Why did fingerprints evolve?

Photo credit: Monty Rakusen/Getty Images/Cultura R

The Guardian recently put forth a reader question for other readers to answer: Do fingerprints serve any evolutionary purpose? Although one reader’s suggestion that fingerprints evolved so that crime novel detectives would have a means of identifying criminals is entertaining, most people thought along the lines of fingerprints improving the grip to aid in climbing, similar to those of primates. (And other animals. Koala bears have unique fingerprints that are very difficult to differentiate from humans.) 

Scientific research from a 2009 study by Dr. Roland Ennos and a team of researchers from Manchester University actually found that fingerprints may hinder the grip on some surfaces. Testing with plastic cups, weight and acrylic glass found that with the rubberiness of skin, ridges actually reduced the friction needed to get a firm grip on smooth surfaces.

The team theorized that fingerprints may better suited to gripping rough surfaces. The ridges of fingerprints may project into the depressions of rough surfaces, providing a higher contact area. Another theory is that fingerprints make it easier to grip wet surfaces. Fingerprints allow a little water run off, similar to the tread of car tires. Friction fails on fingerprints with high levels of moisture, but it fails less quickly than with smooth skin.

Dr. Ennos has a preferred theory on the reason for the evolution of fingerprints. Fingerprints allow the skin to “deform” and thus reduce blistering. This is why we are more likely to blister on the smooth parts of our hand and feet rather than on ridged areas of skin like fingerpads, palms and soles.

A related evolutionary question is why do we have unique fingerprints. We may not know why, but there is research on how they develop. A scientific article in Circulation Research, AMA Journals, explains how the ridges, loops and whorls of fingerprint patterns are formed. Compressive stresses act upon the skin “like the buckling of land masses under compression.” This is why even twins have unique fingerprints.  As twins occupy different positions in the womb, the variations in stress and pressure are enough to create a slight difference in fingerprints. 


Do fingerprints serve any evolutionary purpose?

Published in The Guardian Lifestyle section, Jan. 29, 2018, theguardian.com


Get a grip! Blistering new evidence on why we have fingerprints...

Published in the Manchester University News section, May 29, 2009, manchester.ac.uk


Fingerprints are unlikely to increase the friction of primate fingerpads

Published by Peter H. Warman and A. Roland Ennos, Journal of Experimental Biology 2009 


Wet but not slippery: boundary friction in tree frog adhesive toe pads

Published by W. Federle, et al, Oct. 22, 2006, in the Journal of the Royal Society Interface


Mechanical Control of Tissue Morphogenesis

By Parth Patwari and Richard T. Lee, Circulation Research, American Heart Association Journals, Published Aug. 1, 2008

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