The Fin Whale

The fin whale (scientific name balaenoptera physalus) is a subspecies of baleen whale that inhabits the waters of the Arctic, the Coral Triangle, and the Gulf of California. It is the world's second largest mammal, growing between 65 and 80 feet long and weighing almost 160,000 pounds. It is distinguishable from other subspecies of baleen whale by two of its features. The first feature is a distinct ridge on the portion of its back behind its dorsal fin: this is the reason why it is nicknamed "razorback". The second feature is its multi-colored lower jaw: the left half is black, and the right half is white. It is believed to show this white half to schools of fish while it circles them in an attempt to frighten them into denser schools, which are easier for it to catch. Like other subspecies of baleen whale, it strains these fish from the water through its baleen plates.

The fin whale is classified as an Endangered species. It is this close to becoming extinct because much of its population has been killed by commercial whalers for oil, meat, and baleen. Because of this, the World Wildlife Fund's (WWF's) effort to save it consists of working to make the International Whaling Commission (IWC) more effective in its efforts to reduce the various threats to it and other subspecies of whale.

Source for picture and all information: https://www.worldwildlife.org/species/fin-whale