A Novel Understanding of Phocidae Hearing Adaptations Through a Study of Northern Elephant Seal ( Mirounga angustirostris) Ear Anatomy and Histology
ABSTRACT The most conspicuous aural adaptation in northern elephant seals (NES) is complete absence of an auricle and a tortuous collapsed external acoustic meatus. The NES epitympanic recess contains massive ossicles immersed in the middle ear cavernous sinuses. Engorgement of the cavernous sinuses...
Published in: | The Anatomical Record |
---|---|
Main Authors: | , , , , , , , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2018
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1002/ar.24026 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Far.24026 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ar.24026 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ar.24026 |
id |
crwiley:10.1002/ar.24026 |
---|---|
record_format |
openpolar |
spelling |
crwiley:10.1002/ar.24026 2024-06-02T08:06:01+00:00 A Novel Understanding of Phocidae Hearing Adaptations Through a Study of Northern Elephant Seal ( Mirounga angustirostris) Ear Anatomy and Histology Smodlaka, Hrvoje Khamas, Wael A. Jungers, Hali Pan, Roman Al‐Tikriti, Mohammed Borovac, Josip A. Palmer, Lauren Bukac, Martina Western University of Health Sciences, College of Veterinary Medicine, from Office of the Associate Dean for Research, Focused grant program 2018 http://dx.doi.org/10.1002/ar.24026 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Far.24026 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ar.24026 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ar.24026 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor The Anatomical Record volume 302, issue 9, page 1605-1614 ISSN 1932-8486 1932-8494 journal-article 2018 crwiley https://doi.org/10.1002/ar.24026 2024-05-03T11:33:50Z ABSTRACT The most conspicuous aural adaptation in northern elephant seals (NES) is complete absence of an auricle and a tortuous collapsed external acoustic meatus. The NES epitympanic recess contains massive ossicles immersed in the middle ear cavernous sinuses. Engorgement of the cavernous sinuses would make ossicles fully buoyant during deep diving. NES have a comparatively larger cochlear nerve, which carries a significantly larger number of axons than in terrestrial mammals, which would give them auditory ability similar to the obligate marine mammals such as cetaceans. Our calculations show that the traditional “air‐dependent” impedance matching mechanism in NES functions to just half of the capacity compared with the one described in terrestrial mammals. Impedance matching would be further hindered in NES while diving due to fully collapsed external acoustic meatus. Thanks to similarities of acoustic impedance between the sea water, soft tissues, and blood sinuses, very little sound energy would be reflected and lost. When sound is generated underwater, the large ossicles, buoyant in the cavernous sinus, would not move due to oscillation of tympanic membrane. Rather, they would be oscillating due to their inertia and process of acoustic streaming. Our mathematical simulation shows that an increase in sound frequency would cause increased displacement of the stapedial footplate and thus transmit the sound energy to the inner ear. We contend that during diving, impedance matching and sound signal amplification in the middle ear courses through the cavernous sinuses and oscillates the enlarged ossicles, thus enabling a high‐frequency ultrasonic hearing range in Phocidae. Anat Rec, 302:1605–1614, 2019. © 2018 American Association for Anatomy Article in Journal/Newspaper Elephant Seal Elephant Seals Wiley Online Library Nes ENVELOPE(7.634,7.634,62.795,62.795) Nes’ ENVELOPE(44.681,44.681,66.600,66.600) Recess ENVELOPE(-61.516,-61.516,-64.500,-64.500) The Anatomical Record 302 9 1605 1614 |
institution |
Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
ABSTRACT The most conspicuous aural adaptation in northern elephant seals (NES) is complete absence of an auricle and a tortuous collapsed external acoustic meatus. The NES epitympanic recess contains massive ossicles immersed in the middle ear cavernous sinuses. Engorgement of the cavernous sinuses would make ossicles fully buoyant during deep diving. NES have a comparatively larger cochlear nerve, which carries a significantly larger number of axons than in terrestrial mammals, which would give them auditory ability similar to the obligate marine mammals such as cetaceans. Our calculations show that the traditional “air‐dependent” impedance matching mechanism in NES functions to just half of the capacity compared with the one described in terrestrial mammals. Impedance matching would be further hindered in NES while diving due to fully collapsed external acoustic meatus. Thanks to similarities of acoustic impedance between the sea water, soft tissues, and blood sinuses, very little sound energy would be reflected and lost. When sound is generated underwater, the large ossicles, buoyant in the cavernous sinus, would not move due to oscillation of tympanic membrane. Rather, they would be oscillating due to their inertia and process of acoustic streaming. Our mathematical simulation shows that an increase in sound frequency would cause increased displacement of the stapedial footplate and thus transmit the sound energy to the inner ear. We contend that during diving, impedance matching and sound signal amplification in the middle ear courses through the cavernous sinuses and oscillates the enlarged ossicles, thus enabling a high‐frequency ultrasonic hearing range in Phocidae. Anat Rec, 302:1605–1614, 2019. © 2018 American Association for Anatomy |
author2 |
Western University of Health Sciences, College of Veterinary Medicine, from Office of the Associate Dean for Research, Focused grant program |
format |
Article in Journal/Newspaper |
author |
Smodlaka, Hrvoje Khamas, Wael A. Jungers, Hali Pan, Roman Al‐Tikriti, Mohammed Borovac, Josip A. Palmer, Lauren Bukac, Martina |
spellingShingle |
Smodlaka, Hrvoje Khamas, Wael A. Jungers, Hali Pan, Roman Al‐Tikriti, Mohammed Borovac, Josip A. Palmer, Lauren Bukac, Martina A Novel Understanding of Phocidae Hearing Adaptations Through a Study of Northern Elephant Seal ( Mirounga angustirostris) Ear Anatomy and Histology |
author_facet |
Smodlaka, Hrvoje Khamas, Wael A. Jungers, Hali Pan, Roman Al‐Tikriti, Mohammed Borovac, Josip A. Palmer, Lauren Bukac, Martina |
author_sort |
Smodlaka, Hrvoje |
title |
A Novel Understanding of Phocidae Hearing Adaptations Through a Study of Northern Elephant Seal ( Mirounga angustirostris) Ear Anatomy and Histology |
title_short |
A Novel Understanding of Phocidae Hearing Adaptations Through a Study of Northern Elephant Seal ( Mirounga angustirostris) Ear Anatomy and Histology |
title_full |
A Novel Understanding of Phocidae Hearing Adaptations Through a Study of Northern Elephant Seal ( Mirounga angustirostris) Ear Anatomy and Histology |
title_fullStr |
A Novel Understanding of Phocidae Hearing Adaptations Through a Study of Northern Elephant Seal ( Mirounga angustirostris) Ear Anatomy and Histology |
title_full_unstemmed |
A Novel Understanding of Phocidae Hearing Adaptations Through a Study of Northern Elephant Seal ( Mirounga angustirostris) Ear Anatomy and Histology |
title_sort |
novel understanding of phocidae hearing adaptations through a study of northern elephant seal ( mirounga angustirostris) ear anatomy and histology |
publisher |
Wiley |
publishDate |
2018 |
url |
http://dx.doi.org/10.1002/ar.24026 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Far.24026 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ar.24026 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ar.24026 |
long_lat |
ENVELOPE(7.634,7.634,62.795,62.795) ENVELOPE(44.681,44.681,66.600,66.600) ENVELOPE(-61.516,-61.516,-64.500,-64.500) |
geographic |
Nes Nes’ Recess |
geographic_facet |
Nes Nes’ Recess |
genre |
Elephant Seal Elephant Seals |
genre_facet |
Elephant Seal Elephant Seals |
op_source |
The Anatomical Record volume 302, issue 9, page 1605-1614 ISSN 1932-8486 1932-8494 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/ar.24026 |
container_title |
The Anatomical Record |
container_volume |
302 |
container_issue |
9 |
container_start_page |
1605 |
op_container_end_page |
1614 |
_version_ |
1800750899724812288 |