In November, we set our clocks an hour forward and officially say good-bye to an hour of daylight every evening. From now until spring, we're going to be spending most of our non-working hours in the dark: commuting home from the office when it's dark, making dinner when it's dark, meeting friends when it's dark, getting the kids to and from a million stupid activities in the dark. Ken Jennings, of Jeopardy! fame, is going to brighten this gloomy month with the light of knowledge, debunking some long-held myths about other nocturnal urban wanderers: the birds and critters you might see on a streetlit November night.
The Debunker: Are Bats Blind?
Bats are creepy flying nightmare-rats, but nature has taken pity on them in their grotesquery, and gifted them with one of the animal kingdom's all-time great superpowers: echolocation. Many bats emit ultrasonic chirps whose echoes they can use to navigate, communicate with other bats, and find prey. In other words, they can hunt at night without using eyesight. But bat-sonar wasn't proven until 1940, when Harvard zoologist Donald Griffin published his landmark paper on the phenomenon. The common expression "blind as a bat," however, dates back to the late 16th century. What gives?
Nineteenth-century scholars of English idioms record that "blind as a bat" was coined in reference to a bat's behavior indoors--when a bat accidentally blunders into a well-lighted space, it flies around crazily, as if blind. Blinded by the light, as Springsteen might put it. Given this behavior, even folks with no knowledge of echolocation would suspect that bat eyes, adapted to hunting at night, were next to useless in bright light.
In fact, there is no such thing as a blind bat. Contrary to popular belief, all bats can see. The "megabats," which vary in size from fruit bats all the way up to five-foot-long flying foxes, have large eyes, adapted mostly to daytime flying, and color vision. And scientists have recently discovered that even microbats, the ones with the magic sonar powers, can see passably well through their weak little eyes, even in daylight. You see, they need to know when it's getting dark out, or they can't hunt. Sonar is great, but it can't see a beautiful sunset.
Quick Quiz: The traditional practice of eating "bush meat"--mostly made of fruit bats--has been blamed by some experts for what recent news event?
Ken Jennings is the author of six books, most recently his Junior Genius Guides, Because I Said So!, and Maphead. He's also the proud owner of an underwhelming Bag o' Crap. Follow him at ken-jennings.com or on Twitter as @KenJennings.