They extracted bone collagen from multiple elements of the mastodon’s skeleton and submitted those samples to radiocarbon laboratories for independent analysis.

The results were consistent and precise.

The mastodon dated to approximately 13,800 to 13,900 calibrated years before the present.

This is where it is important to be clear about what “calibrated” means and why it matters.

Radiocarbon dating does not directly measure calendar years.

It measures the ratio of carbon-14 to stable carbon isotopes in a sample and compares that ratio to the ratio expected in a living organism at the same time.

The difference allows calculation of how long ago the organism died.