Blue Whale

The blue whale is the largest animal known ever to have lived, reaching a confirmed length of about 30 m and weighing up to 190–200 tonnes. It has a long, slender body in shades of greyish blue above and lighter below, with a mottled grey-blue skin that looks blue underwater. The upper jaw is lined with 70–400 black baleen plates less than 1 m long. Some individuals have bellies tinged yellow by diatoms (Wikipedia, general species account).

Four subspecies are recognised, and the one in the northern Indian Ocean, Balaenoptera musculus indica, feeds mainly on sergestid shrimp instead of krill. Blue whales are filter feeders, generally solitary or in small groups, and most populations migrate between summer feeding areas near the poles and winter breeding grounds near the tropics, though some stay year-round. They were hunted almost to extinction until the International Whaling Commission banned blue whale hunting in 1966 (Wikipedia, general species account).