The Possible Reason Why People Have Curly Hair

Research suggests that curly hair may have evolved in humans living in Africa thousands of years ago to protect them from the sun. A study published in the journal Proceedings of the National Academy of Sciences sheds light on the evolutionary significance of curly hair as a natural defense mechanism against solar radiation.

According to Nina Jablonski, Professor of Anthropology at Penn State University, "Humans evolved in equatorial Africa... We found that tightly curled hair allowed humans to stay cool and actually conserve water." The coiled structure of curly hair acts as a barrier, providing protection against the intense heat and harmful effects of the sun's rays.

To investigate the impact of solar radiation on different hair types, scientists at Loughborough University conducted an experiment using a manikin powered with electricity to replicate body heat. Various wigs made from human hair were tested, with lamps emitting light that mimicked the sun's rays.

The researchers also measured heat loss at different wind speeds and simulated sweating by wetting the scalp. Their findings revealed that while all types and textures of hair provided some level of protection against solar radiation, tightly curled hair proved to be the most effective shield against the sun's heat.

The study's results support the notion that curly hair may have evolved as an adaptive trait in populations living in sun-drenched regions. The coiled structure of the hair creates an insulating layer that helps to regulate body temperature and prevent excessive water loss through sweat.

While the research emphasizes the protective benefits of curly hair, it is important to note that this is just one aspect of its complex nature. Curly hair is also influenced by genetic factors and has cultural and aesthetic significance across different populations.

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