Baleen this issue. A whale's baleen plates play the most important role in its filter-feeding process. To feed, a baleen whale opens its mouth widely and scoops in dense shoals of prey (such as krill, copepods, small fish, and sometimes birds that happen to be near the shoals), together with large volumes of water. It then partly shuts its mouth and presses its tongue against its upper jaw, forcing the water to pass out sideways through the baleen, thus sieving out the prey, which it then swallows. People formerly used baleen (usually referred to as "whalebone") for making numerous items where
Baleen whale serves as support for whale genitalia. Rorquals, needing to build speed to feed, have several adaptions for reducing drag, including a streamlined body; a small dorsal fin, relative to its size; and lack of external ears or long hair. The fin whale, the fastest among baleen whales, can travel at . While feeding, the rorqual jaw expands to a volume that can be bigger than the whale itself; to do this, the mouth inflates. The inflation of the mouth causes the cavum ventrale, the throat pleats on the underside stretching to the navel, to expand, increasing the amount of water