An adaptation is a feature or behavior that helps a living thing survive in its environment. Structural adaptations are body parts, such as thick fur. Behavioral adaptations are things an animal does, such as moving to the shade.

Hot deserts have very little rain and are hot by day but can be cold at night. A cactus stores water in its thick, waxy stem, has spines instead of wide leaves, and spreads its roots wide to soak up rain quickly. The fennec fox has huge ears that release body heat, and many desert animals are active at night.

Polar regions are freezing and windy. Polar bears have thick fur, a thick layer of fat under the skin and small ears that lose little heat. Emperor penguins huddle in big groups and take turns in the middle where it is warmest.

The deep ocean is dark, cold and has crushing water pressure. Some fish there make their own light to find food.