This distinction matters because the calibrated ages are the more historically meaningful numbers — they tell us not how many half-lives of carbon-14 have elapsed, but approximately where in real time the animal died.

The Horse Mandible Date

The horse mandible — the fragment of horse jaw that carried cut marks confidently attributed to human stone-tool butchery — produced a calibrated radiocarbon date of approximately 24,000 years before present.

Let that number settle for a moment.

Twenty-four thousand years before present is the Last Glacial Maximum.

It is the period when the great ice sheets that covered much of North America were at or near their greatest extent.

It is a period roughly 10,000 years before the Clovis culture appears in the North American archaeological record — the culture whose fluted stone points, found across much of North America, had for decades been considered the clearest and most widespread evidence of the first Americans.