Hunter-gatherers and earliest farmers in western Europe

Our understanding of the appearance of farming in western Europe has undergone a major change in recent years. For decades, the prevailing view was that indigenous Mesolithic foragers (hunter-gatherers) adopted some agricultural practices to supplement their hunting and gathering (1). They did this only gradually, continuing through the earlier Neolithic, so that the full agricultural economy did not take shape until later in the Neolithic (2, 3). This view was based partly on claimed evidence for some agricultural practices among the later hunter-gatherers, partly on an (often unstated) assumption that hunter-gatherer societies have an innate tendency toward greater social and economic complexity through time. However, recent dating evidence has called into question the claims for Mesolithic agriculture. It now appears that the earliest farmers everywhere in Europe were immigrants from Asia Minor, who brought with them a fully functioning agricultural economy. The paper in PNAS by Simões et al. (4) provides firm evidence of a temporal overlap between the last foragers and the first farmers in Atlantic France, showing that they lived as separate communities. The foragers buried at Hoedic and Téviec showed no signs of adopting agriculture or inter-marrying with farmers. They belonged to the Western Hunter-Gatherer (WHG) genetic group, quite distinct from the aDNA of the earliest farmers. Simões et al. (4) offer a major new insight into how the foragers’ society was organized. This casts doubt on the assumption that the foragers were heading toward adopting agriculture.

The top part of the accompanying figure shows the various models for the transition to agriculture (Fig. 1). The dates are based on the situation in southern Scandinavia. The evidence for an overlap between foragers and farmers provided by Simões et al. (4) show that there was a similar situation in Atlantic France, albeit nearly a millennium earlier. In addition, despite this overlap and the presence of farmers nearby, there is no indication that the foragers at Hoedic or Téviec were doing anything other than fishing and foraging. Recent dating evidence from various parts of Europe has shown that this was a common pattern: after decades of searching for Late Mesolithic agriculture, we must admit that the actual evidence for it is minimal. For example, a few domestic cattle bones at Mesolithic Smakkerup Huse (Denmark) turn out, when directly radiocarbon dated, to be later intrusions of Neolithic date (5). A few domestic pigs were claimed at Mesolithic Rosenhof (northern Germany) because they carried a domestic mitochondrial DNA lineage derived ultimately from Asia Minor, but the animals were morphologically wild boar; they probably descended from female domestic pigs that had escaped from farming villages further south, that had joined the local wild boar population and had then produced piglets sired by wild boar males (6). Pollen grains claimed to derive from cultivated cereals such as barley have been found in various deposits dated to Mesolithic time, but these are being called into question because of the difficulty of distinguishing them from pollen of native wild grass species (7). Coastal sites in the western Mediterranean were long claimed to show a gradual transition, with traces of farming in the Mesolithic. However, they were excavated long ago and not to modern standards—this evidence is not replicated by recent work (8, 9). Isotopes in human bone from coastal settlements show that the forager-fishers relied heavily on marine resources (fish, seals, shellfish). Even the earliest farmers in nearby settlements ate a diet dominated by terrestrial resources (presumably agriculture) (10, 11).

Fig. 1.

(A, B and C) Alternative models for the appearance of agriculture in western Europe. Scatter chart: Chart showing correlation between population density, degree of sedentism, and social structure. Each data point is one modern hunter-gatherer society. Based on Keeley (12, 13).

The paper in PNAS by Simões et al. provides firm evidence of a temporal overlap between the last foragers and the first farmers in Atlantic France, showing that they lived as separate communities.

Chronological overlaps between late foragers and early farmers are starting to emerge in various parts of Europe. In Denmark, the complete genome of a female was recovered from saliva preserved within a lump of birch tar “chewing gum.” The woman was genetically a pure WHG with no farming admixture—dating from some 300 y after the arrival of farming nearby (14). Various sites in Denmark with mainly hunter-fisher economies continued in parallel with the earliest farmers (15), and dietary isotopes from human bone similarly reveal the presence of individuals with marine diets overlapping in time with the earliest farmers (16). In Britain, there are possible hints of something similar (17). The western Mediterranean and Portugal saw maritime “leapfrog” colonisation along the coasts, the farmers bypassing hunter-gatherer enclaves, and moving on to new areas (18, 19).

In these areas, the paper by Simões et al. (4) is in line with the most recent evidence elsewhere. Where this paper goes beyond recent work and really breaks significant new ground is in its elucidation of the forager settlement and mate exchange patterns. aDNA reveals that the inhabitants of Hoedic and Téviec fall, as expected, into the WHG genetic group; but they form a somewhat separate subgroup within the WHGs. Thus their mating networks were rather introverted, involving fewer matings with WHGs elsewhere. Furthermore, dietary isotopes reveal that diets at Hoedic and Téviec differed from each other, implying that the two sites comprised distinct communities even though they lie close together. These indications of stable and long-lasting forager communities are at odds with the conventional view that prehistoric European foragers were usually nomadic and lived in small, fluid population units. The evidence is however more in accord with the results of anthropological cross-cultural surveys of modern foragers. The chart in the lower part of the figure presents such an analysis drawn from the work of Keeley (12, 13). Each dot on the chart represents one modern forager society. The horizontal axis is Keeley’s measure of relative population density, increasing to the right. The vertical axis presents settlement stability, measured by the number of months per year the group spends in its longest-occupied settlement. There is a good relationship between the two: the smaller more nomadic groups tend to cluster toward the lower left, the larger more stable ones toward the upper right. Also indicated is Keeley’s measure of the degree of social stratification. Small nomadic groups characteristically display little or no social stratification. As groups become larger and more stable, some individuals may acquire some wealth and increase their status. In the most complex form, these societies can form descent groups, with wealth and status passed down within families or lineages to subsequent generations. Descent groups usually own and store a lot of foodstuffs and also own particular productive resource points. This maintains their high status (12, 13). Descent groups often do not have open mating systems but have prescribed rules about which descent groups may intermarry. One way to display land ownership is to establish a cemetery containing the group’s ancestors, as a means of legitimising long-term territorial claims (20, 21). Foragers living in descent groups most often live on sea coasts because of the much greater availability of food resources in some coastal environments.

The paper by Simões et al. (4) presents a picture of the coastal groups establishing cemeteries at Hoedic and Téviec. The dietary isotopes and aDNA taken together show that the two sites were occupied by distinct groups, and while somewhat separated from other WHG groups they, and no doubt other coastal groups nearby, formed an exclusive mating network. Population density on the coast would have been higher than among inland groups, and the cemeteries suggest territorial ownership characteristic of societies organized into descent groups. This evidence fits well with the conclusions of Keeley’s cross-cultural survey of modern foragers: that forager social forms adapt to the environments in which they live. It does not fit with the assumption that forager societies tend toward socio-economic complexity and agriculture. Simões et al. (4) thus present the clearest demonstration yet available for the internal workings of a forager society in coastal Europe, a society that was evidently able to maintain its separate existence for several centuries in the face of encroaching farmers.