Eleven types of whales ply Antarctic waters, and six of those are baleen whalesblue, sei, fin, humpback, minke, southern rightwhich feed primarily on krill.
Made of keratin, like human fingernails and hair, baleen plates on either side of a whales enormous mouth act as a huge strainer.
>> KRILL DEPENDENCE:
Baleen whales found in Antarctica are only in the region during the austral summer. Here they fatten up on krill before heading north for the winter.
During their months in the Southern Ocean the whales eat an enormous amount of krill. The humpback, in particular, can eat more than a ton of krill in one day. The huge adult blue whale can consume as much as four tons in one day.
For more than half a century, baleen whales were hunted exhaustively in Antarctica. Their numbers have not rebounded fully.
Photograph by Flip Nicklin
© 2001 National Geographic Society. All rights reserved.