How are humans different from other primates? Our main feature is a more developed brain, but there is one particular difference that immediately catches the eye – our body is not covered with long hair. Some other mammals like rhinos, whales, diggers and elephants can boast of the same. At the same time, our distant ancestors were still covered with wool, which protected them from the cold. But why did evolution make it so that now we are all dressed in bare skin and forced to wear clothes? Surprisingly, scientists still cannot give an exact answer to this question. However, they are actively working in this direction and currently have three possible explanations for why modern humans do not have wool. Let’s take a look at them – it’s time to expand your horizons!
Why body hair is needed
First, it is worth noting that the human body is not covered with bare skin. According to scientists, there are about 5 million hair follicles on the surface of our skin, which produce very thin and short vellus hair. Unlike those that our distant ancestors had, they do not perform an important function. As an exception, it can be noted that the hair on the head, face, armpits and inguinal region, which still grows thick and long.
We technically have small hairs all over our bodies that grow from hair follicles. But they are so small that they cannot perform any important function, explained biological anthropologist Tina Lasisi.
According to scientists, modern man needs hair on his head to protect it from hypothermia, overheating and shock. Mustaches and beards are needed by men to attract the attention of women, as well as to protect the face from cold and damage. Armpit hair can also play a protective role because the skin in this area is considered particularly vulnerable. Vegetation in the groin is needed to protect against bacteria, hypothermia and friction. Eyebrows and eyelashes are needed by people as protection for the organs of vision.
Если хотите знать больше, читайте наш материал «Зачем человеку нужны волосы на голове и других частях тела». В свое время она набрала кучу просмотров, так что настоятельно рекомендую!
Why don’t people have fur?
As mentioned at the beginning of the article, scientists do not know exactly why people lost their hair during evolution. They also cannot say exactly when this happened – the long hair of ancient people has long decayed, so it is impossible to understand when they disappeared. However, scientists have some interesting hypotheses.
Интересный факт: английский натуралист и путешественник Чарлз Дарвин считал, что древние люди лишились шерсти потому, что ее отсутствие делало их более привлекательными для противоположного пола. Сегодня эта версия непопулярна.
Body cooling hypothesis
This is the most common version among scientists and is also known as the “savannah hypothesis”. It is believed that during the Pleistocene, representatives of the species Homo erectus and later hominids began to actively hunt animals in the savannah – this is the name given to vast areas that are covered with grassy vegetation with sparsely scattered trees and shrubs. They had to run for hours under the scorching sun, and the wool did not allow the body to effectively remove heat – our ancestors often overheated. Therefore, from an evolutionary point of view, the absence of thick hair was more preferable for survival, and gradually people lost it.
This hypothesis was put forward in the 1980s. Although this explanation of hair loss is acceptable to many scientists, some still question it. A number of researchers believe that if this hypothesis were true, evolution would have made people living in the north more hairy so that they were better protected from the cold. It is possible that northerners have thicker hair, but the difference is not so great that they are not afraid of frost.
Читайте также: Когда древние люди научились шить одежду и какой она была?
In 2003, scientists put forward another version, which is also similar to the truth. In their opinion, the distant ancestors of man lost their hair on their bodies due to the fact that parasites multiplied on it. We are talking not only about fleas – in addition to them, in the ancient world (and even in modern times!) There lived many insects that carried deadly diseases. For example, potentially dangerous flies could sit on the wool and lay their larvae in it. Attacks from parasites significantly reduced the chances of survival, so it was much more profitable for people to remain without wool.
At the moment, these are the two most likely reasons why modern humans do not grow hair: it would prevent us from cooling the body and reduce life expectancy due to the constant threat from parasites. In addition, today’s people do not need wool because we have clothes.
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Finally, it is worth noting that modern man has many rudiments – organs and body parts that used to perform important functions, but today have completely lost their relevance. A complete list of human rudiments is presented in our article “What are vestigial human organs and why are they still needed.”