[ak_aramis]

Originally Posted by Luke Bunyip

Density of food supply determines how many people survive in a particular hunting and gathering range. Aboriginal Australian clans would eke out an existence in a predetermined area, but when there was a localised abundance of food (migratory birds, moths, eels) clans would all congregate, eat, discuss stuff, and arrange marriages. Blood line management (ie prevention of inbreeding) is very big in Aboriginal culture even now for some people.

So, you've got two existing pressures, survival on marginal land, and interaction with people outside your range.

Final point: tribes would have agreements on things like allowing wholesale migration through each others land during times of drought, as well as the movement of traders and tribal shamans for long distances. For instance, the rock formation at what is now the town of Nimbin in NSW, was a pilgrimage site for tribal shamans for hundreds of kilometres around, but no one lived there permanently.

Similar is true of the Alaska Native tribes.