Why Do Humans Have Nails?

June 22, 2015 / Humans / 0 Comments /
Picture of nails for an article explaining the reason for why we have nails

Nothing in our body grows as fast as our nails do, aside perhaps, for our hair. They are strange little additions to our toes and fingers really. Perhaps once something like a claw, they don’t seem to have much purpose in modern life, so why do we have nails, and why do they grow so fast?

Here I’ll discuss the purpose of the finger/ toe nails, and explain why they grow.

 

What is the purpose of nails?

Protection – This is obvious to anyone who have dropped something heavy on their toes or fingers. The nail is a hard surface which offers some (but arguably not enough) protection to the delicate bone underneath. The tip of the finger bones (called phalanges) is actually extremely fragile, and you do not want to get it damaged or chipped, so the nails purpose is to spread the pressure of heavy objects to reduce the damage to the bone. Sadly, this doesn’t make hammering your thumb any less painful, but does protect the bone.

You can see how effectively this is actually. If you just press your finger nail on the top, the pressure quite effectively dispersed to the sides. This is thanks to the curving shape of the nail.

Accuracy – Yes, nails have another purpose other than protecting the fragile bone underneath, and that is to help us grasp minute objects. We are talking things like splinters, which our chubby fingers just cannot grasp, but can cause pain and even infection if not removed. In the days before tweezers, fingernails (and teeth I guess) would have been our only way to grasp very small objects.

Just try and pick up a needle without grasping it with your nails – it is very difficult!

Why do nails grow?

Knowing the purposes of finger and toe nails makes understanding why they grow quite simple. They are (or would have been historically) subject to damage from things hitting them, dropping on them and scraping against them. As nails are not living tissue in the same sense as our skin is, they cannot repair in the same manner as the rest of our body. Once a nail is damaged, it is damaged for good.

So instead of repairing the nails, our body just keeps producing them, which replaces old, damaged nails with new strong nails.

Perhaps with modern lives, our nails grow so much because they do not get damage like they used to. We don’t hunt, climb, build or fight like we would have done 10,000 years ago, and so our nails don’t get damaged. However, we are still genetically programmed for our nails to grow, even though they don’t usually need to.

 

Summary

The purpose of our nails to to offer protection to the delicate bones beneath them, and to help pick up minute objects. Without nails on our fingers and toes, we would be at risk of damaging to delicate phalanges, which can be extremely

Due to their importance in protecting phalanges, and their importance in picking up small objects, they must be kept in good condition. As they cannot repair themselves, the only way we can maintain healthy nails, is to keep growing new ones.

Image courtesy of Shannon Kringen.