Briefing Chat: The epic journey of Stonehenge’s central stone

0:03Hi listeners, Benjamin here. Welcome to the Friday Briefing show where we talk about a couple of stories we've read about in the Nature Briefing and it's me and Nick this week. Nick Petrich how are you doing? I'm doing well Ben how's it going for you? It's going a-okay I've got a story I am excited to talk about today so I'll go first if you'll let me and you know that I love anything related to Stonehenge or other massive neolithic site anything henge or henge adjacent let's be honest. Anything henge or henge adjacent it has come up many times in our chat so what's the new henge news this week?

0:37Well this is a story I read about on the BBC Science Focus website based on a Journal of Quaternary Science paper. And it's a continuation of a story that was published a couple of years ago in Nature about Stonehenge. And it was covered on the podcast, and it was covered by you, Nick. And it was all about the altar stone. Do you remember this one? I do remember the altar stone. This was a paper where people were trying to trace the origins of the altar stone, the big central stone at Stonehenge. And they suggested that it'd come from the Orcadian Basin, which is this part of northern Scotland and the Orkney Islands.

1:12Absolutely right. So a lot of Stonehenge is believed to have come from Wales to the west, about 150 miles, maybe 250 kilometres from where these stones are now standing. But yeah, you're right. This altar stone, which is partially buried by another bit of rock, came from maybe 500 miles, maybe 750 kilometres away. And at the time, a question that you and I and a lot of the news team had, and I think the researchers themselves had, is how on earth did the people who made Stonehenge take this enormous six ton, 16 feet long, five meter long bit of rock from the far north of Scotland to the south of England?

1:48Now, you and I both know this is a difficult journey, right? There's mountains, there's hills, there's a lot of woodland at the time. This isn't just a simple straight shot. No, it's not a straight shot at all. And that's why when I spoke to the researchers on that paper you mentioned, they suggested that perhaps it had come by boat is that what people have found or have they found some other alternative routes they have found another alternative route but it is based on water frozen water specifically nick it may be that ice has done a bit of the heavy lift in here to help move this stone to where it is now so the conclusion that they've come to is that ice flows so a glacier essentially may have carried this stone part of the way at least during britain's last ice age which was about 30 ,000 to maybe 10 ,000 years ago but it gets a bit more complicated because the ice didn't do all of the work it didn't take it all of the way to essentially the Stonehenge site previous work suggested that that area of the UK wasn't glaciated at the time so what this paper suggests is that ice kind of moved this stone not directly south from Scotland to the Stonehenge location but kind of southeast and ultimately maybe took it half the distance depositing it in what's known as dogger bank which was part of this thing called dogger land this was actually suggested to me by researcher at the time that could be a possibility so it's interesting that this analysis seems to support that but that is only half the way that's still quite a way to go and you would have to go from this area still fairly far north of stonehenge so how perhaps did people make the rest of the journey with this massive stone yeah that's a great question and as is always the case with stonehenge there's more mystery to uncover right because dogger bank was part of what was known as dogger land this enormous sort of part of land that connected the uk to the rest of europe now dogger land doesn't exist anymore it is underneath the north sea right the end of the ice age ice melted sea levels rose and this area became inundated so before that happened this stone must have been moved from where it was resting to the mainland and how this happened is a mystery right like it may be involved maritime routes there we are again it may be involved what was known as the Berkshire Ridgeway which is the oldest road in the UK this kind of neolithic trail that crosses a lot of the south of the UK but what is clear is this must have happened say before Doggerland cease to exist but the timeline here gets weird nick because that happened like 3 000 years before stonehenge was put together so a long time before so this stone was maybe important for a reason the folk who moved it clearly saw a need to move it but why shrug i guess lots of different people must have worked together as well so there must have been some cooperation so it's this weird situation that we still haven't quite got to the bottom of yet yeah i'm sure there'll be many more researchers trying to figure this out as well because it is interesting to speculate as to how people at that time would have moved this massacre and also why they would have put that much effort in so with these open questions what are researchers looking to do next well i think at the minute from what i understand they're really trying to hone in on where did this stone come from as you say it was the very far north of scotland like could you get to could you zoom in to work out exactly where and maybe the route it took and maybe even trying to work out more likely where it was dropped before it was rescued from the now no longer existing dogger land well i'm sure you'll be here to update us when the next analysis of what happened with this altar stone comes out but for now I think we can probably safely move on to my story this week and this is also looking back in time but perhaps a little bit further back in time because this is an analysis of what could possibly be 700 ,000 year old coprolites.

6:01Wow coprolites obviously fossilized poo and this makes Stonehenge look like it happened last week right Stonehenge is about what 5 ,000 years ago 700 ,000 years ago is way way back yes and if that date works out these coprolites would actually contain some of the oldest mammoth DNA that's yet been discovered so this was an article I was reading in Nature based on a paper in Nature Communications and so as you say coprolites are fossilized poo which can be useful for researchers for a whole lot of reasons but what you may not have been expecting is for fossilised poo from ground squirrels to contain mammoth DNA.

6:41And contain it, it did, along with DNA from bison and big cats and insects and plants and everything. So it seems like these ancient ground squirrels may have been ravenous for all sorts of things that you may not expect. This is not what I expected you to say at all. Now, I don't know much about ancient ground squirrels living 700 ,000 years ago. That suggests to me that these animals were preying on all those other things if there's evidence of them in their poo. I can't imagine a ground squirrel taking on a mammoth. No, so what has likely happened is these ground squirrels have woken up after their winter, not quite hibernation, a state called torpor, but similar.

7:22Basically, it's like a winter slumber. They would have awoken and been pretty hungry after months spent in their burrows during the winter and would have eaten basically anything and that includes the carcasses of these large animals as you say it's probably unlikely that they took down a woolly mammoth but they may well found a woolly mammoth corpse and fed on it and one of the researchers interviewed in this article wasn't necessarily surprised by this because they said they've seen modern day ground squirrels feeding on other ground squirrels but feeding on carcasses so It's perhaps not surprising for evolutionary biologists.

7:58Right, but it's kind of this wonderful time machine, I guess, a little window into this area. We've talked about how ancient DNA can give a sense of what animals were present in an area, and I suppose this is doing the same. Yeah, exactly. This gives us a window into Canada's Yukon Territory. This is a place where a lot of gold mining is done. And when permafrost deposits are got rid of using jets of water, it can expose these underground burrows and it can expose these coprolites. And as you say, this could be used as essentially like a little archive where you find it. So because these squirrels have been eating whatever it is they've found, we could find like this DNA from all sorts of animals and find it in this region and find potentially really ancient samples.

8:45700 ,000 years old is a really, really, really old DNA. if that is how old it is so i must say that this is the suggested date as is often the case with this sort of dating it's sometimes difficult to date the sample itself the coprolites in this case so they dated some volcanic ash on top of it and that was found to be 700 000 years old but if those days add up this would be an archive that spreads from 700 000 years ago to 17 000 years ago that is quite something anything unexpected in the catalogue of animals we talked about mammoths a few times there but anything else that i wouldn't necessarily think of yeah there was also from big cats they suspect that either north american cheetahs or pumas so there were big cats in there bisons horses and other megafauna that roamed the region but there was another surprise as well which was that originally they thought these samples had come from a type of ground squirrel known as the Arctic ground squirrel which is used to tell us pariae or which are similar to the ones that you find in this area now but actually they may have come from an unknown lineage that are related to some long-tailed ground squirrels that live in areas of Siberia, Mongolia, China and Kazakhstan so perhaps they sort of crossed over to this region so potentially a new whole lineage of squirrels have been discovered here and you mentioned the mammoth DNA the researchers behind this say they've got a paper coming out there's a forthcoming paper that is just focused on the mammoth sequences and intriguingly they say it will reveal further intrigue but for now they're just leaving us with the idea that they hope that researchers could use these coprolites as this archive to find out all sorts of things about animals from this era well who'd have thought ground squirrels hoovering up stuff and depositing evidence in their poo which just let researchers all this time later figure out what was going on that's pretty cool yeah it's pretty cool i mean one of the researchers who was interviewed in this article described them as the zombies of the pleistocene because you can imagine them emerging from the ground and starting to eat just anything that they find so sort of like zombies coming back from the dead although in this case they're just coming back from torpor well what a story that is i think that's a good place to leave it listeners will put links to both of those stories in the show notes where you can sign up to the nature briefing to get even more things like this delivered directly to your inbox but for the time being i've been benjamin thompson and i've been nick patrick howl thanks for listening but i thought what if i've scaled businesses what if i scaled my philanthropy what if i did as much in one year as i've done in my whole life see how your wealth could have even greater meaning at creativeplanning.com slash impact