Classification
The Blue Whale is the largest whale and the largest creature ever to inhabit the earth. It belongs to the family Balaenopteridae of the suborder Mysticeti, order Cetacea and is classified as Balaenoptera musculus.
Appearance
Blue whales may reach 29 m in length; mature females are usually slightly longer than mature males. A small dorsal fin is set far back on the body. The skin has a light-gray-and-white mottled pattern, which appears light blue when the whale is just below the surface of the water on a sunny day. The mottled pattern, which is unique to each animal has been used by researchers to identify individual whales.
Distribution
Blue whales are found in all oceans of the world. Most populations migrate extensively, traveling from the Tropics or near Tropics in winter to the edges of the pack ice in the northern and southern hemispheres in summer.
Behavior
Blue whales produce loud, low-frequency moans that can be heard in deep ocean waters from more than 160 km away. It is likely that they communicate by means of these moans, enabling the members of a group to remain in contact across a vast expanse of ocean.
Diet
Blue whales feed by lunging openmouthed into dense groups of small sea creatures such as krill or fish. As water and food rush into the whale's mouth, more than 60 throat pleats expand so that the whale's throat, or gular pouch, forms a huge bag that extends from the front of the whale's snout to its navel. The whale then partially closes its mouth, leaving a small gap, and forces water past 270 to 390 pairs of wide, black, fringed baleen plates that hang from the roof of the mouth. The plates act as a sieve, catching food inside the fringes. Blue whales often lunge through their prey side by side, apparently using each other to block the escape of their prey.
Breeding
Mature females may give birth once every two or three years. Mating occurs during the summer season, and the gestation period lasts about 11 months. A single young is usually born the following spring; twins are rare. The young nurse for seven or eight months, gaining as much as 90 kg per day.
Conclusion
In conclusion, the Blue Whale is one of the most majestic creatures in the world. Nowadays, they are protected by several nature groups and the 10-12000 left are safe from the threat of extinction.