The late Pleistocene megafauna of North America — species that would be extinct within ten thousand years, lost in a wave of extinction at the end of the Ice Age whose causes are still debated but whose reality is not — were alive and moving through the same landscape.

Some of their tracks crossed the same lakeshore that the people were crossing.

In at least one documented case, human tracks appear to circle and follow sloth tracks in a pattern that suggests awareness, attention, possible intent.

The people were aware of the animals.

They were aware of each other.

They were aware, presumably, of the lake and the mountains and the patterns of weather and season that organized their lives.