Ear-generated Doppler shifts in bat biosonar 

A new study demonstrates that the ears of bats come with a ‘built-in ambulance’ that creates the same physical effect as the sound of an ambulance passing by. Researchers think the study of ear-generated Doppler shifts in bat biosonar could give rise to new sensory principles that could enable small, yet powerful sensors.

Source: Ear-generated Doppler shifts in bat biosonar — ScienceDaily