Bats are not blind. Like many animals, they are born blind, but gain eyesight from the time they are seven to nine days old. Bats are night creatures. They come out only at night to hunt. Although they can see reasonably well they have no special eyesight possessed by other night creatures like the cats and owls. Instead, bats fly in the dark by in the by means of a sonar system. When the bat flies, it emits a high squeaky sound, not audible to the human ear. As the sound travels outward, it hits objects and bounces back. The sound waves tell the bat where the objects are so they can be avoided. This method of locating of the objects is called echolocation. Bats fly safely at night by using their ears, not their eyes. When the bat darts about in the dark it might appear to be flying around blindly. Actually it is hunting insects, which we cannot see in the dark.