What is baleen?
It’s a tough, flexible material, made of keratin protein (the same as a cow’s horn or your fingernails). Baleen grows in feathery fringes from a baleen whale’s upper jaw. Baleen whales use these fringes to strain vast amounts of sea water, catching shrimplike krill and small fishes. Though this prey is small, there’s a lot of it—enough to let baleen whales grow into the largest creatures on Earth.
Plates of baleen are suspended from each side of the upper jaw in baleen or toothless whales. The plates are made of keratin (the same thing hair is made of) that intertwines to form a sieve, which filters food from the water. The baleen whale takes in a huge gulp of water, closes its mouth, and forces the water out through the baleen trapping food particles such as fish, plankton, krill, and other crustaceans. Other baleen whales slide along the bottom stirring up food material and then trapping it in the baleen.
