They may emit as many as 200 beeps per second
I believe the answer is:
bats
(Other definitions for bats that I've seen before include "Hutton and Gilligan" , "out to lunch" , "Loopy; mammals" , "Clubs; flying mammals" , "Crazy; night-fliers" .)
I believe the answer is:
bats
(Other definitions for bats that I've seen before include "Hutton and Gilligan" , "out to lunch" , "Loopy; mammals" , "Clubs; flying mammals" , "Crazy; night-fliers" .)