The first chemists of Europe: Neanderthal production of birch bark tar

For the last few years, I have been working with colleagues Peter Groom and Grethe Moéll Pedersen on the procurement of tar without using pottery. If you, like me, work with Stone age cultures, some things are more spectacular than others, and in this post I am going to introduce you to one of those – pieces of birch bark tar that may be up to 250 000 years old.

250 000 years ago, someone made and used birch bark tar in Central and Southern Europe, well before modern humans entered European history. The people who hafted their flint implements with tar, were Neanderthals: sturdy humans with stocky limbs and big brains well adapted to the cold climate of Europe. Neanderthals are technically called Homo neanderthalensis, first recovered in Neanderthal, Germany. They did, however, live as far east as Georgia and as far west as the Iberian peninsula.

Neanderthals had a complex stone technology centering around Levallois flakes: large-ish flint flakes with two sharp edges, often made into spear points or used as base for other tools.To make a Levallois flake demands a level of skill in flint knapping which is currently beyond my level. You first have to elaborately shape a piece of flint to resemble a tortoise shell, before you strike off the Levallois flake with a well-aimed blow. Around 250 000 years ago, someone made one and hafted it with birch bark tar to form an unknown implement, maybe a spear. This is the earliest find of birch bark tar that has ever been made, found at Campitello quarry, Italy. In Germany, a similar find has been made at Königsaue, but dated to c. 50 000 years ago.The site Inden-Altdorf in Germany also yielded 81 artefacts with tar specks all over, from 120 000 years ago; a number that indicates an ability to produce tar repeatedly and when needed.

But what is the big deal with this tar? Although it may not seem particularly impressive today, there are two reasons for why Neanderthal tar making is special: The only other artefacts we have recovered after this enormous amount of time are made of stone, and tar provides an interesting variation to the discussion. But more importantly, to make tar is actually a complex process that demands a carefully controlled temperature between c. 250-400°C, airtight environments, and a good plan. The fact that Neanderthals were making tar shows a skillful mastery of fire, an understanding of the concept of airtight (and therefore the concept of air), and an ability to plan and monitor a demanding process. This all credits Neanderthals with quite the intelligence!

The author monitoring a tar experiment. Note the necessary provisions.

The author monitoring a tar experiment. Note the necessary provisions.

Many researchers have tried, and most have failed, to make birch bark tar the way Neanderthals did. To achieve tar, you must force birch bark to undergo slow pyrolysis, where bark changes from mass to liquid (tar), gas (volatile, smelly fumes) and waste matter (char). From 6-7000 years ago onwards, the airtight conditions could easily be created by pottery. But before this, we have as of yet found no evidence for how the tar was made. Remains from a bonfire at Abric Romani in Spain, dated up to c. 70 000 years ago, shows evidence of a hydrocarbon spill, but that is all. Many have been puzzled by this mystery of production.

Peter, Grethe and I did 16 experiments with various pit structures in 2009, scratching our heads when structure after structure failed us. Peter and I went on to do a set of experiments with standing structures in 2013. And finally, we made it! We were beyond excited to see tar trickle out of the structures (even though it trickled down a precious piece of equipment..).

The resulting tar after a successful experiment. While not plentiful, it is most definitely viscous.

The resulting tar after a successful experiment. While not plentiful, it is most definitely viscous.

Basically, we had made tar in small heaps of sand, and all that remained was a spill of hydrocarbons in bonfire remains. But it did take us 5 years to get there! Boy, are we impressed with Neanderthals: We barely made it to their everyday level of thought, and I have, for sure, learnt to never call them primitive again.

Tine Schenck is an experimental archaeologist with a special interest in Boreal, seasonal exploitation of resources, and one of the founders of ArchaeologistsEngage. You can read more about the first experiments here.

Tracking hunter-gatherers in Scotland, using experimental archaeology. 

I am an experimental archaeologist, as such I use primitive technologies and ancient skills to understand how our ancestors used to live. Some of my projects have included; stone bead making in Romania, tree bast experiments in Denmark, and Neanderthal birch bark tar production. In short, a range of exciting and fascinating projects. A major recent project for me has been to work on the west coast of Scotland trying to figure out how Mesolithic (11,500–6000 cal BP) hunter-gatherers were living. Archaeologists have evidence for the importance of fish and shellfish to their diet, but virtually nothing is known as to how these were caught or collected.

My research attempted to change this by using a combination of bushcraft/primitive skills and experimental archaeology. Initially, my work focussed on the prehistoric environments of Scottish west coast Mesolithic coastal sites. I then looked at a range of archaeological/traditional fishing gear and food collection strategies to see what might have been used in the Mesolithic. These perspectives, together with the prehistoric environmental data, guided my construction and use of fishing gear, working with the resources and technologies available to Mesolithic hunter-gatherers. Using my bushcraft/primitive skills I was able to make fishing lines from a range of materials; this included nettles as well as the bark from various trees. I also made basketry fish and crab pots that varied in size and shape depending on the type of natural vegetation that I had used. It was vital that I only used natural un-managed vegetation typical of the habitats of the Scottish Mesolithic and that I only used tools of stone, bone or shell. Only by restricting myself to the resources and tool kit of a Mesolithic hunter-gatherer could I go through similar thought processes and experiences.

The author extracting bramble fibres using a mussel shell.

The author extracting bramble fibres using a mussel shell.

I ended up spending much of my time grubbing around on remote Scottish islands, testing whatever I could find to see if I could make fishing lines, hooks or basket traps. This involved travelling to some of the most beautiful parts of Scotland and sitting on the coast fishing with my hand made gear.

I made and tested a wide range of fishing gear and travelled thousands of miles over 4 years and started to feel like a Mesolithic hunter-gatherer; lugging fishing gear to remote sites, planning to maximise the use of tides, experiencing lousy weather. These experiences provided me with an insight into the world of the Mesolithic coastal hunter-gatherer, revealing the extent of organisation and knowledge that they must have had in order to fully utilise their environment. The planning needed to maximise returns, whether foraging, hunting or collecting resources. The knowledge required of the environment; the places to find the best materials for a particular task, knowledge of seasons and the seasonal movement of species, when and where to be at a particular place at a particular time. This is how experimental archaeology can fill in some of the gaps in the archaeologicalrecord, the human facets that are missing.

Walking in Torridon, Scotland.

Walking in Torridon, Scotland.

It is of course very difficult to understand the mind-set of someone who lived 8000 years ago, but by using those ancient hunter-gatherer skills together with experimental archaeology, we can move some way toward them.

Dr Peter Groom is Course Manager of the Environmental Archaeology and Primitive Skills Programme at Reaseheath College, Nantwich, Cheshire, and a Director of the Mesolithic Resource Group mesolithic.org.uk.