Yes, compared to other mammals, humans have very little body hair. Scientists put forward many theories about this. Body hair serves two main purposes - in cold weather it helps the body to keep warm, and in hot weather it absorbs moisture, like a golf shirt. It so happened that men have much more body hair than women.
However, it is the women who are mainly concerned about the fact that they do not have excess hair on the body. But a large amount of hair on the body of a man does not bother women at all. In particular, the opinion is still very popular that the more chest hair a man has, the more masculinity and passion he has.
7 main theories why hair does not grow on the human body
1. The theory of sexual selection
The less hair on the body, the better the genitals are visible. Charles Darwin himself believed that this attracts the attention of the opposite sex and increases the possibility of successful reproductive and evolutionary development.
2. Theory of thermoregulation
Perhaps the lack of hair is somehow related to the thermoregulation of the body of a person living in a tropical environment. At an early stage of their development, people lived within 15°; north or south of the equator. Therefore, the disappearance of hair could be the result of human adaptation to a hot climate, because, unlike most mammals, people hunted during the day, not at night.
3. Brain Enlargement Theory
According to this theory, the development of the human brain to its current form would not have been possible in the presence of dense hair. The presence of additional brain cells reduced the risk of sunstroke during long-distance running in primitive people.
4. The defective gene theory
Another theory is that the person lost their hairline as a result of having a defective gene and therefore a mutation. This mutation probably occurred at an early stage in the development of hominids, since it affected all races.
5. Parasite Defense Theory
There is an assumption that a hairless person is much easier to get rid of parasites (lice, mites, etc.) than a hairy one. Parasites are carriers of diseases and create discomfort.
6. Clothing theory
With the advent of clothing, the need for thick hair that helped people to survive simply disappeared. The hair became unnecessary and eventually disappeared.
7. Aquatic Monkey Theory
This highly controversial theory says that humans emerged from the aquatic environment and lost their hair for the same reason as whales, dolphins and manatees. It is the layer of subcutaneous fat that helps keep the water warm, not the hair.
Needless to say, each of these theories is subject to serious criticism. For example, regarding the theory of thermoregulation, it has been repeatedly emphasized that the human skin, with its abundance of sweat glands, is excellent at dissipating heat – both with and without hair. As the late anthropologist Marvin Harris of Columbia University wrote, "We keep ourselves cool by the moisture our sweat glands secrete. Humans have 5 million of these glands, far more than any other mammal."
With regard to the theory of defense against parasites, for example, Charles Darwin wrote: "Whether [skin parasite infestation] is an evil of sufficient magnitude to cause baldness of the body," is a moot point, since none of the tetrapods that live in the tropics, as far as I know, I am not familiar with any special means of protection against parasites. "
Scientists still disagree on which theory is correct.
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