I’ve always heard the expression, “blind as a bat” and thought that bats navigate by sonar. However recently, I saw photographs of different species of bats an noted that they all have eyes. If they are blind, the why eyes? Help!
terggie
I’ certain that you can find that one in the encyclopedia but I believe that they can see but have very poor vision undoubtedly not developed because of their cave habitat.
Well most bats I’ve seen are bound with tape where you hold them. Frankly they’d slip out of your hands otherwise.
Velcro is also quite effective.
Skelton–you are correct. Bats have normal to poor eyesight, depending on the species. They depend strongly on their accute hearing to zone in on their prey.
The saying probably arose after observing the behavior of bats in well-lighted area. Since they are used to living in dim light, bright light blinds them and causes them to fly about in an agitated manner, crashing into things. People just assumed they were blind, when in fact the bats were blindED.
SWAG: They probably relied their eyesight like most other mammals earlier in their evolution, and it was only once they began their cave habitat and nocturnal activity that the eyesight began to decline (in the species that don’t have normal eyesight).
By the way, shouldn’t this be in General Questions?
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- I got a book somewhere that says that bats have visual ranging ablilty roughly equivalent to mice, but with better low-light response. Which isn’t real surprising since in the midwest United States, bats are basically flying mice, anyway. I don’t know the range of a mouse’s vision, I can’t get them to read the damn chart. Bats do mostly locate airborne insects by listening to the sounds of the insects’ wings and not (primarily) by vision.
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- Somebody once asked if bats turn right when they leave their caves. I couldn’t find that out; a nearby cave has a few residents during the warmer months but they’re dark gray/black, small and pretty fast and they don’t leave till long after dark. I couldn’t keep a flashlight on one long enough to tell which way it turned out of the cave. - And they tell you how bats can fly around in total darkness, and it’s true, but actually being there when they do it is much more impressive than reading about it or seeing it on a TV screen. With the lights on, they avoid you by a wide margin. With the lights out, if you’re quiet they will fly so close that you feel the air disturbed by their wings. - MC
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- By the by, bats navigate by echolocation. Submarines navigate by sonar. - MC
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Some bats eat fruit and fly around in the daytime. These can see pretty well, I think.