Located on the tips of our fingers are features known as friction ridges.

We evolve them to get a better grip on objects.

And it just so happens that those friction ridges are unique to every person.

That allows us to use friction ridges as unique

identifiers and for authorities to use them to catch criminals. And in some ways

we've been using these for centuries. Learn more about fingerprints and fingerprinting on this episode of Everything Everywhere

Daily. Fingerprints are something that have been with us long before we ever became human.

While we don't have fossilized fingerprints from early humans, we do know that closely related animals such as guerrillas and chimpanzees also have fingerprints.

Fingerprints, or friction ridges, are believed to have evolved for several reasons.

The biggest reason is that increasing the surface area on our fingers, even ever so slightly, makes it easier to grip and hold objects.

Additionally, the ridges on our fingertips allow us to detect more subtle textures and variations in the surfaces

we're touching providing us with better tactile sensitivity. Fingerprints

begin to form as early as the 15th week of pregnancy and remain with us until we die.

While fingerprints are unique, they are not totally random.

There are genetic trends that can make fingerprints for related people somewhat similar.

Identical twins will not have identical fingerprints,

but they will often have similar fingerprints.

Fraternal twins may have fingerprints that are not quite as similar as identical twins.

The reason why fingerprints are unique is that they aren't determined solely by genetics.

It seems that even small environmental factors in the womb such as pressure and the position of the fetus can cause fingerprints to develop differently.

The knowledge that fingerprints were unique goes back at least 2,000 years. We know that impressions of thumbs were used

on clay tablets as identification in ancient Babylon as earliest 200 BC.

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