What is a "blue whale"?

The blue whale is the largest animal on Earth, with an elongated body, mottled blue-gray skin, and a distinctive dorsal fin, reaching lengths of up to 100 feet or more and weighing as much as 200 tons, known for its majestic appearance and impressive vocalizations, found in oceans across the globe and known for its filter-feeding behavior that involves consuming tons of krill every day.