Why did early humans have perfectly straight teeth?

Originally published at: Why did early humans have perfectly straight teeth? | Boing Boing


Tl,dw: Human mouths have grown smaller over recent history due to tools and technologies changing the way we use our mouths, and the shape our jaws take over time.

We have smaller mouths, but still the same number of teeth.


plus or minus wisdom teeth. i know only some people get those, i wonder if all early humans did?


Via Lamarckian evolution, presumably.

“TED Talk” is becoming a pretty good synonym for “Just-So Story”.


Welcome! And, no.

AFAICT, forks and knives and cooked prepared food have changed us drastically. We used to rip and tear with our incisors and canines, then chew the heck out of it with our molars and wisdom teeth, now there’s a lot less of that, our lower jaws sit further back, causing issues like snoring among others.

There’s also loads to say for the chewing, and especially chewing greens, berries, roots etc, and all the bacteria we used to ingest from them kept our flora super diverse.


It’s not Lamarckian evolution so much as the fact that our jaws are shaped by how they’re used.

The reason braces can so significantly change our tooth/jaw situation owes to a malleability of our jaw structure that also happens to be the reason why so many people need braces now.

No Lamarckian claim is being made, as I understand it. The genetics don’t change - which is why the number of teeth don’t change. But eating smaller cut up bits of softer cooked food cumulatively lends itself to the formation of a smaller mouth/jaw than the diets of the earlier humans and hominids in the fossil record.

As I understand it, at least.


Excellent dental coverage.


I have not yet watched this but I predict it will tell me the softer foods we all eat as children caused outr jaws to not grow as large and as such, shrank. Less room for teeth, but also less room for sinuses and airways which is also why we have more snoring, and mouth breathers which in turn leads to more bad teeth.

If you have kids, you should feed them hard to chew stuff so they grow strong bones.


Weston A. Price (disclaimer, he was a bit of a quack, so take it with appropriate soluble minerals) did research on this with indigenous populations as they were introduced to a Western diet. Within a single generation they went from well-fitting, straight teeth to severe malocclusion. His conclusion was that the shift in diet was the cause. He also thought the shift in diet was the cause of everything from cavities (sure?) to tuberculosis (huh?), so. (Not to mention doing it all with a strong dose of racist colonialism tropes.)

But anyway, he did produce reams of documentary evidence highlighting the abrupt change in jaw structure as diets in indigenous communities shifted to highly-processed diets. This seems to suggest that the changes in occlusion may be purely (or primarily) developmental, as opposed to having a root in evolutionary biology.

Maybe if we make our kids eat nothing but raw vegetables we can dodge a big orthodontic bill. (/s. A little.)


Did you ever see teddy roosevelt’s teeth? I have a theory that he would grind his teeth. I did read that he would drink a ton of coffee and I sometimes grind my teeth if I have too much caffeine… he was by a lot of accounts pretty high strung in general. Whether the caffeine was a cause or effect I’m not sure. Ha. Anyway. Theorizing a size, look at those unnaturally straight teeth! Ha.

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TED talks are the Malcom Gladwell of science information. Pop culture gets all excited about them and people share this stuff they “learned” everywhere they go, but it mostly all turns out to be made-up and poorly-sourced bullshit.


Cutlery has not existed long enough for evolutionary forces to have acted on us. Humans have cooked our food for around two million years, which could conceivably have had some impact, but our teeth are similar enough to other omnivores that I’m guessing it’s a minor variable. Cooking food was one of our evolutionary advantages over other late-stage primates, since we were so much less disease-ridden as a result.

IANAEvolutionaryBiologist though, so take that free opinion for what you paid for it.


So the answer isn’t something like Neandental hygiene? :frowning:


I always had it in my head that wisdom teeth came in later to replace molars that would have been lost by that point, kinda like a third set of teeth for later life. Now I realize I have no source for that other than my inner evo-bio bullshitter.


This isn’t an evolutionary thing, this is a in the range of expression of genes, as obviously enviromental factors have an influence in both cases, the way trees grow crookedly in very windows locales for example. The way our diets changed us through gene expression might also have effect on who we pick as mates, but now I’ve walked well past the edge of the cliff over the infite depths of stuff I don’t know.


… it’s not “food poisoning,” it’s diversity :nauseated_face:

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Live fast, die young, leave a beautiful corpse?


My teeth look very similar. They’ve always been perfectly straight, but I grind them in my sleep so badly that I now have sheep’s teeth.