High Quality Content by WIKIPEDIA articles! The fin whale (Balaenoptera physalus), also called the finback whale, razorback, or common rorqual, is a marine mammal belonging to the suborder of baleen whales. It is the second longest whale and the sixth largest living animal after the blue whale, bowhead whale, and right whales, growing to nearly 27 metres (88 ft) long. The American naturalist Roy Chapman Andrews called the fin whale "the greyhound of the sea" because of its great speed when chased and slender build.