Localization of acoustic windows in the beluga by acoustic delays from different sound-source positions

Abstract

Acoustic windows were localized by acoustic delays from different sound-source positions in a beluga whale (Delphinapterus leucas). The delays were measured by recording the earlies component of the auditory evoked potential (AEPs) to short tone pips. This component recorded from the lateral head surface reflects the activity of the auditory nerve and features true monaural properties. Monaural nature of the component allows to localize an acoustic window with a better precision than binaural components. The acoustic delays were measured from a sound source at different positions at frequencies from 22.5 to 90 kHz (half-octave steps).A common sound-receiving region was identified for all these frequencies. The relation of the results to hypotheses of sound conduction in odontocetes is discussed. The use and care of the animals were adhered to the guidelines of the Russian Academy of Sciences for Research Involving Human and Non-Human Animals.