ABSTRACT
This chapter examines more closely two social and economic processes associated, and in the historical past, with assertive and specialized pastoralism and well-defined age-sets, in particular that practiced by the Maasai or by groups similar to them in organization. It aims to provide ecological aspects of pastoral movement in cultural perspective, investigating through ethnographic analogy the political and economic pressures towards and methods of pastoral expansion experienced in the past. The Maasai represent the southernmost extension and highest degree of pastoral specialization of the Eastern Sudanic speaking peoples. The manifest aim of pastoral mobility is to gain competitive access to pasture, water and mineral resources, made scarce through both routine and exceptional episodes of aridity in the pastoral zone. A related but conceptually distinct process might be called 'political expansion', which results from conflict engendered by competition between rival age-groups divisions.
