Humans cannot hear what bats can hear. This makes it hard to catch them and figure out how they use their amazing sense of hearing to navigate their environment
Bats are one of the only animals that can hear ultrasound. Humans cannot hear this high-frequency sound, so it is not practical to use ultrasound as an animal tracking method because it can’t be translated into a usable signal by humans. However, bats are able to hear something humans don’t hear and that’s information about objects in the bat’s environment.
Humans cannot hear bats call to each other, but humans can hear the echoes of those calls. A bat uses the distance between the source and the receiver to estimate its position in three dimensions. The bat hears these echoes as sound waves coming from specific directions. Most bats generate calls with a single frequency, though some generate calls that consist of multiple frequencies. These bats’ hearing abilities are different from humans’, who can only distinguish a narrow set of frequencies.
Humans cannot hear bats in the same way they do. Bats are able to detect ultrasonic sounds at an unbelievable frequency of up to 120,000 Hz! This makes them far superior than humans who can only hear up to 6-9 KHz. It turns out that this difference is not some minor detail but rather has a great impact on their ability for echolocation.