Meeting Abstract
P1.105 Saturday, Jan. 4 15:30 Feeding Kinematics, Suction, and Hydraulic Jetting Capabilities of Harbor Seals (Phoca vitulina) MARSHALL, CD*; WIESKOTTEN, S; MARSH, A; KOT, B; HANKE, W; HANKE, FD; DEHNHARDT, G; Texas A and M University; University of Rostock; Texas A and M University; Texas A and M University; University of Rostock; University of Rostock; University of Rostock marshalc@tamug.edu
The feeding performance of harbor seals was characterized during controlled feeding trials. Trials used feeding apparatuses that allowed subjects to choose between suction and biting feeding modes, but also presented food that could only be ingested using suction. Animals were videotaped while feeding and pressures exerted were simultaneously measured directly. Kinematic analysis showed that the mean gape cycle duration during suction events was significantly shorter (0.15±0.09s S.E.; P<0.01) than biting events (0.18±0.08; P>0.05). Subjects favored a suction feeding mode (84% of all events), but biting was also important (16% of all events). Suction and biting were kinematically distinct. Suction was characterized by a significantly smaller gape (1.3±0.23 cm; P<0.001) and gape angle (12.9°±2.02; P<0.001), pursing of the rostral lips to form a circular aperture, and pursing of the lateral lips to occlude lateral gape. Biting was characterized by a large gape (3.63.0±0.21 cm) and gape angle (28.8°±1.80°; P<0.001) and lip curling to expose teeth. Subjects often alternated suction with hydraulic jetting to remove fish from the apparatus. The maximum subambient and suprambient pressures recorded were 48.8 and 53.9 kPa, respectively. Suction and hydraulic jetting were employed 90.5% and 9.5%, respectively, during feeding events. Harbor seals used a wide repertoire of behaviorally flexible feeding strategies to ingest fish from the feeding apparatus. Such flexibility of feeding biomechanics likely forms the basis of their opportunistic, generalized feeding ecology and concomitant breadth of diet in the wild.
