Is Curly Hair More Useful?
People with curly hair sometimes dream of having straight hair, while others use curlers to achieve the opposite. We don’t dare to say that one is more beautiful than the other, but it has now been scientifically proven that curly hair does have one big advantage.
Scientists have been scratching their - um - heads for years over why some people have curls. A recent study has suggested that it is all about protecting us from the sun and regulating our body temperature.
Dummy with a wig
In the study, a test dummy was placed in a wind tunnel inside a climate chamber. Heat lamps were pointed at its head to mimic the sun's rays. First the dummy was tested "bald", and then it was given three different wigs made from human hair: one with straight hair, another with loose curls, and finally one with tight curls. The researchers were then able to measure how different hair textures affect skull temperature. They also calculated the heat loss at different wind speeds, before and after wetting the dummy’s head, to imitate perspiration.
Curls keep you cooler
All the hair types offered some protection against the imitation rays of the sun, but the test dummy that stayed coolest was the one with tightly curled hair. This type of hair does not lie flat, so there is a layer of air between the head and the hair surface. This allows the scalp to breathe while still protecting it from the sun's heat. The tighter the curls on the wig, the less water (or sweat) was needed to prevent the head from heating up.
This is a big advantage: when we sweat, we lose large quantities of precious body fluids. Our human-like ancestors could not just grab a bottle of water, so they had to avoid this situation.
Evolutionary advantage
The researchers think curly hair was beneficial for a two-legged lifestyle, particularly in hot, dry areas, where drinking water was scarce. This allowed our ancestors to sustain physical exertion for longer periods before needing water. Later on, this evolutionary advantage may have disappeared in some humans as they left Africa and moved to live in colder climates.
Further research
The researchers are hoping to find out when and why human hair evolved in the way it did. Of course a test dummy in a climate chamber is not the same as a real person. More studies will be needed in natural environments, with hair of different types and colours. Ideally this should also involve real people.