Most bone from 10,300 years ago is gone — decayed, dissolved, dispersed into the surrounding soil and rock by the biological and chemical processes that break down organic matter.

The fraction that survives is the fraction that happened to be in the right place, with the right chemistry, at the right temperature, for long enough.

Shuká Káa’s bones were in the right place.

The cave protected them from direct rainfall and from the freeze-thaw cycles that shatter bone in open-air contexts.

The limestone neutralized the acidity that would otherwise have dissolved the mineral phase.

The cool, stable temperatures of the cave slowed the chemical reactions that degrade the protein phase.