The oldest evidences for hominins associated with stone tools and cut and marked mammal bones occur in Africa at places such as Gona, Ethiopia, or Olduvai, Tanzania. They clearly indicate that a foraging way of life was responsible for at least part of the assemblages dating 2.6 million years ago or less, and that animal protein was used at that early time. However, in those and other sites of the Pliocene-Pleistocene climatic periods, it is not always clear if the bones are the result of scavenging or of hunting activities by hominins. Recent research showed that scavenging niches probably existed at those times, niches basically created by abandoned field kills, which typically do not use all the tissues available on carcasses. On the other hand, the dental remains of hominins, the results of stable isotopes on their bones, their stone tools, and the placement of sites on the landscape suggest that hunting - a well-developed strategy among living primates, and presumably among primate ancestors - is a strong possibility. It is less evident which fossil markers are useful to distinguish scavenging from hunting activities. All kinds of studies were conducted to interpret the oldest archaeological sites, ranging from the identification and location of cut marks on bones to the representation of different skeletal parts at the sites. The superimposition of stone tool marks over carnivore marks is an important criterion that, in the few cases where they were found, showed that at least some part of the diet may have been related to scavenging. One of the difficulties that exist in order to infer a hunting strategy from the archaeological record derives from the fact that none of these early sites contain bona fide projectiles. Some bola stones in African sites or wooden spears found in northern Europe - where the environment allowed good preservation of organic remains - attest to their existence, but there is still no agreement concerning their importance within those ancient tool kits.
However, the repeated deposition of stone tools and bones at particular places is well testified for those early sites, and taphonomic work demonstrated that those bone accumulations are much more than what can be expected from chance accumulations. The Oldowan industry was defined on the basis of the findings at these sites, a simple industry that by c. 1.6 million years ago was widely distributed in Africa. At that time or slightly earlier, there are evidences of hominins moving out of Africa into Asia and Europe. The process of global dispersion of Homo erectus, which is associated with the use of a bifacial lithic technology, began to fill the available habitats in new continents. Initially the dispersion was restricted to tropical climates, but at some point around 500 000 years ago or before, the peopling of Northern Europe took place. In Europe and the Near East they were replaced by Homo neanderthalensis, and by a different lithic technology. Systematic use of caves as habitation sites was one of the many behavioral characteristics that were acquired by people colonizing cold Europe.
Foraging Homo sapiens
In a later period, with a chronology that is still disputed among archaeologists, the systematic accumulation of bones from a single or dominant species plus the presence of stone projectiles, makes it clear that the use of a strategy for hunting was a strong possibility. The study of the stable isotopes of European human bone and teeth samples from near the end of the Pleistocene suggests that animal protein was an important part of the diet. It must be noted that this technique of stable isotopes can also enlighten on the importance of maritime versus terrestrial protein in the diet. The available results indicate that none of the early samples attest to the use of marine resources. The first evidences of their consumption are provided by faunal remains, basically mollusks. Then, in the long term it is clear that maritime foods were a very late addition to the diet. What these findings show is that a marine component was systematically incorporated in the subsistence at least at the time when modern humans appear. The oldest and well-supported evidence for the consumption of marine resources comes from South Africa. However, the archaeological record of modern humans includes marine resources almost everywhere, from Gibraltar to England, and from Australia to the Americas. This use of the coastal resources attests to the systematic incorporation of a new habitat into the hominin world. This incorporation is easy to understand when we realize that the global dispersion of humans required the use of sea routes and oceanic navigation skills. The continent of Australia, for example, was reached sometime between 60 000 and 40 000 years BP, implying the use of open sea routes. The use of aquatic routes is a simple and economic way of dispersion, and many recent theories purporting to explain the human peopling of the Americas invoke Pacific or Atlantic coastal routes as alternatives to the classic - and, it must be said, better supported by the evidence - route across the Bering land bridge.
At the end of the Pleistocene much of the known variation in subsistence strategies was already present in different and unrelated parts of the world. Human adaptations including systematic hunting of ungulates, differential transport of their bone parts, central home bases, and sophisticated techniques of lithic reduction, which are similar to those recorded during the Holocene, were established in America since the beginning of human colonization - at least 12 000 years ago - and in Australia, Asia, or Europe since c. 40 000 years ago or before. In Africa, on the other hand, they appear to be older than 100 000 years. In all these cases stone tools, hearths, sometimes bone tools, and varied subsistence remains are associated with modern humans Homo sapiens. In some places these early colonizers preyed upon what are today extinct animals, and humans are considered by some authors as crucial factors in the extinction process. However, nothing approaching hard proof of human involvement in the extinction was really offered by the archaeological record, and the reasons behind the removal of dozens of faunal species near the end of the Pleistocene in many places around the world still remains an unanswered question. Many sites where mammoth (Mammuthus sp.) and other extinct animal bones were deposited in association with hearths, projectile points, or other artifacts exist in North America or Siberia, but the situation is different in other regions of the world. For example, few sites with good stratigraphic association between human artifacts and bones of extinct animals exist in whole continents, such as South America or Australia. It appears that different extinction mechanisms need to be considered for different continents, or that other models need to be considered as well. The most important alternative to the human-caused extinction model defended by Paul Martin and others, takes into account climatic changes that occurred at the end of the Pleistocene, particularly the Younger Dryas Cold Event. Again, since the Younger Dryas was basically a Northern Hemisphere phenomenon; it is difficult to see the climatic model as simply replacing the human model.
Most of the technological flexibility that is observed in contemporary hunters and gatherers groups - as expressed in weaponry, hearths, tents, boats, burial, processing tools, adornments - can already be documented for early modern humans in Europe, Asia, Australia, and America. Moreover, they are usually older in Africa. There are many regional differences, as we will see below, but still it can be defended that the basic skills and capacities that are known through ethnographic and ethno-archaeological research, were already in place several thousand years ago. Then, the process of dispersal implied the selection of the most appropriate strategies and techniques from an ample pre-existing pool.
It must be noted that the dispersal of the species around the planet implied a change from tropical to a variety of nontropical environments. Accordingly, this process required a number of cultural and physiological adaptations to cold weather. This was the only way to colonize the lands located in the far north of the planet, including Scandinavia, Siberia, and Beringia. The expansion of foragers to America at the end of the Pleistocene was probably based on the existence of this knowledge. In the beginning the occupation of the northern lands was probably discontinuous, a pattern that was archaeologically detected even some 22 000 years ago, during the Last Glacial Maximum. Effectively, at this time the archaeological record shows that humans abandoned most of the Northern lands and concentrated in the Southern peninsulas of Europe where climate was milder. On the other hand, navigational skills were necessary in order to populate
Southeast Asia, Australia, New Zealand, and the Southern and Central Pacific Ocean. All these enterprises required the capacity for cooperation and coordination of human populations that were dispersed across large distances. Cooperation is a basic way of reducing risks in adverse environments, and may hold the key for the successful colonization of distant and unknown lands. In terrestrial settings foragers needed to learn the basic trends in the use of places and their surroundings, including the acquisition of knowledge about the location of the lithic sources, the seasonal availability of different faunal and plant resources, or the less costly paths within the selected foraging areas. Communication was essential in order to make this kind of knowledge available for widespread peoples.
On the other hand, in maritime settings foragers also needed to deal with long-term subsistence planning, since many of the lands that were populated by sea required several days of navigation. The process of dispersal across long sea routes probably implied a degree of isolation for the initial colonizers. Then, successful colonizers in new lands needed to be able to reproduce the basic technological repertoire of the original land. It can be defended that the process of global colonization was only possible using fine-tuned exploration skills. The acquisition of these skills was probably costly in terms of time, and may have required many generations.
Once the process of human dispersal of Homo sapiens around the planet was basically completed, another process was initiated, one of cultural differentiation. Fusion and fission of bands, changes in band membership, demographic increases, and changes in hunting and collecting ranges were among the many small-scale processes that were contributing to this differentiation, which sometimes was prompted by differences in habitat, degrees of isolation, and historical reasons. In the end, cultural divergence was one of the basic results of these complex processes. Through different mechanisms, both isolation and marked proximity of bands or populations could precipitate cultural differentiation.
As a result of the dynamic interaction occurring among different populations, hunters and gatherers experimented with drastically differing cultural trajectories. Some of these trajectories culminated in the abandonment of the forager way of life. The saturation of space in some regions, the beginnings of territorial organization, and the implementation of other ecologic and social strategies were just some of the paths that were taken by human populations. Cultural complexity and economic intensification was sometimes the result, a process that under certain conditions helped to constitute semisedentary societies. Classic ethnographic examples of this semisedentary condition are the societies of the British Columbia, which always defied classification. In other cases sedentary societies exerting a tight control over the reproduction of animals and plants were formed, resulting in the domestication of several species in different parts of the world.
However, as already mentioned, sedentarization was not always the path selected by humans, and many populations maintained a highly mobile forager way of life well into the Holocene. In fact, in many places like the Near East, archaeological research demonstrated that hunting of wild animals continued to be an important task even after the beginning of sedentarization and food production. With the exception of Europe, the forager lifestyle was still practiced by a high proportion of the world population in the eighteenth and nineteenth centuries. The twentieth century saw an important decline in the number of people living from hunting, gathering, and fishing, and at this time the process of their geographic encroaching was almost completed. In part as a result of this distribution, it must also be said that many societies were not constant in their economic orientation; for example, many bands were alternating between foraging and horticulturalist lifestyles in the Amazon and between foraging and pastoralist lifestyles in sub-Saharan Africa. The reasons behind these changes are to be seen not only in their geographic, but also in their social marginality. These changes in economic orientation usually constituted the only alternative that these people had to work independence of their sedentary neighbors.
World History
