The high northern latitudes have been inhabited by humans since the end of the last Ice Age, approximately 12,000 years ago. Conditions that far north, where the Earth’s circumference is about half that at the Equator, are extreme. On the 60th parallel north, for example, the sun is visible for just under 19 hours on the summer solstice, but only for about 6 hours during the winter solstice. Although temperatures may soar above 30°C in exceptional years, the average daily mean is closer to a chilly 6°C (depending on your exact location along the parallel), with record lows in the -30’s–and, of course, you can expect at least a meter of snow in the winter. In other words, this is not an easy place to live even now, with our modern conveniences; it’s hard to imagine what it must have been like for the region’s earliest settlers, who eked out a living by hunting, fishing, and gathering.
At some point, these intrepid northern colonizers began farming, making use of techniques originally developed in the Fertile Crescent 11,000 years ago. Above the 60th parallel, however, farmers were more vulnerable to climatic stochasticity; archaeologists have uncovered settlements that appear to have been abandoned after the environment became too hostile. In northwestern Europe, exposure to the Gulf Stream allowed Early Neolithic people to initiate farming economies that last to this day. Elsewhere on the continent, however–in Finland, for example–the low average temperature, persistent snow cover, and not-infrequent appearance of summertime snow and ice combined to diminish vegetation periods and make farming a more challenging endeavor.
Until recently, it has been difficult to pinpoint exactly when early Finnish settlers achieved domestication, since there is very little evidence from prehistoric times; the region’s acidic soils took care of the majority of useful artifacts long ago. However, those same conditions are favorable for the preservation of biomolecules harvested from the few remaining pieces of ancient ceramic cooking vessels. Analysis of these fragments–via techniques such as high-temperature gas chromatography, mass spectrometry, and ion monitoring–allows researchers to determine the composition and structure of the molecules, and to look for pre-identified biomarkers. Cumulatively, these characteristics can be used to determine whether the vessels are saturated with aquatic fats (indicating storage of fish and other seafood), terrestrial fats (from species hunted on land), and dairy fats (from domesticated livestock).
Out of a collection of 70 prehistoric fragments unearthed at sites across southern Finland, an interdisciplinary team of researchers was recently able to isolate 19 that were suitable for just such an analysis. The pottery was representative of a range of prehistoric eras, from the Comb Ware period (ca. 6000-4300 years ago) through the Corded Ware (ca. 4800-4100 years ago) and Kiukainen Ware (ca. 4400-3500 years ago) periods, all the way to the Early Iron Age (ca. 2500-1600 years ago).
The earliest molecular samples (dated to approximately 3900-3300 BC) were predominantly marine in origin, indicating a heavy reliance on fishing; the ceramic fragments themselves may have come from vessels used for cooking, storage, or even transport. On the other hand, residues from pottery shards dating to approximately 2500 BC were from terrestrial ruminants. Though they could have come from either wild or domesticated stock, there was evidence of milk fat–indicating that the settlers had begun farming and were now heavily dependent on land animals despite their relative proximity to the coastline. Interestingly, the final Neolithic samples, dating to the Kiukainen Ware period, contained a mixture of terrestrial and aquatic compounds, suggesting that local climate changes may have required a diversification in subsistence techniques. By the Early Iron Age (approximately 1200-500 BC), however, agricultural intensification seems to have allowed population growth and a renewed focus on farming; pottery fragments from this time yielded only dairy fats.
Although these patterns may initially seem relevant only to the small portion of researchers specializing in ancient Finnish history, they actually offer some interesting insights to the rest of us, too. For one thing, these archaeological results map nicely onto spatial patterns showing the prevalence of the lactase persistence (LP) genotype–which confers the ability to continue digesting dairy products well into adulthood. While this may be a fairly common characteristic throughout much of the developed West, it is either rare or lacking in parts of the world without a strong tradition of dairy farming. This correlation helps validate the molecular results, and also can be used to draw conclusions about gene flow in Europe. There is a SW-NE gradient of LP allele frequency in Finland, suggesting several separate waves of immigration over the past 6000 years. Further, low LP frequencies in some parts of the eastern Baltic indicate that this region may have acted as a “genetic refuge” for populations who continued to lead a hunter-fisher-forager lifestyle rather than pursuing farming. Pretty amazing that all of this ancient history can be inferred from gene patterns analyzed thousands of years after the fact.
Another interesting implication of the findings is related to what they reveal about how early humans dealt with their difficult and variable habitat. The analyses suggest that animal domestication occurred in southern Finland much earlier than previously thought (ca. 2500 BC), but that use of aquatic resources lasted much longer, post-domestication, than it did in other places settled by Neolithic peoples. In fact, Late Corded Ware Finns appear to have responded to their changing environment by vacillating between hunting/gathering, farming, and some mixture of the two as required. This sort of flexibility is probably one of the major reasons why early settlers were able to maintain populations in such marginal habitat.
The authors of the study write that, even today, “conventional” farming in this part of the world is not for the faint-hearted. A changing climate may prompt humans to push their boundaries ever northwards, but conditions above the 60th parallel will likely always be challenging. If we hope to utilize this “frontier zone” in order to increase food production and make use of the available land, we will probably have to follow our predecessors’ example and demonstrate a willingness to adapt.
Cramp, Lucy J.E. et al. 2014. Neolithic dairy farming at the extreme of agriculture in northern Europe. Proceedings of the Royal Society B 281:20140819.