The ancient people of Danger Cave lived well. They ate freshwater fish, ducks and other small game, according to detritus they left behind. They had a lush lakeside view, with cattails, bulrush and water-loving willows adorning the marshlands.

But then, the good life became history. As heat and drought set in, the freshwater dried up and forced the ancients to survive by plucking tiny seeds from desert shrubs called pickleweed. Archaeologists know this from a thick layer of dusty chaff buried in the cave’s floor.