ELI5: Why do fingerprints stay the same despite pressure and stress throughout our lives

Read the Story

Show Top Comments

The outermost layer of your skin is primarily dead cells. It’s a very thin but very effective plating of armor that is constantly getting worn away by the environment, but it’s getting replaced from underneath just as fast as it wears away, if not faster. Those dead cells keep growing into the same paterns (AKA your fingerprints) because they’re growing in the same pattern as the deeper layers of your skin. That underlying skin stays relatively unchanged since the outer layers protect it. If you manage to damage these layers from severe burns, corrosive chemical exposure, or deep flesh wounding, you *can* permanently alter or even destroy your fingerprints. But common activities practically never make it past the outer layer, so in most situations fingerprints will always grow in the same pattern across your entire life.


Had a guy at work who polished/regrained metal stuff with wire wool for years as part of his job, I ended up giving him a fob to get in the doors as he had absolutely no fingerprints whatsoever and that was with a reader at max sensitivity as well.


Just to elaborate on the other answer, it’s the dermal layer of skin that contains the blueprint. The epidermis is the part you see and the “dead skin” which gets old and wrinkly. There are changes with time to skin flexibility but the blueprint remains the same


It was my understanding that fingerprints actually don’t stay the same because of the reasons you stated. They actually do change a bit, so often times you do need to get reprinted. Also the reasons scanners eventually don’t work.


My finger tips were burned when I was a child and I tried picking up a hot pie dish. Going through LAX airport is fun on an international trip. Takes ages for the machine to go green on all 5 finger tips. I get lots of questions