Rorquals and Gray Whales

Rorquals are whales with pleats in their throat skin running from the chin to the navel. These pleats allow he throat to expand enormously when feading, so that the whale may process immense volumes of water with one gulp. They feed on krill and schools of fish. Typically, they approach a large accumulation of their prey at high speed, then open their mouths to engulf as many as they can - a procedure known as lunge feeding. Rorquals are slender whales, capable of swimming at high speeds, and have large wing-like front flippers.

• The humpback whale Megaptera novaeangliae is famous for its complex and haunting songs sung by the males during the breeding season, and for its acrobatics - humpbacks often breach high into the air and crash back down in an explosion of spray, a very impressive spectacle when performed by a 35-ton animal. Humpbacks are found world-wide. They calve and breed in tropical waters, then migrate to feeding grounds in cold temperate and arctic waters in the summer.
• The blue whale Balaenoptera musculus is the world's largest animal, at 30 meters in length and 180 tons in mass, and exceptional individuals even larger. They are found world-wide.
• The fin whale Balaenoptera physalus is a slender rorqual which holds the title of the world's second longest animal, measuring a good 27 meters long and 74 tons in mass. They are found in all the world's oceans except for those permanently covered by pack ice, although their populations are higher in the rich waters near the poles than in the tropics.
• The sei whale Balaenoptera borealis is the fastest cetacean. It is also the world's third largest animal, reaching 20 meters in length and 28 tons in mass. It is found in all the world's oceans. They spend the summer feeding in the rich waters near the poles, and the winter in temperate and sub-tropical waters.
• The minke whales Balaenoptera acutorostrata and Balaenoptera bonaerensis are relatively small rorquals, with lengths of "only" 7 to 10 meters and masses of 6 to 9 tons. Between the two species, they are found nearly world-wide.
• The gray whale Eschrichtius robustus is not usually included in the rorquals, because it lacks throat pleats. However, some rorquals are more closely related to the gray whale than they are to other rorquals. They typically feed on the sea bottom, turning on their side and scooping up sea-floor sediment which is then processed by ther baleen filters. Gray whales feed in the rich arctic waters in the summer, then migrate south for the winter.

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