Why human lost body hair?

Scientists believe that the need to keep cold heads is the reason why humans become the only 'naked' creatures.

Reducing heat in the body by sweating is one of the important processes that can help prehistoric people to walk with two legs and a larger brain.

The brain's temperature is too great to be life-threatening. This means that the process of evolution has been put on a great pressure to eliminate the body temperature through the evaporation of sweat on the skin.

"This is the main reason why people have lost body hair more than 1 million years ago," said Nina Jablonski, professor of anthropology at Pennsylvania Federal University.

Human skin has a lot of endocrine sweat glands, and this is the way in which sweat escapes to reduce body temperature. A thick layer of hair on the body can cause the process of sweating and water evaporation to hinder and affect the body's ability to reduce heat.

People lose body hair to travel with two legs more easily and let the brain grow.

' Losing body hair is a way to regulate body temperature. We lose body hair, but increase the amount of endocrine sweat glands. Anthropological research on ancient people, like the skeleton of the 'Turkana boy', living in eastern Africa more than 1 million years ago, shows activities such as running, walking with two feet and many other activities during the day can overheat your body. This high body temperature must be adjusted '.

However, a 'naked ' skin is very vulnerable to the Sun. And dark skin color to protect the skin from the Sun's destruction is also considered a human evolution when body hair disappears.

Only when the first ancient people in Africa, which appeared about 70,000 years ago, migrated to the northern parts of Europe and Asia, their dark skin was replaced by skin colors. Brighter to produce vitamin D from ultraviolet rays.