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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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said i wouldn't post anymore....well sorry.
indeed: and in that you can even include: environment adaptation mutation (we live to long to see it), hasardous mutation and interspecies gntic transfert through consumption (you are what you eat ^^) even though this stuff are minimals.
I find many evolutionary explanations for human anatomic features and human behaviour to be very lacking, including this one, they aren't necessarily incorrect,techinically speaking, but they simplify human anatomy and behaviour into having very basic and trivial reasoning when creatures evolve and behave the way they do for plentiful and complicated reasons.
Black and Asian people have thinner hair and some noticed very smooth so this is very likely from evolved as white people come from Europe and cold so the hairs still showing but I believe also to do with sexual attracted. I'm very attracted to women with armpit and some hairy down there :)
Around 50,000 years ago, we were the weakest, slowest and barest species Homo of the four that existed then. Our Human Genome studies have shown that the FoxP2 mutated to the FoxP2 forkhead box P2 by adding a protein. From that day forward we started on the path to intelligence that eventually led to Homo Sapiens Sapiens being the only Homo species left. The agent that led to this discovery, along with our genome mutation?
The body louse..they can't live without us!
when one knows what a photon is a messenger particle that delivers information to the brain and the Adam and eve story his story the bible writers when splitting the atom nuclear fusion this is our true beginning star formation
What!?
why not study more important things like curing cacner or a new energy source
You know they said almost exactly the same to one of the early guys who presented electricity in scientific demonstrations. 'Yes, but what USE is it', they asked? His beautiful reply was 'What use is a newborn baby?'
And if you read the article, this research is in aid of controlling and combating insect-borne disease and bites. Sounds useful to me.
search out DMSO and be aware its been around for about 50 yrs
Easy answer (the Keep It Simply Stupid rule/Occam's Razor) is there is no such thing as evolution. That's why we still have hair and it is the simplest answer.
It is not true that all females prefer non-hairy men. Male models in advertising are not really meant to appeal to females, any more than the average ultra-skinny female model is particularly attractive to most men. Hair is not just for looks: running your hand through someone's head hair, or through a man's chest hair, is a very nice sensation.
Parasites like bed bugs is from a lack of cleanliness, which in today's society should not be prevalent.
That is biggest load of rubbish anyway bug headlice prefer clean hair they struggle to survive in greasie hair, bed bugs are attracted by any human and all it takes is a visitor to you home for them to thrive in your home.
Infact 80% of bugs prefer clean enviroments to dirty ones
You are actually very wrong.
http://www.msnbc.msn.com/id/11915026/ns/dateline_nbc-dont_let_the_bed_bu...
I know for certain that body hair makes it a tad difficult for mosquitoes to find a suitable landing spot.
I have always woundered, doesn't the Hair under your pits and inbetween your legs help keep your arteries warm from cold wheather? if your arteries dont stay warm your body starts to freeze faster and slows down faster too.
yep you're right it's one of the main functions. that and cushioning. it helps stick transpiration in little drops so air passing through it refresh it to drop your temperature too. but aye i'm not a scientist. just read this stuff a lot in different sourcebook while i was getting older.
I always had a theory of body hair, could it act as a heat sink as well? similar to a cpu heat sink, the heat goes to the copper, and wind cools the copper, or in this case the body heat goes towards the hair and wind blows off the heat.
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.
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