During the 1970s, Lewis Binford suggested that early humans were obtaining food via scavenging, not hunting. Early humans in the Lower Paleolithic lived in forests and woodlands, which allowed them to collect seafood, eggs, nuts, and fruits besides scavenging. Rather than killing large animals for meat, according to this view, they used carcasses of such animals that had either been killed by predators or that had died of natural causes. Archaeological and genetic data suggest that the source populations of Paleolithic hunter-gatherers survived in sparsely wooded areas and dispersed through areas of high primary productivity while avoiding dense forest cover.
According to the endurance running hypothesis, long-distance running as in persistence hunting, a method still practiced by some hunter-gatherer groups in modern times, was likely the driving evolutionary force leading to the evolution of certain human characteristics. This hypothesis does not necessarily contradict the scavenging hypothesis: both subsistence strategies could have been in use – sequentially, alternating or even simultaneously.
Hunting and gathering was presumably the subsistence strategy employed by human societies beginning some 1.8 million years ago, by Homo erectus, and from its appearance some 0.2 million years ago by Homo sapiens. Prehistoric hunter-gatherers lived in groups that consisted of several families resulting in a size of a few dozen people. It remained the only mode of subsistence until the end of the Mesolithic period some 10,000 years ago, and after this was replaced only gradually with the spread of the Neolithic Revolution.
Starting at the transition between the Middle to Upper Paleolithic period, some 80,000 to 70,000 years ago, some hunter-gatherers bands began to specialize, concentrating on hunting a smaller selection of (often larger) game and gathering a smaller selection of food. This specialization of work also involved creating specialized tools such as fishing nets, hooks, and bone harpoons. The transition into the subsequent Neolithic period is chiefly defined by the unprecedented development of nascent agricultural practices. Agriculture originated as early as 12,000 years ago in the Middle East, and also independently originated in many other areas including Southeast Asia, parts of Africa, Mesoamerica, and the Andes.
Forest gardening was also being used as a food production system in various parts of the world over this period. Forest gardens originated in prehistoric times along jungle-clad river banks and in the wet foothills of monsoon regions. In the gradual process of families improving their immediate environment, useful tree and vine species were identified, protected and improved, whilst undesirable species were eliminated. Eventually superior introduced species were selected and incorporated into the gardens.
Many groups continued their hunter-gatherer ways of life, although their numbers have continually declined, partly as a result of pressure from growing agricultural and pastoral communities. Many of them reside in the developing world, either in arid regions or tropical forests. Areas that were formerly available to hunter-gatherers were—and continue to be—encroached upon by the settlements of agriculturalists. In the resulting competition for land use, hunter-gatherer societies either adopted these practices or moved to other areas. In addition, Jared Diamond has blamed a decline in the availability of wild foods, particularly animal resources. In North and South America, for example, most large mammal species had gone extinct by the end of the Pleistocene—according to Diamond, because of overexploitation by humans, one of several explanations offered for the Quaternary extinction event there.
As the number and size of agricultural societies increased, they expanded into lands traditionally used by hunter-gatherers. This process of agriculture-driven expansion led to the development of the first forms of government in agricultural centers, such as the Fertile Crescent, Ancient India, Ancient China, Olmec, Sub-Saharan Africa and Norte Chico.
As a result of the now near-universal human reliance upon agriculture, the few contemporary hunter-gatherer cultures usually live in areas unsuitable for agricultural use.
Archaeologists can use evidence such as stone tool use to track hunter-gatherer activities, including mobility.