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Why do humans still have body hair?
Hairs serve as motion detectors for alerting us to insects, like bedbugs, before they can bite us.
Wed, Dec 14 2011 at 8:20 AM
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Photo: Lee J Haywood/Flickr
Human body hair might seem to be useless on today's modern man, but it could help us detect parasites, researchers suggest, adding there's a chance our female ancestors preferred a bug-free mate, and so opted for hairier guys.
Humans appear relatively hairless compared with our ape relatives, but the density of hair follicles on our skin is actually the same as would be expected of an ape our size. The fine hairs that cover our bodies, which have replaced the thicker ones seen on our close relatives, are thought to be an evolutionary leftover from our hairy ancestors.
Now scientists find these fine hairs are useful after all — people with more of them are better at detecting bedbugs.
"I run a research group that seeks to understand the biology of bloodsucking insects," said researcher Michael Siva-Jothy, an evolutionary ecologist at the University of Sheffield in England. "Our aim is to find ways of controlling these insects effectively and thereby preventing the transmission of insect-vectored disease."
Investigators recruited 29 university student volunteers through Facebook and shaved a patch of hair from one of their arms. The scientists then tested how long it took the volunteers to detect bedbugs placed on each arm and how long it took the parasites to find a good place to feed on. (The bugs were removed before they started feeding.)
The researchers found that body hair significantly enhanced how well people detected the bedbugs, with participants noticing the bugs on the hairy arm quicker than they did when tested on the "hairless" arm, with the hairs serving as motion detectors. The hair also prolonged how long it took the parasites to find places to feed, presumably because they hindered movement, Siva-Jothy told LiveScience.
Men seemed better at detecting parasites — they are generally hairier than women because of higher testosterone levels. This does not necessarily mean that women are more likely to be bitten — blood-sucking insects likely prefer to bite hosts in relatively hairless areas such as ankles.
Although the researchers stress they are not saying that the differences in male and female body hair are due to parasites, they do speculate that in our evolutionary past women might have preferred men with fewer parasites on them — hairier men.
The scientists detailed their findings online Dec. 13 in the journal Biology Letters.
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Yes actually it could our hair is sort of like antler that you would find on a deer moose or any other horned animal it simply helps us stay warm or cool off.
There's also just as much "evidence" that human perceptions have any basis in reality. The scientific method is flawed because it depends too much on human perception and intellect. Ignorance is part of the human condition. To under value someone else's opinion because it is not your own could be considered the greatest representation of ignorance that there is.
Anything derived from 29 samples from Facebook is pseudoscience. No control, no considering demographic variations, not even a good explanation how more hair helps prevent bugs. Plus, women don't judge men on the amount of bugs on them alone, there are far more important factors on this evolution trail. Fail!
Seems odd that some evolutionists concluded that losing hair is progression. Only 3% of this planet's surface is habitable by human beings (without technology like clothes and shelter). Which means losing more hair makes us less likely of the surviving candidate. The only thing that makes us fit for survival on this planet is our intellect, creativity and reason which evolution cannot explain.
Slight contradiction there. If it makes us "fit for survival" it's a feature which by definition will be favoured by evolution, since it will increase the chances of passing on those genes. Intellect, creativity and an ability to "reason" are all features which can be selected either naturally or sexually, and are therefore completely explained by the evolutionary process.
If intellect, creativity, and the ability to reason are traits which are desirable for survival, then why are we the only species on the planet that have those traits? Wouldn't being smarter allow most other species to be even more able to survive?
well they try actually, but it is a long process. we evolved in that direction and a lot of our characteristic helped that. animals try to go in that direction too but if we don't intrude in their evolutionary process it will take a while for them.
I don't think we (human) losing hair. All the hair folicals are still there but for more or less the hair become thicker or thinner (finer hair). Something control in the hair cell control the thickness of the hair. For example, I used to have hair on my leg that are real fine then I got scrap off at the knee from roller bladding. At that area of the hair become 3 time thicker and 10 longer.
"Which means losing more hair makes us less likely of the surviving candidate."
quite wrong thinking.
because we have no hair we hardly are able to die from overheating. (while running after food(animals). that technique was the very first one and common in the past, and still in use in some deserted parts of africa) and protection from freezing is amazingly easy- wearing a cloth/fur, or setting a fire.
Evolution is change + selection. Smart people conserve energy and have a higher chance of survival than dumb people. Thus, useless features like fur in the tropics can be dropped in favor of buildings that keep out bugs and tigers.
Ok, so the more hairy, the less lice and mites you will have? Excellent article!
Joking aside. Climate and diet played a role in human physical variation throughout our evolution. Yes, that includes body hair.
well also the hair on the chest helps keep the Heart warm, also keep it cool in warm whether as its like a heatsink for a cpu.
So the Chinese people are "bug free" so that "evolution" stopped/reduced producing body hair on them??????
Why do we "still" have body hair..???
Honestly - why are people "still" so deceived by the notion that evolution from an ape-like ancestor has ANYTHING to do with reality - or reasonable evidence, for that matter?
Thee is as much evidence for UFOs as there is for GOD or " intelligent design"
Mostly they believe it because blind faith in ancient mythologies that cause people to overlook overwhelming evidence that disagrees with those mythologies is no longer as widespread as it once was.
Depends, there is no edvidence that egyptians beleived in gods with animal heads, since curtain gods had their heads changed, depending on the context of the story or teaching. We assume they did, but we forget its a language, and animals are really attributes or qualites, the egyptians are trying to express by using animals.
We are really just as ignorant as we think they are, thier language is very abstract, yet we study it like our literal languages now, cant be done.
If you buy into the presupposition that humans evolved from apes....which has NOT been proven.
Actually human chromosome #2 is shown to be a fusion of two ape chromosomes, and far more importantly than that it just happens to be a fusion of the two ape chromosomes we don't have.
Also it has always struck be as strange that people who dismiss geneticists who tell them that DNA proves we are related to apes are quite happy to see criminals executed on the DNA evidence of the same geneticists, it truly is madness
We did not evolve from apes, however we do share a common ancestor.
Yes, it's as ridiculous as the notion that the world is round, and that it orbits around the sun. Utterly preposterous!
the flat earth theory was never popular, even in the ancient world. in hermetic (which came from Egypt) call planet's are called heavenly spheres. Arab countries saw it as a sphere as well. I think the only people that thought it was flat was europe. And in our ignorance, we assume the rest of the world thought that. Even ancient cathedrals observatories had planets shown as spheres.
Most people view on history is terrible.
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