A prediction of the minke whale (Balaenoptera acutorostrata) middle-ear transfer function

Abstract

The lack of baleen whale (Cetacea Mysticeti) audiograms impedes the assessment of the impacts of anthropogenic noise on these animals. Estimates of audiograms, which are difficult to obtain behaviorally or electrophysiologically for baleen whales, can be made by simulating the audiogram as a series of components representing the outer, middle, and inner ear (Rosowski, 1991;Ruggero and Temchin, 2002). The middle-ear portion of the system can be represented by the middle-ear transfer function (METF), a measure of the transmission of acoustic energy from the external ear to the cochlea. An anatomically accurate finite element model of the minke whale (Balaenoptera acutorostrata) middle ear was developed to predict the METF for a mysticete species. The elastic moduli of the auditory ossicles were measured by using nanoindentation. Other mechanical properties were estimated from experimental stiffness measurements or from published values. The METF predicted a best frequency range between approximately 30 Hz and 7.5 kHz or between 100 Hz and 25 kHz depending on stimulation location. Parametric analysis found that the most sensitive parameters are the elastic moduli of the glove finger and joints and the Rayleigh damping stiffness coefficient b. The predicted hearing range matches well with the vocalization range.

A sense of scale: Foraging cetaceans' use of scale‐dependent multimodal sensory systems

“…, Tubelli et al . ). The low frequency calls produced by baleen whales facilitate large propagation distances, dependent on transmission loss due to environmental conditions and source level.…”

Relationships of cochlear coiling shape and hearing frequencies in cetaceans, and the occurrence of infrasonic hearing in Miocene Mysticeti

“…In odontocetes, a high-frequency waterborne sound is transmitted through the lower jaw via a fat pad to the tympanic plate and then through the ossicular chain to the oval window (Nummela et al, 2007). The sound perception pathway in mysticetes remains unknown, but several mechanisms have been presumed by different hearing models, such as the fatty sound reception pathway in minke whales (Balaenoptera acutorostrata; Yamato et al, 2012), a skull-vibration-enabled bone conduction mechanism in fin whales (Balaenoptera physalus; Cranford and Krysl, 2015), or a sound pathway via the glove finger and via the thin region of tympanic bone for lower and higher frequencies, respectively, in minke whales (Tubelli et al, 2012).…”

The Malleable Middle Ear: An Underappreciated Player in the Evolution of Hearing in Vertebrates

“…Also, in mysticetes the tympanic and periotic bones are fused to a closed bulla, but this bulla is firmly attached to the squamosal bone, so the acoustical isolation of the ear is not as complete as in the odontocetes . Most notably, however, the middle ear ossicles are considerably more massive and the connections between them looser than in the odontocetes (Tubelli et al, 2012). The skull also contains a large fat body that contacts the ossicles.…”

“…The workings of the mysticete middle ear are unknown. A recent study (Tubelli et al, 2012) investigated the middle ear transfer function (in response to vibration stimulation) in the minke whale (Balaenoptera acutorostrata) using anatomical measurements of the middle ear and finite element modeling. This study suggests that the glove finger is the most efficient input for low frequency sound to the inner ear (peak vibrations at 100-2000 Hz), whereas the thin portion of the tympanic bone may be a secondary input for higher frequencies (peak vibrations at 3000-4000 Hz).…”