: Just before capture, the bat emits a rapid-fire burst of sound—sometimes hundreds of pulses per second—to get high-resolution tracking data in the final milliseconds [4, 6]. How We Record It

: When slowed down, these high-frequency "clicks" and "chirps" often sound like a series of rhythmic bird-like chirps or metallic "tinks" [4, 5].

When you listen to a recording of a bat approaching prey, the rhythm changes distinctly:

Since we cannot hear these sounds naturally, researchers use [5, 7]. These devices use specialized microphones to capture high-frequency audio and then either heterodyne it (shifting the pitch) or use time expansion (slowing it down) so humans can study the intricate patterns of their "acoustic maps" [5, 7].