Endangered Animals: Blue Whale

Reaching sizes of more than 100 feet long and weighing 150 tons, the blue whale possibly is the largest animal ever to inhabit the earth. Blue whales can be found in every ocean on the planet and migrate to warmer waters in the winter to breed. Food sources are available for them in all waters, polar, temperate and tropical. Because of their enormous size, blue whales were not pursued by early whalers. However, in the early 1900s whaling was revolutionized with exploding harpooning guns and factory ships, making them a prime target. One blue whale can produce 120 barrels of oil, so blues were widely hunted and their numbers were reduced by up to 99 percent, according to the American Cetacean Society. In 1966, the International Whaling Commission gave them worldwide protection and banned all hunting of blue whales.

  1. Big and Loud, Too

    • Not only is the blue whale the largest mammal on earth, it's also the loudest. The call of the blue whale reaches 188 decibels, and this low whistle can be heard for hundreds of miles. A jet engine only reaches 140 decibels and sounds over 120 decibels can be harmful to the human ear. Their song is used for locating large groups of plankton or krill to eat. They also use their low-frequency call to communicate with other whales, mostly for mating purposes.

    What They Look Like

    • The top of the blue whale usually is blue-gray with whitish-gray spots. Its underbelly has yellow, brown or gray specks. Blues have 8-foot long flippers and a very small dorsal fin located near the tail. The tail, also known as a "fluke," can be up to 25 feet across. The blue whale's body is long and tapered, and its head makes up less than a quarter of its body length. The upper part of its head, or rostrum, is broad, flat and U-shaped. It has two blowholes, and can "blow" upwards to 50 feet in the air.

    What They Eat

    • Blue whales are seasonal feeders and carnivores that "filter feed" on copepods, plankton and small shrimp-like krill. They lunge into huge masses of krill or plankton with an open mouth and gulp them in. They can eat up to 4 tons or more than 40 million krill a day. Pleated grooves in the whale's throat expand to allow huge amounts of water and food into the mouth. As the mouth closes and water is expelled, baleen plates trap the food near the tongue where it can be swallowed.

    How Many Are Left?

    • Because over-hunting so dramatically reduced their numbers, blue whales are on the endangered species list, with only about 10,000 to 14,000 remaining worldwide. Before being hunted, there were an estimated 350,000 blue whales in the seas. While their numbers still are low, blue whale populations are beginning to show signs of recovering, according to Enchanted Learning,com. The blue whale can live 35 to 40 years.