Baleen

Baleen or whalebone is the means by which baleen whales feed. These whales do not have teeth, but instead have rows of baleen plates in the upper jaw; flat, flexible plates with frayed edges, arranged in two parallel rows, looking like combs of thick hair. Baleen is not bone, but is composed of keratin, the same substance as hair, horn, claws and nails. Whales use these combs for filter feeding. Whales are the only vertebrate group to use this method of feeding in great abundance.

Depending on the species of whale, a baleen plate can be 0.5 to 3.5 metres (2 to 12 ft) long, and weigh up to 90 kg (200 lb). Its hairy fringes are called baleen hair or whalebone-hair. Baleen plates are broader at the gumline (base). The plates have been compared to sieves or Venetian blinds.