Living in the distant past
Rebecca Wragg Sykes’ interest in Neanderthals goes back to childhood. Now she pieces their lives together by studying the tools they used, writes Fiona Gruber.
It is 50,000 years ago and the climate fluctuates wildly in a sub-ice age environment. A chilly Britain is attached to the European landmass thanks to sea levels which are 50 to 60 metres lower than today. Ancient humans hunt across the low-lying tundra of Doggerland, the modern-day North Sea, but then Europe’s northwest peninsula. It is rich with mega fauna including deer and mammoth, cave bear and woolly rhino.
Using tools of stone, bone and wood, and wearing fitted furs and hides against the harsh climate, these heavy-set, large-brained hominins live in caves and shelters. They have fire to keep them warm and cook, they decorate objects with red and black pigment, and they bury their dead.
This is the world of the Neanderthal, an extinct branch of the human family that evolved in Europe during the Pleistocene, a geological period between 2.6 million and 11,700 years ago. The Neanderthals’ world during this huge span of time was sometimes one of icy tundra and glaciers, but at others, warm deciduous forests, with hippos and macaques.
The Neanderthals take their name from Germany’s Neander valley, where in 1856, a large skull cap with protruding brow ridges was first identified as that of a novel hominin, a term encompassing all modern humans, extinct human species and their immediate ancestors. Neanderthals first appeared about 400,000 years ago and became extinct according to current estimates (changing all the time), about 30,000 years ago.
Their population density would have been tiny, comparable to hunter-gatherers in the Arctic today, dotting the landscape at a density of about two people per 100 square kilometres, says archaeologist and Neanderthal specialist Becky Wragg Sykes. But by 40,000 years ago, they were not alone. To the east, a new group of hominins, lighter-boned and fleeter of foot, were slowly fanning out across a rich landscape teeming with animals, birds and fish.
They are Homo sapiens, the primate species to which we all belong, but their early history is murky. When did they first arrive in Europe? Did they displace the Neanderthals? Such questions are a hotly contested issue right now and Wragg Sykes is part of an effort to winkle out the truth.
“It looks like modern humans came out of Africa about 90,000 years ago but the question is, when did they move further north? No modern humans appear to have been in Europe before 50,000 years ago.”
The 32-year-old Englishwoman is a Marie Curie Intra-European fellow at the University of Bordeaux. Her current research aims to trace the territories of Neanderthals in the Massif Central region of France. And she does it by studying rocks, specifically the stone tools of the Mousterian – one of the Middle Palaeolithic Neanderthal “cultures” dated to between 120,000 and 40,000 years ago.
“Working with stone tools can be just as intimate as studying Neanderthal skeletons. These are the things they used every day, carried with them and repaired. You can even trace how they thought their way through working the stone, as well as see their mistakes”.
For Neanderthals, stone was the most important resource in their lives. And they went to great lengths to find just the right type and transport it. Wragg Sykes is curious about the minute details. “Are they moving it in lumps straight from the ground or are they moving it only as heavily worked tool kits?” she asks.
Studying tool transport provides a window into Neanderthal mobility: how they travelled through their landscapes and interacted with each other. Her research deploys new techniques including microscopic analysis to trace rocks in the journey from sources to living sites. Minute analysis of the region’s stone varieties, including the silica-rich silcrete, chemically similar to the flint they favoured, can give a picture of pathways through the environment, she explains.
Neanderthals were more diverse than they’re given credit for.
Wragg Sykes’ interest in Neanderthals goes back to childhood. Her imagination was fired when she read The Clan of the Cave Bear series by Jean M. Auel. Then on family holidays she encountered the famous cave paintings of southwestern France and her fascination for the Ice Age was rekindled. For her PhD from Sheffield University, she studied the 23 best-dated British sites, last explored in the late 1980s. A PhD spanning Britain’s late Neanderthal record sounds impressive but is only possible, she explains, because Britain was so sparsely populated.
“The kind of PhD I did couldn’t have been done in France, for that period. There are a million or more artefacts.” Wragg Sykes only had 1,000 to examine. “The British record is tiny.”
Britain, then a peninsula of Europe, was first inhabited by Neanderthals around 300,000 to 200,000 years ago. But as the climate became harsher, it was abandoned and then, following rapid sea-level rise, not re-occupied again until about 60,000 years ago. “It was a very ephemeral occupation,” says Wragg Sykes, but one with stone tool technologies adapted for flexibility: colonisation is a risky business.
Alongside questions of when modern humans reached Europe and where and when they overlapped with Neanderthals, the most heated debates in human evolution centre on technological innovation. Who was responsible for the so-called “transitional” stone tool cultures that seem to occur just before the appearance of Homo sapiens? This technology uses a different method of preparing the core to make stone blades and much more use of bone and ivory. But was this learnt from the incoming modern humans or developed independently by Neanderthals? The question divides academics.
“One camp says it’s too much of a coincidence that they changed only when modern humans arrived, but I don’t think that’s true,“ says Wragg Sykes. “Neanderthal cultures were more diverse than they’re given credit for. They were doing different things through time and across geographic regions,” she argues.
Neanderthals are known to have been living in Europe as well as western Asia and Siberia, and genetic analysis is painting a picture of interaction between them, Homo sapiens, and yet other hominins. Modern humans today have up to 4% Neanderthal DNA. Those of African descent are an exception, supporting the hypothesis that Neanderthals never travelled into the African continent, although they were in the Middle East. Neanderthal DNA is also present in the peoples of Oceania and Australasia, presumably picked up during the Aborigines’ journey to Australia out of Africa more than 60,000 years ago.
One of the burning questions is when interbreeding took place. Did these groups meet soon after modern humans came out of Africa, perhaps in the Middle East, or was it much later as modern humans pushed into northern and Western Europe to encounter the very last of the Neanderthals?
The world might have been very sparsely populated in the Middle Palaeolithic, but there was more than just one kind of ancient human around. Alongside Neanderthals lived the mysterious Denisovans, another hominin whose remains have thus far only been found in one cave in Siberia. DNA from this site tells us the Denisovans represented a sizable population, and bred with both Neanderthals and Homo sapiens, but we know virtually nothing about their culture or what they looked like.
Wragg Sykes may spend her days immersed in the minutiae of Neanderthal technology but the technological advances of her own species are a boon to her work. In particular, advances in the treatment of material prior to radiocarbon dating are resolving finer and finer dates. Artefacts once considered all the same age are now found to be thousands of years apart. And DNA can now be extracted from ever-older remains (a recent Nature paper reported DNA extracted from a 400,000 year old fossil hominin from a cave in Spain). “In the past five years they’ve been throwing data at us almost faster than we can process it,” she says. It’s also possible now to track the migration and diets of humans using natural tracers. The element strontium exists in different isotopic forms in different rocks. It is also taken up into the body replacing the calcium in the enamel of an infant’s developing teeth. So the strontium “signature” of a fossil tooth can identify the geology of the place where the person spent the first few years of their life. It may be quite a distance from where their bones end up being buried.
I want people to understand how dynamic human evolution research is.
Wragg Sykes is particularly interested in investigating how far Neanderthals travelled. Recent analysis of leg musculature suggests they were very mobile.
Ice cores and other evidence such as ancient pollen reveal that the Neanderthals’ environment fluctuated widely over time, including climates as warm as today. It also covered a huge variety of terrain. Wragg Sykes is eager to explore how this affected Neanderthals. “I want people to understand how dynamic human evolution research is. You have to have an open mind,” she says.
There will always be those who underplay the technological and cognitive powers of Neanderthals. “Some people have entrenched opinions and I wonder what level of proof is required – a Neanderthal dug up with a sign round its neck saying ‘I made this’?” says Wragg Sykes. But she thinks many recent finds point to Neanderthal ingenuity.
These include a collection of bone tools interpreted as lissoirs, or burnishers. The discovery in southwest France by a team led by Marie Soressi of Leipzig’s Max Planck Institute is some of the earliest evidence of a specialised bone industry. Extraordinarily, the slender tool form with a rounded tip used for softening hide is still in use by leather workers today.
Neanderthals also used fire for a range of uses, a practice Wragg Sykes explores as part of her contribution to an up-coming book on Neanderthal cognition, discussing their use of birch bark to create pitch. The process involved “cooking” the bark for several hours in a low-oxygen environment (possibly a pit or under a stone in the fire) until the sticky pitch was produced. This was used to secure two parts of a tool together, a process known as hafting. It is one of the major milestones in the evolution of technology.
Findings like this should help improve the Neanderthal’s still lamentable public image as what she terms “the losers of the Ice Age”. “I’m amazed that there’s not been more fuss, as it’s the first synthetic material ever made and it’s Neanderthals that did it,” she says enthusiastically.
Wragg Sykes’ passion for her subject is evident on her blog “The Rocks Remain”.
Another passion – bird-watching – is being turned into a book, Dawn Chorus in Eden, to be published in 2016.
And after more than a decade following their tracks, have Neanderthals become real for her?
“Neanderthals are endlessly fascinating because they don’t let you get complacent; sometimes they can seem really familiar, other times I feel like they were living in ways quite alien to us. Each time we add to our knowledge, it shifts things, sometimes confirming what I think they were like, other times challenging that.”