Who What Why: How durable is a fingerprint?

American Hans Galassi lost several fingers in a wakeboarding accident several months ago. Now one of them has been found in a trout - and identified as Galassi's from its fingerprints. So how long do fingerprints last?

The vast majority of people are born with a unique set of fingerprints which remain the same for life.

These patterns, known as friction ridges by experts, are found not only on our finger-tips but also on the flanges of our fingers, on our palms, our toes and on the soles of our feet.

The patterns are permanent, but can wear down. Builders who lay bricks and people who frequently wash dishes by hand lose some of the detail. Once they stop these activities, the ridges will grow back.


As fans of crime movies will know, from time to time people have tried to change their fingerprints patterns artificially.

A deep cut through the outer layer of the skin, the epidermis, and down to the dermis leaves a scar that will change a fingerprint, but not make it any less unique.

People have also sought to erase their fingerprints by burning the finger-tips with fire and acid, as the notorious 1930s American gangster John Dillinger did. It works for a while but the skin grows back.

Another criminal, Robert Phillips, famously grafted skin from his chest on to his fingers to erase his fingerprints - but he was identified from the prints of his palms. Others have tried smoothing their finger-tips with glue and nail varnish. Again they were caught from palm prints.

Friction ridges are remarkably long lasting even after death, says fingerprint expert Allen Bayle, author of the UK's standard police manual on dead hands.

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