It's commonly believed that humans first settled in North America about 14,000 years ago, but a recent study suggests our kind arrived on the continent some 10,000 years earlier.
According to researchers from the Université de Montréal' and University of Oxford, animal bones found decades ago in the northwestern Yukon's Bluefish caves in Canada show evidence of marks left by human-made tools.
Among them is a horse mandible that dates back roughly 24,000 years.
This is not the first time the remains, which also includes the bones of bison, mammoth, and caribou, have been studied.
Back in the 1970s, a researcher dated them, but beyond the fact that they were concentrated in a small, sheltered area, produced little to support his theory that humans had contact with them.
In the more recent study, an exhaustive review of each of the 36,000 fragments in the collection revealed, according to Ariane Burke, one of the team members, "Series of straight, V-shaped lines on the surface of the bones..." which she characterizes as, "indisputable cut-marks created by humans."
Despite that compelling discovery, it is anticipated that the study will be met with some doubt.
Nonetheless, one critic of the findings does note that if the earlier arrival date theory is true, additional evidence supporting it is likely to surface at some point in the future.