Hearing in the North Atlantic right whale: Anatomical predictions

• Published in: The Journal of the Acoustical Society of America 2004-05, Vol.115 (5_Supplement), p.2442-2442
• Main Authors: Parks, Susan E., Ketten, Darlene R., O’Malley, Jennifer Trehey, Arruda, Julie
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4782113

Understanding the hearing abilities of large whales is important to determine the impacts of anthropogenic sources of sound. Right whales are not amenable to traditional physiological techniques to test hearing. Previous research on the hearing of marine mammals has shown that functional morphometric models are reliable estimators of hearing sensitivity in marine species. Morphometric analyses of 18 inner ears from 13 stranded right whales were used in the development of a preliminary model of the frequency range of hearing. All ears were scanned with computerized tomography (CT). Four ears showing the best preservation were processed into slides for measurements of the basilar membrane. Calculated basilar-membrane length averaged 55.7 mm (range 50.5–61.7 mm). The ganglion cell density/mm averaged 1842 ganglion cells/mm. Membrane length and ganglion cell density were used to predict a total ganglion cell count of approximately 102 500 ganglion cells for right whales. The thickness/width measurements of the basilar membrane from slides resulted in an estimated frequency range of approximately 10 Hz–22 kHz based on established marine mammal models. Additional measurements from more specimens will be necessary to develop a more robust model of the right whale hearing range. a)Currently at Cornell University Bioacoustics Research Program.