The endangered blue whale has achieved the position of the single largest organism ever to live on Earth. Blue whales have baleen plates instead of teeth, migrate long distances, and communicate through vocalizations. Whaling during the early 20th century all but wiped out this magnificent animal.
As a mammal, a blue whale must breathe air, stay warm, and give birth to live young. It breathes through two blowholes at the top of its head, and usually a single breath lasts 15 minutes. Since blue whales are found in every major ocean, they migrate to follow the temperate current. During winter, they swim around the subtropical or temperate regions closer to the equator, but for summer they travel long distances to reach the cooler arctic regions.
The blue whale, or Balaenoptera, stretches an incredible 70-80 ft (21-24 m) on average, and weighs 90-150 tons (82-136 metric tons). These giant creatures need about 4 tons (3.6 metric tons) of krill, a type of shrimp, per day. They feed by filtering water through their baleen plates, catching tiny bits of food. If not caught in fishing nets, illegally harpooned by whalers, or adversely affected by pollution, a blue whale should live from 40-80 years.
The three species of blue whale look similar. The musculus lives in Northern oceans, the
A blue whale breeds during the winter, every 2-3 years, while it fasts and lives on accumulated fat. After a gestation period of a year, a female will give birth to one calf that nurses for 6 months to a year. Gradually, the calf will transition to eating krill, but will probably stay with its mother for a couple of years for protection. It will reach sexual maturity when its 5-7 years old.
Sadly, the large populations of whales have dwindled in the last century due to new technology that made killing them easier for whalers. Along with pollution and other threats from mislaid fishing nets, the number of blue whales has plummeted to a few thousand. Many efforts, including limited whaling and regulated fishing, work to keep this whale from extinction.