the fin whale ("balaenoptera physalus") is a huge baleen whale. it is the second largest animal on earth (the blue whale is the biggest). this whale is sometimes called the "greyhound of the sea" because of its fast swimming speed; it can swim up to 23 mph (37 km/hr) in short bursts. the fin whale is also called the finback, finner, razorback, common rorqual, and herring whale.