Have you ever seen a bird that can sleep in the air? This bird is actually a seabird, but unlike other seabirds, its feathers are not protected by grease, so it cannot be like other seabirds, burrowing into the sea to hunt, once into the sea, it can no longer get up, so it can only eat some jellyfish, small fish, or some dead fish floating on the surface of the sea. But it is delicious by nature, can not catch fish to grab other seabirds of food, bold, so people compare it to pirates, and named frigate bird, the English meaning of warship, so the country is called warship bird. Since it can't go into the water, then how can it rest, can't fly all the time, always have to stay, for this reason, scientists installed brainwave detectors and some tracking instruments on them, collecting a large amount of flight data. After research, it is impossible for frigate birds to find a place to stay at night, and when they need to rest, they can only sleep in the sky, which sounds very incredible, since they are sleeping, why did the birds not fall from the sky? After careful research by scientists, they can actually use the brain separately, half resting, and the other half staying awake. This is called single-hemisphere half-wave sleep, so that they can keep half of the brain awake and constantly monitor the surrounding environment to avoid danger. Humans sometimes use this mode, such as obviously you have fallen asleep, when there is a little wind and grass around, you can immediately turn over, especially in an unfamiliar environment, your vigilance is high. Scientists recently found that when people fall asleep in an unfamiliar environment for the first time, their left and right brain hemispheres show different degrees of sleep depth. In general, most people are right-handed, so the left side of the brain is relatively lacking in deep sleep. However, the left brain, as the half of the head that is better equipped to monitor its surroundings and remain vigilant, is more active at night, responsible for keeping vigil and protecting the safety of sleepers. Experiments have also shown that when there are sounds such as barking and knocking on doors in the environment at night, the protector's left brain responds immediately and wakes up the other half of the head to further process and store the relevant information.
