Blind as a Bat
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Pictures taken from Google Images, “Blind as a bat”
Click on the image to watch the video of the song, “Blind as a bat” in the Corpse of the Bride by Meatloaf
Meaning:
When someone is as blind as a bat, that person is not able to see anything at all, or at least that person has a very poor vision.

Pictures taken from Google Images, “Blind as a bat”
Click on the image to watch the video “Blind as a bat” in Smallville by Meatloaf
Origin:
There are many expressions that use analogies; as deaf as a doornail, as slow as a turtle, as sly as a fox. Bats are animals which can´t see anything at all. The way they guide themselves while flying is by sonar waves they shout out.

Pictures taken from Google Images, “Blind as a bat”
Click on the image to watch a video about echo location for blind bikers by HDNetworldReport
Example:
Hello to every one, since I am in fact keen of reading this website’s post to be updated regularly. It consists of nice information.