Q: Hey Doug, why do humans have fingernails? It seems we should have evolved past them, seeing as they don't do more than fray and annoy and grow funny. Do you see a future without them?
A: Most sources say basically the same thing about fingernails and toenails: that nails protect sensitive nerve endings in the fingers, that both sets are leftovers from claws, and that they are (just FYI) made of
keratin - the same material that claws and hooves are made of in other animals. Some sources claim, incorrectly, that the nails developed to protect the delicate nail bed. That's like saying phones lines were developed to give telephone poles meaning and purpose. But I digress. At least one source explains the current shape of fingernails and toenails as an adaptive reaction to the broadening of our grasping appendages, used to lift us off of the plains and into the safety of the trees. Our fingers developed more surface area for gripping, so nails became a flatter protection for the sensitive ends. Probably true, but that doesn't really explain "why nails instead of claws?", since many tree-living species get along just fine with claws to adhere themselves to branches and tree trunks. My favorite suggestion was that fingernails made it easier to pick body lice off of oneself or a comrade. I guess that was a pretty serious problem at the time. Or a source of protein.
As for whether we will ever lose nails for lack of use, I recommend that you try getting along without them for a few days. Trim them back or tape your fingers, as one writer suggests, and you'll see how soon you miss them. Having recently had two of my fingernails gouged out, I can tell you I missed them more than I ever missed a phillips head screwdriver. When the bomb drops and everyone is scrambling for that last FreshPak of bologna, I think the survivors will be the ones who can get that little zipper thing open without having to hunt down a pair of scissors from the smouldering, radioactive wreckage.
