In that co-evolutionary account, what is not addressed is that the walnut existed well before the chipmunk, being a form of vegetation - this points to the chipmunk settling here because it found walnuts and had corresponding sharp teeth.
This appears similar to human pops settling near easy water and food [fish] supply, the latter event pre-dating the former: IOW, the water nor the fish acted to exploit the humans factor.
Is there a different view, as both appear wanting?