Bats Are Not Blind

The popular phrase 'blind as a bat' has done a great disservice to the complex sensory world of these mammals. In reality, no bat species is blind. In fact, many have excellent eyesight perfectly suited for their environment. The most notable examples are the large fruit (Review) bats, or megabats, which possess big, well-developed eyes. These bats navigate twilight forests much like an owl or a cat, using their keen vision to locate fruit and flowers and to avoid obstacles. They rely almost entirely on sight, forgoing the sophisticated sonar used by their insect-eating relatives.

The misconception likely arose from observing the seemingly erratic flight of the smaller, echolocating bats, or microbats. These species are masters of bio-sonar, emitting high-frequency calls and interpreting the returning echoes to build an intricate, real-time map of their surroundings. This acoustic snapshot is so detailed it allows them to hunt minuscule, fast-moving insects in complete darkness. While this is their primary tool for hunting, it is not their only sense.

Even for these sonar specialists, vision remains a crucial part of their navigational toolkit. They use their eyes for long-distance travel, spotting large landscape features like mountains or rivers that are too far away for echolocation to be effective. Sight is also essential for detecting predators from above and for social interactions with other bats. Ultimately, bats use a sophisticated combination of senses, switching between or integrating sight and sound to create the most complete picture of their world.