Antarctica is home to many whales. Every summer, the Baleen whales (mysticeti, whose members include the Minke, blue and humpback whales) return to Antarctica from the tropics to feed on krill. These whales don't have teeth but rather a fingernail-like material that grows in plates from their upper jaws. The plates are frayed creating a broomlike surface on which krill and other creatures become stuck as the whale takes in huge gulps of water.

Humpback whale and calf
(Illustration: Katherine Zecca)

Toothed whales (or odontoceti) include sperm and killer whales as well as porpoises and dolphins.

Krill underwater (photo: NOAA)

Whale Food
Krill (euphausiids) are shrimp-like crustaceans with a hard exoskeleton and many legs. Masses of krill come together in "swarms" or "clouds," turning the ocean's surface pink in color. Krill can be as small as 0.5 inch or as large as 5.5 inches and live up to 10 years. Krill is called a keystone species of the Antarctic because it is a food source for so many other animals.