why do we need hair on our body
We're a pretty resourceful species, but when it comes to body parts, humans definitely have a couple that seem like a waste of space. After all, we could do perfectly well without the appendix, male nipples, and our wisdom teeth, and scientists think these could simply be a hangover from our evolutionary past. But what's the point of all that hair on our bodies, and why do we have eyebrows anyway? The
of the University of New South Wales' (UNSW) How Did We Get Here explains. For starters, even though we might consider ourselves pretty hairless, humans are actually covered in around five million hair follicles - tiny organs on our skin's surface that produce hair. In fact, after our heads, the area with the highest concentration of hair is our nostrils. But why aren't we as hairy as our ape cousins? As evolutionary biologist Darren Curnoe, it's believed that our ancestor's body hair got a lot shorter as they evolved from walking on all fours to standing, and this allowed them to keep cool while walking and running long distances in pursuit of food.
And our hair still plays a very important role in regulating our body temperature. When it's cold outside, tiny muscles surrounding the hair follicle cause the hairs to stand up, to trap more heat near the body. This is what happens when you get goosebumps. So those tiny hairs all over our bodies make sense. As do nostril hairs and eyelashes, which keep dirt out of our bodies. But what about things like chest hair, pubic hair, and eyebrows? Why do they grow so much longer than the hair on our arms, and what's the point of them? Scientists still aren't entirely sure, and we'll let you to find out why. But one thing's for sure, our hair definitely isn't useless. В Don't forget to to see new episodes of How Did We Get Here? as they're released, and find out more about the research happening at 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.
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