OK so imagine you're an archaeologist and you're looking at a tooth from a person who lived like 25,000 years ago, in what's now Indonesia, and the tooth basically walks up to you and says "hey, this person had a habit." That's essentially what just happened, and I love it so much.

A new study published this week found what may be the earliest direct evidence of drug use by humans anywhere, and it's not some elaborate ritual scene or a cave painting situation. it's teeth. One hunter-gatherer's teeth, worn down and stained in a very specific way that points to regularly chewing betel nuts, which release psychoactive compounds when you suck on them. The research was covered in detail by The New York Times, and the whole thing has me grinning at my laptop.

So how does it work? Betel nut chewing is still a thing today across parts of South and Southeast Asia, and it leaves a signature: a distinctive reddish-brown staining on the teeth, plus a particular kind of wear on the biting surfaces from all that gnawing. The researchers found those exact patterns on teeth from a burial site in Indonesia, dated to somewhere between 25,000 and 13,000 years ago. Long before farming. Long before villages. Long before anyone was writing anything down. Someone in a hunter-gatherer community may have been popping betel nuts on the regular, and their teeth kept the receipt for twenty-five millennia.

And I know what you're thinking, because I thought it too: couldn't the staining be from something else? I can't tell you exactly how the researchers worked through that question, and I'm not going to pretend I can. What I can tell you is how they framed their conclusion, which is carefully. The person, they say, may have regularly sucked on betel nuts, and not as a one-time accidental snack. This was a routine. Possibly even a pleasurable little ritual shared around a fire at the end of a long day of hunting and gathering.

What gets me is the humanity of it. We tend to picture Ice Age people as pure survival machines, just mammoth this and flint that, and then a tooth shows up and reminds you they also had downtime, and favorite things, and maybe a friend who chewed too much betel and got a little chatty. People have been people for a very long time. We've always wanted to feel slightly different on a Tuesday.

The timing matters too. If this holds up, it's the earliest evidence of drug use anyone has found, full stop. And it comes from deep hunter-gatherer territory, which suggests humans were experimenting with the plants around them, and figuring out which ones did something interesting, basically as soon as our brains gave us the curiosity to try. That is, when you think about it, extremely on brand for us as a species.

The researchers are careful to say "may," and I respect that. Science moves slow on purpose. But whether the final answer lands at definitely betel or probably betel, the picture is the same: a person who lived an unimaginably long time ago, in a world of ice and islands, kept a small comfort going long enough that their teeth recorded it for us to find.

Twenty-five thousand years later, the habit outlived the person, the language they spoke, and the entire world they knew. The teeth remembered. Joy leaves a fossil record too, if you know where to look, and that's the kind of thing I'll never get tired of writing about.