Prey catching with and without echolocation in the Indian false vampire (Megaderma lyra)

Summary

• 1. Under laboratory conditions echolocation sounds were recorded from four Megaderma lyra catching a mouse in complete darkness from an experimental table. Flight paths and sequences of sound emission were synchronously recorded by stroboscopic photography and high-speed tape-recording (Figs. 1 and 2).

• 2. During approach toward a live mouse in 54% of 35 completely recorded flights, the bat emitted ultrasounds, but only up to five sounds could be recorded during a complete approach (Fig. 1a). During the other 46% of the 35 flights, the bat did not emit a sound, yet successfully caught the prey (Fig. 1 b).

• 3. When a dead mouse was offered, only one bat successfully echolocated the dead mouse and emitted a specific double sound sequence of intense ultrasounds. The other three bats did not take off for an approach. When mouse noises were substituted for the live mouse, the approach flight of two of the bats was immediately triggered as if a live mouse were offered. Only a few echolocation sounds were emitted in both cases.

• 4. It is concluded that M. lyra can locate the noise of live prey in complete darkness, without the use of echolocation.