It is a sound which produces when strikes through a surface. or repetition of original sound is known as echo.

Conditions of echo:
1. the sound source should be 17 m away from the reflecting surface.
2. the echo should be heard after 1/10 seconds after the original sound.

Bat catch their prey by the help of echo which they produce.
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FIRST OF ALL >>> Bats can see (it is a common misconception that they can't)

Reflection of sound is known as an echo.

The 2 conditions are -

> Distance between the source and reflecting object should be at least 17.2 meters.

> The interval between original and reflected sound should be at least 0.1 seconds.

They can't see at night but due to echolocation they can sense their surroundings. Their high pitched ultrasonic waves bounce back from any object and alerts them.