Blue Whale

Blue WhaleFactoid: The blue whale is the largest animal ever to inhabit the Earth.Status: EndangeredPopulation: Estimated between 1,300 and 2,000, the population of blue whales is dangerously low.Threats: Blue whales face threats from entanglement in fishing nets, pollution, and illegal whaling.Survival: The lifespan of blue whale is estimated to be 80 years.Blue whales are found throughout the worlds oceans. These gentle giants have grayish-blue skin with light spots. Measuring 70 to 80 feet in length (the longest recorded length was 106 feet), blue whales can weigh as much as 90 to 150 tons, although females are larger than the males.Blue whales generally spend winters in temperate and subtropical zones, migrating toward the polar regions in spring and summer. They swim 14 miles per hour (with bursts as fast as 30 mph) and feed at depths of less than 330 feet (but can dive as deep as 1,640 feet). Dives last from 10 to 20 minutes. Usually they travel alone or in small groups of two to four, although off the coast of California some groups as large as 60 have been seen.Blue whales have about 300 to 400 baleen plates instead of teeth which they use to strain food from the ocean water. A blue whale can eat up to 7,715 pounds of krill (small shrimp-like organisms) per day!Blue whales were once considered too difficult to hunt because of their speed and tremendous size. However, with the introduction of factory ships and the harpoon gun in the 1920s, blue whales were hunted intensively. By the 1960s they were nearly extinct.Description:It is scarcely possible to imagine the size of the blue whale, the largest animal inhabiting the earth. There are records of individuals over 100 feet, but 70-90 feet is probably average. An average weight for an adult is 200,000-300,000 pounds (100-150 tons). Its heart alone is as large as a small car.Blue whales are an overall blue-gray color, mottled with light gray. Cold water diatoms sometimes give their bellies a yellowish tinge, giving the blue whale its nickname of Sulfur bottom. Blue whales are long and streamlined. The dorsal fin is extremely small, and the pectoral flippers are long and thin.Range/Habitat:Blue whales have been found in every ocean of the world. Blue whales swim individually or in small groups. Pairs are very commonly seen.Notes:Blue whales are rorqual whales, a family of baleen whales with pleated throat grooves that expand when the animal takes in water while feeding. More than 55-68 throat grooves extend from the throat to the navel. The favorite food of these giants is krill, or shrimp-like euphausids, that are up to three inches long. Blues must eat one to two tons of krill a day during the feeding season. They concentrate on feeding during the polar summers, and migrate to warmer waters in the winter. Blue whale baleen is black.Gestation lasts about one year, and at birth, the blue whale calf is about 23 feet long and weighs 5,000-6,000 pounds. A nursing blue whale mother produces over 50 gallons of milk a day. The milk contains 35-50% milk fat and enables the calf to gain weight at a rate of up to nine pounds an hour or over 200 pounds a day! At eight months of age and an average length of over 45 feet, the calf is weaned. The blue whale reaches sexual maturity around 10 years of age.The blue whale was too swift and powerful for the 19th century whalers to hunt, but with the arrival of harpoon cannons, they became a much sought after species for their large amounts of blubber. The killing reached a peak in 1931 when 29,649 blue whales were taken. By 1966, blues were so scarce that the International Whaling Commission declared them protected throughout the world. Today, there are fewer than 10,000 blue whales in the oceans, and they are considered an endangered