A pastoral use of even a good district necessitates a move of five or ten miles every few weeks.

The whole, large as it may be, is absolutely necessary for the annual support of the tribe.

Hence any outside encroachment upon their territory calls for the united resistance of the tribe.

This joint or social action is dictated by their common interest in pastures and herds.

The social administration embodied in the apportionment of pastures among the families or clans grows out of the systematic use of their territory, which represents a closer relation between land and people than is found among purely hunting tribes.