Blue Whale

Blue Whale belongs to baleen whale and the largest marine mammal in the rorqual family Balaenopteridae. Reaching a maximum confirmed length of 29.9–30.5 m (98–100 ft) and weighing up to 190–200 t (190–200 long tons; 210–220 short tons), it is the largest animal known to have ever existed. The blue whale's long and slender body can be of various shades of greyish-blue on its upper surface and somewhat lighter underneath. (Wikipedia, general species account).

There is also evidence of year-round residencies, and partial or age- and sex-based migration. Blue whales are filter feeders; their diet consists almost exclusively of krill. They are generally solitary or gather in small groups, and have no well-defined social structure other than mother–calf bonds. One of the first published descriptions of a blue whale comes from Robert Sibbald's Phalainologia Nova, after Sibbald found a stranded whale in the estuary of the Firth of Forth, Scotland, in 1692. (Wikipedia, general species account).