29 fossil prints provide rare evidence of early New World settlers’ coastal travels
D. McLaren et al/PLOS ONE 2018
People who reached what’s now Canada’s Pacific coast around 13,000 years ago made some lasting impressions — with their feet.
Beach excavations on Calvert Island, off British Columbia’s coast, revealed 29 human footprints preserved in clay-based sediment, says a team led by archaeologist Duncan McLaren. About 60 centimeters below the sandy surface, the deposits contained the footprints of at least three individuals, the Canada-based researchers report March 28 in PLOS ONE.
Smudged remains of many more footprints surrounded these discoveries. Ancient people walking on the shoreline apparently trampled those footprints and distorted their shapes, the scientists say.
Radiocarbon dating of bits of wood from shore pine trees found in the clay sediment narrowed the age of the footprints from 13,317 to 12,633 years old. Who these footprints belonged to is unknown. Their arrival roughly coincided with the North American appearance of Clovis people, makers of distinctive spearpoints who may have entered the New World via an ice-free, inland route (SN: 5/13/17, p. 8). But stone tools unearthed with the Calvert Island footprints were not made by Clovis people, says McLaren of the Hakai Institute, a research organization in Heriot Bay, and the University of Victoria.
“This discovery places Clovis-age people on the British Columbia coast, far from a so-called ‘ice-free corridor’ and where no Clovis technology has ever been found,” says archaeologist Jon Erlandson of the University of Oregon in Eugene. A long-standing idea that Clovis people were the first Americans, already challenged by recent finds, “is dead in the water,” he argues.
Beach excavations on Canada’s Calvert Island revealed 29 distinct human footprints (dark brown in this illustration of one excavation site) from around 13,000 years ago. The array of foot impressions was made by at least three individuals, researchers say.
Recent challenges to the Clovis-first proposal include evidence that humans inhabited Florida’s Gulf Coast about 14,550 years ago (SN: 6/11/16, p. 8) and South America as early as 18,500 years ago (SN: 12/26/15, p. 10). A 14,500-year-old child’s footprint has also been unearthed in South America.
People disembarking from canoes or other vessels may have created the Calvert Island footprints when preparing to move from an ancient shoreline to drier ground, the researchers propose. No sets of tracks made by individuals walking in any particular direction were found.
“Only an expanded excavation can capture how the track makers were moving,” says biological anthropologist Neil Roach at Harvard University. Patterns in the tracks indicate that people repeatedly walked across Calvert Island’s shoreline, but whether they came to gather food or for some other reason is unknown, Roach adds.
The new discoveries add to evidence that people inhabited Canada’s Pacific coast 14,000 years ago or more, as the last ice age wound down and glaciers retreated from coastal areas. Evidence of mastodon hunting dates to around 13,800 years ago at a coastal site in Washington state.
Some researchers suspect that initial settlers of the Americas came from northeast Asia and traveled down the Pacific coast, making inland forays along the way. Rising sea levels from melting ice sheets presumably submerged coastal campsites of these ancient people, erasing most evidence of them.
Between 14,000 and 11,000 years ago, the sea level was two to three meters lower on Calvert Island than today, McLaren’s group estimates. The researchers looked for archaeological remains at shoreline spots exposed at low tide and underwater at high tide. Excavations in 2014 revealed a suspected human footprint. Continued digging in 2015 and 2016 uncovered 28 more footprints.
Many foot impressions included toe marks, indicating that individuals who made the prints were not wearing shoes. Digital enhancement of a footprint with no clear toe marks showed drag marks made by two toes, apparently while slipping on soft ground.
D. McLaren et al. Terminal Pleistocene epoch human footprints from the Pacific coast of Canada. PLOS ONE. Published online March 28, 2018. doi:10.1371/journal.pone.0193522.
B. Bower. Shock-absorbing spear points kept early North Americans on the hunt. Science News. Vol. 191, May 13, 2017, p. 8.
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