Right Whale Feeding and Baleen Rattle

Abstract

Surface and subsurface feeding behavior of right whales, Eubalaena glacialis (Borowski, 1781), has been observed in Cape Cod waters since 1956. During surface feeding the whales follow discrete rows of concentrated plankton, and in subsurface feeding they also appear to be feeding on specific patches of food at particular depths and localities. No purposeful underwater sounds are heard during feeding, but the rattle of baleen is often audible during surface feeding and appears to be an adventitious sound. Baleen rattles only when it is held so that some of the forward plates are out of the water while others are partly immersed and subject to movement by passing waves. The rattle is a low level, highly variable sound, composed of sporadic sequences of two to 10 broad bandwidth pulses at uneven repetition rates and widely varying levels. Dominant frequencies are usually between 2 and 4 kHz.