Meeting Abstract

P1.102  Thursday, Jan. 3  Comparative Feeding Performance In Odontocetes KANE, E. A.*; MARSHALL, C. D.; Department of Marine Biology, Texas A&M University at Galveston; Department of Marine Biology, Texas A&M University at Galveston ekane@tamu.edu

Suction is the ancestral feeding mode among aquatic vertebrates. However, the terrestrial origin of odontocetes resulted in an ancestral ram feeding morphology. The recent evolution of suction feeding in some species has given rise to morphologies such as blunt and wide rostra, reduced dentition, and a circular oral aperture, which converge with other known aquatic suction feeders. Unfortunately, few data exist that quantify feeding performance in odontocetes. Therefore, the objective of this study was to directly measure intraoral suction generation during controlled feeding trials in presumed suction and ram feeding odontocetes (beluga whales, Delphinapterus leucas and Pacific white-sided dolphins, Lagenorhynchus obliquidens). Analysis of 883 feeding events from 6 belugas and 7 Pacific white-sided dolphins demonstrated that the maximum negative suction pressure measured in belugas in this study was �122 kPa, which was 4.5 times greater than the maximum value generated by Pacific white-sided dolphins (�27 kPa). Hydraulic jetting was also measured in belugas with approximately equal magnitude (128 kPa). Although the use of suction in belugas is well known, these are the first data to measure the magnitude; the suction capability of belugas appear to be comparable to walruses. Despite long rostra, numerous teeth, and a limited ability to occlude lateral gape, Pacific white-sided dolphins are also capable of using suction, but to a lesser extent than belugas. Their suction capability is likely limited to the intraoral transport of prey whereas in belugas it is a primary method of prey capture.