Bats can see as well as humans can, but they have evolved a
sophisticated method of using sound that enables them to
navigate and find food in the dark called echolocation. Bats
produce echolocation by emitting high frequency sound pulses
through their mouth or nose and listening to the echo. With this
echo, the bat can determine the size, shape and texture of
objects in its environment. Bat echolocation is so sophisticated
that these animals can detect an object the width of a human
hair. Shouting Bats & Whispering Bats Bats can be broadly
characterized by their echolocation calls as shouting bats and
whispering bats. Big brown bats and little brown bats are
shouters and produce sounds (if we could hear them) of 110
decibels or similar to the loudness of a smoke alarm. Northern
long-eared bats are whispering bats and produce sounds of 60
decibels (similar to the levels of normal human conversation).
Shouters tend to forage for food in open spaces; whisperers
glean insects from the foliage of trees and forage