Baleen Baleen Baleen is a filter-feeder system inside the mouths of baleen whales. The baleen system works by a whale opening its mouth underwater and taking in water. The whale then pushes the water out, and animals such as krill are filtered by the baleen and remain as food source for the whale. Baleen is similar to bristles and consists of keratin, the same substance found in human fingernails and hair. Baleen is a skin derivative. Some whales, such as the bowhead whale, have longer baleen than others. Other whales, such as the gray whale, only use one side of their
Baleen whale D. W. Rice (of the Society for Marine Mammalogy) in assumed was an ironic reference to the animals' great size. An alternate name for the parvorder is "Mystacoceti" (from Greek "mustache" + "whale"), which, although obviously more appropriate and occasionally used in the past, has been superseded by "Mysticeti" (junior synonym). Mysticetes are also known as baleen whales because of the presence of baleen. These animals rely on their baleen plates to sieve plankton and other small organisms from the water. The term "baleen" (Middle English "baleyn, ballayne, ballien, bellane", etc.) is an archaic word for "whale", derived from the