Long-finned baleen whale (Megaptera novaeangliae). They live along all major ocean coasts, sometimes swimming close inshore or even into harbours and up rivers. Humpbacks grow to 40–52 ft (12–16 m) long. They are black above, with some white below, and have large knobs on the head and jaws. The humpback migrates between polar waters in summer and tropical or subtropical breeding grounds in winter. It feeds on shrimplike crustaceans, small fish, and plankton. It is probably the most vocal of all whales (with songs of 5–35 minutes) and one of the most acrobatic (capable of turning a somersault). Much reduced in number by overhunting, humpbacks have been protected worldwide since the 1960s, and some populations seem to be increasing.