10 Surprising Reasons Why Humans Have Fingernails

When you think of all the things your fingernails help do, it makes sense that evolutionary adaptation didn’t eliminate them (unlike the tail). You can peel an orange easily, undo knots, scratch an itch, and pick your nose, all with the help of fingernails. They can even function as an early warning sign of potential malnutrition or risks.

And how about toenails? Why do we have toenails? Early humans were thought to use all four limbs for climbing, and toenails definitely help with gripping (think about longer, thick, claw-like nails that early humans would have had). Useful back then, but why do we still have toenails? Why do humans have nails, period? Read on to discover all the fascinating reasons why humans have nails!

There Is Debate Over the Origin of Fingernails

Are fingernails an evolution of claws or an unrelated adaptation? Scientists say their origins are murky, but archeological finds suggest that human fingernails broadened and flattened around the same time humans began using stone tools. The findings suggest that once we started using tools all the time, we no longer really needed nails for certain things, so they changed, radically. It makes sense: why use a fingernail to dig if you have a primitive shovel?

Today, we use tools way more than other primates Рthough there are some orangutans getting too clever for their own good Рso it makes sense that our fingertips remain the broadest in the primate kingdom. You might say we evolved to need claws the least, so our claws followed suit and became very un-clawlike.

It’s All About the Branches

Whether humans developed fingernails to support our broadening fingertips or if they were just a “side effect” of losing our claws is still¬†unclear, but we’re pretty sure we¬†know which of¬†our primate cousins first¬†had¬†fingernails:¬†Teilhardina brandti, a six-inch-long primate from the Eocene that resembled a lemur (that’s the gnarly claw of a¬†black-and-white ruffed lemur¬†pictured above).

Researchers¬†believe¬†T.¬†brandti¬†evolved its tiny nails – and in a sense,¬†our¬†nails? – to make it easier to grasp small branches, as well as hold on to¬†food. They’re the smallest “true” fingernails on record, but they may¬†have offered a big advantage to¬†T. brandti.

Fingernails Are Perfect for Certain Manipulations

We don’t need fingernails to perform essential survival tasks, the way, say, a tiger needs¬†claws, but they really come in¬†handy sometimes, as we all know.¬†For instance,¬†they¬†work for scratching, picking and peeling fruit and veggie skins, and cleaning certain body areas (such as the scalp). These everyday tasks would be a¬†lot¬†more time-consuming without fingernails.

The theory that¬†humans using tools¬†caused¬†our fingernails to get less and less claw-like has support in the evolution of the so-called “grooming claw”¬†or “toilet claw” in certain primates. Like it sounds, it’s a specialized nail used for personal grooming. Perhaps the use of tools prohibited humans from evolving this nifty nail? Regardless, the nails we know and love (and chew) today still prove useful in a number of applications.

In the Distant Past, Fingernails Helped Humans Capture Body Lice

From an evolutionary standpoint, fingernails allowed early primates to more easily perform certain daily tasks, but unlike how we use them, fingernails really did help keep them alive. Grooming each other with their fingernails helped reduce skin parasites such as lice and also was a means of social bonding in the group (and we all know what that leads to).

Unfortunately, gorillas may have given¬†early¬†Homo sapiens¬†one kind of lice that their fingernails were no match for:¬†pubic lice.¬†That doesn’t mean anything “unnatural” was going on (not necessarily);¬†we may have gotten them from living near gorillas or killing them for their meat.

Fingernails May Have Inspired Early Weapons and Tools

Early¬†Homo sapiens¬†didn’t have a whole lot to work with, weapon- and tool-wise. Rocks and primitive spears, sure, but sometime they had to use their bare hands. That’s where the fingernails come in.

Colin McGin argues in his¬†Prehension: The Hand and the Emergence of Humanity¬†that early humans drew inspiration from their fingernails: “the fingernails themselves provide an excellent prototype for tools designed to score and tear – the ingenious early human just needed to make sharper and more powerful nail-like implements.”

It’s an intriguing and romantic thought: early humans, inspired by their own bodies to create an¬†extension¬†of their bodies.

Reasons Why We Still Have Toenails Are Hotly Debated

Some in the¬†scientific community¬†insist that¬†toenails are, in fact, useful. Perhaps they help us balance by exerting pressure on the toe and providing a counterweight. Or maybe they exist to protect our vulnerable toes when we aren’t wearing shoes, especially given how¬†recent a development protective footwear is on the timeline of human evolution. It’s also possible we have toenails¬†simply because our ancestors did – at some point in human evolution, toenails¬†were functional and claw-like, but now they’re something to trim and paint.

They Protect Our Fingers

The chief function of a fingernail is¬†likely¬†protection. Nails have no nerve endings, which is helpful, considering they’re constantly in contact with our environment. It’s¬†argued¬†that they evolved to be so tough in order to protect us from trauma both minor and major.

Horse hooves, similarly, have no nerve endings, allowing us to “shoe” them the way we do. We don’t put our nails through that kind of punishment, but think how many more broken thumbs there would be in the world if the “shield” of a thumbnail wasn’t there to absorb the blow of a hammer?

They Provide Support (By Getting Out of the Way)

Here’s an interesting thought, courtesy of¬†Tim Ryan at Penn State: our nails evolved into their flat and wide shape¬†so they would be out of the way.¬†Take a look at the above pic of the gymnast on the pommel horse: you can’t do¬†that¬†with claws.

Ryan says that nails “allow the fingers and toes to be spread flat which provides a more solid support for the hands and feet during grasping.” So along with added grip on branches in the treetops from broader fingertips, our lack of claws let primates and early humans¬†use their¬†palms for extra support.

Nails Are Indicators for Certain Health Conditions

Doctors can identify certain health conditions by looking at someone’s nails.¬†Beau’s Lines, for example, are nail ridges that can be a result of poorly controlled diabetes or a heart or liver condition, among other things.¬†Researchers¬†say¬†even bowel diseases can be “seen” in the nails: “clubbing,” for example, indicates pulmonary or inflammatory bowel disease.¬†Spoon-shaped nails, meanwhile,¬†may be a sign of anemia.

Nails Are Also Indicators of Overall Health and Nutrition

Fingernails and toenails can indicate the presence of certain diseases, but may also point to overall problems with your health and nutrition. For example, if nails are weak and brittle, you may need more keratin. Vitamin deficiencies can also cause issues with your nails.

Research has shown that not getting enough vitamin B12, for example, can cause brown-gray nail discoloration. Pink or red nails that got that way without nail polish suggest malnutrition, which is ironic, considering that those colors are considered healthy and sexy when artificial.