Bats are active mainly at night. So the majority of bats must find their food (flying insects) in the dark while both hunter and prey are moving through the air. Cave based bats must also fly around obstacles without the light of the moon or stars.
They do this by the use of an amazingly complex system called echolocation. They emit sounds in specific ultrasonic frequency ranges that are outside the rage of human hearing… and aren’t we glad, since some of them emit sounds at over 140 decibels (dB). A loud rock concert is usually 115dB to 120dB, and 120dB is the human pain threshold.
An echo of the sound blast returns to the bat. From there the sound goes through an exquisitely designed biological system that begins with special ears used to help collect and analyze the direction and trajectory of the sound waves. The sound design of the bat ear is visible in the pictured horseshoe bat. Then the waves are directed to refined sensory cells tuned for specific frequencies used by the bat’s brain to locate and identify the flying insect. Yes... it is believed that some bats can identify the type of insect by the data in the echo.
Some bats are bisonar which means they produce two frequency types. One (CF) for detecting the target, and the other (FM) for distance and finer detail. The bat’s brain then uses all this information to identify, locate, and track the prey until the bat has it in its mouth. The whole system is tuned for specific bats and their environment. Bats flying through forests use a differently tuned system than bats which fly in the desert sky. Another complex system designed by an amazing Creator!