Sound-absorbing fur helps moths avoid bat predation.
Neil and his colleagues measured the acoustic qualities of fur found on the thoraxes and wing joints of moths and butterflies. Their analysis showed moth fur was thicker and denser than butterfly fur. In the lab, tests showed moth fur was better at absorbing ultrasonic waves.
The less a bat's acoustic signals echo off an object, the harder it is for a bat to recognize the object.
https://www.upi.com/Sound-absorbing-fur-helps-moths-avoid-bat-predation/4801541531170/