And I'm only half-kidding, because they basically are rocks made of millions of tiny mineralized crystals.

But things get tricky when that mineral degrades.

Because unlike bones or skin, your teeth can't heal themselves.

So when we get a cavity or a hole in our tooth, we need help fixing it.

So you might be thinking that before modern dentistry became a thing, people must have had even worse teeth, rotting out of their heads left and right.

And yeah, while there are some gnarly examples of ancient humans with cavities, they weren't like, eating candy by the handful and washing it down with energy drinks.

At the same time, the story isn't as simple as humans get a lot of cavities now that we eat processed foods, either.

So let's take a peek back in time and figure out why humans have the worst teeth in the animal kingdom.

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The most common tooth problem in our species is cavities, also known as caries.

Over 90% of us will get at least one at some point in our adult lives.

And the cause of this pesky tooth decay is the presence of certain bacteria in our mouth.

Or, more precisely, in the dental plaque that builds up on the surface of our teeth.

The bacterium Streptococcus mutans is the main culprit, breaking down sugars in the food we eat and creating acidic byproducts in the process.

And it's those acids that erode or weaken our enamel, making it susceptible to cavities.

There are other factors that play into it, too, like how much saliva you produce, whether you practice good dental hygiene, or even your genetic makeup.

But the biggest factor we have to come back to is sugar.

Now, sugar can mean a lot of things, and not just candy.

And it's not just classic table sugar that leads to cavities, but also starches found in foods like bread, rice, and pasta.

Our love of sugary and starchy things goes way back to before farming, and even before our species existed.

Humans are primates, and our extinct ancestors and living relatives are mostly fruit-eaters.

Since fruit is basically sugar plus fiber, it's not surprising that fossil primates from as long as 54 million years ago had cavities in their teeth, as do some fruit-loving monkeys and apes alive today.

Primates can definitely have a sweet tooth.

There are chimps who eat huge amounts of fruit, and like to chew and suck on wads of fig gunk for hours on end.

And yet, chimps only have something like a 45% max cavity rate across individuals, which is half of the 90-plus percent in present-day humans.

So when did things really pop off for us, tooth decay-wise?

Well, the short answer is the Agricultural Revolution, around 10,000 BCE.

It happened at different times all across the globe, but in general, it caused massive dietary changes to the majority of people on Earth.

Because before farming, people hunted and gathered foods that grew wild in their environment.

If we flash back to, say, 1.5 million years ago, early human relatives, like Paranthropus robustus, were eating different kinds of plants, but not a ton of sugary stuff.

So it's not surprising that even though they had a few cavities, they had way fewer than the later, and more like us, Homo erectus from the same site.

Neanderthals had cavities too, but not many at all, despite the fact that they too carried the Streptococcus mutans bacterium.

We know that because some clever scientists chipped off the hardened dental plaque from some Neanderthal teeth and found DNA evidence of their microbiome inside.

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Now, back to the show.

If we look at our own species, Homo sapiens, we see variation in how many people were affected by tooth decay.

And groups that ate more sugary foods were usually the ones with more cavities.

Take a site in Morocco from around 14 to 15,000 years ago known as La Grotte des Pigeons.

In a 2014 study, researchers found that around half of the teeth and 94% of the people had cavities, similar to modern industrialized populations.

Compare that to most other hunter-gatherer societies, which at most have cavities in, like, 15% of their teeth.

But how could that happen without gummy worms and Coca-Cola?

Well, evidence suggests that they ate a boatload of an especially sweet kind of acorn that gets soft and sticky when cooked, in addition to wild oats and legumes.

But the fun for Streptococcus mutans and its cavity-making pals really got started when we figured out how to farm grains, like wheat and barley.

And it got even worse with heavy food processing, and eventually adding sugar to everything from bread to sauces to fruit juice.

We have plenty of evidence that shows once farming was invented, people across the world had the potential to develop roughly modern-day levels of cavities.

But we can also see evolution in the cavity-causing bacterium itself that came along with our changes in food production.

While ancient human relatives have been plagued by Streptococcus mutans since at least the Neanderthal days, there was a bump in the bacterium's genetic diversity around 10,000 BCE.

These changes coincided with the advent of farming, and more changes have happened in the last 750 years since we started actively cultivating sugar.

Just like any good pathogen, it adapts to get better and better at exploiting its environment and doing its evolutionary job.

Which is ruining our teeth.

In fact, we might have to start worrying about it again, because it's becoming resistant to antibiotics.

The story of us, our teeth, and Streptococcus mutans is long, twisty, and far from over.

But even though most of us will have to deal with a cavity at some point in our lives, at least we will live long enough to get them these days.

Which I can't say was true for many of the ancient people we talked about in this video.

Tooth problems just come along with the territory.

But it's a small price to pay to be able to eat handfuls of candy in my jammies.

[♪ OUTRO ♪)]