Bears and Their People
It turns out that distinct populations of grizzly bears match indigenous language families. The hypothesis of environmental factors affecting both large mammals is plausible.
But if I were studying this, I'd check for cultural factors too. For example, how does each human culture relate to bears? Some cultures like bears, others really don't, and that can influence the behavior of both bears and humans. Does anyone's mythology claim a relationship with bears? If humans and bears both want the same berry patch or salmon-fishing spot, are the humans permitted to kill or drive away the bears, or are they directed to back off and let the bears have it? I'd start looking in that middle range, because if the people there are bear-hostile, that could discourage the bears from traveling between the other two groups.
Also, I'd check for timing. About how far back do scientists think those bear populations split? And how does that compare with the various theories of when humans reached Turtle Island? Does it match anything in anybody's oral history?
But if I were studying this, I'd check for cultural factors too. For example, how does each human culture relate to bears? Some cultures like bears, others really don't, and that can influence the behavior of both bears and humans. Does anyone's mythology claim a relationship with bears? If humans and bears both want the same berry patch or salmon-fishing spot, are the humans permitted to kill or drive away the bears, or are they directed to back off and let the bears have it? I'd start looking in that middle range, because if the people there are bear-hostile, that could discourage the bears from traveling between the other two groups.
Also, I'd check for timing. About how far back do scientists think those bear populations split? And how does that compare with the various theories of when humans reached Turtle Island? Does it match anything in anybody's oral history?