The water table rose gradually, intruding further into the cave system from the coast as the ocean level climbed.

By the time the flooding reached Hoyo Negro and began to fill the chamber from below — the water rising slowly up the walls of the pit as the water table climbed — the bones of Naia and the megafauna had probably been on the chamber floor for some time.

The exact period between Naia’s death and the flooding of her chamber is not known, but the radiocarbon dates of the human remains and the geological evidence of when the region’s caves flooded are broadly consistent with a scenario in which the chamber was dry for at least some centuries after her death before the water came in.

The rising water would have gradually submerged the chamber floor, covering the bones and sealing them from the air and the organisms that break down organic material in terrestrial environments.