End of Ice Age Britain

Summary

Podcast Summary: The Ancients – "End of Ice Age Britain"

Episode Information:

• Title: End of Ice Age Britain
• Host: Tristan Hughes (History Hit)
• Guest: Professor Danielle Shreve, Paleobiologist, University of Bristol
• Release Date: February 23, 2025

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Introduction

In the final installment of The Ancients Ice Age mini-series, host Tristan Hughes delves into the transformative period marking the end of the Ice Age in Britain. Joined by Professor Danielle Shreve, an esteemed paleobiologist from the University of Bristol, the episode unpacks the intricate climatic shifts, the consequential impact on both fauna and early humans, and the invaluable lessons gleaned for today's climate challenges.

Key Quote:

[01:11] Tristan Hughes: "The Ice Age took thousands of years to end in Britain and had a massive impact both on the animals and humans that then called Britain their home."

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The Last Glacial Maximum

Professor Shreve begins by contextualizing the timeframe, emphasizing that the end of the Ice Age spans thousands of years, particularly highlighting the Last Glacial Maximum (LGM), which extended from approximately 26,000 years ago until the onset of the current interglacial period.

Key Points:

• Extent of Ice Sheets: During the LGM, ice sheets covered vast regions of Britain, including all of Scotland, most of Wales, northern England, and stretching into East Anglia and the North Sea basin.
• Climate Conditions: Britain experienced permafrost and polar desert conditions, making it a harsh environment for both fauna and early humans.
• Land Bridge: Lower global sea levels (<120 meters) due to water being trapped in ice sheets allowed Britain to remain connected to continental Europe via a land bridge in the southern North Sea basin.

Key Quote:

[15:14] Professor Danielle Shreve: "The last Glacial maximum... witnesses the coldest point of the last ice age."

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Fauna of Ice Age Britain

The discussion transitions to the diverse range of animal species that inhabited Britain during this period. Despite the inhospitable conditions, a surprising variety of cold-adapted fauna thrived.

Key Points:

• Megafauna: Includes woolly mammoths, woolly rhinoceroses, and reindeer, which were emblematic of the era.
• Adapted Species: Smaller mammals like mountain hares and musk oxen also populated the region, indicating varied survival strategies.
• Research Methods: Examination of animal remains, including bones and fossils, alongside sediment analysis, provides insights into species distribution and environmental conditions.

Key Quote:

[17:07] Professor Danielle Shreve: "We have remains of cold adapted species, such as woolly mammoth... and musk ox, which are obligate cold species."

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Excavations at Eber Gorge and Gough's Cave

Professor Shreve highlights her extensive work at Eber Gorge, a previously unexplored cave site in the Mendip Hills, Somerset. This site has yielded a rich assemblage of mammal bones and has been pivotal in understanding the paleoecology of the period.

Key Points:

• Eber Gorge Findings: Over 50,000 years of sedimentary deposits containing hundreds of mammal bones, including small species like bats and shrews, brought into the cave by predators such as birds of prey.
• Gough's Cave: A renowned site within the Mendip Hills, Gough's Cave has provided substantial evidence of human activity, including butchery marks on animal bones and unique human remains, despite previous destructive excavations.

Key Quote:

[12:19] Professor Danielle Shreve: "We have a sequence that goes back over 50,000 years now, and it's one of the most important sites, certainly in Britain and in northwest Europe."

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The Younger Dryas: A Climate Reversal

The episode delves into the Younger Dryas, a dramatic climatic event occurring approximately 12,900 to 11,700 years ago, characterized by a sudden return to colder conditions after an initial warming trend post-LGM.

Key Points:

• Causes: Possible intensified volcanism in regions like Germany's Eifel area and massive meltwater influx from decaying ice sheets in North America disrupting ocean currents.
• Environmental Impact: Britain experienced another cooling phase, leading to a contraction of temperate-adapted species and an expansion of cold-tolerant fauna such as Arctic foxes and multiple lemming species.
• Human Activity: Limited evidence suggests minimal human presence during the Younger Dryas in Britain, with possible sporadic forays but no substantial habitation.

Key Quote:

[33:09] Professor Danielle Shreve: "This is a period called the Younger Dryas... marks... a significant warming... later interrupted, but a warming and really sort of... the end of the last ice age."

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Human Adaptations and Extinctions

As Britain transitions out of the Younger Dryas, the fauna begins to reflect the warming climate with species like aurochs, elk (moose), red deer, roe deer, and wild boar becoming prevalent. Concurrently, human populations, chiefly Mesolithic hunter-gatherers, adapt their subsistence strategies from hunting megafauna to focusing on smaller game.

Key Points:

• Species Migration: Animals either adapt to the new conditions or migrate to more favorable environments. Some, like the woolly rhinoceros, become extinct in Britain but persist elsewhere.
• Human Behavior: Evidence from sites like Gough's Cave indicates sophisticated hunting practices, including butchery and tool usage, tailored to the shifting availability of prey.

Key Quote:

[28:54] Professor Danielle Shreve: "Humans are around during the late glacial interstadial and they come back just before the warming event... primarily hunting horse, but also going after things like red deer."

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Implications for Modern Climate Change

Concluding the discussion, Professor Shreve emphasizes the relevance of paleoecological studies in informing contemporary climate change mitigation and conservation efforts. Understanding past species responses to climatic shifts can guide current biodiversity preservation and habitat restoration initiatives.

Key Points:

• Ecosystem Insights: Lessons from the past highlight the adaptability of species and the importance of habitat connectivity.
• Conservation Strategies: Reintroducing species like bison and elk can restore ecological balance, drawing parallels from historical precedents.
• Future Applications: Fossil records aid in predictive modeling for species distribution under ongoing climatic changes.

Key Quote:

[46:54] Professor Danielle Shreve: "The fossil record can help us make better informed decisions in terms of the conservation of those species. So a really important role to play and some really exciting work to be done in the future."

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Conclusion

The episode "End of Ice Age Britain" masterfully charts the climatic and ecological transformations that Britain underwent as the last Ice Age drew to a close. Through the expertise of Professor Danielle Shreve, listeners gain a comprehensive understanding of the complex interplay between climate, fauna, and early human populations. The insights garnered not only illuminate a pivotal chapter in Britain's ancient history but also resonate with present-day environmental challenges, underscoring the timeless relevance of studying our planet's past.

Closing Quote:

[45:35] Professor Danielle Shreve: "Round about that, you know, 11,700 years before the present day, that would be when we consider the Ice Age to be finished and we've got those warm and wooded conditions."

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Additional Resources: For those intrigued by the post-Ice Age human activity in Britain, The Ancients recommends exploring their previous episode on Star Carr, an eminent Mesolithic site in Yorkshire, offering further insights into early human settlement patterns following the Ice Age.

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This summary encapsulates the critical discussions and insights presented in the "End of Ice Age Britain" episode, providing a coherent and comprehensive overview for both avid history enthusiasts and curious newcomers.

Transcript

[Tristan Hughes]

Hi, I'm Tristan Hughes and if you would like the Ancients ad free, get early access and bonus episodes. Sign up to History Hit with the History Hit subscription. You can also watch hundreds of hours of original documentaries, including my recent documentary All About Petra and the Nabateans, and enjoy a new release every week. Sign up now by visiting historyhit.com subscribe.

[Professor Danielle Shreve]

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[Tristan Hughes]

The end of Ice Age Britain A time of rapidly changing temperatures, of ice sheets melting, sea levels rising, and humans adapting to a more expansive and warmer Britain. A Britain that became cut off from the rest of Europe, that became an island. But these changes didn't happen overnight. And it wasn't a simple straight line case of things going from cold to warm either. The Ice Age took thousands of years to end in Britain and had a massive impact both on the animals and humans that then called Britain their home. Extreme temperature switches that forced them either to adapt, leave or die. It's an extraordinary story starring various animals ranging from Siberian lemmings to and of course humans. So what sorts of animals lived in Britain during these last fluctuating throes of the Ice Age? Why did the climate suddenly get much colder again roughly 13,000 years ago, the so called Younger Dryas period? And how were humans affected by all of this change? It's the Ancients on History hit. I'm Tristan Hughes, your host. Today we're releasing the final episode of our Ice Age mini series this February. And boy, what an episod. This is the end of the Ice Age in Britain. Joining me to explain what we know, I was delighted to interview the paleobiologist Professor Danielle Shreve from the University of Bristol. Danielle studies animal remains, particularly mammals, to understand how they responded to these abrupt changes in climate that defined the end of the Ice Age and what lessons we can learn from this when tackling climate change. Today. She's an expert on the end of the Ice Age in Britain and how this tumultuous period affected life on this edge of the Ice Age world. Enjoy Danielle, it is a pleasure to have you on the podcast today.

[Professor Danielle Shreve]

Thank you very much. It's great to be here to talk.

[Tristan Hughes]

About the end of the Ice Age in Britain. And I know it's quite a massive statement to start, but it feels like this is a time when Britain's world, it completely transformed.

[Professor Danielle Shreve]

Absolutely. I think some of the changes that were witnessed, whether it's to do with the landscape, the environment, the fauna, they're just some of the most remarkable changes that Britain has ever witnessed.

[Tristan Hughes]

And just first of all, I mean, do we know how much time we can roughly talk about if we're exploring the end of the Ice Age? Should we be thinking in thousands of years?

[Professor Danielle Shreve]

Definitely thousands of years. So I think probably a sensible starting point is probably the period that we would call the last glacial maximum. So from about 26,000 years ago until really the early parts of the current warm stage, or interglacial that we're in now.

[Tristan Hughes]

Yeah, that's more than 10,000 years in total, isn't it? And it's absolutely extraordinary. But before we delve into that, and you mentioned the last glacial maximum, archaeological material that you have to study to learn more about this important period, do you have quite a lot of information surviving for what actually happened at the end of the Ice Age?

[Professor Danielle Shreve]

We do. So I think it's important to make a difference between archaeological material, which would be that related exclusively to humans, so things like human artifacts, whether that's stone tools or other types of evidence, and the sort of paleobiological evidence that we might have. So things like fossils of animal bones, plant remains, shells, that kind of thing. So we have lots of different types of evidence that are available to us. And sometimes that comes in the form of the sediments themselves, because the deposits of sands and gravels and all sorts of things, you know, that we might actually dig into, we can understand a story of how climate changed from those. We can also look at the remains of animals and plants, and they tell us very clearly how things change in response to climate change. Often very rapid and abrupt climate change. And there's also different types of evidence out there as well. So, for example, things like sea level rise, we know that at times Britain was connected to the continental mainland. And then as we come towards the end of the last Ice age, the sea level rises and Britain becomes cut off. So actually, there's a whole host of different types of evidence out there.

[Tristan Hughes]

Slight tangent straight away, but I remember doing an interview a few months back where they were analyzing deep sea cores, kind of taking up information from the sediment beneath the sea to get a sense of climate and the ecological world. And in that case, it was more than a million years ago. I'M guessing, whether it's a million years or 10,000 or 20,000 years ago, is that one of the ways that you can learn more about the whole landscape and environment at that time?

[Professor Danielle Shreve]

Definitely. So one of the things we try to do is to reconstruct that landscape. So to understand, for example, the changing coastline of Britain. Britain is in quite an extraordinary position, really at the edge of the North Atlantic. So it's very sensitive to climate change. And we can get at that evidence for change through doing things like coring into deposits that might be, for example, buried below the sea now, but also on land as well, and actually looking at those cores of sediment through time and extracting as much information from them as possible.

[Tristan Hughes]

So does this all belong to the field of study that I know is very close to your heart? The name paleoecology?

[Professor Danielle Shreve]

Yes. So paleoecology or paleoecology really deals with the ecology of the past. So the paleo bit just means the old parts. So in the same way that an ecologist today would look at the habitats, the behavior, all aspects of the ecology of the animals that they might study today, this is what I'm trying to do in the past. And sometimes it's easy or relatively easy, because the animals that I study are still around today or very close relatives. In other cases where you've got animals that are extinct today, we have to draw on different lines of evidence in order to try and reconstruct something of their life ways.

[Tristan Hughes]

And I must also ask about the word fauna. Now, what does this word entail? How big a term is it when, when studying paleoecology and so on?

[Professor Danielle Shreve]

So fauna is animal life, and by that anything could come into fauna, whether it's, for example, vertebrates, so that might be fish, reptiles, amphibians, birds, mammals, but it could also include all sorts of invertebrates as well, so particularly things like beetles or snail shells, that kind of thing as well. So it covers a very broad range of different types of material.

[Tristan Hughes]

So whereas megafauna is kind of related to the big beasts like mammoths, rhinos and so on, fauna is a more, more wide reaching term for all different animals living in the past, is it?

[Professor Danielle Shreve]

Definitely. And one of the things that I am interested in is studying the fauna as a whole, so not just focusing in on sort of the biggest, most impressive species, although obviously things like the megafauna are really interesting and charismatic animals, but actually things like small mammals as well, they can tell you a phenomenal amount about the local environment, about climate. Small things like beetles are really good for reconstructing climate events in the past, telling you about local vegetation. And some sites preserve some types of evidence better than others. So we need to go after all of them in order to try and reconstruct the best, most holistic picture that we can.

[Tristan Hughes]

I know it's archaeology, but can human remains and human interactions with these fauna, can they help in that puzzle too?

[Professor Danielle Shreve]

They can indeed. So I guess it's a moot point whether you want to include humans as part of the fauna. I think for much of the past, the Paleolithic or old Stone Age, humans are doing something interesting in the landscape. They are certainly doing unusual things like making stone tools, but they're very much part of a wider fauna. They're responding to the same kind of climatic and environmental trends that other species are. Luckily, they do leave behind useful things like stone tools. So we are able to derive an enormous amount of information from that in terms of their behavior. Remains of the actual early humans themselves are very rare in the uk, but we do have other types of evidence. For example, things like cut marked bones and broken bones, which tell us about butchery and hunting practices as well.

[Tristan Hughes]

And talking about something that seems to have been important for early humans at that time and for these animals, a particular type of site. Cave sites, Daniel, for deriving more information about the end of the Ice Age. How important are cave sites for finding that information and piecing together more of this puzzle?

[Professor Danielle Shreve]

So cave sites are often really good places to target for this type of information. They can be very rich resources of information. Often, of course, we have caves that form in limestone areas across the uk, so things like the southwest of England, the Peak District, South Wales, for example, North Wales, these are all really good places for finding material. In caves. You can often get a build up of quite sequences through time as well. And that's because caves act as large sort of repositories or archives for material coming in. And sometimes it might be washed in by a river or a mudflow. But a lot of times you get cave sediments building up over time and containing the remains of animals that were either living in the cave. So things like carnivores, for example, or which were brought in as remains of prey, and that can build up over long periods. Caves are great generally for preserving animal remains in the form of bones or teeth. They're also very good for preserving mollusc and shell, but they are not so good at preserving things like pollen or what we call plant macrofossils. So bits of plant, whether it's bits of leaf or twig, or seed, for example. That's just because limestone, it's a very calcareous environment. It's good at preserving things like bones, and it's not good at preserving things like the pollen, which needs a more acidic type of depositional environment.

[Tristan Hughes]

Is limestone, kind of alkaline. And that's why preservation is better in limestone cave environments than other types of stone.

[Professor Danielle Shreve]

Yes, it's very alkaline, so that's good for the preservation of bones and teeth. So we get different types of evidence from these caves, but they can often contain really detailed sequences that allow us to examine how animals, and indeed people, on occasion, if we have evidence for archaeology in those caves, we can examine how the fauna, how people have been responding to climate and environmental change.

[Tristan Hughes]

Before we go through almost the main phases of those last, well, quite a few thousand years in the story of the end of the Ice Age, I feel it's important, first of all, to highlight your work at a particular site, because it feels like we'll explore examples from these sites and dot them throughout the interview today. So tell us about your work at Ebil Gorge, where this is and what this is, why it's important to today's discussion.

[Professor Danielle Shreve]

This is work we've been doing for a number of years now, about 15 years, and it's based in previously unexplored cave site in the Mendip Hills in Somerset. It was a wonderful opportunity to explore a site that had not had any previous excavation in it already. That's quite rare because many cave sites have been discovered. They were discovered by Victorian antiquarians. A lot of them were dug out.

[Tristan Hughes]

Yes. They liked to dig to find the big stuff, didn't they?

[Professor Danielle Shreve]

They certainly did. So they were very keen on finding things like specimens for their cabinet of curiosities. So they would. They would go out. I mean, in some cases, there were very rather systematic excavations done. In other cases, people were literally going along and looking for souvenirs. And all of this happened at a very exciting time. And in fact, really sort of Britain and places like the Mendip Hills played a crucial part in that move away from the teachings of the Church and understanding about evolution. The discovery of the bones of extinct animals and then later in association with human tools as well. This was really the first insights into the antiquity of humans. So the Mendip Hills have always been a great place to work. And the research that we've been doing in this particular cave site has generated some fantastic information. We have a sequence that goes back over 50,000 years now, and it's one of the most important sites, certainly in Britain and in northwest Europe.

[Tristan Hughes]

And I mean, how rich a site is this? Are we talking about hundreds of mammal bones or are we talking a bit more than that?

[Professor Danielle Shreve]

We're talking about hundreds of mammal bones. Now, they're not all complete. It's important to say that, because at some levels within the cave, we have things like spotted hyenas that have been denning there and they're crunching up the bones. So we collect all of the fragments because even the very broken, broken bits tell us something about the origins of what we call an assemblage. So that collection of bits of bone, and they tell us what those animals were up to. But at this particular cave site in Eber Gorge, we have, for example, in some of the upper layers, we have got hundreds of thousands of bits of small mammal. These might be things like bats, mice, voles, shrews, lemmings, and they've been brought in by birds of prey that have been hunting over the landscape that have swallowed this material down. They come back to the cave to roost and then they regurgitate the undigested bits as pellets. And eventually, thousands of years later, those have started to turn into fossils, and that's when we can come along and collect them.

[Tristan Hughes]

Well, let's start going through the chronology, Danielle, and should we go to maybe 25, 20,000 years ago, what does Britain look like at that time in this period that you've mentioned, this last glacial maximum?

[Professor Danielle Shreve]

The last glacial maximum, Britain was a pretty chilly place, so subject to really savage cold. So as the name implies, the last Glacial maximum witnesses the coldest point of the last ice age, which began about 100,000 years ago. And round about 26, 25,000 years ago, you get the expansion of ice sheets in Britain. They covered all of Scotland, they cover almost all of Wales, they cover most of northern England, and they just reach down into the northern coast of East Anglia. So if you can imagine a huge, glassier, a huge ice sheet going pretty much all the way from East Yorkshire at an angle down to South Wales, that's the extent of the ice sheet and extending into the North Sea basin beyond. And in front of that ice sheet, there would have been really a polar desert. So permafrost conditions, very, very cold indeed. Britain is connected to continental Europe at that time because sea level was much lower. And that's because water is drawn off during the buildup of the ice sheets on land. There's evaporation of the water from the oceans and sea Levels fall by about 120 meters globally. That's more than enough to reconnect Britain to the continent. So there is a land bridge in the southern part of the North Sea basin. So it would be possible for species that were able to toler those conditions to move in and out. But it would have been a pretty inhospitable place.

[Tristan Hughes]

I was going to say almost kind of reinforcing literally what you just said there, Danielle, that even below, even south of that great ice sheet that you highlighted there, it's still quite, as you said, inhospitable barren landscape. And so I'm guessing, is there a rich diversity of species able to adapt and live in that incredibly cold environment at that time?

[Professor Danielle Shreve]

There's a surprising number of species, I would say. I mean, biodiversity is of course, much lower than you would find in many warmer climate periods, but nevertheless, we still get some smaller species around. We find, for example, evidence of mountain hare. We also have remains of cold adapted species, such as woolly mammoth. We have also reindeer around, for example. But some of the most interesting remains that we've got are things like musk ox, which are obviously obligate cold species. They live today up in the high Arctic, and yet they were living around, for example, Northamptonshire, we've got a series of musk ox remains that are dated to about 20,000 years ago. So that is a really, really clear indication of just how different conditions were on the ground at that time, basically.

[Tristan Hughes]

Arctic conditions, isn't it? It's really, really interesting. Naturally, there were humans and early humans in Britain before that time. So many sites talk about the Neanderthals and early Homo sapiens as well. But are humans there at that time, when it gets much colder? Again in that. In that last glacial maximum, there's no.

[Professor Danielle Shreve]

Unequivocal evidence of humans being present. So it's a tricky one because I think when you have certainly a period of very cold climate conditions, often it's hard for material to get preserved because just the cold and the action of ice sheets, it's not conducive to the preservation of fossil material. Now, certainly across northern Europe, there were other areas that were believed to be abandoned by modern humans at the time, but of which have been demonstrated subsequently to have some limited evidence. So it's possible that humans were making forays into Britain at that time, perhaps during the slightly warmer parts of the summer months, but we really don't have any good evidence. We don't have any artifacts. And there is a putative human humerus from a site in South Wales that may date to this period, but certainly if people were around, they are in low numbers and they are not long term residents.

[Tristan Hughes]

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[Professor Danielle Shreve]

It has to be lower than the ice sheets. And I think you might have had some species that perhaps could tolerate being out on the open ice so much further to the north, although we don't have evidence preserved. You might have got things like polar bear, for example, at sort of the highest, the very highest latitudes. But really for the herbivores, of course, they need something to eat, they need vegetation, so they cannot survive out on an open ice sheet. They have to have vegetation. And in the case of something like a reindeer, that can be, you know, sort of fairly short grasses and lichen that they might be feeding on. But it's not like having a herbivore. You know, there's not a herbivore bonanza up on the ice sheet. You might have had, you know, polar bears that are predating on seals, for example, in the way that they would do in high latitudes today. But really everything is going to be south of that ice sheet limit.

[Tristan Hughes]

So when does the ice sheet, when does it start to recede? And what's the story of the end of the last glacial maximum? What happens?

[Professor Danielle Shreve]

So at the end of the last glacial maximum, we enter a period of abrupt warming, and this is referred to as the late glacial interstadial. It's about 14,500 years ago and it marks the sort of first evidence towards a significant warming, albeit later interrupted, but a warming and really sort of you know, the end of the last ice age. So that warming event is very abrupt. Really. You're looking at rapid warming conditions in northwest Europe. So the ice sheets begin to retreat. And really by, you know, sort of about 16,000 years ago, they are much, you know, they're much reduced up to the northern part of Britain.

[Tristan Hughes]

And I mean, when talking about, you know, kind of rapid changes, I know when looking at Paleolithic history, rapid can sometimes mean hundreds of years. Do we know roughly like, how rapid we're talking about with the climate changing back then?

[Professor Danielle Shreve]

We do, because we can measure these things, for example, by going to the ice sheets in Greenland.

[Tristan Hughes]

Oh, wow.

[Professor Danielle Shreve]

Yes. So you can extract ice cores from Greenland and they have annual records in them where they've got things like greenhouse gases trapped. So we're able, able to measure this and document this really, really closely. We can date those, you know, those bands in the ice. And so we do have a very good idea about just how quickly some of these transitions took place. Wow.

[Tristan Hughes]

So you can do that today. You can go and get ice cores from Greenland and that's almost undisturbed natural resources that can tell you that the speed of the changing climate and I guess give you more of a sense, an environmental record of what happened at that time.

[Professor Danielle Shreve]

It's a great sort of archive, if you like. It's a great benchmark for understanding how climate change in this part of the Northern hemisphere happened. And because Britain is really quite close in that part of the North Atlantic, we can actually see the major transitions as we come out of the last glacial maximum, the rapid warming into the late glacial interstadial, and then some of the subsequent oscillations, the climatic fluctuations that we see. We can actually see that. We can see that evidenced on land in Britain.

[Tristan Hughes]

Well, let's focus first of all on that first great warming period, Danielle. I mean, if it is pretty rapid that it happens, how does this affect those animals that had adapted to survive on that far, far edge of the hospitable world?

[Professor Danielle Shreve]

So at that time, you would see a retreat of some of the species that had been adapted to very cold conditions. So things like mammoths begin to contract their range back to Siberia during the late glacial interstadial. In Britain, you do get other species that are cold adapted that still hang on. So things like reindeer are still regularly present. But because of the warming event that we see, we get other types of herbivores in particular coming in. So at first things like horse and then subsequently red deer, we get a real mix of species at that time, though. So, for example, in the cave sites that we're working in in Somerset, we get both species that are today indicative of cold climate conditions. For example, things like collared lemmings. And those are mixed in with other small mammal species that require more temperate, but also some kind of vegetation cover as well. These might be things like wood mice, for example, or common shrews. These are small mammals that we think are probably able to eke out in existence in summ of these very deep limestone gorges. So particularly where there are more shrubby habitats or even trees that are growing there, there would have been sufficient shelter to support both the ones that needed more temperate conditions. But also up on the plateau, you've still got pretty exposed conditions and you would have been able to support things like reindeer up there as well.

[Tristan Hughes]

So from that cave site, so from that time period in southern Britain, you need to imagine collared lemmings alongside dormice. I mean, that's extraordinary. That's such extraordinary breadth and variety. I mean, kind of in the, in the environments, as you say, that they would have to live in. And yet they were able to live side by side at that time.

[Professor Danielle Shreve]

Yes, and I think, you know, certainly back in the past we used to wonder whether these were sort of, sort of jumbles in the fossil record, that there wasn't good resolution in these sites, that we didn't have the precision to say level by level exactly what was going on. But now, now, for example, with the types of sites that we're working on, we have got really good resolution. So actually we can see that within just a few centimeters of sediment, we can extract these animals that have rather different habitat preferences together. It really has an important lesson, I think, for how we understand fauna and responses to climate change at the present day, because it shows us how quickly animals can respond to these events. And obviously one of the challenges that they have today is the fact that we have changed their landscape, we've removed connectivity of habitats. But in the past, even very small animals could expand or contract their range according to changing environments, changing climates. They could do that really, really rapidly.

[Tristan Hughes]

So it's interesting there. So for those animals that were already there before it gets warmer, is it very much a choice of adapt or move incredibly long distances away, like the woolly mammoths?

[Professor Danielle Shreve]

So animals such as, you know, many of these, these animals would be relatively more tolerant as mammals, because mammals are warm blooded and they would have had certain adaptations as well. They're certainly more tolerant than things like reptiles or amphibians that are obviously completely dependent on external temperatures. So mammals can often, because they can maintain their body against temperature gradient, they can often survive in more marginal areas outside their sort of core range. But, yes, the story there is very much one of move, adapt or die out. We've already seen some species, such as woolly rhino, disappear from Britain about 35,000 years ago, but they live for another 20,000 years up in Siberia. When we look at, for example, the extinction of species, we need to understand that it's different triggers in different parts of their range at different times. Species are not necessarily responding as communities here, but very much as individuals. And some of them, you know, the climate change is too quick for them to adapt, really. So actually, although some of them may be able to switch to different food sources, often the way that they would sort of get out of difficulty is to change their range, so they would migrate to areas that were more favorable.

[Tristan Hughes]

And how does this climate change? How does it affect humans? Do humans come back at this time?

[Professor Danielle Shreve]

Humans are around during the late glacial interstadial and they come back just before the warming event. So they're really poised and ready to come back into Britain, and they seem to occupy areas of the southwest first and then move further north into the Midlands. And we're able to establish this because of very precise radiocarbon dating. We know that when they come in at about 14 and a half thousand years ago, or just before, they are primarily hunting horse, but also going after things like red deer as well. And then later on, they move to doing things like trapping mountain hare and exploiting those. So that's really interesting that there is a switch to smaller game, and that's consistent with the disappearance of things like the megafauna, that people are having to adapt their diets as their own environment changes and they're having to switch to different food sources.

[Tristan Hughes]

Sources, yeah, exactly. The days of humans hunting or scavenging off mammoths has long gone by that time in Britain, isn't it? It's really, really interesting and I'm guessing, should we mention one of those key sites, which is Gough's Cave, this feels an important site to highlight for evidence of humans returning at this time.

[Professor Danielle Shreve]

Indeed. So Gough's Cave was a really spectacular site and probably supported a decent group of individuals for perhaps a couple of hundred years. And even though this site was dug, primarily excavated, a long time ago during the Victorian period, there have been more recent excavation of remnants of the sediments that were preserved below overhangs on the side of the cave walls, and those were carried out by colleagues from the Natural History museum in the 1980s. One of the most astonishing things about Gough's Cave is the abundance of actual human remains. So in fact, human remains generally, whether it's modern humans, whether it's Neanderthals or their forebears, are so incredibly rare in Britain and yet they make up, you know, approximately a quarter of all the material that came out of Gough's Cave. And in fact there are sort of anecdotes about, I think, 12 tea chests full of bones being removed from the cave and essentially destroyed because they were viewed as duplicates. And when you think about the amount of material that must have been lost. So the Gough's Cave remains are very special partly because there's good evidence of humans, but also because of the superb preservation of the material. And we can see the remains of animals, whether it's for example, butchered horses, we see cut marks on horse teeth, on horse bones, we see exploitation of red deer. There's remains of carnivores such as lynx that are present in the site and almost certainly exploited in the case of the lynx for its lovely pelt, for the fur. We see exploitation of things like mountain hair and the modification of hair bones into little tools such as piercing sort of awl type tools. Really just a very sort of complete picture of what humans are doing. And of course one of the most notorious things there is that there is also evidence of breakage of bone for marrow extraction and butchery of the human remains themselves. So those humans are being treated in exactly the same way as any other butchered animal bone at the site.

[Tristan Hughes]

Gough's Cave. So is that southwest England as well? Is that Somerset or Wiltshire? It's near the Mendips. Is it?

[Professor Danielle Shreve]

It's Somerset, right in the Mendips, so it's partway up Cheddar Gorge. So a really well known area that people can go and explore and you can walk into the cave today and it's a, you know, it's a visitor attraction. And the Paleolithic or old Stone Age deposits are very close to the entrance of the cave, just sort of tucked away on the left hand side as you come in.

[Tristan Hughes]

So let's move on to the next stage. Danielle, it looks like things are getting warmer. Humans are back. New species are in the fold in Britain. But as time goes on, what happens? Something very different happens.

[Professor Danielle Shreve]

Yes, I think just as we seem to be climbing out of the last Ice Age, we have a sudden reversal of conditions and a huge climatic deterioration. This is a period known as the Younger Dryas, it starts about 12,900 years ago and it finishes about 11,700 years ago.

[Tristan Hughes]

Pretty precise dates as well for Paleolithic times too.

[Professor Danielle Shreve]

Pretty precise dates. And again, we can get that chronology from the Greenland ice core, but also, of course, with the benefit of radiocarbon dating as well. So we know quite a lot about this time period in terms of the effects on land of this sudden deterioration in climate. And broadly speaking, that's caused by a mixture of factors. So there is some evidence, for example, from Germany, from the Eifel region, that there is a period of intense volcanism, so volcanic activity that precipitates a cooling in climate. But also there are other things going on at this time. So particularly in North America, you've got the decay of the big ice sheets, the Laurentide ice sheet, and pulses of very cold meltwater that are entering the North Atlantic. And what they do is to disrupt the ocean circulation and Britain is plunged back into the freezer once more.

[Tristan Hughes]

And how does this rather abrupt switch of climactic conditions, how does it affect the, I guess, the lifestyle, the world of Ice Age Britain at that time, and the animals, and I guess humans as well, that were living in it.

[Professor Danielle Shreve]

So, again, this would have been an abrupt reversal of fortune for a lot of the more temperate adapted species. And certainly in the caves that we've been digging in Eber Gorge, we can find, for example, evidence of reindeer. There's also evidence of Arctic fox in there. So there's several individuals, including a complete specimen that was curled up in a little niche at the back of the site, so beautifully preserved. There's lots of crunched up bone in there as well. So you can imagine the Arctic foxes running in and out, out of the cave. They are predating small mammals. So we get a variety of small mammal species that are present, but also things like birds as well, species that we would find in the northern part of Britain today, things like ptarmigan. Again, those small species are on the move very rapidly. Within the cave site, we have remains of three species of lemming that today are not sympatric, by which I mean they don't live together today. So we have remains of Norway lemming which come from Scandinavia. We have remains of collared lemming that today have a sort of circumpolar distribution in the Northern Hemisphere. And we have only the second record from Britain of a Siberian steppe lemming. And all those three species congregate in the southwest of Britain during the Younger Dryas. So, again, these things were expanding their range Very rapidly.

[Tristan Hughes]

I want to talk a bit more about lemming. So if you discover the remaining remains of a lemming, is that one of the go to signs that that was a cold climate time in Britain's Ice Age story?

[Professor Danielle Shreve]

Yes, it certainly is for those particular species. There is a another species called a wood lemming, though it inhabits more boreal forests today in Scandinavia. Traditionally very difficult to separate from things like the Norway lemming, but through a mixture of ancient DNA and also very novel types of shape analysis on the teeth, we've been able to separate out the wood lemming species from the Norway lemming species because they both like different types of environment. That's been really important for us in terms of understanding the local vegetation. If we have something like a Norway lemming, these are typical tundra species. They can tolerate fairly boggy types of environment. They would feed on grasses and sedges, and we know that obviously they can tolerate snow cover and they are a great indic of local conditions on the ground.

[Tristan Hughes]

And in regards to those conditions, do we think the temperatures during the Younger Dryas in Britain, do we think it was as cold as it had been in the last glacial maximum, or not quite as cold, but still a shock to the system?

[Professor Danielle Shreve]

Perhaps not quite as cold, but still a shock to the system. So you're looking at really a sort of, I guess, a decrease of perhaps 4 or 5 degrees centigrade in terms of air temperature, certainly for the Younger Dryas across Europe. It's not the same globally. So the Younger Dryas is manifested differently in different parts of the world, but certainly that's what we would expect for Northwest Europe.

[Tristan Hughes]

And is it an alternate name for the Younger Dryas in Britain? Is it the Loch Lomond Stadium or something like that? Do we need to say that name too?

[Professor Danielle Shreve]

It is indeed. So we often use local stage names which are particularly appropriate for Britons. So if you were to say the Loch Lomond Stadial people would understand exactly what that was and that also it conjures up a very specific set of circumstances. So the presence of ice sheets up in Scotland, the kinds of cold climate animals that we've been describing just now. Whereas obviously, if the Younger Dryas is manifested differently in different parts of the world, then they would also have their own local stage names as well. Right.

[Tristan Hughes]

So Scotland's covered in ice sheets again, good for the skiing in Aviemore, but not much else at this period. I'd like to ask about one more particular type of animal before we move on to the next stage and this was just a name that really caught my eye when doing some research on this topic, and it's the saiga antelope. Danielle, what is this?

[Professor Danielle Shreve]

So Saiga antelope are fantastic animals and they are a small bovid, a small antelope. They live today in really the sort of heartlands of dry central and eastern Asia, so particularly populations in Mongolia and Kazakhstan. Until recently they have been critically endangered. But thank goodness their numbers are now on the rise again. And they are very well adapted to living in arid and, you know, pretty dusty environments. So if you happen to look them up and you see photos of them, you'll see that they have this fantastic nozzle like nose and they can use it to filter that dry, dusty air, cold air, before it gets into the lungs. And although they are essentially Central Asian animals and always have been, in response to this sort of cold and arid pulse that we find in the Younger Dryas, they expand their range. At the time we find them over in Alaska and to the west we find them over in Somerset. So there are radiocarbon dated remains from Gough's Cave and also from some other cave sites in Cheddar Gorge as well. So a fantastic but rare addition to the fauna in Britain at this time.

[Tristan Hughes]

Now, I know that absence of evidence is not evidence of absence, but is there any evidence at all for humans at this period of time or do we just not have that surviving?

[Professor Danielle Shreve]

No, again, we just don't have the sites, certainly at the sites that we've been working on in Eber Gorge, we don't have evidence of artifacts, we don't have evidence of cut marked remains, and we certainly don't have evidence of people themselves. So again, it's perfectly possible that people were making occasional forays into Britain, but we think that Britain was largely abandoned during this period until.

[Tristan Hughes]

Because the Younger Dryas does reach its end. Is it right about 11,000 or so years ago, as you mentioned, what happens, what happens when this shock to the system, this reversal in temperatures, this cooling time, what happens when that ends? Is it a continuation of the warming again?

[Professor Danielle Shreve]

So we're back on that warming trajectory and again there is rapid warming and the early part of the current interglacial, the Holocene, is even warmer than at the present day. And then we sort of settle down to a period of relative climatic stability. But yes, the real end of the Ice Age you start to see really up in Scotland, you start to see the last of those glaciers, those ice sheets retracting and leaving behind what we call dead ice environments. So for example, lakes, you would have had the ice melting and creating a lot of lakes in areas of sort of deeper topography. You would have had a window of opportunity for animals and people to come back into Britain before sea level rises and cuts us off completely. So remember that land bridge that had existed for pretty much all of the last Ice age, that is becoming smaller and smaller. As that ice across the Northern Hemisphere melts and the water is returned to the ocean, that land bridge becomes more and more compressed and harder and harder to access. And so, yep, people and animals would have come back into Britain very rapidly. We see things like reindeer hanging on for a little while into the early part of the current warm stage, but eventually it becomes too warm and too wooded for them to survive and they go locally extinct. And instead we see a whole suite of fauna that we would regard as native species coming into Britain in the early part of the warm stage. So these are things like aurochs, the ancestor of our domestic cattle. We had things like elk or moose, as it's known in North America. Red deer would have been abundant. Roe deer, wild boar. These are the major sort of herbivore food stock, really, for the last hunter gatherers that we find in Britain. And those are the Mesolithic people.

[Tristan Hughes]

So that's the Mesolithic people. And then you get amazing sites like Star Car, which we've done an episode about in the past, exploring country, kind of those human people right after the end of the Ice Age. But it's fascinating, isn't it, Danielle? For the animals involved, I'm guessing it was those who were able to adapt to that change in temperature, to the warming period. Those are the animals, as you say, become the most recognizable in the British landscape. And for many of them, like red deer, down to the present day.

[Professor Danielle Shreve]

Yes. So some of those species have gone right the way through to the present day. So red deer, roe deer would be a case in point. Others, such as the last remaining carnivores, whether they happen to be brown bears, lynx or wolves, we hunted to extinction, really, sort of from the Middle Ages onwards. Other things like elk disappear quite early on in the Holocene, again, probably hunted to extinction. Some of those smaller species as well. The Arctic foxes have gone, but instead we have red fox. We have things like wildcat as well, and they're all distributed really all over Britain. Things like wildcat, which today survive only up in the Scottish Highlands. Their natural habitat, which we can see from the fossil evidence, is actually deciduous woodland. The fossil record can play a really important role here in helping to address modern conservation issues today by giving more detailed baseline information about where species should be distributed or where they should be reintroduced. Today, one of the youngest specimens that we have from the Mendip Hills, from the excavations, is a beautiful complete skeleton of a wildcat. And it was found in association with other evidence that indicates warm and wooded conditions. So this was really optimal habitat for them.

[Tristan Hughes]

It's such a fascinating journey. Thank you so much for talking us through this. 10,000 years ago, it feels like by then it's kind of definitive. End of the Ice Age. If you say the the ice caps have receded from Scotland, Britain is now an island again, at least in the story of Britain. Is 10,000 a good number to say.

[Professor Danielle Shreve]

The Ice Age is now over, technically by 11,700. That's when we would say, yep. I mean, it depends whether you count in radiocarbon years before the present or, you know, some people look at it from a sort of, you know, B.C. or before the Common Era. So round about that, you know, 11,700 years before the present day, that would be when we consider the Ice Age to be finished and we've got those warm and wooded conditions and then obviously some spectacular transitions further in the human journey, really, and the move from hunter gatherers to settled peoples and agriculture, all of these things then kick off.

[Tristan Hughes]

It's fascinating to think that actually those 15,000 years we've just covered is less time than between the 10,000 BC or 11,700 years ago and today. So we've actually covered more time than between the end of the Ice Age and where we're sitting now, recording this interview together. Lastly, Danielle, as you've kind of hinted at there, but I feel it'll be nice to do this as a final remark, how important is studying the end of the Ice Age, the paleoecology, looking at the animal remains and the climate and the effect of humans as well. How important is all of that when exploring current issues like climate change today?

[Professor Danielle Shreve]

It's a really nice question to end on because this is one of the things that I think is so important and it's something that we're really trying to push and to work with modern ecologists. And so I've got a lot of great work that's starting with, for example, Natural England and other colleagues, particularly around some of these sort of joined up super national nature reserves, where there are some really exciting developments that are in play involving perhaps reintroduction of large herbivores to modify the landscape. The disappearance of many species is only just starting to be understood in terms of their legacy. The important things that elk and bison, for example, that they had in terms of opening up the vegetation, in terms of fertilizing the land with their their dung, in terms of transporting seeds around, all sorts of things that we have lost in the way of ecological benefits. We are understanding very well now how animals such as beavers, ecosystem engineers, the role that they can play in terms of helping to control completely cost free flooding episodes by trapping water upstream and away from areas of human settlement. But there's a lot more to be done and really the fossil record can give a really important insight. Working hand in hand with ecologists in terms of understanding the range, the habitats, coexistence of different species and different behaviors in the past, we can provide a more nuanced insight into for example, things like species distribution models where we think about where animals could and should be distributed, especially in view of climate change in the future. And the fossil record can help us make better informed decisions in terms of the conservation of those species. So a really important role to play and some really exciting work to be done in the future.

[Tristan Hughes]

Absolutely. Indeed. Well, Danielle, it just goes to me to say thank you so much for taking the time to come on the podcast today.

[Professor Danielle Shreve]

Thank you, Tristan.

[Tristan Hughes]

Well, there you go. There was Professor Daniel Shreve talking you through the story of the end of Ice Age Britain. I hope you enjoyed today's episode. As mentioned, if you want to find out what happens right after the end of the Ice Age in Britain, then you can search in the Ancients archive for an interview we did last year about Star Carr, this incredible Mesolithic site and one of the earliest sites we know of for humans post Ice Age living in Britain. Star Car in Yorkshire. Search Star Car Ancient and you'll find that episode too. With this episode we also bring to an end our special Ice Age miniseries this February. I hope you've enjoyed it. Please let us know your thoughts. We love hearing your feedback for episodes like this. This for special miniseries episodes like our Ice Age miniseries. Thank you for listening to this episode of the Ancients. Please follow this show on Spotify or wherever you get your podcasts. It really helps us and you'll be doing us a big favor. Now don't forget you can also listen to us and all of History Hits podcasts ad free and watch hundreds of TV documentaries when you [e-mail] subscribe.