This paper forms part of a project to describe and analyse historically and anthropologically nomadic pastoralism. It reflects on mobility, its forms and scale, and more especially on the critique of predominant classical, even banal ideas which assimilate nomadism to mobility. Nomadic pastoral mobility occurs in a context that separates it radically from migratory movement. In fact, nomadic mobility constitutes a strategy that stabilizes resources and populations and whose basic foundation is the appropriation of a territorial base that is established as durably as possible. Just as, and following sedentary settlement, nomadic pastoralism puts an end to migratory mobility. Thus it seems that a single idea of mobility is inappropriate to describe the two fundamentally independent phenomena represented by transcontinental migration, partly arising from the effects of the ice age, and nomadic pastoralism.