For HG groups, any risk of subsistence crisis will be reduced where (1) food energy derives from a diverse set plant and animals and (2) aggregate food resources are continuously available during the year, even if certain foods are more abundant in certain seasons. If a preferred food such as meat is temporarily scarce, then, through more intensive efforts and high spatial mobility, other less desirable foods (e. g., edible plants) can usually be accessed elsewhere. As a result of these strategies, basic supplies of food energy can be secured throughout the year, and what is produced is almost immediately shared and consumed.
Both the Anbarra Gidjingali (Section 4.1.2) and the Dobe! Kung San (Section 4.2.2) are examples of HG societies that can exploit such circumstances, but with somewhat different mobility patterns. Dobe campsites must be moved frequently, whereas the Anbarra can be semisedentary, with long-term seasonal residence at the boundary between land and estuary. But even in their arid ‘‘desert wasteland’’ (judged from an agropastoralist standpoint), the Dobe! Kung strategy can be judged as highly efficient in maximizing leisure time. According to Lee’s data, they devoted only 12-19 hours per week to food – gaining ‘‘work’’ to achieve a state of subsistence energy balance (nobody hungry, but no storage). The surprisingly low level of energy input resulted in the San (and, by extension, all HG societies) being characterized by Marshall Sahlins as ‘‘the original affluent society.’’ Agriculturalists, by contrast, usually have to work harder, enjoy less adequate diets, and sometime suffer harvest failure.
In this situation, there is no urgent reason for an HG society to produce a food surplus even if circumstances permit, and there is also little incentive to invest in techniques for food storage. Such ‘‘hand – to-mouth’’ strategies characterize the relatively nonseasonal environments of tropical forests, midlatitude deserts, and productive high-latitude coasts such as the Aleutian islands, Tierra del Fuego, and Tasmania. HG societies that occupy such environments share a number of features in common. Robin Torrence has demonstrated that the technologies employed by such societies involve relatively few types of tools. Hunting focuses on the most rewarding methods of securing prey, and gathering is equally focused on plant foods with the highest returns per unit of gathering effort. New tools and new techniques are added to the HG repertoire in order to reduce the probability of failure, but this only tends to happen in more uncertain environments where the costs of concentrating efforts on only the ‘‘best’’ (i. e., most rewarding) food sources can be very high.