Why Do Humans Have Toenails?

Let’s face it: toenails aren’t exactly the stars of the human body. They’re kind of like the background dancers in a music video—rarely in the spotlight, but you’d miss them if they weren’t there. We only seem to notice those nails when they’re causing trouble, like when we stub them or clip them too short. But have you ever stopped to wonder why these bony little toe sheaths even exist?

1. The Origins of Toenails
2. The Benefits of Toenails
3. Why Do Toenails Get Thicker and Change Color?

The Origins of Toenails

Like so many aspects of the human body, the answer lies in our evolutionary history. Our primate ancestors needed serious gripping power to swing through trees, which is where claws came in handy. These claws were essential for climbing, grasping branches, and generally navigating a life lived high in the canopy.

Then something happened that changed the game altogether: we started walking upright. Some experts speculate that mammalian claws may have unfurled and evolved into nails. With bipedalism, natural selection resulted in flatter, less cumbersome nails, which supported the development of wider toes and fingertips for more precise gripping. So was born the modern nail, which offers much more protection for fingers and toes. 

The Benefits of Toenails

Toenails aren’t just vestigial leftovers from our tree-dwelling days; they actually still serve a few important purposes. Made of keratin, an essential protein also found in skin and hair, toenails act as shields for delicate toes, protecting bones and nerves from bumps, scrapes, and the occasional rogue LEGO.

They also provide counter-pressure to the fleshy part of our toes, aiding our sense of balance and proprioception, a fancy word for your awareness of your body’s position in space. You can think of proprioception as something akin to a built-in GPS for your feet, constantly whispering directions like, “Hey, you’re about to veer off course and stub me on the corner of the couch!” Plus, it helps maintain the structural integrity of the toe itself. 

Why Do Toenails Get Thicker and Change Color?

But just like the rest of our bodies, toenails can change as we get older. They often become thicker, more brittle, or even develop ridges, and several factors contribute to these transformations.

First, circulation and blood flow to our extremities can diminish or become impaired, meaning toenails could receive fewer nutrients and, as such, may grow more slowly. This can lead to a buildup of cells (known as onychocytes), resulting in thicker nails.

Another factor is the cumulative effect of minor trauma. Think about all the times you’ve stubbed your toes or worn tight shoes: these little injuries can add up over time, affecting nail growth and appearance. Fungal infections, which are more common in older adults, may also lead to thickening and/or general discoloration. 

And speaking of discoloration, you might notice your toenails taking on a yellowish hue with age. This can be due to changes in the nail’s structure or, again, a fungal infection. It’s important to note that while some changes are expected as a normal part of aging, others may indicate an underlying health issue. If you notice any significant changes in your toenails, it’s a good idea to consult a doctor or podiatrist just to be on the safe side.

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