Frequency Tuning of Hearing in the Beluga Whale

Abstract

Data on frequency tuning in odontocetes are contradictory: different authors have reported filter qualities from 2 to almost 50. In this study, frequency tuning was measured in a beluga whale (Delphinapterus leucas) using a rippled-noise test stimulus in conjunction with the auditory evoked potential (AEP) technique. The response to ripple reversions was considered to indicate resolvability of the ripple pattern. The limit of ripple-pattern resolution ranged from 20 to 32 ripples per octave (rpo). A model of interaction of the ripple spectrum with frequency-tuned filters suggests that this resolution limit requires a filter quality of 29-46.