Why do we have hair?

The human body contains roughly 5,000,000 hair follicles. The function of each hair follicle is to produce a hair shaft. The function of human hair depends on the part of the body from which it grows. Human hair performs several functions. It protects the skin from environmental influences. It responds to external input and translates this information into neurological impulses that are interpreted as sensory stimuli by the brain. Scalp hair is also the only part of the human body that can be readily and consciously modified to change an individual's external appearance. So it also serves as an important means of allowing individuals' to socially communicate.
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
Hair is great for running your fingers through and growing make-a-statement goatees, but having hair was once far more purposeful than simply serving as bodily ornamentation. For early humans, hair kept them warm, protected them from cuts and scrapes, provided camouflage, and even served as a nice handhold for the young. They were much hairier than modern humans, and the reason that we lost a lot of body hair over time isn't because we invented heaters and parkas. More likely, our ancestors started hunting in hot, tropical areas -- and bare skin adds to the efficiency of our cooling system. The reason why we kept the tuft at the top? Many experts agree that it had to do with a mating ritual that went a little something like this: The male with the most impressive hair -- or he who could make it look that way -- frightened away his rivals, got his girl, and fathered the next generation. Hence, head hair played a major role in obtaining a partner and successfully producing offspring.

Today, our hair still performs many useful functions, in addition to keeping barbers employed. The hair on our scalps protects us against the sun, and our eyelashes act as our first defense against bugs, dust, and other irritating objects. In the phase of human development when our ancestors had lost their full-body follicular coverage but clothes were still as scarce as skyscrapers, the hair in our nether regions camouflaged our reproductive parts from generation-threatening spears. And by lining our armpits -- we docs call this the axilla -- and groins, our dry hair actually acts as a lubricant, allowing our arms and legs to move without chafing.

Also, both then and now, our body hair serves as a protector against malaria. The Anopheles mosquito -- a low-flying bug that likes the legs -- hates hair, in part because hair warns its victim to start swatting. While their bite is painless, our hair signals the presence of mosquitoes before they bite (it's why kids are at greater risk -- they have less hair on their legs). That's most likely the original purpose of hair: it served as an early warning system of bodily threats. We seem to ignore the armor function of our hair today, removing it every chance we get, except on our heads and eyes.
YOU: Being Beautiful: The Owner's Manual to Inner and Outer Beauty

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YOU: Being Beautiful: The Owner's Manual to Inner and Outer Beauty

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.