Name: Why Do We (Still) Have Wisdom Teeth?
Uploaded: 2025-02-01T21:01:10.000Z
Duration: 7 min 1 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

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Show of hands, who had to spend a week on the couch eating ice cream because of your wisdom teeth?

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They sit way back in our mouths, they don't grow in until we're basically full-grown adults, if they grow in at all, and then most of the time they end up causing problems and have to be pulled out.

This might make you wonder if wisdom teeth are such oddballs and troublemakers, why they're even there in the first place.

Way in the back of our jaws, behind our premolars, we have teeth called molars.

When we're young, two molars develop in each of the four corners of our mouths.

Much later in our lives, we get our final teeth, the third molars, aka wisdom teeth.

These usually don't emerge from the gums until our late teens or early twenties.

In English, we call them wisdom teeth because they show up around the age of adulthood.

In Thai, they're called huddling teeth, since there's not a lot of space back there, so they end up squeezed in.

And in Spanish, they're called judgment molars, for similar reasons to English, in that it's when you have sound judgment, but it sounds cooler.

But wisdom teeth aren't just painful, they can cause serious dental problems.

Due to the lack of space for them, these teeth often become impacted, meaning they don't grow properly.

They might come in crooked or not fully emerge from the gums.

Impacted teeth can cause swelling in the gums, damage other nearby teeth, and even lead to serious problems like tooth decay.

Wisdom teeth aren't the only teeth that can become impacted, but they are by far the most common culprits.

Around 98% of all impacted teeth are wisdom teeth, and well over half of all people may end up with at least one impacted wisdom tooth.

In fact, the lack of space is probably the reason these teeth come in so late.

They have to wait until their jaw is developed enough to handle the strain of their arrival.

And even then, they still cause all these problems.

And that's if they even bother showing up at all.

It's very common for wisdom teeth to simply not develop.

Around 1 in 5 people are completely missing one or more of their wisdom teeth.

Not only do they cause problems, but we clearly don't need them to survive since so many of us either never grow them or get them removed.

And this leaves us wondering why we even have them at all.

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Well, like so many things that don't fit quite right, wisdom teeth are hand-me-downs.

Our ape ancestors had wisdom teeth, and so do our close cousins like chimpanzees and gorillas, but theirs rarely become impacted like ours do.

And that's because, as you might have guessed, they have bigger mouths.

Our ancestors, like our living cousins, had bigger and broader jaws.

But in our lineage, starting with species like Homo erectus, the shape of our skulls began to change.

Our cranium got bigger to accommodate our expanding brains, and at the same time, our jaws grew shorter and narrower, leaving less space for our wisdom teeth.

Over time, our wisdom teeth developed later and later in life, and they even began to disappear.

There are skulls of early Homo species with third molars that never developed, and this has become more common in modern humans.

But exactly why our jaws became smaller is a bit of a mystery.

The most obvious suspect is our changing diet.

Our distant ancestors, species like Australopithecus, ate lots of tough foods like nuts and raw veggies, and their big, strong jaws and teeth were great for that.

Over time, some of our ancestors, like Homo erectus, changed their diet, eating more meat, and then eventually using technology like stone tools and fire to make food easier to eat.

Fire can be used to cook food, which makes it softer, and tools can cut or crush food into smaller pieces that are easier to swallow.

As ancient humans got better at preparing meals, it took a lot of the work out of chewing.

This also meant that there was less pressure to develop big, strong jaws.

We can even see a similar trend among living humans.

People who live in highly industrialized societies, where we have lots of cooking tools and ready-made meals, have more wisdom tooth problems compared to hunter-gatherer societies.

In fact, impacted wisdom teeth are ten times more common in industrialized people than in hunter-gatherers.

It seems that chewing tough food while we grow up can help strengthen our jaws, making them more resilient to the potential problems of wisdom teeth.

Yet, plausible as it seems, diet isn't the whole story.

Some researchers have looked at trends across primate teeth, and they've found that the size of certain teeth does line up with diet, but molar size tends to have more to do with body size and ancestry.

And other studies have found that certain genetic factors are important in determining whether or not wisdom teeth develop in humans.

But we also know it's not all about genetics, since studies on the teeth of twins have found that the environment we grow up in can affect our wisdom tooth development.

And even more confusing, the effects of genetics and environment are different for wisdom teeth in the upper jaw versus the lower jaw.

So our diet is clearly a significant factor in the evolutionary path of our wisdom teeth, but it's clearly not the only one.

And that means there's plenty we still don't know about why wisdom teeth are so weird, or why they cause so many problems in our mouths, or why they're still here at all.

Our wisdom teeth have changed a lot since the days of our ancient ancestors.

They develop later in our lives, cause more dental issues, and more frequently fail to develop.

But if evolution ever does get rid of them completely, wisdom tooth extractions will be a thing of the past.

And our descendants will have to find other excuses to lay on the couch and eat ice cream.

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