Numerical-modeling-based investigation of sound transmission and reception in the short-finned pilot whale (Globicephala macrorhynchus)

Abstract

The sound-transmission, beam-formation, and sound-reception processes of a short-finned pilot whale (Globicephala macrorhynchus) were investigated using computed tomography (CT) scanning and numerical simulation. The results showed that sound propagations in the forehead were modulated by the upper jaw, air components, and soft tissues, which attributed to the beam formation in the external acoustic field. These structures owned different acoustic impedance and formed a multiphasic sound transmission system that can modulate sounds into a beam. The reception pathways composed of the solid mandible and acoustic fats in the lower head conducted sounds into the tympano-periotic complex. In the simulations, sounds were emitted in the forehead transmission system and propagated into water to interrogate a steel cylinder. The resulting echoes can be interpreted from multiple perspectives, including amplitude, waveform, and spectrum, to obtain the acoustic cues of the steel cylinder. By taking the shortfinned pilot whale as an example, this study provides meaningful information to further deepen our understanding of biosonar system operations, and may expand sound-reception theory in odontocetes.

Swim bladder resonance enhances hearing in crucian carp (Carassius auratus)

“…Recently, a new experimental setup was used to visualize the motion of the isolated otoliths in 4D, providing insights into the motion of auditory structures (Maiditsch et al, 2022). Besides, finite element modeling offers an alternative way to study the roles of the otoliths in fish hearing and has been widely used in odontocetes to investigate sound transmission and reception (Cranford and Krysl, 2015; Song et al, 2021; Tubelli et al, 2018), which may facilitate more studies on hearing mechanism in fish.…”

Sound Reception in the Yangtze Finless Porpoise and Its Extension to a Biomimetic Receptor

“…More details concerning computed tomography scanning, sound speed, and density measurements can be found in our previous paper [ 32 ]. The compressional and shear wave speeds of the skull structures were set as 3380 m/s and 2200 m/s respectively, and the density was 2035 kg/m 3 [ 16 , 39 ].…”

“…More details concerning computed tomography scanning, sound speed, and density measurements can be found in our previous paper [32]. The compressional and shear wave speeds of the skull structures were set as 3380 m/s and 2200 m/s respectively, and the density was 2035 kg/m 3 [16,39]. The directivities of sound reception were addressed for 54 kHz at frequency domain, at which the finless porpoise had the best hearing sensitivity [35,36].…”