it´s all about bats
Most bats are nocturnal creatures. Their daylight hours are spent grooming, sleeping, and resting; it is during the nighttime hours that they hunt. The means by which bats navigate while finding and catching their prey in the dark was unknown until the 1790s, when Lazzaro Spallanzani conducted a series of experiments on a group of blind bats. These bats were placed in a room submerged in total darkness, with silk threads strung across the room. Even then, the bats were able to navigate their way through the room. Spallanzani concluded that the bats were not using their eyes to fly through complete darkness, but something else.
Spallanzani decided that bats were able to catch and find their prey through the use of their ears. To prove this theory, Spallanzani plugged the ears of the bats in his experiment. To his pleasure, he found that the bats with plugged ears were not able to fly with the same amount of skill and precision that they were able to without their ears plugged.
Bats seem to use their ears to locate and catch their prey, but how they accomplish this was not discovered until the 1930s, by one Donald R. Griffin. Griffin, who was a biology student at Harvard College at the time, discovered that bats use echolocation to locate and catch their prey. When bats fly, they produce a constant stream of high-pitched sounds that only bats are able to hear. When the sound waves produced by these sounds hit an insect or other animal, the echoes bounce back to the bat, and guide them to the source.