Yes a?? the bats squeak.

Q:  Last week my wife and I watched the bats leave from under the Congress Ave. bridge, but she couldn’t hear them.  She even asked, “Don’t bats usually squeak?”  She’s not deaf, so why can’t she hear them? 

A:  The squeak bats make is very high pitched.  At the Congress Ave. bridge, there are so many bats, the squeaking is normally easy to hear.  Your wife might have lost a lot of hearing at the frequency range, or pitch, that matches the bats’ squeak.  This means even though you could hear the bats easily, she could not. 

  Your wife’s hearing at other lower frequencies might be closer to normal, which means she can hear and understand voices well.  If she says ‘what’ a lot, asks people to repeat words, or does not respond well to questions, she may have hearing loss in the range where we detect and decipher speech