'Silent bats' echolocate while gleaning noisy prey: Implications for spatial memory and attention
Department of Zoology, University of Toronto
Abstract ID Number: 129
Last modified: May 20, 2003
In familiar laboratory settings, Indian false vampire bats (Megaderma lyra) have been observed to successfully capture terrestrial, noisy prey with and without emitting echolocation calls in the absence of light. Again under familiar lab conditions, it has been shown that hunting false vampires shut off echolocation when simulated moonlight conditions allowed the use of visual information. The results of more recent research suggest that echolocation calls are emit throughout attacks in darkness but at an emission rate lower than reported for other gleaning bats. Here I present data from wild caught bats capturing prey in unfamiliar environments. The results show that under these conditions, first, this species always emits echolocation calls during attacks on noisy prey regardless of light condition and, second, this speciesí rate of emission is similar to that of most gleaning bats. I suggest that false vampires use spatial memory, vision, or both to reassess familiar hunting grounds and, as an adaptive consequence, stop emitting echolocation calls under these conditions. Among several benefits, bats might be able to pay more attention to prey-generated noises, and thus more successfully localize prey, rather than deal with the demands of processing both these and echoes in parallel through the auditory system.