Humans have long found comfort on Calvert Island, just off the coast of mainland British Columbia. For millennia, they have climbed the island’s rocky outcrops, walked through its rainy conifer forests, and waded through its chilly intertidal pools to collect crabs, mussels, and other marine life.
There, in 2014, a group of Canadian researchers uncovered human footprints pressed into a prehistoric layer of soil. The footprints, 29 in total, are the oldest found in North America. They suggest an intimate scene in which, 13,000 years ago, at least three people may have hopped out of a boat onto the damp shore. One person appears to have slipped as the group walked toward drier land. The footprints also speak to a much larger and contested story — the tale of the humans who first set foot in North America.
North and South America were relatively lonely places for our species 13,000 years ago. The continents were the last major landmasses in the world to be populated by Homo sapiens. But the explanation of how and when this peopling happened has needed to be heavily revised in the last two decades.
“This field is bonkers right now,” says anthropological geneticist Jennifer Raff of the University of Kansas. “I think there’s a new important paper coming out every three or four months.” Indeed, no tidy, new framework has arisen to take the place of older theories. Instead, new data, including genetic findings, continue to complicate the story of how these continents came to be peopled.