Figure 2.

Sound-pressure waveforms for a representative echolocation sound emitted by Eptesicus and for echoes a or b₁ + b₂ delivered to the bat by the apparatus in Fig. 1A. Overlap and interference of b₁ and b₂ alters the waveform of two-point echoes according to their time separation (0, 3, 10, 30, 100 μs). The stimuli reaching the bat are not “points” as implied schematically by Fig. 1 but sounds several milliseconds long, and the apparent separation of b₁ and b₂ in Fig. 1 is obscured when the echoes overlap and interfere with each other.