Oldest human footprints in North America discovered
Source: Live Science
About 13,000 years ago, two shoeless adults and a child squished their bare feet through wet clay near the water's edge, leaving footprints that still exist today. The footprints, recently unearthed by anthropologists on an island in British Columbia, Canada, are the oldest known human track marks in North America, according to a new study, and provide more evidence that humans were thriving on the Pacific Coast of Canada at the end of the last ice age, said study lead researcher Duncan McLaren, an anthropologist at the Hakai Institute and the University of Victoria, in Canada. The footprints — 29 in all — were so well preserved that McLarenand his colleagues could assign modern-day U.S. shoe sizes to the prehistoric individuals: a junior size 8; a junior size 1 (or a woman's size 3); and a woman's size 8 or a man's size 7. The researchers made the remarkable discovery on Calvert Island, located off the western coast of British Columbia, about 62 miles (100 kilometers) north of Vancouver Island. At the end of the last ice age (about 11,700 years ago), the North American Cordilleran Ice Sheet ended along the Pacific coastline, leaving "refugia," or iceless areas where plants and animals could survive. Calvert Island fell right into one of these refugia, prompting modern-day researchers to dig there, looking for artifacts. However, excavations in refugia aren't always easy, as today much of the region is covered with dense temperate rainforest, the researchers wrote in the study. Moreover, the geography there was different at the end of the last ice age because more of Earth's water was frozen in huge glaciers. This explains why sea levels were as much as 9.8 feet (3 meters) lower about 14,000 to 10,000 years ago on Calvert Island than they are today, McLaren said. "We were testing this shoreline, below the beach in the intertidal zone, when the first footprint was discovered," McLaren told Live Science. This was in 2014, when the team — which included members of the Heiltsuk First Nation and the Wuikinuxv First Nation — unearthed a single human footprint about 24 inches (60 centimeters) below the beach's surface on Calvert Island. Two pieces of ancient wood found by the footprint dated to between 13,300 and 13,000 years ago, according to radiocarbon analyses, the researchers found. Encouraged, the researchers returned to the island during the 2015 and 2016 field seasons, eventually uncovering 28 more human footprints from the same period. Normally, footprints last only a moment. But in this case, "they were impressed into a wet clay that hardened and then was filled by sand, likely washed in from the beach below," McLaren said.