How Do Baleen Whales Eat?
Not all whales have big teeth, or throats large enough to swallow a man. Whales known as “baleen” whales have throats that are so small that they can only feed on tiny sea organisms called “krill.”
In the place of teeth, these great whales have long, stringy plates in their mouths called “baleen.” When feeding, the whale opens its huge mouth and swims into a mass of krill. It then closes its mouth and forces the water out through the stringy baleen.
The baleen acts like a big strainer, letting the water out but trapping the food, which the whale swallows. A whale’s baleen plates play the most important role in its filter-feeding process.
Baleen is similar to bristles and is made of keratin, the same substance found in human fingernails and hair. 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.
These baleen bristles are arranged in plates across the upper jaw of the whale. Baleen is often called whalebone, but that name also can refer to the normal bones of whales, which have often been used as a material, especially as a cheaper substitute for ivory in carving.
Depending on the species, a baleen plate can be 0.5 to 3.5 metres (1.6 to 11.5 ft) long, and weigh up to 90 kilograms (200 lb). Its hairy fringes are called baleen hair or whalebone-hair.
They are also called baleen bristles, which in sei whales are highly calcified, calcification functioning to increase their stiffness. Baleen plates are broader at the gum line (base). The plates have been compared to sieves or Venetian blinds.