Meeting Abstract
P2.69 Monday, Jan. 5 Ecological morphology of the flippers of cetaceans based on two-dimensional geometry FISH, F.E.*; TIMM, L.L.; MURRAY, M.M.; HOWLE, L.E.; West Chester Univ.; West Chester Univ.; U.S. Naval Academy; Duke Univ. ffish@wcupa.edu
The pectoral flippers of cetaceans are mobile control surfaces with a wing-like morphology that are associated with the ecology of these aquatic mammals. The flippers contribute to lateral turning, diving, surfacing, braking, trim control, and reduction of recoil from propulsive movements. Biomechanically, the flippers are subjected to flows in water, which must be controlled by the flipper geometry to reduce drag and produce lift. The flippers of 36 species from 9 taxonomic families of cetaceans were analyzed with regard to body length, body mass, flipper span, and flipper area. Body mass of cetaceans was measured directly or estimated from body length. Both flipper span and area increased isometrically with body mass with exponents of 0.32 and 0.66, respectively. The humpback whale (Megaptera novaeangliae) and the right whale (Eubalaena glacialis) had larger flipper areas for their size than expected, whereas the sei whale (Balaenoptera borealis) had smaller flippers than expected for its size. The aspect ratio, span squared divided by area, and the flipper loading, animal weight divided by flipper area, were calculated as indicators of shape and functionality, respectively. To compare species, the effects of size were removed by using principal-components analysis. In general, cetaceans with low loadings are inshore and coastal species that specialize on fish prey, whereas high loadings are found in cetaceans that feed on cephalopods or crustaceans. High aspect ratio flippers are associated with pelagic species. The cetaceans show a broad range of flipper shapes, which reflect different operational habitats and prey types.