Northern Elephant Seal Field Bioacoustics And Aerial Auditory Masked Hearing Thresholds In Three Pinnipeds PDF Download

The data obtained during this award period provide comparative measurements of underwater and aerial hearing sensitivity in pinnipeds and the effects of exposure to underwater and aerial noise. Much greater aerial sensitivity than previously documented in pinnipeds was demonstrated in individuals from three species. These data were obtained in a highly controlled acoustic testing environment and suggest that most, if not all, previous aerial pinniped audiograms were noise limited. Similar simultaneous (masking) and residual (auditory fatigue) effects of noise exposure were demonstrated in air and water. Noise exposure in the auditory fatigue experiments was systematically varied in both exposure level and exposure duration to investigate the relative importance of these noise parameters in causing temporary changes in hearing sensitivity. Age-related changes in hearing were also demonstrated and indicated most severe hearing losses at relatively high test frequencies. The combined results have a number of practical and theoretical implications and, most notably, indicate that pinniped cochlear processes are similar both in air and water to those occurring in terrestrial mammals.