Blind as a bat is an expression people use to describe those who cannot see very well. Now, mind you, bats actually see quite well. Despite this, bats are nocturnal animals and so they hunt when it is dark out. Therefore, they cannot see very well when they are hunting. So they use another form of “seeing” called echolocation. Although, not all bats do this; most megabats do not echolocate.

Most bats, including the vampire bat, begin feeding at dusk. They use their eyes until the light fades away and seeing becomes difficult. Then they use another way of “seeing”, which involves sounds and echoes. In the dark, these bats send about 20 to 30 squeaks or clicks per second. The sounds are so high pitched that we cannot hear them. They have to be high pitched, because the higher the pitch, the smaller the object that can be detected. Each species has its own way of sending out these sounds, through either the nose or the mouth. In the case of the vampire bat, it is through the nose.

The sound waves spread out in a small arc in front of the bat’s face. These sound waves or pulses are also called ultrasound. When the sound waves strike an object they echo, or bounce back. The sound waves are then picked up by the bats ears. Ever wonder why bats have such large ears? Well, that is why. The echoes tell the bat where things are as well as what they are. Now, Vampire bats are also unique among other bats because they are known as leaf nose bats.

Leaf nose bats have highly developed folds of skin called nose-leafs around their nose. Scientists think that these nose leafs help the bat to direct the echolocation calls. Work with these bats has found that the nose-leaf is important in the transmission of echolocation calls. Although bats use echolocation while hunting, it is also used so that they may fly at night without hitting branches or other objects.