The fin whale is a streamlined whale that is found worldwide; it is most common in the North Atlantic. There are three separate populations of fin whales, one in the North Pacific, one in the North Atlantic, and one in the Southern Hemisphere; they do not interbreed. Many groups of fin whales migrate between feeding grounds and breeding grounds. This whale usually swims in pods of 3-7 whales but larger groups (up to 300 animals) may form at rich feeding grounds.