Big feet. Little feet. A heel here. A toe there.
Stamped across the shoreline of Calvert Island, British Columbia, are 13,000-year-old human footprints that archaeologists believe to be the earliest found so far in North America.
The finding, which was published Wednesday in the journal PLOS One, adds support to the idea that some ancient humans from Asia ventured into North America by hugging the Pacific coastline, rather than by traveling through the interior.
"This provides evidence that people were inhabiting the region at the end of the last ice age," said Duncan McLaren, an anthropologist at the Hakai Institute and University of Victoria in British Columbia and lead author of the study. "It is possible that the coast was one of the means by which people entered the Americas at that time."
Dr. McLaren and his colleagues stumbled upon the footprints while digging for sediments beneath Calvert Island's beach sands. Today, the area is covered with thick bogs and dense forests that the team, which included representatives from the Heiltsuk First Nation and Wuikinuxv First Nation, could only access by boat.
At the close of the last ice age, from 11,000 to 14,000 years ago, the sea level was six to ten feet lower. The footprints were most likely left in an area that was just above the high tide line.