There are two kinds of creatures on the earth that are particularly concerned about their appearance, one is a feline, and the other is a human being. Pet cats at home should be familiar, and cats only have two jobs a day: one is to constantly lick their hair, and the other is to sleep.
Humans are the second largest after cats to pay attention to their own grooming, such as men in order to keep their faces clean and tidy, they will carefully and repeatedly shave and trim nose hair every day, while women have also been committed to decorating their hair and trimming their armpit hair and leg hair.
There was an article on the Internet about "beard and longevity", which described: The longer the beard, the longer the life span of a person. Beard is also considered to be the hair of the human body, in the history of human evolution, it is not difficult to find that the same are primate mammals, why in the process of evolution, human beings have faded the hair of the whole body, leaving only the hair as large as hair, leg hair, armpit hair, pubic hair, small to eyebrows, eyelashes, nose hair and other hairs?
The same primates, like monkeys, orangutans no matter how to evolve, but on the surface of the body line is still thick hair, if according to the relationship between hair and lifespan, human beings in the evolution from apes, why did they degenerate such "important" hair?
<h1 class= "pgc-h-arrow-right" > the history of human hair. </h1>
According to the theory of scientists, it is generally believed that we humans have evolved step by step from ancient apes. From some pictures of ancient apes on the Internet, we can find that the hair on the ape is particularly lush, they used to walk on four feet, with continuous evolution, the ancestors of humans began to slowly learn to use two feet to walk upright, and the hair on the body gradually became less.
Human hair doesn't evolve suddenly, it's a very long process.
1. In 1967, the British zoologist Morris briefly mentioned the "water ape hypothesis" in "Naked Ape", believing that the ancestors of humans were originally "apes" who lived in water. This hypothesis was later overturned because scientists believed that in the shallow waters suitable for the survival of aquatic apes, there were a large number of crocodiles that humans could not live in at all.
2. After dr. Reed of the University of Utah proposed "fleas science", scientists believe that the gradual reduction of human hair is related to fleas, because the emergence of fleas is a creature that accelerates the degradation of hair. Fleas were originally parasitic on wild animals, human ancestors in the process of hunting, fleas parasitized from animals to humans, in order to avoid the harassment of parasites, occupy more survival advantages, humans began to slowly degenerate the hair on the body.
3, with the migration of the times, human concept of the existence of hair has also changed, human beings have a higher intelligence and culture, in order to distinguish from animals, humans are more concerned about the existence of hair, after all, only animals and livestock will grow long hair. In ancient Egypt and the Plains of Mesopotamia in 3000 BC, humans have been keen on hair removal, and from the murals of that time, we can see that human women are particularly smooth, which shows that humans had the habit of artificial hair removal at that time.
4, in 1904, human beings invented the hair removal knife, men mainly use it to shave, in 1915 women's hair removal knife entered the market. In the 1960s, the mainstream of society's aesthetic for women was still that the limbs should be smooth and smooth, and there was no hair, so people invented hair removal wax.
<h1 class= "pgc-h-arrow-right" > why do humans shed their hairs all over their bodies? </h1>
Modern humans are slippery, and if anyone in life is covered with black hair, or the sweat hair is slightly heavier, it will be called "the phenomenon of return to the ancestors". The reason why I say this is because in ancient times, the hair on human beings was particularly thick, just like monkeys and orangutans today.
As mentioned above, the evolution of human hair is a long process, and it does not suddenly disappear. Scientists can only hypothesize the reason for the loss of hair all over the body by fossils and some murals left by ancient times.
1. The life-saving hypothesis.
In ancient times, there were many large carnivores, and humans were particularly small in front of these large animals. Human ancestors lived on this land, in order to avoid the attack of large carnivores, when carnivores forage during the day, most of the human ancestors hid in caves or trees during the day, they lived by collecting the fruits of trees, and occasionally ate some other small animals.
Later, with the movement of the earth's crust, the forest degenerated into grassland, and the human ancestors on the trees were forced to live on the ground, so in order to "save their lives", they had to force themselves to evolve, from the initial four-limbed running to two-legged running, and a lot less hair, the body will become lighter, and the speed of running will be faster.
2. The fire source hypothesis.
Ancient humans discovered the use of fire by drilling wood for fire. Most beasts are afraid of fire, and fire not only helps the ancestors of mankind to drive away the beasts, but also brings them cooked food and warmth. Because of the source of fire, ancient humans began to become hunters in nature, and also found that even in the cold winter, as long as there is a flame, it will not feel cold, and thick hair is no longer so important, without them can withstand the cold.
Therefore, with the widespread use of fire, human ancestors were still able to resist the cold and maintain survival by drilling wood for fire after shedding their full body hair.
3. Parasitic hypothesis.
As mentioned above, scientists speculate according to the fossils of fleas and lice that in ancient times this creature existed, human ancestors mainly lived in groups, hunting for a living, the hair on the body is a place of dirt and dirt, it is easy to breed a variety of parasites, parasites lurking in human fur will not only spread diseases but also be particularly unhygienic.
Therefore, in order to avoid being harassed by parasites, and even endangering life, human beings gradually degenerate and lose hair, and there are fewer hairs, and it is not easy for parasites to hide.
4. The gender hypothesis.
We can see from some ancient murals that in ancient times, human beings in ancient times were full of long hair, whether men or women have thick hair, and there is no difference between them and the orangutan monkeys in zoos now, and it is almost difficult to distinguish gender without exposing sensitive organs.
In his 1871 book The Origins and Survival Choices of Human Beings, Darwin used the "theory of sexual selection" to explain the disappearance of human body hair.
Scientists later showed that ancient humans chose a mate relationship not to value their power and power, but more to look at appearance, popularly speaking, ancient humans also had "appearance associations". If it is beautiful-looking, or even smooth-looking, it is more likely to be favored, people are more willing to choose the opposite sex with less hair as a partner, and the disappearance of hair is more conducive to consolidating the relationship between spouses, and the hair can better distinguish each other after fading.
<h1 class= "pgc-h-arrow-right" > what is the reason for the only hair, beard, leg hair, and pubic hair left in the process of human evolution? </h1>
Regardless of the reasons why humans shed thick hairs, there is a question that has always puzzled people: why do humans shed hair all over the body, but leave hair, beard, leg hair and pubic hair?
Observing some newborn babies, we can find that when the baby is just born, the whole body will be covered with a thin layer of velvety black hair, which is also called "fetal hair", especially some premature babies, the hair on the body is thicker, but as the baby continues to develop, the hair on the body slowly fades, and the skin becomes smooth and delicate.
However, there are also some special children in life, as soon as they are born, they are full of thick black hairs, and as they grow older, these black hairs do not retreat but more, such children are also called "hairy children", such as Yu Zhenhuan, who is known as "China's first hairy child", has more than 96% of the hair on his body.
Well, the reason why the individual feels that in the process of evolution, only hair, beard, leg hair, and pubic hair was left:
<h1 class= "pgc-h-arrow-right" > hair: protects the brain from damage. </h1>
One of the most important parts of the human body is the heart, one is the brain, and if one of the two is damaged, the person will die. And there are a lot of nerves and blood vessels in the brain, and if there is no protection from hair, the bare one is easily injured.
Ancient human life had to avoid the attacks of some large predators and attacks between the same kind, and the hair protected the brain and buffered the damage to the brain. Secondly, ancient humans used to run constantly in hunting, and hair had the dual function of both heat preservation and heat dissipation. For example, in the hot summer, the bald head will feel hotter than the person with hair, and having hair can help the human body dissipate heat to the outside world.
<h1 class = "pgc-h-arrow-right" > beard: personal charisma that increases same-sex competition. </h1>
To reproduce offspring, it's often not enough to be attractive, you have to compete with the same sex to compete for more mating opportunities. Although modern women are deeply impressed by online information, they prefer to like some fine skin and tender meat, clean and fresh "small fresh meat" on the face, and contemporary men are popular in the "feminine and feminine" style.
But in ancient times, both men and women saw the beard as a symbol of maturity, strength, and aggression. Tall and burly men, especially men with thick beards, give people a reliable feeling in appearance, women will also have a sense of security, if they can often scare opponents away on the battlefield, when women choose a mate, bearded men have more mating opportunities than beardless men.
< h1 class = "pgc-h-arrow-right" > leg hair: protects against sunlight and mosquito bites. </h1>
In ancient times, the sunlight may be more dazzling than it is now, and mosquitoes will certainly be larger than they are now, and it will certainly be more painful to bite people. Leg hair can help find parasites, and even prevent pest bites, and the leg hair is connected to the human nerves, if there are mosquitoes crawling on it, the human body can immediately perceive.
Leg hair has the effect of blocking bacteria and regulating body temperature, when the temperature becomes cold, leg hair can play a warm function, when the weather can play a heat dissipation function, but also to prevent human skin from being sunburned, after all, there was no sunscreen in ancient times.
<h1 class="pgc-h-arrow-right" > pubic hair: protecting women from fertility problems. </h1>
The hair here is more intimate because it is close to the genital organs. A large part of the reason why humans did not degenerate the hair here during the evolutionary process is also to better protect the reproductive organs from harm, so as not to affect the survival of the race.
Just like armpit hair, if there is no armpit hair, when the arm is rubbed, the skin under the armpit is more delicate and will be injured, and the role of pubic hair is also to prevent friction injury.
< h1 class="pgc-h-arrow-right" > concluding remarks. </h1>
Kurt Stein has a famous book, Hair: An Interesting History of Humanity, in which he famously says: Humans grow hair to survive, and hair is shed to survive better.
Hair is particularly important for both animals and humans, mammals rely on hair to protect themselves from harm and the cold of winter, without the protection of hair, it is difficult to survive in the fierce competition in nature. Similarly, humans are also prone to injury in life without the protection of hair in these special parts.
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