by Daniel Laberge
Human grooming

Nails and fingers

At last we know why we have flat nails at the tip of our fingers

Nails are made for grooming

Your nails are a product of evolution, they have evolved from claws.

We've been told we had them:

•To protect our fingertips,

•To help us pick small objects,

•To climb trees,


Well, I have a hard time picking small objects with them unless they are trimmed short.

Claws, such as those of a squirrel, seem quite appropriate for climbing.

In fact, humans didn't know why they had nails;

Nails are specialized tools for grooming

Nail evolution - 1

From claws to nails

Just like hooves, fingernails have evolved from the claws of reptiles.

About sixty-five million years ago, a reduction in the thickness of the deep layer of the claw led to the advent of nails in the first primates.

Primates aren't the only ones to have flat nails, some marsupials also have them.

This is a good example of parallel evolution; which is the development of similarities in separate lineages.

It shows that flat nails are an important goal for evolution.

Nail evolution - 2

The toilet-claw

There is an intermediate evolutionary step between claws and nails; it is called the toilet-claw.

The first primates had them on the second digit of their hands and feet.

Just like nails, toilet claws are made of keratin.

Their shape is similar to claws, but their tip isn't as pointed.

Prosimian primates still have toilet-claws nowadays, while the nails of a few South American monkey species have reversed back to claws.

Your nails can feel

We don't think of our nails as sensitive since we cut them painlessly.

This is because the nail plate, made of hard, translucent keratin, cannot feel.

Yet, below the plate lies the nail's bed.

The nail's bed is, as you would expect, packed with nerve endings and blood vessels, giving the nails their pinkish color.

Sensations received by the nail itself are amplified by this system.

Nails more sensitive than fingers?

Try this comparison experiment!

While reading this, move your fingertip and nail over your clothes.

You want to compare the sensations you get using;

•Just your fingertip, with those using

•Just your nail.

Pass them alternatively over the seams of the clothing and try to determine how these two probes differ.

Notice how much more detailed the nail feel is.

You can reach inside and explore the fabric's structure.

Cutting your nails

Nail length

Nails grow about ⅛ of an inch (3 mm) a month.

Your nails can be too short or too long to perform adequately your grooming activities.

Lengths needed for grooming

Shortest nail length


The nail barely exceeds the top of the finger when  seen from under.

Longest nail length


When the nail reaches ¼ inch above the fingertip, it  starts bending under the  pressure.

The grooming range

You end up keeping your nails within a grooming range.

Range of nail lengths

•When your nails are too short, the sensory signals from the nail and the fingertip get mixed.

Worse, the nail doesn't extend long enough to secure any hold on the folds it passes and, of course, cannot reach the bottom of deep crevices and pits.

•Too long, nails become brittle and loose some rigidity. They get curved and crooked.

Cutting your nails

Trimming your nails with scissors or a clipper is essential if you want your grooming to be productive.

You don't want to cut them too short.

They should be brought back to the briefest of the grooming range.

This is a time to be very attentive. It's so easy to go crookedly.

Be especially careful not to create dents because they are hard to file off.

Nail styling

It is the corners of your nails that you will be using most for grooming.

For this reason, I recommend not trying to give your nails a rounded style.

•Cut or clip each one with only a slight curve.

How to cut your nail

This operation leaves the corners of the nails too sharp.

•In a second operation, give a slight finishing cut on both sides of the nail.

Cutting the nail corners

Finishing cut

Removing these pointy tips helps the nail flatten and makes your grooming less hazardous.

•The third step involves using a file to remove sharp edges and to perfect your work.

Personalized styling

Some fingers are used much more than others while carrying out grooming operations.

You may decide to keep some nails longer than others as your grooming technique develops or for personal reasons.

Ideally, all four nails on your fingers of both hands should be kept in the grooming range.

Your thumbs are optional since less than 1% of the grooming is done with them.

Cutting them makes your life easier, but having them when they are needed, is quite enjoyable.

Grooming fingers and nails

Lefties and righties;

groom with your writing hand

You will be using your writing hand, be it the right or the left, to perform most of your grooming.

Throughout your life, you have developed a great deal of specialization for each hand.

One hand has become the one you prefer when doing exact and delicate work.

Writing usually tops the list of such activities with its need for precision and detail, much like grooming.

Your grooming finger

When digging and cutting deep into your own skin, you want to use the most dexterous and sensitive finger you can.

Grooming is very precise and tricky work where any mistake provokes immediate pain and possibly injury.

The finger to use is the index finger of your writing hand.

It is called that way because it was used to flip index cards.

Now, I am offended by such an artificial name and prefer naming it after its natural usage; grooming.

Finger's names

The nail at the end of that finger is particularly important.

Avoid using that nail in any damaging way.

Finger sensitivity

In my case, sensitivity is greater on the fingers of my writing hand than those on the other.

Also, my fingers decrease in sensitivity as they get farther from the index.

Finger's sensitivity

This creates a finger sensitivity map.

You can use fingers with less sensitivity on tasks that demand less exactness.

Nail care

Healthy nails

Your nails, like many other body parts, reflect your health.

Keep an eye on any growing malformation.

Color changes, depressions and grooves, curbing, fragility, ... could be signs of health problems.

With grooming, your nails become essential to your well-being and looks, as well as being indispensable in your everyday life.

Take a proud care of them, wear gloves when doing risky or damaging work.

Cleaning your nails

You can usually clean the top side of your nails easily with water in a few seconds.

Their shiny, smooth texture makes cleansing a breeze.

It is the underside that represents a problem.

Before growing longer than your fingertip, this surface was attached to the nail's bed.

It is porous and dirt is hard to clear off from it.

•To clean your nails, soap and water, with the help of your other nails, do a fine job.

•Only use a hard object, such as the tip of a file, if you need to.

•Try not to go too deep when going beneath the nail.

This area is easily hurt; it is normal that you can't reach the bottom.

Keeping your nails clean

while grooming

The nail on the finger you use to groom becomes dirty quite fast.

In reality, the space beneath the blade gets filled with epidermis cells that you rake off your skin.

The color of the cells that gather there depends on your natural skin tone and on how tanned you are.

So, their dark coloration is no sign of uncleanness.

The area can fill up in less than two minutes of grooming.

The presence of litter in the gap can reduce the sensations you receive from the nail.

Since it would not make sense to wash your hands every few minutes, it is best to keep a piece of facial tissue close by.

The natural nail look

Don't apply any nail polish or try to embellish your nails in any manner.

You wouldn't want to groom with nails covered with dubious chemicals.

Stop thinking of nails as useless decorations.

They are naturally beautiful, with nothing added, mostly when their length is in the grooming range.

Bad habits

Many people have acquired uncontrolled behaviors with this part of their body.

Nail biting, peeling skin removal and auto-mutilation are common practices.

Continuing or stopping these practices says a lot on the control you have on yourself.

Take responsibility for these actions.

Peelings around the fingernail

Though I advocate removing chapped or flaking skin in most areas of the body, the nail-fingertip junction demands special care.

If you pull on the hanging peelings, you may rip the skin and hurt yourself.

Cut them clean instead and groom the area very delicately.

Long nails and everyday life

I had a hard time getting used to having long nails.

They make simple things, such as picking a coin, more difficult.

Typing on a keyboard becomes an adventure.

We need a new line of instruments made for long nail bearers.

But, in any event, humans will have to adapt to life with long nails.

It is part of being a primate.

A wonderful tool

Your nails are formidable tools for grooming.

Sensitive and tough, they can be pressed strongly against your skin without harming it.

Their shape and dimensions are just right for the task they were conceived to achieve.

Humans are branded as a tool-making race, but these have been designed by God, so they feel and grow.