“Bats are blind.”

The enduring phrase "blind as a bat" has led many to believe that these fascinating creatures lack the ability to see. This common misconception dates back centuries, with origins possibly traced to ancient observations by figures like Aristotle over 2,000 years ago. Early beliefs were likely influenced by bats' nocturnal habits, their seemingly erratic flight patterns, especially during daylight hours, and their comparatively small eyes, which gave the impression they were bumbling through the air due to poor vision. These factors, combined with a general lack of understanding about their unique sensory adaptations, cemented the idiom in popular culture.

However, scientific evidence clearly busts this myth. Bats are not blind; in fact, all species possess functional eyesight, and many have vision comparable to, or even superior to, humans, particularly in low-light conditions prevalent at dusk and dawn. While bats are famous for their remarkable echolocation, which allows them to navigate and hunt in complete darkness by emitting sound waves and interpreting the echoes, this sophisticated "sonar" system complements their vision rather than replacing it. For instance, larger fruit (Review) bats often rely heavily on their well-developed eyes to locate food and can even see in color, sometimes with better daylight vision than humans. Even smaller, insect-eating bats, while more reliant on echolocation, use their sight for long-distance navigation, distinguishing between day and night, and spotting predators.

The persistence of the myth can largely be attributed to the widespread use of the idiom itself, alongside the prominent role of echolocation in a bat's life. People mistakenly assume that because bats use sound to "see" in the dark, they must not possess the ability to see with their eyes. Additionally, their nocturnal lifestyle means humans rarely observe their visual capabilities firsthand. However, bats deftly integrate both sight and sound, utilizing their vision for broader environmental awareness and longer-range navigation, while echolocation provides detailed information about their immediate surroundings.