# Animations of vibration modes obtained from finite element simulations performed on the skull of a juvenile gray whale [https://doi.org/10.5061/dryad.dbrv15f8w](https://doi.org/10.5061/dryad.dbrv15f8w) ## Description of the data and file structure All animation files are GIFs. Download and open in a browser to view the animation. Mode 16: 'gw_fs_real_transdec_Esk=8_Etp=35_m=3_nev=400_a=0_sw=1k-mode_16_anim.gif' Mode 18: 'gw_fs_real_transdec_Esk=8_Etp=35_m=3_nev=400_a=0_sw=1k-mode_18_anim.gif' Mode 26: 'gw_fs_real_transdec_Esk=8_Etp=35_m=3_nev=400_a=0_sw=1k-mode_26_anim.gif' Mode 29: 'gw_fs_real_transdec_Esk=8_Etp=35_m=3_nev=400_a=0_sw=1k-mode_29_anim.gif' The geometry of the skull was extracted from a CT image, and a finite element model of the bones was constructed. Four vibration modes are shown, two for each of the ears. The modes that result in large motion of the middle ear bones are selected. Modeled modes of vibration for the tympanic bullae (a) mode 16 (324.9 Hz), (b) mode 18 (342.0 Hz), (c) mode 26 (646.8 Hz), and (d) mode 29 (718.0 Hz). The magnitude of the motion is color-coded: red is high, light blue is low. The skull is upside down, i.e., ventral side up. * Mead JG, Fordyce RE. The Therian skull: a lexicon with emphasis on the odontocetes. *Smithsonian Contributions to Zoology.* 2009; 627: 1–249. doi:10.5479/si.00810282.627. * Cranford T, Krysl P. Sound Paths, Cetaceans. Encyclopedia of Marine Mammals. 2018; (1989): 901–904. doi:10.1016/b978-0-12-804327-1.00236-3. ## Sharing/Access information Links to other publicly accessible locations of the data located in the Related Works section.

The tympanoperiotic complex (TPC) plays a crucial role in whale hearing. It is a functional unit composed of three bony structures: the periotic (firmly embedded in the skull), the tympanic bulla (suspended from the skull on flexible suspensory pedicles), and the ossicular chain that connects the stapes footplate closing the oval window in the periotic with the tympanic [Mead 2009]. Hearing of mysticetes is ostensibly facilitated by the same mechanism as in most mammals: the ossicular chain is set in motion, and the stapes footplate consequently pushes on the cochlear fluid [Cranford 2018]. The ossicular chain connects the periotic bone, which houses the inner ear, with the bulla. Therefore, the most plausible mechanism for setting the ossicles in motion is a vibration of the bulla relative to the periotic bone. A juvenile gray whale head (LACM 97758) was acquired from the Natural History Museum of Los Angeles County. The specimen had been collected and transferred to a freezer soon after death, thereby preserving its fresh condition. The specimen underwent X-ray computed tomography (CT) scanning in two phases, first intact with all tissues and subsequently after removal of soft tissues superficial to the skull, as described by Cranford [in preparation].