Aerial view of a fin whale, showing V-shaped chevron

Fin Whale from the air. Photo: Protected Resouces Division, Southwest Fisheries Science Center, La Jolla, California. http://swfsc.nmfs.noaa.gov/PRD/

Source: https://commons.wikimedia.org/wiki/File:Fin_whale_from_air.jpg

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-largest animal after the blue whale.