The political organization of the native Australians, low as they were in the social scale, seems to have been based chiefly on the claim of each wretched wandering tribe to a definite territory.[88] In north central Australia, where even a very sparse population has sufficed to saturate the sterile soil, tribal boundaries have become fixed and inviolable, so that even war brings no transfer of territory. Land and people are identified. The bond is cemented by their primitive religion, for the tribe's spirit ancestors occupied this special territory.[89] In a like manner a very definite conception of tribal ownership of land prevails among the Bushmen and Bechuanas of South Africa; and to the pastoral Hereros the alienation of their land is inconceivable.[90] [See map page 105.] A tribe of hunters can never be more than a small horde, because the simple, monotonous savage economy permits no concentration of population, no division of labor except that between the sexes, and hence no evolution of classes. The common economic level of all is reflected in the simple social organization,[91] which necessarily has little cohesion, because the group must be prepared to break up and scatter in smaller divisions, when its members increase or its savage supplies decrease even a little. Such primitive groups cannot grow into larger units, because these would demand more roots sent down into the sustaining soil; but they multiply by fission, like the infusorial monads, and thereafter lead independent existences remote from each other. This is the explanation of multiplication of dialects among savage tribes. [Sidenote: Land bond in fisher tribes.]