Noseleaf furrows in a horseshoe bat act as resonance cavities shaping the biosonar beam.
Horseshoe bats emit their ultrasonic biosonar pulses through nostrils surrounded by intricately shaped protuberances (noseleaves). While these noseleaves have been hypothesized to affect the sonar beam, their physical function has never been analyzed. Using numerical methods, we show that conspicuous furrows in the noseleaf act as resonance cavities shaping the sonar beam. This demonstrates that (a) animals can use resonances in external, half-open cavities to direct sound emissions, (b) structural detail in the faces of bats can have acoustic effects even if it is not adjacent to the emission sites, and (c) specializations in the biosonar system of horseshoe bats allow for differential processing of subbands of the pulse in the acoustic domain.
Zhuang
Qiao
Q
School of Information Science and Engineering, Shandong University, Shanda Nanlu 27, 250100 Jinan, China.
Müller
Rolf
R
D000162:Acoustics; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002685:Chiroptera / Q000033:anatomy & histology* / Q000502:physiology*; D021621:Imaging, Three-Dimensional; D008953:Models, Anatomic; D014465:Ultrasonics