Audible range

　Human ear can hear sounds between frequencies of 20Hz and 20000Hz. The range is colled the audibility range.
Sound waves of more than 20000Hz are ULTRASONIC and cannot usually be heard by humans.

　　　　

Animals audible range

　Bat emits ultrasonic waves to catch flying insects. Many of the animals can hear sound at a higher frequency than humans.

　　　　　　　　　　Comparison