The large range of territory held by a nomadic tribe is all successively occupied in the course of a year, but each part only for a short period of time. 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. Overcrowding by men or livestock, on the other hand, puts a strain upon the social bond. When Abraham and Lot, typical nomads, returned from Egypt to Canaan with their large flocks and herds, rivalry for the pastures occasioned conflicts among their shepherds, so the two sheiks decided to separate. Abraham took the hill pastures of Judea, and Lot the plains of Jordan near the settled district of Sodom.[103] [Sidenote: Geographical mark of low-type societies.] The larger the amount of territory necessary for the support of a given number of people, whether the proportion be due to permanent poverty of natural resources as in the Eskimo country, or to retarded economic development as among the Indians of primitive America or the present Sudanese, the looser is the connection between land and people, and the lower the type of social organization. For such groups the organic theory of society finds an apt description. To quote Spencer, "The original clusters, animal and social, are not only small, but they lack density. Creatures of low type occupy large spaces considering the small quantity of animal substance they contain; and low-type societies spread over areas that are wide relatively to the number of their component individuals."[104] In common language this means small tribes or even detached families sparsely scattered over wide areas, living in temporary huts or encampments of tepees and tents shifted from place to place, making no effort to modify the surface of the land beyond scratching the soil to raise a niggardly crop of grain or tubers, and no investment of labor that might attach to one spot the sparse and migrant population. [See density maps pages 8 and 9.] [Sidenote: Land and state.]