Why Do Humans Have Fingernails And Toenails?

Human fingernails are actually flattened versions of claws. All primates, including ancient ancestors of humans, had claws that supported their broad fingertips. The broad fingertips helped primates maintain a strong grip around objects, including trunks and tree branches.

Humans are distinct from other animals in many ways—cognitive capacity, hairlessness, and our opposable thumb—but having nails isn’t one of them. Our ancestors, primates, also have finger and toenails that look like ours. In fact, mammals, birds and reptiles have similar features at the ends of their appendages, such as claws and talons.

These nails or claws or talons are made of a protein called keratin. This is the same protein that makes up your hair, the horns on cows and sheep, and the hooves of horses, zebras, bulls, and other ungulates.