Quantifying the noseleaf and pulse dynamics in rhinolophid and hipposiderid bats

Abstract

Horseshoe bats (Rhinolophidae) and Old-World leaf-nosed bats (Hipposideridae) are two related bat families that emit their biosonar pulses nasally and diffract the outgoing wave-packets with elaborate baffle shapes (“noseleaves”). Since the noseleaf surfaces are frequently in motion during pulse emission, an experimental setup has been established to characterize the dynamics in their geometry in conjunction with the effects that this dynamics may have on the ultrasonic pulses. To achieve this goal, greater horseshoe bats (Rhinolophus ferrumequinum), great roundleaf bats (Hipposideros armiger), and Pratt's roundleaf bats (Hipposideros pratti) were trained to emit biosonar pulses while seated on a platform. At least 10 landmarks were placed on the noseleaves of the animals to track the dynamic geometry of these structures with an array of four high-speed video cameras (frame rate 400 Hz). Pairs of video frames were used to reconstruct the 3d trajectories of the noseleaf landmarks, and from these trajectori...