"The sea is wide with fish leaping, the sky is high and the birds are flying" Do you imagine birds soaring freely in the blue sky?
Let's take a look at how the birds skyrocket.
Having a pair of wings is the first condition for birds to fly. Scientists believe that the structure of bird wings is extremely complex, no less complex than the overall function of birds. The feather construction of the bird's wings cleverly uses the principle of aerodynamics to push the air and use the reaction force to fly forward. The structure of the feather gap is scientific and reasonable, which can effectively reduce the air resistance encountered during flight, and some can also de-vibrate and eliminate noise, so that the difference in wings alone has created many excellent or general "pilots".
Birds flying, in addition to relying mainly on their wings, but also on their special skeletons. Bird bones are excellent "lightweight materials" with light hollow weight. According to the analysis, bird bones only account for 5%-6% of the body weight of birds, while human bones account for 18% of body weight. Due to the light bones, the wings are easily moved, and there are many air sacs in the bird's body that are connected to the lungs, which is very beneficial for reducing self-weight and increasing buoyancy.
In addition, birds, like humans, will undergo "hyperventilation" in the absence of oxygen, and unlike humans, birds perform double-flow breathing: lungs - air sacs - lungs. At an altitude of 6,000 meters, the oxygen content is only 1/2 of the sea level, and birds can increase their breathing rate by 5 times and the amount of air they can breathe twice when flying at this altitude. When birds are at very high altitudes, the amount of blood flowing into the brain does not decrease, and under the same conditions, the cerebral blood flow in mammals is reduced by 50%-70% compared with normal.
Excessive ventilation allows the lungs to quickly inhale more air, which delivers large amounts of oxygen to all parts of the body, especially the brain. Under normal circumstances, the direct cause of brain damage is because the cerebral blood vessels begin to contract during excessive ventilation, becoming narrower than normal, and brain cells do not have enough oxygen to replenish, and death will accelerate. However, birds can succeed in the same situation, and some people think that they do not have cerebral vasoconstriction during excessive ventilation, so they can overcome the limits that humans think are unbearable.
Some people say that the reason why birds can overcome complex air currents, alpine cold, lack of oxygen and other unfavorable conditions, only the special function of over-ventilation is obviously not enough. Such as strange cold, complex air current impact, unexpected hail and snow, etc., so it is necessary to have a comprehensive strain capacity. Birds are so different that they must have a set of reasonable and scientific strains. However, where this "device" is hidden, human beings still do not know.