1, open your eyes. Animals can sleep with their eyes open, such as fish. Therefore, when raising fish and animals, whether you are asleep or not can not be judged by the eyes of the fish, but by whether the fish are swimming.

2. Sleep standing up. Animals can sleep standing up, such as horses, giraffes, elephants, penguins, red-crowned cranes and so on. Among them, the red-crowned crane sleeps independently on one foot, and horses and penguins are more alert. When sleeping standing makes them feel dangerous, they can escape quickly.

3. Sleep while swimming. Dolphins can sleep while swimming. At this time, one eye of the dolphin is open and the other eye is closed to sleep. In addition, dolphins are marine mammals with constant body temperature and no hibernation habit.

4. sleep on your stomach. Dogs, wolves, leopards and other animals will put their ears to the ground when they sleep, so that they can quickly feel the movement around them and respond accordingly. In addition, cats, lions, tigers and other animals often lie down and rest during the day.

5. bury your head in the sand. Ostriches sleep in a very special way. When they sleep, they will bury their whole heads in the sand. Note that ostriches are huge birds in Africa. They can't fly but are good at running.