Peer-Reviewed Journal Details
Mandatory Fields
Davenport, J;Cotter, L;Rogan, E;Kelliher, D;Murphy, C
2013
December
The Journal of Experimental Biology
Structure, material characteristics and function of the upper respiratory tract of the pygmy sperm whale
Validated
Optional Fields
DOLPHIN TURSIOPS-TRUNCATUS KOGIA-BREVICEPS PHOCOENA-PHOCOENA HARBOR PORPOISE WEDDELL SEALS NASAL COMPLEX DIVES COMPRESSION MORPHOLOGY COLLAPSE
216
4639
4646
Cetaceans are neckless, so the trachea is very short. The upper respiratory tract is separate from the mouth and pharynx, and the dorsal blowhole connects, via the vestibular and nasopalatine cavities, directly to the larynx. Toothed cetaceans (Odontoceti) are capable of producing sounds at depth, either for locating prey or for communication. It has been suggested that during dives, air from the lungs and upper respiratory tract can be moved to the vestibular and nasal cavities to permit sound generation to continue when air volume within these cavities decreases as ambient pressure rises. The pygmy sperm whale, Kogia breviceps, is a deep diver (500-1000 m) that is known to produce hunting clicks. Our study of an immature female shows that the upper respiratory tract is highly asymmetrical: the trachea and bronchi are extremely compressible, whereas the larynx is much more rigid. Laryngeal and tracheal volumes were established. Calculations based on Boyle's Law imply that all air from the lungs and bronchi would be transferred to the larynx and trachea by a depth of 270 m and that the larynx itself could not accommodate all respiratory air mass at a depth of 1000 m. This suggests that no respiratory air would be available for vocalisation. However, the bronchi, trachea and part of the larynx have a thick vascular lining featuring large, thin-walled vessels. We propose that these vessels may become dilated during dives to reduce the volume of the upper respiratory tract, permitting forward transfer of air through the larynx.
CAMBRIDGE
0022-0949
10.1242/jeb.083782
Grant Details