Bats and Rock Concerts

What is the similarity?  Well a new study as detailed by National Geographic suggests it is along the lines of decibels (which, if you are wondering, is a measurement for sound pressure).  It turns out that bats are able to produce up to 140 decibels in their high pitched voices which they use for echolocation.  A loud rock concert might do up wards of 115 to 120 decibels.  So why are we not hearing noisy bats all the time.  because humans ears are not made to hear the frequency at which bats make their shrieks.  Further the bat noise doesn’t maintain it’s strength that far (only a few inches from the animals mouth), the sound quickly diminishes in decibel power.