The expansion of European live-stock in America since the XVI century led to the emergence of two different economic systems: one of the hunter horsemen (many Plains groups in both Americas) and the other of the agriculturalists practicing trans-humance (Navajo, Goajiro).
Chapter IV contains a general theoretical model of the origins and early history of animal husbandry. Food production was born in a few primary centres and later spread into other regions. The foundations for domestication evolved under the conditions of specialized hunting on the basis of intensive food-gathering which was becoming transformed into agriculture, and much rarely on the basis of fishing. Imprinting served as the main means of the earliest domestication. Later forceful domestication through hunger appeared. The domestication of animals was brought about by the attempt to preserve an important source of the protein while agriculture was developing and the hunting being turned into a subsidiary occupation.
The spread of productive economy took place in the forms of both migration and borrowing (diffusion). In both cases new distinct economic systems emerged including both autochthonic and introduced elements and well adapted to the local environment. These processes were often followed by the domestication of local fauna.
The book traces the ways of the formation and evolution of the technological base of the animal husbandry: the rise of dairy economy, wool weaving gelding technique, the exploitation of the domesticated animals in agriculture and transport. Owing to all these factors animal husbandry became ripe for separation from agriculture and the nomadic pastoralism emerged.