Naked Science Forum
General Science => Question of the Week => Topic started by: thedoc on 22/09/2009 17:11:08
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Why do we have fingerprints?
Asked by Simon, Japan
Hear this Question on our Podcast (http://www.thenakedscientists.com/HTML/podcasts/show/2009.09.20/)
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We put this question to Dr Roland Ennos from the University of Manchester...
[img float=right]http://www.thenakedscientists.com/forum/copies/RTEmagicC_Fingerprintforcriminologystubs_03.jpg.jpg[/img]Well, the answer, I’m afraid, is that no one truly knows. The most obvious idea is that they roughen our fingers to increase the friction. But we’ve done some test here in Manchester and we found that in fact the fingers actually behave rather like car tyres and because the fingerprints reduce our contact areas with a surface, they will actually reduce friction, just like the grooves in car tyres in a wet weather tyre and reduces the grip of the formula one car. Another possibility which I must say I favour, is that the ridging could actually help to prevent blister formation because the pattern will allow our skin to have much greater compliance and so that can help to reduce the sheer stresses around the edge of our contact zone. And the reason I believe is that if you ever do DIY tasks, what you tend to find is that the only bits where you get blisters is the bits, not on your fingerprints or wherever the big pattern of your palms, but in areas where there aren’t any prints. Well, of course there is no doubt that one of the roles the fingerprint must be to improve tactile discrimination because rubbing you finger over a surface, when it hits the rough projections they seem to help to detect vibrations and so, it is likely that one of the roles of finger prints is to improve touch discrimination. But that can’t be the main function because the soles of our feet, the palms of our hands also have finger prints. So, that must be just the secondary function.
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The ruffled skin improves grip? I dunnow, just what i think.
Fingerprints also provide more skin surface, which allows more nerve endings per square cm, so that also explains why our finger tips are so sensitive, and this is actually an evolutionary advantage.
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there was a great selective pressure to allow detectives to catch criminals!
hmm. i would say it is something to do with allowing greater sensitivity and grip, as nizzle said. the whorls and swirls are also found on the rest of the palm.
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Someone recently did an experiment that they claim shows that fingerprints do not help with grip:
http://jeb.biologists.org/cgi/content/abstract/212/13/2016
Of course, this was a limited study of fingerprints on dry acrylic glass, so fingerprints might help grip on wet surfaces or rough surfaces.
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I am also guessing for grip. Maybe that's why my fingers and palms feel a bit more moist. So maybe it helps to hold moisture? Or maybe i just have sweaty hands
I also used my fingerprints as a little maze game when i was young. just take a pen and try to find you way out from the middle.
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I read that it helps us feel tiny objects. The ridges vibrate as we move our fingers across them.
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Maybe its just because at some point women found it attractive to have finger prints. Therefore it got ingrained into our genetic code. It is almost like art on the tip of your finger. Although, grip and sensitivity is most likely the best answers.
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