Because many bats hunt at night and rely on a sonar system to “see” using reflected sound waves – a system known as echolocation – people once assumed these flying mammals were blind. Hence, anyone with poor eyesight might be called “blind as a bat.” But although many species of bats have small eyes, they can all see quite clearly. In fact, researchers have learned that bats will trust their eyes more than their sonar when flying in low light. Bats evolved echolocation to hunt for bugs at night, which gave them a survival edge over mammals and birds that competed for food during the daylight hours. So think twice before you call someone blind as a bat – unless you actually want to compliment their eyesight!
Picture Credit : Google