Many experts think it's to improve grip, but a British study from a few years back suggests otherwise. Researchers found that a fingerprint's ridges actually made it harder to hold flat, smooth surfaces, like Plexiglas, becasuse they reduced the skin's contact area.  Instead, they think our prints might help wick water off our fingertips or allow our skin to stretch ore easily, which can protect it from damage and help prevent blisters. Other scientits have suggested fingerprints could improve our sense of touch, What we do know for sure is that no two people's fingerprints are the same, even among identical twins. - V. Patteson Lombardi, PhD, research assistant professor of biology at the University of Oregon