The absence of evidence, as the Yana discovery illustrated, was not evidence of absence.

It was evidence of inadequate sampling of an extremely large and difficult-to-access region.

At 70 degrees and 43 minutes north latitude, the Yana site is well above the Arctic Circle.

It is in the same general latitude as the northern coast of Alaska, or the coast of northern Norway.

These are places that in the modern world are considered extreme environments even with modern technology.

In the Pleistocene, without that technology — but with the adapted technology of the people who lived there — they were apparently survivable and productive.