Why do we have fingernails?

Nails are made of keratin, the same protein in hair. Primates, including humans, evolved flat nails instead of claws, which scientists link to grasping branches and handling food with sensitive fingertip pads. The nail acts as a rigid backing that the fingertip pad presses against, sharpening the sense of touch and allowing precise pinching. Nails also shield the tip of the finger from injury. Their appearance can reveal health information too: changes in colour, shape or ridges can signal issues such as iron deficiency, lung disease or skin conditions.