When did the first settlers arrive in North America? What routes did the first Americans use to get here? How did they adapt to climate and environmental conditions in the Arctic territories? Are they responsible for the megafauna extinction close to 14,000 years ago? Lauriane Bourgeon attempts to answer these questions based on a zooarchaeological survey and taphonomic analysis of the Bluefish Caves site located in Canada's Yukon Territory. A little over 36,000 animal bone samples were painstakingly examined under a microscope to identify traces of cultural activity. Six of the samples bore evidence of butchery marks produced by stone tools and were sent for radiocarbon dating. Results indicate human occupation at Bluefish Caves 24,000 years before present, in the middle of the ice age. This considerably pushes back the timing of humans' first entry into North America, previously thought to be around 15,000 years ago. Supported by genetic data, the archaeological survey suggests it was only after North America's ice masses gradually receded some 15,000 years ago that an isolated human population left the Far North to disperse across the continent. Published in French.