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marine mammal information
    classification
    pinnipeds
        harbor seals
        northern elephant seals
        california sea lions
        steller sea lions
        northern fur seals
        guadalupe fur seals
    sea otters
    cetaceans
        toothed whales
        dolphins and porpoises
        baleen whales
    manatees
    polar bears
    endangered

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sea lions at PIER 39

Mysticetes (literally, "mustached whale") are the baleen whales. Baleen whales have two openings in the blowhole, tend to be larger and swim more slowly than toothed whales, and have small or no dorsal fins. Instead of teeth, they have hundreds of rows of baleen plates like brooms in their upper jaws. Baleen is made of keratin, a substance in our hair and fingernails. They act as filters for catching small fish and floating animals (zooplankton).

Baleen whales are divided into three groups based on their feeding strategies. The rorquals, such as humpback and blue whales, feed by gulping a large mouthful of food and water and expanding the throat pleats that extend to their navel like a balloon. Then they push the water out through their baleen plates with their tongues, and the food gets trapped behind the baleen. Another type of baleen whale is the skimmer, which includes right and bowhead whales. As they swim, water and zooplankton flows through a gap in the front of their 14-foot-long baleen plates, the food gets trapped inside the baleen, and the water flows out through gaps on the sides of their mouths. The gray whale has a third, unique feeding strategy. They feed on shrimp-like animals living in the mud in shallow water by turning on their sides and slurping the mud through the side of their mouths.

Despite eating very small animals, baleen whales can be very large. The efficiency of their feeding strategies is what allows them to get so large. They can eat up to four tons of food in one day! Their large size helps to get rid of excess body heat, keeps them from being eaten by most predators, and allows them to fast for months at a time. The blue whale, which eats tiny krill, is the largest animal on earth. Adult blue whales may be up to 100 feet (30.5 m) long and weigh 150 tons.

Most of the large baleen whales are endangered due to past hunting. While they are protected by law now, they still face many threats. Find out more about these issues and what you can do to help.

Learn more about the following:

Toothed whales
Humpback whale
Blue whale
Gray whale