Antarctica. Wildlife. Life in the ocean

Many millions of years ago, Antarctica was an ice-free continent. Scientists have found fossils of trees, dinosaurs, and small mammals that once lived there. Today, only a few small plants and insects can survive in Antarctica's dry interior. Most land animals live at the edges of the continent. The continent's largest land animal is a wingless midge, a type of fly no more than 1/2 inch (12 millimeters) long. To avoid freezing to death, some lice, mites, and ticks cling to mosses, the fur of seals, or the feathers of birds.

Few plants grow in Antarctica's forbidding, ice-covered land and harsh climate. Mosses, the most common Antarctic plants, cling to rocky areas, mostly on the coasts. Only two flowering plants grow in Antarctica, both on the northern part of the Antarctic Peninsula. One is a grass that forms dense mats on sunny slopes, while the other, an herb, grows in short, cushion like bunches.

A Weddell seal nuzzles her pup. Seals have few enemies besides people and killer whales. To escape enemies, Weddell seals of the Antarctic can dive as deep as 2,360 feet (719 meters) and stay underwater as long as 43 minutes

Life in the ocean. The Antarctic Ocean has abundant wildlife. The most common ocean animal is the krill, a small, shrimplike creature that feeds on tiny floating organisms. Many other Antarctic animals depend on krill for food. Many Antarctic animals also eat squid—a soft, boneless sea animal. In addition, about 100 kinds of fish live in the ocean, including Antarctic cod, ice fish, and plunder fish.

Several kinds of whales migrate to Antarctica for the summer. The blue whale—the largest animal that has ever lived—is one of these. This rare mammal feeds on krill and grows up to 100 feet (30 meters) long.

Humpback whales and killer whales are among the other kinds of whales that spend summers in Antarctica. Various kinds of seals also live in Antarctica, spending most of their lives in the water, where they swim, dive, and catch food. Most of them nest on the coasts, but the

Antarctic fur seal nests on nearby islands. The southern elephant seal, the largest seal in the world, also lives in the Antarctic region. These seals have large noses and tough skin, and the males may reach a length of 21 feet (6.4 meters).

The Antarctic food chain nourishes a great variety of wildlife. Tiny floating organisms known as plankton (1 ) support krill (2), a small, shrimplike creature that is the most common animal of the Antarctic Ocean. Swarms of krill form huge red masses in coastal waters during the day and glow bluish-green at night. Krill is rich in protein and a key source of food for many varieties of fish (3), birds (4), and larger creatures such as fin whales (5). Fish, in turn, provide food for penguins (6) and several species of seal (7). Leopard seals (8) hunt other seals as well as penguins. Killer whales (9) also hunt seals, penguins, and smaller whales

Birdlife. Four kinds of penguins, the well-known flightless birds, breed on the continent. On land, these birds waddle awkwardly, but in water they are swift, skillful swimmers that feed on fish and other food they find in the ocean.

Adelie penguins, the most common kind, build nests of pebbles on the coasts. Other inhabitants of the mainland are the quieter emperor penguins. After the female emperor lays an egg on the ice, the male rests the egg on his feet to warm it. Chinstrap and Gentoo penguins nest on the Antarctic Peninsula and on islands. Others, including kings, macaronis, and rockhoppers, nest only on islands north of Antarctica.

Emperor penguins, above, are the world's largest penguins, growing to about 4 feet (1.2 meters) tall. Young emperors huddle under the body of an adult bird to keep warm

More than 40 kinds of flying birds spend the summer in Antarctica. Birds that nest on land but spend most of their time diving for food include albatrosses, prions, and a large group of sea birds known as petrels. Other birds, such as cormorants and gulls, return to land more frequently. Some steal food from the nests of other birds.