Suction cup transducers, also known as “jawphones,” are now commonly used to deliver acoustic stimuli to odontocete cetaceans during hearing studies. It is often assumed that stimulation is primarily limited to the ear ipsilateral to a jawphone; however, the actual differences in auditory stimulation at the two ears are not well understood. To examine these differences, auditory evoked potentials (AEPs) were simultaneously recorded from both ears during jawphone stimulation in two bottlenose dolphins. The amplitudes and latencies of auditory nerve responses (ANRs) elicited by broadband clicks were measured as functions of stimulus level and used to estimate the difference in received level and interaural time difference (ITD) between the two ears. Results indicated that clicks received at the ear contralateral to the jawphone were attenuated by approximately 20 dB relative to the level at the ipsilateral ear. The ITD between the contralateral and ipsilateral ears was 70 μs for the first dolphin and 118 μs for the second dolphin. While these results provide support for a notable degree of acoustic isolation of the ears for jawphone-delivered stimuli, there are implications for studies involving processes such as sound localization and unilateral hearing loss.
References
1.
Aroyan
, J. L.
(2001
). “Three-dimensional modeling of hearing in Delphinus delphis
,” J. Acoust. Soc. Am.
110
, 3305
–3318
.2.
Brill
, R. L.
, and Harder
, P. J.
(1991
). “The effects of attenuating returning echolocation signals at the lower jaw of a dolphin (Tursiops truncatus)
,” J. Acoust. Soc. Am.
89
, 2851
–2857
.3.
Brill
, R. L.
, Moore
, P. W. B.
, and Dankiewicz
, L. A.
(2001a
). “Assessment of dolphin (Tursiops truncatus) auditory sensitivity and hearing loss using jawphones
,” J. Acoust. Soc. Am.
109
, 1717
–1722
.4.
Brill
, R. L.
, Moore
, P. W. B.
, Helweg
, D. A.
, and Dankiewicz
, L. A.
(2001b
). Investigating the Dolphin's Peripheral Hearing System: Acoustic Sensitivity About the Head and Lower Jaw
(SSC, San Diego
, CA
), pp. 1
–14
.5.
Brill
, R. L.
, Sevenich
, M. L.
, Sullivan
, T. J.
, Sustman
, J. D.
, and Witt
, R. E.
(1988
). “Behavioral evidence for hearing through the lower jaw by an echolocating dolphin (Tursiops truncatus)
,” Mar. Mammal Sci.
4
, 223
–230
.6.
Bullock
, T. H.
, Grinnell
, A. D.
, Ikezono
, E.
, Kameda
, K.
, Katsuki
, K.
, Nomoto
, M.
, Sato
, O.
, Suga
, N.
, and Yanagisawa
, K.
(1968
). “Electrophysiological studies of central auditory mechanisms in cetaceans
,” Z. Vergleich. Physiol.
59
, 117
–156
.7.
Cranford
, T. W.
, McKenna
, M. F.
, Soldevilla
, M. S.
, Wiggins
, S. M.
, Goldbogen
, J. A.
, Shadwick
, R. E.
, Krysl
, P.
, St. Leger
, J. A.
, and Hildebrand
, J. A.
(2008
). “Anatomic geometry of sound transmission and reception in Cuvier's beaked whale (Ziphius cavirostris)
,” Anatomical Record
291
, 353
–378
.8.
Elberling
, C.
, and Wahlgreen
, O.
(1985
). “Estimation of auditory brainstem response, ABR, by means of Bayesian inference
,” Scand. Audiol.
14
, 89
–96
.9.
Finneran
, J. J.
(2008
). Evoked Response Study Tool (EVREST) User's Guide
(SSC
, San Diego, CA)
, 112
pp.10.
Finneran
, J. J.
(2009
). “Evoked Response Study Tool (EVREST): A portable, rugged system for single and multiple auditory evoked potential measurements
,” J. Acoust. Soc. Am.
126
, 491
–500
.11.
Fraser
, F. C.
, and Purves
, P. E.
(1960
). Hearing in Cetaceans: Evolution of the Accessory Air Sacs and the Structure and Function of the Outer and Middle Ear in Recent Cetaceans
[The British Museum (Natural History)
, London
], 140
pp.12.
Houser
, D. S.
, and Finneran
, J. J.
(2006
). “Variation in the hearing sensitivity of a dolphin population obtained through the use of evoked potential audiometry
,” J. Acoust. Soc. Am.
120
, 4090
–4099
.13.
Houser
, D. S.
, Finneran
, J. J.
, Carder
, D. A.
, Van Bonn
, W.
, Smith
, C.
, Hoh
, C.
, Mattrey
, R.
, and Ridgway
, S. H.
(2004
). “Structural and functional imaging of bottlenose dolphin (Tursiops truncatus) cranial anatomy
,” J. Exp. Biol.
207
, 3657
–3665
.14.
Ketten
, D. R.
(1994
). “Functional analyses of whale ears: adaptations for underwater hearing
,” in IEEE Proceedings in Underwater Acoustics
, pp. 264
–270
.15.
Ketten
, D. R.
(1997
). “Structure and function in whale ears
,” Bioacoustics
8
, 103
–135
.16.
Ketten
, D. R.
, and Wartzok
, D.
(1990
). “Three-dimensional reconstructions of the dolphin ear
,” in Sensory Abilities of Cetaceans: Laboratory and Field Evidence
, edited by J. A.
Thomas
and R. A.
Kastelein
(Plenum Press
, New York)
, pp. 81
–105
.17.
McCormick
, J. G.
, Wever
, E. G.
, Ridgway
, S. H.
, and Palin
, J.
(1980
). “Sound reception in the porpoise as it relates to echolocation
,” in Animal Sonar Systems
, edited by R. G.
Busnel
and J. F.
Fish
(Plenum Publishing
, New York)
.18.
Møhl
, B.
, Au
, W. W. L.
, Pawloski
, J.
, and Nachtigall
, P. E.
(1999
). “Dolphin hearing: Relative sensitivity as a function of point of application of a contact sound source in the jaw and head region
,” J. Acoust. Soc. Am.
105
, 3421
–3424
.19.
Mooney
, T. A.
, Li
, S.
, Ketten
, D.
, Wang
, K.
, and Wang
, D.
(2014
). “Hearing pathways in the Yangtze finless porpoise, Neophocaena asiaeorientalis asiaeorientalis
,” J. Exp. Biol.
217
, 444
–452
.20.
Mooney
, T. A.
, Nachtigall
, P. E.
, Castellote
, M.
, Taylor
, K. A.
, Pacini
, A. F.
, and Esteban
, J.-A.
(2008
). “Hearing pathways and directional sensitivity of the beluga whale, Delphinapterus leucas
,” J. Exp. Mar. Biol. Ecol.
362
, 108
–116
.21.
Moore
, P. W. B.
, Pawloski
, D. A.
, and Dankiewicz
, L.
(1995
). “Interaural time and intensity difference thresholds in the bottlenose dolphin (Tursiops truncatus)
,” in Sensory Systems of Aquatic Mammals
, edited by R. A.
Kastelein
, J. A.
Thomas
, and P. E.
Nachtigall
(De Spil Publishers, Woerden
, The Netherlands
), pp. 11
–23
.22.
Norris
, K. S.
(1964
). “Some problems of echolocation in cetaceans
,” in Marine Bio-acoustics
, edited by W. N.
Tavolga
(Pergamon
, New York)
, pp. 317
–336
.23.
Norris
, K. S.
(1968
). “The evolution of acoustic mechanisms in odontocete cetaceans
,” in Evolution and Environment
, edited by E. T.
Drake
(Yale University Press
, New Haven, CT
), pp. 297
–324
.24.
Norris
, K. S.
(1969
). “The echolocation of marine mammals
,” in The Biology of Marine Mammals
, edited by H. T.
Andersen
(Academic Press
, New York)
, pp. 391
–423
.25.
Popov
, V. V.
, and Supin
, A. Ya.
(1991
). “Interaural intensity and latency difference in the dolphin's auditory system
,” Neuroscience Letters
133
, 295
–297
.26.
Popov
, V. V.
, and Supin
, A. Ya.
(1992
). “Electrophysiological study of the interaural intensity difference and interaural time-delay in dolphins
,” in Marine Mammal Sensory Systems
, edited by J. A.
Thomas
, R. A.
Kastelein
, and A. Y.
Supin
(Plenum Press
, New York)
, pp. 257
–267
.27.
Popov
, V. V.
, and Supin
, A. Ya.
(2001
). “Contribution of various frequency bands to ABR in dolphins
,” Hear. Res.
151
, 250
–260
.28.
Popov
, V. V.
, Supin
, A. Ya.
, Klishin
, V. O.
, and Bulgakova
, T. N.
(2006
). “Monaural and binaural hearing directivity in the bottlenose dolphin: Evoked-potential study
,” J. Acoust. Soc. Am.
119
, 636
–644
.29.
Reysenbach de Haan
, F. W.
(1956
). “Hearing in whales
,” Acta Otolaryngol. Suppl.
134
, 1
–114
.30.
Ridgway
, S. H.
(1999
). “An illustration of Norris' acoustic window
,” Mar. Mammal Sci.
15
, 926
–930
.31.
Ridgway
, S. H.
, Bullock
, T. H.
, Carder
, D. A.
, Seeley
, R. L.
, Woods
, D.
, and Galambos
, R.
(1981
). “Auditory brainstem response in dolphins
,” Neurobiology
78
, 1943
–1947
.32.
Supin
, A. Ya.
, and Popov
, V. V.
(1995
). “Temporal resolution in the dolphin's auditory system revealed by double-click evoked potential study
,” J. Acoust. Soc. Am.
97
, 2586
–2593
.33.
Supin
, A. Ya.
, Popov
, V. V.
, and Klishin
, V. O.
(1991
). “Electrophysiological study of interaural sound intensity difference in the dolphin Inia geoffrensis
,” Experientia
47
, 937
–938
.34.
Supin
, A. Ya.
, Popov
, V. V.
, and Mass
, A. M.
(2001
). The Sensory Physiology of Aquatic Mammals
(Kluwer Academic Publishers
, Boston, MA
), 332
pp.2014
U.S. Government
You do not currently have access to this content.
