A horse mandible from the Bluefish Caves with number of cut marks on the lingual surface. The animal’s tongue was cut out with a stone tool.
The timing of the first arrival of the humans into North America across the Bering Strait has now been pushed back 10,000 years, claim researchers from Université de Montréal and Oxford University’s Radiocarbon Accelerator Unit.
Analysing over 36,000 animal bone fragments from Bluefish Caves in the northern Yukon, Canada, the study, led by Lauriane Bourgeon, Ariane Burke, and Thomas Higham, discovered multiple instances of stone tool cut marks – traces left by humans skinning and butchering the animals. The oldest finds date to between 23,000 and 24,000 years ago.
The bones were recovered during excavations led by Jacques Cinq-Mars between 1977 and 1987 and were then controversially associated with human deposits and dated to between 11,000 and 30,000 years ago. New radiocarbon dates of bones bearing straight, V-shaped scratches from tools now confirm that the Bluefish Caves are the earliest known sites of human habitation in North America.
The study supports the ‘Beringian standstill hypothesis’ as proposed by geneticists: that a few thousand individuals lived in isolation 15,000-25,000 years ago on Beringia, a vast region between the Mackenzie River in north-west Canada and the Lena River in eastern Russia, a land bridge at the time. As Bourgeon explained to CWA, ‘the area acted like a refugium for humans and animals since it was never glaciated, unlike much of North America which was covered by a huge ice-sheet’. The inhabitants of the Bluefish Caves could therefore be ancestors of people who colonized the entire continent along the coast of North and South America after the last ice age.