Largest Mammal on Earth

Blue whale is not only the largest mammal on earth, but also bigger than any living creature. Everything related to Blue whales is gigantic. The length of these cetaceans can be more than 100 feet, while their weight is around 170 metric tonnes. It is said that a Blue whale's tongue weighs more than that of an African elephant! The zoological name of this sea animal is Balaenoptera musculus. Musculus is a Latin word meaning "muscular". The Blue Whale comes from a family which includes the Humpback Whale, Fin Whale, Sei Whale and the Minke Whale. Earlier, it was also identified by names like 'Sibbald's Rorqual', Great Blue Whale and the Great Northern Rorqual.

Anatomy
Females are bigger than males in this species of whales. The Blue whales are longer and slender in comparison to other whales. Also the U-shaped head and blowhole, are its unique body features. Blowhole - an opening on the dorsal side of its body, helps at the time of breathing and swallowing because it pumps water out of the whale's body. As Blue whales are huge animals, they possess a big respiratory system. Its aorta - an artery in the heart is so big in diameter that a human being can easily pass through it. Unlike the fish which uses gills to respire, these huge mammals breathe with the help of lungs and need to come to the water surface to take in oxygen.

Eating Habits
These whales require a lot of food to satiate their huge appetite. They feed mainly on krill - a small marine invertebrate. A single Blue whale can consume up to 40 million krills in a single day. At the time of feeding, these whales swallow water along with krills. In removing this water and keeping the food inside the body, baleen plates play an important role. These 300 one-meter plates, lined along the whale's upper jaw, trap the krills inside the mouth while the blowhole removes excess water.

Reproduction
The mating in Blue whales takes place between the autumn and winter season. Gestation period extends up to one year and the baby whale weighs about 2.5 tonnes at the time of birth. It drinks around 400 liters of milk daily and grows at the rate of 1.5 inch everyday.

Sound Produced by Whales
Blue whales produce sounds ranging between 155 and 188 decibels, which is greater than a jet! According to experts, the sounds produced by whales serve some meaningful purposes. These low frequency sounds produced by whales are helpful in locating food, finding the right directions, communicating with other whales etc.

Mindless Hunting of Blue Whales
It was difficult to hunt whales in earlier days due to their massive size. It was only after the invention of a specially designed harpoon that the whalers went on a hunting spree. Mindless hunting of Blue whales was carried in different parts of the world including Norway, Iceland, Newfoundland, etc. The hunting of this large mammal was carried out till 1960, after which it was banned by the International Whaling Commission; but it continued till 1970. By this time, around 3,30,000 whales were killed by whalers. Although it is difficult to estimate the total Blue Whale population of the world, in 2002 it was estimated to be between 5000-12000.

Present Condition of Blue Whales
Blue whale is declared as an endangered species today. After taking steps for its preservation, the population is slowly but steadily increasing day-by-day; the Antarctic region among all showing the highest rise of 7.3%.

Blue whales need longer time than other animals for reproduction. Strict measures to stop whale hunting, coupled with an effort, to raise their number will help preserve this endangered species. It is necessary to speed up efforts in order to save these beautiful massive creatures from getting wiped off this planet.