Introduction

1Before the development of more advanced human societies (discussed in other contributions in this book), the daily lives of hominins (all of our ancient relatives since the last common ancestor with chimpanzees) were mostly devoted to finding food and shelter, making and using tools for these tasks, and avoiding attack by predators, probably living in small mobile groups. Our understanding of changes in these behaviors across time is based on the durable materials they left behind, mainly in the form of stone tools and fossilized bones. Stone tools can tell us about cognitive and technological abilities, as well as social behaviors, whereas fossilized bones can tell us about ancient environments, how hominins procured their food, and how their bodies were adapted for these tasks. Much current research focuses on how hominin lifeways have changed over time: when hominins increased their focus on acquiring meat and other animal tissues, how they developed more advanced technologies to solve their problems, and how they overcame predators and other challenges to expand their territories across Africa and then throughout the rest of the old world. The geospatial scale and patterning of hominin behaviors certainly evolved along with these other processes. Here we examine the current state of the evidence of changes in our early ancestors’ lifeways and movement patterns through three different yet interconnected aspects: territory, the home ranges which determine the types and amounts of food and other physical resources available to hominin groups; mobility, our ancestors’ ability to move about within, and then beyond, typical home ranges for a medium-sized primate; and technology, the types and complexities of which are determined by the raw materials available in a territory, but also determines what food and other resources can be extracted from that territory.

Territory

2How do we reconstruct the size and types of territories in which our hominin ancestors were living? Three commonly used ways are: via analogy with our closest living relatives, the African great apes; via reconstruction of the degree of diversity in diet and technology that might have required a larger and more varied territory; and evidence from our fossil ancestors themselves that their bodies were becoming more adapted to efficient travel on the ground across larger areas.

3Chimpanzees, bonobos and gorillas are territorial animals, but don’t share the same social structure. Gorillas, thanks to their strength and dissuasive aspect, don’t seem to fear many predators and live in small familial structures. Chimpanzees and bonobos, whose height and morphology are closer to those of the australopithecines and early Homo, are more social animals living in groups which can reach several dozens of individuals. They can collectively defend themselves against predators (Kortland 1962; Boesch 1991) and also can have collective aggressive strategies towards other groups of chimpanzees to widen their territory (Wilson & Wrangham 2003). In the wild, chimpanzees are also well known to use different kind of tools for several purposes (cf. infra) although they have never been seen knapping hard rocks to produce artefacts which can be used as tools. These are some of the reasons why it seems more appropriate to choose chimpanzees, rather than gorillas or bonobos, as references to try to model what the lifeway of early hominins could have been like.

4Thanks to 50 years of intensive primatological studies in the wild, chimpanzees’ ways of life are now well known and used to try to model some aspects of our earliest ancestors’ life. Chimpanzees are territorial animals and they use well-defined home ranges (they can use the same location for decades, e.g. Williams et al. 2002). To understand differences in territorial utilization among chimpanzee communities, it is important to consider not only ecological factors, such as food availability and distribution, but also social factors such as intercommunity relationships. Home-range sizes in chimpanzees are large compared to those of most other primates (Harvey & Clutton-Brock 1981). They typically range between 10 and 40 km². However, significant variability has been found in home-range sizes, from 3.1 km² for the Taï Middle community (lowland forest, Ivory Coast; Fig. 1; Herbinger et al. 2001) to 63 km² for the Fongoli community (savannah habitat, Senegal; Fig. 1; Pruetz 2006). Various social and ecological factors, including the distribution and availability of food, predation risk, and community size and composition, affect chimpanzee ranging and home-range size (Lehmann & Boesch 2003).

5Chimpanzees live in fission-fusion societies that move nomadically through their territories, following no fixed circuit or timing. Long-term studies of chimpanzee ranging have shown that their feeding territories include a heavily used central area surrounded by a less frequently used periphery that may overlap extensively with neighboring territories (Herbinger et al. 2001). This pattern of ranging suggests that chimpanzees actively avoid border areas, thus diminishing intergroup interactions, which can turn violent (Wrangham 1996). Nevertheless, observations of chimpanzee communities in the Taï Forest, Ivory Coast (figure 13.1), demonstrate that in times of relatively low food availability the benefit of finding other food sources in peripheral areas outweigh the costs of encountering neighboring communities to a larger extent than in times of high food availability, influencing territorial utilization (Herbinger et al. 2001). Recent genetic approaches (e.g. Arandjelovic et al. 2011) offer a complement to traditional field-based approaches for understanding some aspects of wild chimpanzee population dynamics, and allow to estimate group sizes over a larger area. For central chimpanzee populations (Loango National Park, Gabon, figure 13.1), a recent study proposes a density estimate of 2.14 chimpanzees/km² (range of 1.58-2.39; Arandjelovic et al. 2011). Chimpanzees are opportunistic omnivores and their diet is dependent on their environment, which means they don’t feed the same way everywhere. Chimpanzees spend half of their day feeding and much time moving from one food source to the next. Mainly frugivorous, they can also eat nuts, leaves, pith, honey, eggs, insects and small animals: monkeys and other herbivores that they can obtain by hunting (the practice of seeking, pursuing, and capturing or killing a wild animal), and also infant chimpanzees. On average, about 3% of a chimpanzee’s diet comes from meat.

6The origins of our lineage date to around 6 million years ago (Ma) or more, based on fossils from eastern and central Africa (e.g. Senut et al. 2001; Brunet et al. 2002) that bear anatomical features associated with upright bipedal walking, a unique characteristic of the human family. The record becomes richer after 4.5 Ma with more fossils recovered from two genera, Ardipithecus and Australopithecus. Anatomical and trace evidence suggests that these hominins spent a good amount of time in the trees, probably to find food and seek shelter and safety from predators. The diet of these early hominins was probably much like that of chimpanzees, who generally inhabit forest and wet savanna environments in equatorial Africa. It had long been debated whether Australopithecus ate significant amounts of meat and if so, whether they made or used tools to acquire it. The conventional wisdom for most of the 20th century has been that making and using tools, hunting animals and eating meat was the domain of our genus only. This started to be challenged in the early 21st century based on advances in several lines of research and gained further support in 2010 with the announcement of 3.4 Ma cut marked bones from Dikika, in Ethiopia (figure 13.1, McPherron et al. 2010). Although the anthropogenic nature of the cut marks was challenged (see for example Dominguez-Rodrigo et al. 2010), this evidence, if accepted, pushed back the date for the earliest hominin meat-eating by 800,000 years (800 ka) and before the first appearance of the genus Homo. No stone tools were found with the cut marked fossils, but early hominins may have used their teeth, as chimpanzees do, or naturally sharp stones for butchery and therefore meat consumption and stone tool use may have predated stone tool manufacture. These cut marks are the same age as the fossils of Australopithecus afarensis found in nearby deposits. The implication of this evidence was that Homo had not been the only meat-eater among human ancestors; Australopithecus had also been capable of butchering and eating animals, if only on rare occasions. Two stronger lines of evidence for cut marked bones and stone tool use in the record of human evolution come from the sites of Bouri and Gona (figure 13.1, de Heinzelin et al. 1999; Dominguez-Rodrigo et al. 2005), two paleoanthropological excavation sites in the Awash River valley in the Afar region of Ethiopia. Isotopic studies of the diets of hominins living between 4 and 3 Ma show that diets broadened to include more foods from grassy environments compared to earlier hominins, though it cannot be determined if they were plants, insects, or animal tissues (Levin et al. 2015; Cerling et al. 2013; Sponheimer et al. 2013). Several separate independent lines of evidence have been converging over the past decade towards the conclusion that hominins likely started consuming meat earlier than previously thought, potentially 1 Ma before the appearance of our genus.

7If australopithecines were knapping simple stone tools and butchering animal carcasses, what behavioral advances might have been associated with the origins of our genus, Homo? It appears to have been more a matter of degree, rather than presence or absence. The earliest evidence of the intensification and expansion of meat-eating comes from Kanjera, southwestern Kenya (figure 13.1), dating to 2 Ma (Ferraro et al. 2013). The archaeological evidence includes dozens of bones bearing cut and percussion marks. An early hominin, most likely Homo habilis or Homo erectus, processed dozens of animal carcasses during repeated visits to the same location over decades, centuries, or millennia. Yet the stone tools found alongside butchered bones at Kanjera and dozens of other sites in Africa during this period, called the Oldowan, do not seem suitable for hunting large animals (>40 kilograms); these tools were most likely used for cutting and pounding, and did not include spear tips. If early humans weren’t hunting the large animals they were eating, how did they get access to them? Hominins might have used tools for hunting small prey from a different kind of material than stone and possibly from perishable or organic tools, not or rarely preserved in the archaeological record. Such organic tools are the kinds most used by chimpanzees and other non-human primates. We know little of the use of organic materials by early hominins because of preservation biases in favor of durable stones. Hayden (2008) argued that Oldowan hominins probably had a rich non-stone technology, including digging sticks, spears and throwing sticks, based upon his observations of the material culture of Australian Aboriginal foragers. Hominins might have scavenged carcasses killed by the lions, hyenas, leopards, cheetahs, wild dogs, and saber-toothed cats with which they were sharing the African landscape. They could have passively waited until the carnivores had finished their meal and left the area to safely move in and take what was left. Conversely, they could have confronted carnivores while eating and chased them off their prey by throwing stones or sticks, rushing the predators in a big group, waving arms and making noise, etc. This presumably would have yielded substantial portions of meat, especially from larger prey animals, such as hippos or elephants, the active hunting of which would have been quite dangerous to a small-bodied hominin.

8If hominins were pursuing a scavenging strategy, relying heavily on the behavior of the surrounding carnivore guild for access to carcasses, then it would be predicted that hominins would need to move regularly though the large territories that carnivores maintain to sustain themselves (cf. Foley 2002). Hominins would likely have selected key locations throughout that territory to which to remove carcasses to avoid further confrontation with carnivores, and where they could make, store, and use stone tools to process the animal tissues. Over time, interacting with more and diverse species of carnivores, and needing to increase the number of cache sites for tools and carcasses, would naturally lead to home ranges that were many times larger than those of the African great apes. Hominin demography is equally important to consider during this transition. Presumably, group sizes would have increased concomitant with range size, but reconstructing group sizes in the prehistoric past from archaeological and fossil material is notoriously difficult (Goren-Inbar & Belfer-Cohen 2020).

Mobility

9Reconstructing how far individual hominins might have moved around in the past, or how far or efficiently certain species were adapted to move, is rather difficult. One method is to measure the ratio of two isotopes of strontium, ⁸⁷Sr and ⁸⁶Sr, in fossil tooth enamel. The ⁸⁷Sr/⁸⁶Sr ratios of animals’ teeth directly reflect the ratios of the foods they ingested during development while young, which in turn are primarily a reflection of ratios in the local geology that vary across most landscapes. A tooth’s enamel does not remodel once erupted, and therefore retains this signal of the individual’s juvenile environment throughout its life. Bones, in contrast to teeth, continue to exchange calcium and strontium with the environment during the life of an individual. Bone ⁸⁷Sr/⁸⁶Sr changes if there is a move of residence to a region with contrasting geology. If the ⁸⁷Sr/⁸⁶Sr in a hominin tooth matches the signal in the local geology, then it likely did not travel very far during its life. If they are different, that individual likely travelled into the area where it was found from somewhere else during its adult lifetime (Hodell et al. 2004). Copeland et al. (2011) investigated landscape use in Australopithecus africanus and Paranthropus robustus from the Sterkfontein and Swartkrans cave sites in South Africa (figure 13.1) using strontium isotope analysis. They show that a higher proportion of small hominins than large hominins had non-local strontium isotope compositions. Given the relatively high levels of sexual dimorphism in early hominins, the smaller teeth are likely to represent female individuals, thus indicating that females were more likely than males to disperse from their natal groups. This is similar to the dispersal pattern found in chimpanzees, bonobos, and many human groups, but dissimilar from that of most gorillas and other primates. Research is ongoing to determine if and how strontium isotope variation in several sedimentary basins of East Africa can be used to reconstruct individual mobility, but for now results are inconclusive.

10Another way to infer hominin mobility patterns from the past is via the sourcing of raw materials that end up in archaeological sites. Studies of raw material selectivity and the distributions of these raw materials on the landscape play an important part in the understanding of technological decision-making processes by hominins and their organization in the landscape. Using petrological or geochemical methods and determining the location of the potential sources of raw materials used at a site, one can identify with varying degrees of precision where that stone material was brought from, and thereby calculate a minimum diameter of territory size and therefore mobility (e.g. Braun et al. 2008; Harmand 2009a, b; Goldman-Neuman & Hovers 2012). For example, in all of the West Turkana archaeological sites, from Lomekwian times to the early Acheulean, the sourcing for raw materials was local- gathered in nearby stream beds a few hundred meters to a few kilometers away, and selected according to the size of the cobbles and the petrographic nature of the rocks (mainly basalt, phonolite and trachy-phonolite; Harmand et al. 2015, Harmand 2009a, b). At the 2 Ma site of Kanjera, mentioned above, the hominin knappers used stone materials located up to 10-13 km from sources (Braun et al. 2008), well outside the range of carrying stone seen in modern apes, which is usually much less than one kilometer. Lithic provisioning distances increase from then, as is documented in the more expanded distribution of sites away from raw material sources in the Lower Pleistocene (Harris & Capaldo 1993; Rogers et al. 1994; and see overview in Féblot-Augustins 1997).

11Despite the advent of making stone tools and butchering carcasses before 2.0 Ma, fossil representatives of the genus Homo from this time do not display the increases in brain size, changes in cranial and facial features, and reorganization of body and limb proportions for energy-efficient movement that would be expected to accompany complex tool making, increased meat eating, and larger territories (Antón et al. 2014). Most of these developments start showing up in the fossil record between 1.9 and 1.5 Ma. This period also saw: the first hominin expansion outside of Africa, recorded at Dmanisi, Republic of Georgia, at c. 1.8 Ma (Gabunia et al. 2001); the origin of the Acheulean stone tool culture around 1.7-1.6 Ma at Kokiselei 4 in West Turkana, Kenya (figure 13.1, Lepre et al. 2011), Konso (figure 13.1, Beyene et al. 2013) and Gona (figure 13.1, Semaw et al. 2009) in Ethiopia; evidence of a larger, more linear body plan in fossils such as the famous Nariokotome Boy H. erectus skeleton from West Turkana, Kenya at 1.6 Ma (and the possible earliest evidence for the use of fire at 1.5 Ma at FxJj 20 Main in Koobi Fora, Kenya (figure 13.1, Antón et al. 2014). These developments are not ordered chronologically as one might expect: hominins living outside Africa before 700 ka were still making the Oldowan- not Acheulean handaxes - and not using fire, neither of which appear in the record there until afterwards (Roebroeks & Villa 2011). Early Acheulean industries do not contain stone implements considered as suitable spear or projectile technology, raising questions about whether hominins were able to truly hunt large game. Increases in brain size and changes in body plan may have been more associated with the advent of cooking, especially meat. Early hominin dispersals may be better envisioned as driven more strongly by biological and ecological factors than by technological breakthroughs.

Figure 13.1

12Whenever large game hunting did fully develop, such a hunting and foraging lifestyle generally imposes an increase degree of nomadism on its practitioners. This may range from daily movements, as among some Kalahari San, to monthly, quarterly, or semiannual shifts of habitat. In areas where resources are abundant or where there are storage facilities, populations may be more or less stable. Nomadic hunter-foragers are usually organized into small, isolated bands that move through a delimited territory where they know the water holes, the types and locations of edible or useful plants, and the habits of game species. These levels of geospatial and social organization were predominant for hominins until just before to throughout the Holocene, or the last 15 thousand years. This is when specific technological advances (complex projectiles, netting, storage containers, the advent of agriculture, etc.) allowed modern human groups to extract enough resources from their local environments such that they didn’t need to move throughout or across territories as before (Bar-Yosef 2001).

Technology

13Chimpanzees use tools for foraging activities and to accomplish tasks associated with cleaning, investigating out-of-reach objects, drinking water, and less frequently to threaten conspecifics (flailing branches, throwing rocks as missiles). The use of tools to obtain food has been documented across all chimpanzee populations, starting in the 1960s with the pioneering work of English primatologist Jane Goodall in Gombe Park in Tanzania (see for example Goodall 1971). The two best known examples of tool-using among chimpanzees are nut-cracking and ants or termites “fishing”. For the first activity, they put the nut on a flat stone or a piece of log, and use a stone to smash the hard shell and free the seed. In terms of technology, these behaviors only involve tool using, i.e. they use natural raw materials (stones, pieces of wood) as tools (see below, and Harmand 2018). However, one can say they have invented the principle of the anvil/hammer binomial and there are sufficient occurrences of such technical behavior to know that chimpanzees are able to adapt the weight of the hammer to the hardness of the shell, that they reuse their tools and can memorize the location of the most adequate ones (see Carvalho et al. 2008 for demonstration). For ant fishing, they select a thin branch, from which they remove the leaves and/or make a brush with their teeth; then they introduce the stalk within the ant hill, and remove it once the ants have hung on and are ready to be eaten. In both cases, they are capable of modifying a soft material to render it more efficient. It has recently been claimed that chimpanzees select and leave behind recognizable assemblages of stone hammers for nut-cracking that lead to tool transport (figure 13.2, Carvalho et al. 2008). Thus, Bossou chimpanzees in Guinea transport hammers and anvils for nut cracking, and transport is related not only to natural-resource availability, but also to tool preferences or tool possession (Matsuzawa 1999). Spatial analysis of chimpanzees’ nut cracking activity suggests differential resource-exploitation strategies, echoing the optimization of time and management of energy investment that constrains the social lives of chimpanzees (Boesch & Boesch 1982; Carvalho et al. 2008). These strategies are 1) the optimization of time and energy investment by exploiting resources closest to the food source; 2) the transport of nuts to a different site or transport of the raw materials for tools to the food; 3) the transport of tools and food to a more distant area where resource processing and consumption activities will be carried out (figure 13.2). The reason for the latter could be a social strategy, related to sharing of space and resources when various individuals occupy the same area. It has been suggested that these different resource-exploitation strategies in wild chimpanzees show affinities to Oldowan strategies because both are flexible, dynamic, opportunistic, and low-energy strategies to solve problems (Carvalho et al. 2008). In that sense, chimpanzees’ exploitation strategy of their territory may “act as a proxy in our evolutionary scenarios” (McGrew 2004).

Figure 13.2

14Published in 2015 (Harmand et al. 2015; Lewis & Harmand 2016), the discovery of the oldest known hominin stone tool technology at the site of Lomekwi 3 (LOM3, figure 13.1) pushed back its origin by 700 ka. The 140 surface and excavated artefacts recovered at LOM3 do not conform to any of the observed patterns from Early Oldowan assemblages and challenged what we thought we knew about the development of early technologies. The excavation recovered cores and flakes (figure 13.3) that are significantly larger than those from the Early Oldowan along with heavy anvils, percussors, worked and split cobbles, all made predominantly from locally selected lava rocks. Two simple modes of knapping rarely identified in the Oldowan have been used by the Lomekwian knappers to produce flakes. They are the passive hammer technique, in which the core is held in both hands and struck downwards onto an anvil (both arms performing the same motion), and the bipolar technique, in which one hand stabilizes the core on an anvil and the other strikes the hammer down vertically onto the core. Both bipolar and passive techniques do not require the human-like manipulative capabilities necessary when using the direct freehand percussion technique prevalent during the Oldowan and which doesn’t involve the use of an anvil. The arm and hand motions involved in the percussion techniques identified in LOM3 are arguably more similar to those involved in the hammer-on-anvil technique chimpanzees and other primates use when engaged in nut-cracking. The LOM3 anvils and percussors are strikingly larger and heavier than those chosen by wild chimpanzees when cracking nuts. Furthermore, the technical skills inferred from the technological study of the artefacts at LOM3 largely surpass the stone-using skills seen among living primates. Even though the Lomekwian artefacts do not indicate a mastery of stone knapping like that shown during Oldowan, they provide clear evidence of sensorimotor performance and an effective control of elementary percussive gestures beyond what our nearest living relatives have been seen doing in the wild —where none have been seen flaking hard rocks so far— or during experiments in captivity.

15Lomekwian knappers were able to repeatedly detach series of adjacent and superposed invasive flakes and continue knapping by rotating the cores. Furthermore, the percussive marks visible on numerous artefacts at LOM3 suggest that the knappers were able to combine core reduction and battering activities and that they may have used artefacts for multiple purposes: as anvils, cores to produce flakes, and/or as pounding tools. The use of the same objects for several distinctive tasks reflects a degree of technological diversity both much older than previously acknowledged and different from the generally uni-purpose stone tools used by extant primates.

Figure 13.3

16The technology seen at LOM3 at 3.3 Ma is already far more complex compared to the stone technology used by other primates, and may imply less prefrontal and motor cortex asymmetry in the brain of the knappers compared with modern humans, but more than that of living great apes. The available fossil evidence for both brain and body size of hominins living in East Africa at 3.3 Ma suggests that the degree of encephalization had only modestly surpassed what is observed in the extant great apes (Kimbel & Delezene 2009; Leakey et al. 2001). Recent analyses have demonstrated different scaling coefficients in the left versus right prefrontal hemisphere of the brain of monkeys, apes and living humans. Those results suggest that the primary factor underlying the evolution of primate brain architecture is left hemispheric prefrontal hyperscaling, and humans are the extreme of a left prefrontal ape specialization in relative white to grey matter volume (Smaers et al. 2011). Language, handedness, tool use, planning and coordinating actions towards higher-level goals and social information processing have all been associated with prefrontal, motor and parietal cortex asymmetries (e.g. Johnson-Frey 2004; Bril et al. 2012; Stout & Chaminade 2012). The passive hammer knapping technique, in which both arms are performing the same motion, arguably requires less lateralization in upper limb motor control than does direct freehand knapping. The bipolar knapping technique is arguably more similar to those involved in the hammer-on-anvil technique chimpanzees and other primates use when engaged in nut cracking (Bril et al. 2012) than to the direct freehand percussion evident in Oldowan assemblages. The use of these two techniques may imply less prefrontal and motor cortex asymmetry in the brain of the LOM3 knappers compared with modern humans, but more than that of living great apes (Bril et al. 2015). Hence, the origins of stone knapping may have been associated with increased development of prefrontal, motor, and parietal cortex asymmetries, and consequent cognitive and physical capabilities, but not with the drastic increases in absolute and relative brain size seen after 2 Ma in the genus Homo (Harmand & Lewis 2018).

17The LOM3 site corresponds to different facies of the same sedimentary environment related to the distal fan deposit in which the artefacts were abandoned by the hominins. The accumulation of hundreds of “megacores” and percussive tools selected from a nearby source of raw materials may well reflect the recurrent occupation by a small group of hominins of a preferred location to which hominins repeatedly transported carcass parts for processing and reusing of remaining usable stones. LOM3 could fit in a model of landscape use in which favorite places were used for a delayed consumption and transport of food and where food-sharing and “social” activities could have taken place. The formation of a site would then depend on the vegetation structure, the distribution of fixed resources, the density and feeding adaptations of carnivores and the particular socioeconomic structuring of the hominin group itself. In times of strong predator pressure, such a territorial organization with fixed, defendable resources (trees, water, plant foods, or sleeping sites) could have generated a cooperative protection against predation and minimize competitive interactions with carnivores over faunal resources. The discard of lithics at “favored places” during the Lomekwian still needs to be confirmed with the finding of additional sites similar to LOM3. Such a model of landscape use (“the favored place hypothesis”; Schick & Toth 1993) could have led to the passive accumulation of raw materials frequently visited and where hominins would consume food, rest, carry out social activities and sleep. In that sense, this model for hominins 3.3 Ma ago shows affinities with the resource exploitation strategies described above for wild chimpanzees, without the food sharing component.

18The hominins who, from 2.6 Ma onwards, produced the Early Oldowan had become used to flaking smaller cobbles by free hand direct percussion (Semaw et al. 1997). This technique requires better precision grip to handle and manipulate the core with one hand and the hammer with the other one and good neuromotor control not to miss the right place to hit the striking platform of the block being knapped. These new technological requirements are perfectly illustrated at the 2.3 Ma site of Lokalalei 2C (LA2C, West Turkana, Kenya, figure 13.1). With this small site, the hominins’ ability to produce many flakes (up to 70 for only one core) was demonstrated (Delagnes & Roche 2005): after having chosen medium size cobbles of specific plano-convex morphology, they conducted a controlled débitage of flakes following constant technical rules and resulting in high productivity. Their manual dexterity was also shown, since there is no sign of misplaced strikes on the platform of the flakes for instance, or on the hammerstones themselves. It is the only example of such productivity, which couldn’t have been seen without the refits. The tool makers at LA2C (either early Homo or Paranthropus boisei, cf. supra) may have been particularly skillful. However, even if the previous techniques (bipolar and passive) described at LOM3 were not abandoned (Roche et al. 2018), they were used less than the free hand direct percussion technique.

19Moving forward in the archaeological record through the Oldowan and early Acheulean, Isaac (1978), building on Mary Leakey’s pioneering work (e.g. Leakey 1966) and based on his own excavations of early sites in East Africa, and ethnographic studies of living hunter forager groups, developed hypotheses about the origins and evolution of hominin social structure, central place foraging behaviors, and food sharing. In Isaac’s view, a sexual division of subsistence activities, with females focusing on gathered plant and small animal foods and males focusing on larger animal tissues (whether hunted or scavenged), and the sharing of those resources, are what led to the returning each evening to a central place. The accumulation of the material remains of these activities over time would produce the concentrations of artifacts and animal bones that we see in the archaeological record today. Isaac proposed three different types of sites: Type A sites only contain scatters of knapped stone tools; Type B sites contain stone tools and the remains of a single animal carcass; and Type C sites contain stone tools and multiple animal carcasses. Isaac interpreted Type A sites as possible places where hominins were procuring stone raw material, making stone tools, or some other activity not involving animal remains; Type B sites were interpreted as possible kill or butchery sites, from which animal pieces were transported to Type C sites, or Home Bases, where hominins slept and shared food. These models spurred decades of research and debate on early hominin ranging and subsistence behavior, initiating a critical step in Oldowan studies toward proving rather than assuming a behavioral relationship between fauna and artifacts at Oldowan sites and for a more accurate modeling of Oldowan site dynamics (e.g. Potts 1984, 1994; Schick & Toth 1993).

Conclusion

20Over the past 6 Ma the ways in which our hominin ancestors went about their daily activities has drastically evolved. Hominin diets changed from consisting largely of fruits, leaves, and other plant parts, with insects and meat when possible- similar to the diet of modern great apes- to one dominated by cooked domesticated grains and large quantities of meat today. Our social behavior, stone-tool-making developments, and landscape use evolved- not necessarily in lock step- towards the mobile, cooperative, symbolic, and projectile-wielding hunter-foragers from which agriculture and complex civilization later sprang. The earliest evidence of each of these developments is found in Africa, even after hominins were also living in Eurasia. These transitions were longer and more gradual and multifaceted than previously thought. The exact causes of, and specific adaptive processes leading to, these behavioral changes are still under investigation.

21In terms of mobility patterns, in our hominin ancestors these evolved from a probable chimpanzee-like loosely structured fission-fusion pattern within circumscribed territories, through stages of increasing territory size and movement organization as foraging (including both gathering and hunting) behavioral complexity increased throughout the Plio-Pleistocene. We can track this evolution via: the fossil and artifactual evidence for increases in hominin dietary breadth (the inclusion of a more diverse range of plant and animal foods); strontium and other isotopic evidence of individuals moving across more disparate landscapes; and lithic evidence for the selection of stone raw material resources in increasingly complex and specific ways and their movement across longer distances.

22It is for now difficult, if not impossible, to propose a solid model for landscape occupation and socio-economic organization for Pliocene hominins. LOM3 is the only known archaeological occurrence dated to >3.0 Ma and there is a critical need to expand the sample of well dated Lomekwian and Oldowan sites preserving artefacts and fauna to better understand landscape use and mobility patterns during this time. After 2.6 Ma, transport distances for lithic raw materials were sometimes on the order of several kilometers and less frequently up to 10 km, but this could represent several cumulative movements over separate transport rounds. Fauna was probably obtained through a combination of hunting small prey and scavenging for both flesh and within-bone nutrients from larger animals; detecting the transition to hunting large prey remains contentious. Clearly, more survey and excavation of fossiliferous and artifact-bearing deposits in Africa would do much to address these deficiencies in our knowledge of the evolution of nomadism in our early ancestors. The continent’s vast size and often challenging landscapes have delayed exploration and research in its prehistory compared to other parts of the world. Increasing interest, funding, and infrastructural development within Africa is leading to a quickening pace of discovery in archaeology and paleontology, with dramatic impacts on our understanding of human prehistory.

Acknowledgements

23We are grateful to the office of the President of Kenya, the Ministry of Education, Science and Technology, the National Council for Science and Technology (NCST/RCD/12B/012/25) and the National Museums of Kenya for permission to conduct research in West Turkana. Funding was provided by the French Ministry of Foreign Affairs, the French National Research Agency (ANR-12-CULT-0006), and the private support of INTM Indigo Group France. We also thank the Turkana Basin Institute for logistical assistance in the field and in the lab. We gratefully acknowledge the Mission Préhistorique au Kenya/West Turkana Archaeological Project team which, since 1996, has been searching for evidence of human origins on the western shores of Lake Turkana in Kenya. Finally, we thank Aline Averbouh, Nejma Goutas and Sophie Méry for inviting us to participate to this festschrift in honor of our respected colleague archaeologist Claudine Karlin. On a more personal note, the elder of the three authors of this chapter is owing to Claudine Karlin her vocation for field archaeology. This happened in Pincevent towards the end of the 60’s, quite a while before she embarks herself for an African carreer, searching for technical evidence of our early ancestors…