Habitat
Like other marine mammals, blue whales are descended from early land animals. Millions of years ago, the richness of life in the sea lured them to the water; aquatic life gradually changed their physical characteristics. Today, they spend most of their time in the Arctic and Antarctic oceans, where plankton is plentiful. In winter, the whales migreate to the warm waters of the tropics. But food in the tropics is scarce, so the whales depend heavily on their thick layer of blubbler for nourishment.
Food and Hunting
In the Antarctic, blue whales feed on vast quantities of a plankton called krill. In Arctic waters, they feeed on only three species of crustacean plankton. Icy water contains more oxygen and carbon dioxide than warm water, which makes it rich in marine life. Plankton is up to 20 times more abundant in the Arctic and Antarctic than it is in the warmer waters of the tropics. In spite of its bulk, the blue whale can reach speeds of 10 to 15 knots; however, it catches most of its food b diving. It can dive to depths of 1,650 feet and lie submerged for up to two hours. Rising from the depths, the whale feeds by collecting a large amount of seawater in its mouth, and then straining out the plankton.
Whale and Man
Because of its great size, the blue whale was a prime target for the whaling industry. Its body was a source of oil, and the baleen was used to make women's corsets. Antarctic whalers slaughtered 30,000 blue whales from 1930 to 1931. The population has since recovered, but there are probably fewer than 10,000 alive today; they are now protected.
Size
Length: Average 85 feet, but can reach 100 feet.
Weight: 175,000-285,000 lbs.
Distribution
Limited, scattered aresas all around the world; based mainly in Arctic and Antarctic waters.
Lifestyle
Call: Low-frequency moan. Produces ultrasonic chirps and whistles when feeding.
Habits: Social and migratory.
Lifespan: 80 years.
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