Sounds humans can't hear
There's more to this familiar animal as a number of elephant sounds fall in the inaudible infrasonic range of between one and 20 hertz.
A tiger's roar is known for paralyzing its victims. Still, there may be more to tiger sounds than just what humans hear.
Bats do this by using squeaks and clicks up to 160 times per second, which range in frequency from 20 to 200 kilohertz.
Ultrasonic finger friction:
When you gently rub your thumb and index finger together, the friction creates an ultrasonic signal.
Lightning bolts are associated with thunder, but these powerful phenomena also produce sounds that humans can't hear.
Whales have enchanted people for centuries, and what's even more fascinating is that these animals can vocalize and hear very low-pitched, or infrasonic, sound.
Acoustic weapons may emit audible and inaudible sounds that humans can't even hear.