Meeting Abstract

P2.68  Monday, Jan. 5  Morphology of the bumpy profile of phocid vibrissae GINTER, C.C.*; FISH, F.E.; MARSHALL, C.D.; West Chester Univ.; West Chester Univ.; Texas A&M Univ. Galvestron cg611398@wcupa.edu

The geometry of projecting sensory structures may use a passive mechanism of flow control. The vibrissae of phocid seals have an ellipsoidal cross-section with a regularly repeating sequence of crests and troughs to give a wavy or bumpy profile along the length. This morphology suggests hydrodynamic properties when swimming. The morphology of phocid seal vibrissae was investigated for harp (Phoca groenlandica), grey (Halichoerus grypus), and hooded (Cystophora cristata) seals. The overall length of each vibrissa, the number of crests, wavelength, width of crests and width of troughs were measured. Mean number of crests per vibrissa ranged from 9 for the grey seal to 12 for the harp seal. For all species, the middle of the vibrissae showed the greatest wavelength, crest width and trough width, while the tip showed the lowest wavelength, crest width and trough width. The grey seal vibrissae showed the greatest wavelength, crest width and trough width at 3.91 mm, 0.97 mm and 0.79 mm, respectively. The hooded seal vibrissae showed the lowest wavelength and crest width at 1.77 mm and 0.26 mm, respectively, and the harp seal vibrissae showed the lowest trough width at 0.19 mm. The number of crests increased toward an asymptote with increasing vibrissae length for all species. The crest to trough ratio was 1.38, 1.33 and 1.23 for the harp, hooded and grey seals, respectively. The bumpy profile of the vibrissae may modify the flow of water to reduce vibrations as the seal swims. Decreased vibration on the vibrissae could increase the signal to noise ratio of the tactile vibrissae and aid in the detection of turbulent flow fields generated by prey organisms.