Blue Whales Giant Mammals

Blue Whales Giant Mammals

Introduction Far out at sea, scientists scan the horizon. They are looking for the largest creature on Earth. You would think that finding an enormous animal would be easy, but oceans are vast and wide. Suddenly, a thunderous roar sounds as a blast of water shoots high into the air. The scientists have found what they were looking for--the mighty, magnificent blue whale.

A blue whale's size is impressive. It can weigh as much as 200 tons (181. 4 mt) and be as long as approximately 100 feet (30. 5 m). Its tongue alone weighs as much as an elephant. Its heart is so large that a person could crawl through its main blood vessels!

The blue whale has a mammoth body. Its skin actually looks blue underwater, but from above it looks blue-gray. The underside of a blue whale sometimes appears to be pale yellow thanks to tiny organisms called diatoms that often hitch rides on the whale's skin.

Blowholes and Blubber Blue whales live in the sea, but they are not fish. These graceful giants are the world's largest mammals. Blue whales have lungs and breathe air just like humans. They inhale and exhale through two blowholes on top of their heads. In order to breathe, a whale must come to the ocean's surface. The blowholes open and the whale expels air, sending water spouts up to 30 feet (9. 1 m) into the sky. Then the whale quickly inhales, filling its massive lungs. All of this happens in under two seconds!

A whale breathes in and out several times at the surface before beginning a dive. It uses its flexible spine and wide tail flukes to navigate through the water. Flukes are made up of tissue, not bone, so they are flexible. Blue whales leave circles called “ flukeprints" on the water's surface when they dive. These whales usually cruise along at 5 miles per hour (8 kmph), but they can travel as fast as 20 miles per hour (32 kmph). Blue whales can stay underwater for about thirty minutes. They are considered shallow divers because they rarely go deeper than 700 feet(213. 4 m). In contrast, sperm whales dive about 3, 280 feet (1, 000 m)-more than four times deeper!