a frequency higher than that, making us unable to hear them. The science that studies this type of sound is called ultrasonic.
The ultrasonic squeaks of the bat help it to avoid obstacles because the sounds are reflected towards the bat as echoes from anything solid with which it might collide. This process is called echolocation, which means locating something by the use of echoes. It is often rumored that bats are blind. However, they are not blind, but as the experiment proves, it would not make much of a difference. During one experiment undertaken by naturalists, some bats were masked so that they could not see at all. Then they turned loose in a room where metal wires were strung a foot apart. The bats flew without any difficulty. But when their ears were plugged, or their mouths were gagged, they collided with the wires and even with the walls of the room.
The bats produce a sharp clicking sound that echoes back from any obstacle in their way. They use these to navigate and find food. They can detect insects as small as a mosquito in their way which they can then plunge on and eat. Some insects like moths, beetles, or crickets have the ability to hear the squeaks of the bat, and upon hearing them, they either change their path or start to fly in a zig-zag manner to confuse the bat.
For a long time, people thought that bats were guided by special senses in their wings, but when the wings were covered with nail polish, the bats flew as usual. We know now that their system for avoiding collision depends on their ability to hear ultrasonic echoes. In short, bats are equipped with a sort of natural radar.
Many myths have surrounded this creature of the dark. People think they are blind, or they have some special powers to see in the dark. It turns out that these are only myths after all. The bats are like all animals who have been equipped by nature in a special scientific manner. The scientists who developed radars and locating systems for military usage were actually inspired by the bats. But unlike bats’ built-in radar system, they used electromagnetic radiation and received their reflections back to detect and identify objects that may be too far to be seen yet.