The adult’s stride changes in ways consistent with carrying a child part of the way, and the child’s tracks appear and disappear in patterns that could indicate the child was sometimes carried and sometimes walking independently.

Researchers have been appropriately cautious about overstating this interpretation, but the physical evidence is striking and the pattern is recognizable.

These are not abstract chronological data points.

They are the traces of human lives — of people walking muddy shores, following or avoiding large animals, carrying children through difficult terrain, doing the ordinary and extraordinary things that humans do when they move through a landscape.

The preservation of that behavior in physical form, at an age when such preservation seemed impossible, is what makes White Sands genuinely unprecedented in the North American archaeological record.

The Ice Age World They Inhabited