The auditory anatomy of the Minke Whale (Balaenoptera acutorostrata): Insights into potential sound reception pathways in a baleen whale

ShareThis
TitleThe auditory anatomy of the Minke Whale (Balaenoptera acutorostrata): Insights into potential sound reception pathways in a baleen whale
Publication TypeConference Paper
Year of Publication2011
AuthorsYamato, M., D. R. Ketten, J. J. Arruda, S. R. Cramer, and K. Moore
Conference Name19th Biennial Conference on the Biology of Marine Mammals
Pagination319
Date Published11/2011
PublisherSociety for Marine Mammology
Conference LocationTampa, FL
Keywordsauditory anatomy, balaenoptera acutorostrata, baleen whale hearing, marine mammal hearing, minke whale, sound reception pathway
AbstractKen Norris first described a potential mandibular sound reception pathway in odontocetes in 1964. To date, sound reception paths in mysticetes remain unknown. To understand hearing mechanisms in baleen whales, a thorough examination of their auditory anatomy is required. This study combines classical dissection with biomed1cal imaging techniques such as X-ray, computerized tomography (CT), and magnetic resonance imaging (MRl) to describe the anatomy of the Minke Whale head with a focus on the ear region.
Full TextKen Norris first described a potential mandibular sound reception pathway in odontocetes in 1964. To date, sound reception paths in mysticetes remain unknown. To understand hearing mechanisms in baleen whales, a thorough examination of their auditory anatomy is required. This study combines classical dissection with biomed1cal imaging techniques such as X-ray, computerized tomography (CT), and magnetic resonance imaging (MRl) to describe the anatomy of the minke whale head with a focus on the ear region. Six individuals have been examined to date. Findings include a large, well-formed fat body adjacent to the posterior mandibular ramus and lateral to the tympano-periotic complex. This structure tapers medially, attaching to the tympano-periotic complex near the base of the tympanic membrane. The fats appear to be continuous with a smaller fat pad within the tympanic cavity, contiguous to the tympanic membrane and ossicles. Odontocetes receive sound via distinctive perimandibular fats that lead to a similar region of the tympano-periotic complex. While a fat body in baleen whales has been described in the context of the temporo-mandibular joint (Beauregard, 1882; Lambertsen et al., 1995), its relationship with the ears and auditory implications were not the focus of prior functional analyses. Notably, the majority of the tympanic bone is surrounded by a thick, fibrous, multi-layered connective tissue adjacent to the peribullar tissue dorsally. This fibrous tissue may serve as an acoustic baffle limiting incoming sound from locations other than the fat body. References: Beauregard, H. 1882. L'articulation temporomaxillaire chez les Cetaces. Journal de l'Anatomie et de la Physiologie, 18:16-26. Lambertsen R, Ulrich N, Straley J. 1995. Frontomandibular Stay of Balaenopteridae: A Mechanism for Momentum Recapture during Feeding. Journal of Mammalogy 76:877-899.