Life on the Tundra: Science Words in Context

Life on the Frozen Tundra

1Far to the north, near the Arctic Ocean, lies a cold, windy land called the tundra. Scientists call the tundra a biome, which is a large region with its own kind of climate, plants and animals. Winters on the tundra are long and dark, and summers are short and cool. Few trees can grow there, so the land stretches out flat and open for miles.

2Just under the surface of the tundra is permafrost. Permafrost is ground that stays frozen all year long, even in summer. When the summer sun warms the land, only the top layer of soil thaws. The melted water cannot soak down through the frozen layer below, so it collects in puddles and soggy bogs. Because the permafrost blocks them, plant roots must stay shallow, close to the surface.

3Tundra plants have adaptations that help them survive. An adaptation is a body part or behavior that helps a living thing survive where it lives. Most tundra plants grow low and close together, which keeps them out of the strongest winds. Many have fuzzy hairs on their stems that help them hold in warmth. The growing season, the part of the year when plants can grow, lasts only a short time each summer. During the long winter, the plants are dormant. They stop growing and rest until the warm days return.

4Animals are adapted, too. The arctic fox has thick fur that insulates its body. To insulate something means to cover it in a way that keeps heat from escaping. The fox's fur even grows on the bottoms of its paws. In winter, the arctic ground squirrel hibernates in a burrow. Its body cools down, and it sleeps deeply for months, saving energy until spring.

5Some animals do not stay all year. Each spring, huge flocks of birds migrate to the tundra. To migrate is to travel from one region to another when the seasons change. The birds build nests, raise their chicks and feast on the swarms of insects that hatch near the summer bogs. When autumn comes, they fly south again to warmer places.