Can't hear it!
The sounds emitted by bats are so high-pitched that humans cannot hear them. The acute hearing of young people can detect frequencies up to 20,000 cycles per second, but the highest frequencies produced by bats are around 50,000 cps.
Sounds to prey with
Sounds at such high frequencies yield especially clear echoes from objects that measure 5-10 millimetres, the size range of many insects.
No chance?
Does an insect stand a chance against an onrushing bat? Yes, because insects also have ears. Just behind the wings of a noctuid moth, is a tiny hearing organ sensitive to frequencies that bats produce.
