Great ears: functional comparisons of land and marine leviathan ears

TitleGreat ears: functional comparisons of land and marine leviathan ears
Publication TypeConference Poster
AuthorsKetten, D. R., J. Shoshani, J. J. Arruda, S. R. Cramer, J. S. Reidenberg, and M. Yamato
Conference Namesixth Triennial Conference on Secondary Adaptations of Tetrapods to Life in Water
Conference LocationSan Diego, CA
Year of Publication2011
Date Published2011

Elephants and baleen whales are massive creatures that respond to exceptionally low frequency signals.
We have many examples of LF and even seismic elephant and whale vocalizations, but little direct knowledge of their hearing abilities. Playbacks and behavioral observations suggest proboscidean and mysticete hearing abilities are similarly specialized for low or even infrasonic signals (Langbauer, et al 1991; Payne, et al 1986; Wartzok and Ketten 1999). This raises several interesting questions: First, their vocalizations are emitted and perceived in two media, air and water, which have radically different physical acoustic properties: 4.5-fold differences in sound
speed; three magnitudes greater acoustic impedance: Intensity = Sound Energy perpendicular to the direction of sound propagation I = pv = p2 / cr; Iair = p2/(340m/sec)(0.0013 g/cc); Iwater = p2/(1530m/sec)(1.03 g/cc); for Iwater = Iair; Pwater = 59.7•Pair Therefore, for elephants and whales to have the same percept, whale ears must accommodate 60-fold acoustic pressures. Further, a common concept is that the upper limit of hearing is inversely correlated with body mass, implying there should be little mid to high frequency hearing in any mysticete and little overlap in the hearing of these two taxa.

Keywordsauditory, baleen whale hearing, basilar membrane, cochlea, elephant, elephant hearing, elephantidae, elephants, elphantidae, impedance, infrasonic, inner ear, low frequency, mammal, mammalian, morphometry, mysticete, mysticeti, propagation, radii, signal, sound, sound signal, structure, vocalizations, whale, whales
Citation Key3585