Underwater deer trap discovery delights archaeologists

Chris Smith interviewed archaeologist Emma Pomeroy about the findings...

Chris - I'm actually in the Deer Park, which is at Peterhouse College in Cambridge. No deer here these days. Haven't been for about a hundred years or so. But animals similar to deer, their relatives, reindeer, were thought to be being caught thousands of years ago by our more primitive ancestors using stone walls. An incredible discovery has been described in the journal PNAS this week where researchers have discovered submerged, 20 metres down in the Baltic Sea off the coast of Germany and south of Denmark, a long wall structure that they think might have been used for this purpose. And with me is an expert on our more primitive ancestors, Emma Pomeroy from the University of Cambridge - she's an archeologist. What have they actually discovered, do they think, Emma?

Emma - So what we've got is about a kilometre long, sort of very small wall if you like. It's not a wall where the stones are kind of tightly put together, but it's punctuated with some bigger stones. So you've got sort of bigger stones and then a collection of smaller stones joining those up. There's more than 1600 stones. And the interpretation that the authors put forward is that this was a wall that was used to help limit the movements of migrating reindeer so that they could be more easily hunted and kind of picked off.

Chris - It's a kilometre or so long, it's quite big. So someone made it with a purpose, they speculate maybe hunting animals. Maybe we can come to that in a second. How is it found in the first place if it's 20 metres underwater?

Emma - So there is a whole sort of sub-discipline of underwater archeology. And this involves obviously surveying what's underneath the water off the coast or in lakes. And what they've done is used technology that can kind of tell you what's down there, sonar. And in doing so, in trying to map this region of the sea floor, they've noticed that there's this kind of linear structure. So a straight line that doesn't look at all natural. And so then they've gone and investigated further as to what this could be and who might have built it.

Chris - When does it date from and why is it 20 metres underwater?

Emma - So it probably dates from around 9,000 years ago and it's currently underwater because sea levels have changed over the years. And so parts of what was once dry land is now inundated with water. This period is sort of about 9,000 years ago, it's during the Holocene. The Holocene is characterised by much more stable environmental conditions. So the temperature, the plants around you are all much more predictable and associated with this. We see some interesting changes in people's behaviour. So this is what we would refer to as the Mesolithic period. So it follows the Paleolithic, the Old Stone Age and precedes the neolithic, which is what we associate with farming and agriculture. But it's this early period of there being sort of quite a stable climate and stable environment and we see some real creativity in how people are gathering their food, gathering their resources. In some places we see the beginnings of more complex societies. Some places people are able to be a bit more settled. But yeah, some really interesting kind of specialisation to local resources and innovating about how they're gathered.

Chris - How would they have used this structure then? What was its purpose?

Emma - So that's a bit of a tricky question, but it's one that I think the authors of this paper make a good case for. So they argue that this long structure went along the edge of a bog or an old lake. And what it effectively did was as herds of reindeer were coming past, they would be channelled, if you like, between this low structure and the bog or the water next to it. And basically it controlled where they were going. And so it makes it easier to hunt those animals to pick them off, which you can then make use of the meat, the hides and all the products that come from them.

Chris - Do you think it's significant that around the time that this is thought to date from, agriculture is just getting started? So is it a prelude to the way we started to do farming and husbandry or is it that that came along and displaced the need for things like this? People just built rectangular fields and stonewalls and kept their animals there and they didn't have to hunt them.

Emma - So I think the evidence we have is that agriculture and animal husbandry is actually introduced from elsewhere. So in Europe it's mainly coming with peoples moving from Southwest Asia or what we might call the Middle East. But I think it is significant that it's perhaps linked to the same time period because the environmental conditions and climatic conditions of the Holocene where you've got much more stable, much more predictable climates and environments probably play a role both in the development of these kind of new technologies, but also in the development of agriculture. Perhaps a little more recently than this.