Like humans, animals need sleep too. A big problem for animals in the wild is keeping their enemies away while they sleep. Animals take care of this problem in different ways.
Anolis lizards live in many areas including tropical rainforests. They often sleep on leaves at the end of long branches. A leaf might seem like a strange bed, but it works like an alarm. If a hungry snake wiggles a branch, the lizard wakes up and leaps to safety.
Chimpanzees take their sleep very seriously. Each day, a chimpanzee builds itself a new, comfortable bed to sleep in. Scientists believe chimpanzees carefully choose a tree that is strong, where they build a nest using branches and leaves.
Parrotfish live among coral reefs in oceans. Every night, parrotfish usually sleep close to the rock in sheltered places. Some parrotfish go one step further by quickly making a slime layer that covers their whole body. This covering acts like a sleeping bag that provides a barrier against danger.
Bottle-nosed dolphins need to sleep, but they have to be on the ocean's surface to breathe. They also need to watch over their young. What do they do? While half of the dolphin's brain sleeps, the other half stays awake. After a while, the sleeping half wakes up while the other half snoozes.
Sooty terns have the most amazing sleep. They nest on islands. When they are not nesting, they live for many years in the sky and on the sea's surface. When and where can they sleep? Scientists believe they are able to sleep while they are flying, staying out of the reach of enemies.
