On the Feeding Mechanisms of the Sei Whale (Balaenoptera borealis)

The sei whale (Balaenoptera borealis) is a medium sized rorqual with basic features similar to the larger fin and blue (Balaenoptera sp.). While the sei whale has an expandable buccal pouch, it’s capacity is substantially reduced by the length of the ventral grooves relative to fin and blue whales. The finer filtration capacity of the baleen allows predation on smaller prey spectra as a skim-feeder, with the option to engulf where prey are larger, or in greater densities. The sei whale exhibits some features of the mouth cross-section which are reminiscent of right whales (Eubalaena sp.) and there appears to be a difference in the degree of arch of the rostrum when comparing the sexes. The dynamics of skim-feeding and prey reaction are discussed.