Meeting Abstract

49.2  Tuesday, Jan. 5  Behavioral performance of ram and suction feeding odontocetes, and a preliminary evolutionary analysis using functional data KANE, E. A.*; MARSHALL, C. D.; Texas A and M University; Texas A and M University ekane@clemson.edu

During their re-invasion, some cetaceans independently and secondarily evolved prey capture modes that are often described as convergent with other more basal aquatic vertebrates. However, cetacean feeding biomechanics have been largely ignored by functional biologists, and systematic analyses of odontocete feeding mode and feeding evolution are lacking. This study investigated the feeding performance of three odontocetes with varying feeding modes (belugas, Delphinapterus leucas; Pacific white-sided dolphins, Lagenorhynchus obliquidens; and long-finned pilot whales, Globicephala melas). In combination with morphology, functional data were mapped onto a composite odontocete phylogeny to reconstruct the likely ancestral feeding mode, and to begin to examine feeding mode evolution. Beluga feeding was composed of discrete ram and suction components, while Pacific white-sided dolphins used ram, with some evidence for suction. Pilot whales relied on a combination of ram and suction that was less discrete than belugas. Subambient pressure was measured in all species, with belugas reaching 126 kPa. Belugas were able to purse the anterior lips to occlude lateral gape and form a small, circular anterior aperture that is convergent with feeding behaviors observed in more basal vertebrates. These data also suggest that ancestral odontocetes relied upon ram feeding to capture prey, but also some suction generation capability, perhaps for prey manipulation or transport. Suction specialization arose independently at least four times, and many-to-one mapping of performance and morphology to function may account for odontocete feeding diversity.