Largest Mammal on Earth

The largest mammals on earth - blue whales, have always been a matter of curiosity and amazement for us, human beings. Here is a short account about these gentle giants living in the seas.
The blue whale is not only the largest mammal on earth, but also bigger than any living creature. Everything related to them is gigantic. The length of these cetaceans can be more than 100 feet, while their weight is around 170 metric tons. It is said that their 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.
The females are bigger than males in this species. The blue whales are longer and slender in comparison to other species. Also the U-shaped head and blowhole, are its unique body features. The 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 fish, which use 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 krill in a single day. At the time of feeding, these whales swallow water along with the krill. Baleen plates play an important role in removing this water and keeping the food inside the body. These 300 one-meter plates, lined along the whale's upper jaw, trap the krill inside the mouth while the blowhole removes excess water.
Mating takes place between the autumn and winter season. The gestation period extends up to one year and the baby whale weighs about 2.5 tons 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 was carried in different parts of the world including Norway, Iceland, Newfoundland, etc. This carried on till 1960, after which it was banned by the International Whaling Commission; but it continued illegally 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
The 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 more 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.