Children of the night! What music they make!
No, they didn't spontaneously break into song. It was a bit more complicated:
Bats produce sounds that are not audible to human ears. First these ultrasounds were digitally reduced to frequencies that are audible. Then the different batsounds were assigned different keys on a keyboard. On this keyboard - the only real Bat-Organ - Ulrich Seidel played the Batman Theme
Same Bat-timing...very different Bat-channeling...after the jump