0:00:07 > 0:00:10Two and a half million years ago,
0:00:10 > 0:00:15life on Planet Earth faced the dawn of a new era.
0:00:22 > 0:00:23The Ice Age.
0:00:28 > 0:00:30Now, we can go back in time.
0:00:32 > 0:00:36Because out of the permafrost,
0:00:36 > 0:00:39from deep inside caves,
0:00:41 > 0:00:44and from hostile deserts,
0:00:44 > 0:00:49the astonishing remains of giant animals are emerging.
0:00:50 > 0:00:54How amazing to be one of the first people to see this ancient creature.
0:00:58 > 0:01:02The Ice Age was the last time such creatures would walk the Earth.
0:01:05 > 0:01:10A lost Eden with mammoths taller than any elephant,
0:01:10 > 0:01:13cats with seven-inch teeth,
0:01:15 > 0:01:20and some of the strangest beasts that have ever existed.
0:01:20 > 0:01:24I'm fascinated by what the remains of ancient animals can tell us
0:01:24 > 0:01:29about them, and the world they lived in.
0:01:29 > 0:01:34Using new scientific advances, we can reveal how they lived,
0:01:34 > 0:01:36and why they died out.
0:01:45 > 0:01:49Come with me, back to the Ice Age...
0:01:50 > 0:01:53..a world ruled by giants!
0:02:22 > 0:02:2780,000 years ago, our planet began to cool,
0:02:27 > 0:02:30heralding the beginning of the last Ice Age.
0:02:36 > 0:02:40The Arctic ice sheets expanded.
0:02:40 > 0:02:45The impact on everything alive was huge,
0:02:45 > 0:02:48and sometimes in ways you wouldn't expect.
0:02:50 > 0:02:55The largest ice sheet covered half of North America.
0:02:55 > 0:02:59But south of the ice, the lands became richer than ever.
0:03:01 > 0:03:07Last time, I saw how the Columbian mammoth, the glyptodont,
0:03:07 > 0:03:12the giant ground sloth, and the sabre-tooth cat all flourished here.
0:03:17 > 0:03:20But in the rest of the Northern Hemisphere
0:03:20 > 0:03:22the story was very different.
0:03:26 > 0:03:30These lands had their own cast of giants,
0:03:30 > 0:03:35magnificent animals that now faced a huge battle for survival.
0:03:38 > 0:03:44Here, the impact of the Ice Age was to be especially severe.
0:03:44 > 0:03:48I want to find out what chilled Europe to the core
0:03:48 > 0:03:53and what it took to survive the harshest conditions of the Ice Age.
0:03:56 > 0:04:01My first encounter is with a truly ferocious beast.
0:04:03 > 0:04:08No other creature has left us such vivid clues about its life
0:04:08 > 0:04:10and its struggle for survival.
0:04:13 > 0:04:16I'm here in the Romanian province of Transylvania,
0:04:16 > 0:04:19which is the traditional home of Count Dracula,
0:04:19 > 0:04:21but I'm not looking for vampires.
0:04:21 > 0:04:25Here in the Apuseni mountains there's a remarkable cave which
0:04:25 > 0:04:30has kept a dark secret from the Ice Age for tens of thousands of years.
0:04:36 > 0:04:40The cave was discovered by a group of miners, rock-blasting for marble.
0:04:51 > 0:04:54This is what they found inside.
0:04:57 > 0:04:59Once, these bones would have been
0:04:59 > 0:05:02assumed to be from unicorns or dragons.
0:05:06 > 0:05:13But scientists identified them as Ursus spelaeus - the cave bear -
0:05:13 > 0:05:17the greatest heavyweight of all Ice Age bears.
0:05:20 > 0:05:24Cave bears were even larger than grizzlies.
0:05:24 > 0:05:27Analysis of their flat, grinding teeth
0:05:27 > 0:05:30reveals that they were vegetarian.
0:05:30 > 0:05:33They ate mainly berries and alpine plants.
0:05:36 > 0:05:41Their remains tell a story from around 40,000 years ago.
0:05:42 > 0:05:47Average global temperatures were about six degrees lower than today.
0:05:53 > 0:05:56Marius Robu, an Ice Age mammal expert,
0:05:56 > 0:06:00has spent years piecing together the cave bear's story.
0:06:02 > 0:06:04There's bones everywhere. Are these cave-bear bones?
0:06:04 > 0:06:07Yes, they belong to cave bears.
0:06:07 > 0:06:09How big are these bones, Marius?
0:06:14 > 0:06:15- Really?- Yeah.- Yeah.
0:06:18 > 0:06:20And what were they doing in here?
0:06:20 > 0:06:23Were they coming in here...to den? To hibernate?
0:06:32 > 0:06:34It's quite a difference as well, isn't it?
0:06:34 > 0:06:36I mean, we've come in... It was what, about minus 12 outside?
0:06:36 > 0:06:39And this must be plus 10.
0:06:43 > 0:06:45I wouldn't mind hibernating in here.
0:06:48 > 0:06:51But these bones can only mean one thing.
0:06:51 > 0:06:55Many hibernating animals never woke up.
0:06:56 > 0:07:01And the reason for that is what was happening outside the cave.
0:07:03 > 0:07:05Autumn.
0:07:05 > 0:07:08A young mother searches for food.
0:07:13 > 0:07:17To see the winter through, she and her cub must fatten up.
0:07:20 > 0:07:23But this year the high-energy berries she needs
0:07:23 > 0:07:25are scarcer than ever.
0:07:30 > 0:07:35As winter approaches, the bears head for their hibernation cave.
0:07:43 > 0:07:48She must choose the perfect spot - warm and safe.
0:07:58 > 0:08:0240,000 years later, we're following in their footsteps.
0:08:12 > 0:08:13Really?
0:08:13 > 0:08:16This isn't just water flowing down the side of the cave, then?
0:08:21 > 0:08:26So many bears passed this way that over thousands of years,
0:08:26 > 0:08:29they've rubbed the rocks smooth.
0:08:29 > 0:08:33This is like looking at ancient steps which have been worn down
0:08:33 > 0:08:36by people walking up and down them. This is amazing.
0:08:36 > 0:08:41- This isn't just one or two cave bears, this must be generations of them.- Definitely, yeah.
0:08:41 > 0:08:44Massive beasts, pushing their way in to this cave
0:08:44 > 0:08:46and polishing the walls as they go.
0:08:55 > 0:08:59It's hard to believe they came so far in,
0:08:59 > 0:09:01and through such tight passageways.
0:09:08 > 0:09:12There's something very unusual about this place.
0:09:14 > 0:09:17Thanks to the constant conditions, the mud on the walls
0:09:17 > 0:09:23is just as soft as it was all those thousands of years ago.
0:09:23 > 0:09:27And 250 metres in, etched into the mud,
0:09:27 > 0:09:30is something truly extraordinary.
0:09:34 > 0:09:37That's just amazing, look at that.
0:09:37 > 0:09:39'Scratch marks.'
0:09:41 > 0:09:46Marius and his team can only find one explanation -
0:09:46 > 0:09:51these impressions were made by cave bears during the Ice Age.
0:09:53 > 0:09:56I just can't believe that these traces are still there,
0:09:56 > 0:09:58from tens of thousands of years ago.
0:09:58 > 0:10:00The bones are one thing,
0:10:00 > 0:10:04and it's amazing to have those fossils preserved here,
0:10:04 > 0:10:06but to have these traces of life, and to...
0:10:07 > 0:10:09They do, they do.
0:10:11 > 0:10:15Another hundred metres in, there's a big drop.
0:10:23 > 0:10:27Now Marius has told me that this is absolutely worth it,
0:10:27 > 0:10:30and what's at the bottom of this long drop,
0:10:30 > 0:10:35that I'm now going to try and negotiate, is very exciting indeed.
0:10:39 > 0:10:41OK. Yeah.
0:10:43 > 0:10:45Oh! Goodness me, it's covered in them.
0:10:47 > 0:10:50Oh, this is just astounding.
0:11:03 > 0:11:06Yeah. Yeah.
0:11:14 > 0:11:17I want to know what became of them.
0:11:20 > 0:11:22The trail takes us deeper in.
0:11:32 > 0:11:33Oh! My goodness.
0:11:40 > 0:11:42It's like looking at a tomb.
0:11:42 > 0:11:46These are the remains of the cave bears
0:11:46 > 0:11:50that left all those scratches in the clay above me,
0:11:50 > 0:11:55scrabbling to get out. But they never made it.
0:11:55 > 0:12:02Just imagine, dying here in the dark, alone, in desperation,
0:12:02 > 0:12:05gradually starving to death.
0:12:05 > 0:12:06It's not a nice way to go.
0:12:15 > 0:12:20It makes me wonder why the bears even took this risk,
0:12:20 > 0:12:23going so deep inside to hibernate.
0:12:26 > 0:12:29It seems they were not always alone.
0:12:34 > 0:12:37Deep in another tunnel, there are traces
0:12:37 > 0:12:39of a different Ice Age giant...
0:12:43 > 0:12:47..Panthera spelaea - the cave lion.
0:12:51 > 0:12:54Look at that. That is magnificent.
0:13:06 > 0:13:08Superficially, they look quite similar
0:13:08 > 0:13:10and I can imagine if it was covered in a bit of mud
0:13:10 > 0:13:13you might have thought it could be a cave bear,
0:13:13 > 0:13:15but...when you look at these teeth...
0:13:15 > 0:13:20Wow, look at that. I mean, huge canines, and meat-slicing molars.
0:13:20 > 0:13:21That is wonderful.
0:13:25 > 0:13:30Cave lions were 25% larger than African lions.
0:13:32 > 0:13:36Chemical tests on their bones reveals that they preferred eating
0:13:36 > 0:13:41large herbivores, but under pressure would hunt just about anything.
0:13:43 > 0:13:45So what was this cave lion doing in the cave?
0:13:45 > 0:13:48Was he making a den here, in a similar way to the bears?
0:13:51 > 0:13:53So he's hunting the cave bears?
0:13:55 > 0:13:58But what a risk for a cave lion to take,
0:13:58 > 0:14:00coming in to a cave like this knowing that, OK,
0:14:00 > 0:14:02there might be cubs there that he could take easily,
0:14:02 > 0:14:04but their mothers are likely to be there as well,
0:14:04 > 0:14:06and they're big animals with big teeth.
0:14:08 > 0:14:12Extraordinary as it may sound, Marius is convinced
0:14:12 > 0:14:17that a lion fought a bear in this very cave.
0:14:17 > 0:14:20The lion's bones were found close to a bear's nest
0:14:20 > 0:14:25and there are some intriguing marks on the lion's skull.
0:14:29 > 0:14:32Right, yeah. OK, so this has been gnawed.
0:14:37 > 0:14:41I know it would have been a formidable predator,
0:14:41 > 0:14:45but I do find it astounding that he would have faced up to a cave bear.
0:15:03 > 0:15:08A cave lion tracks its favourite prey - reindeer.
0:15:12 > 0:15:15But each year, there are fewer of them.
0:15:23 > 0:15:26High in the mountains, driven by desperation,
0:15:26 > 0:15:28the cat approaches a cave.
0:15:33 > 0:15:35He can smell a meal.
0:15:47 > 0:15:52In total darkness, the lion must use its senses of smell and hearing
0:15:52 > 0:15:54to land a killer blow.
0:15:59 > 0:16:03SNARLING AND ROARING
0:16:30 > 0:16:33It's a harrowing story of animals
0:16:33 > 0:16:38forced into desperate measures as the Ice Age changed their world.
0:16:49 > 0:16:54The puzzling thing, though, is that at this time, the nearest ice sheet
0:16:54 > 0:16:56was still far to the north.
0:17:04 > 0:17:09Could it really have had such a long-range impact?
0:17:20 > 0:17:25Well, there is a place that shows us how the Ice Age took hold.
0:17:45 > 0:17:47It's so incredible to see this.
0:17:47 > 0:17:50I've never seen anything like this before.
0:17:55 > 0:17:58Now this is just a fragment, a remnant,
0:17:58 > 0:18:01of that once-gargantuan ice sheet
0:18:01 > 0:18:04which dominated the Northern Hemisphere,
0:18:04 > 0:18:08stretching right down into North America and Europe.
0:18:08 > 0:18:10This is the Greenland ice sheet.
0:18:20 > 0:18:26Like icy fingers radiating outwards from the ice sheet,
0:18:26 > 0:18:28glaciers stretch out to the sea.
0:18:36 > 0:18:43These rivers of ice can move at over 35 metres a day.
0:18:43 > 0:18:46And when they meet the ocean, this is what happens.
0:18:56 > 0:18:59Icebergs are born.
0:19:06 > 0:19:13But this is nothing compared with what happened during the Ice Age.
0:19:13 > 0:19:15As the Arctic ice sheet grew,
0:19:15 > 0:19:20its glaciers spewed out great flotillas of icebergs,
0:19:20 > 0:19:23many the size of large islands.
0:19:23 > 0:19:26They floated out into the Atlantic.
0:19:28 > 0:19:30When one large iceberg melts,
0:19:30 > 0:19:33it releases millions of tons of cold water.
0:19:34 > 0:19:40When a thousand icebergs melt, they can disrupt ocean currents.
0:19:40 > 0:19:44And that changes the climate right across the world.
0:19:52 > 0:19:56Between 50,000 and 30,000 years ago,
0:19:56 > 0:20:02Europe was rattled by three massive deep freezes - Heinrich events.
0:20:08 > 0:20:11It was these intense, savage pulses of cold,
0:20:11 > 0:20:15produced by Heinrich events, when whole armadas of icebergs
0:20:15 > 0:20:19were released, which kick-started the Ice Age.
0:20:19 > 0:20:22And as the temperature continued to drop,
0:20:22 > 0:20:25the great polar ice sheet advanced ever southward.
0:20:27 > 0:20:31And its influence began to alter the habitats of Europe.
0:20:40 > 0:20:43For the cave bears back here in Transylvania,
0:20:43 > 0:20:46those sudden brutal cold pulses were tough.
0:20:54 > 0:20:58The woodland glades which provided the rich vegetation
0:20:58 > 0:21:02that the cave bears depended on were disappearing in those
0:21:02 > 0:21:05Arctic conditions and being replaced by much hardier shrubs
0:21:05 > 0:21:10and grasses, useless for a giant calorie-hungry bear.
0:21:19 > 0:21:23Each autumn saw more bears starting their hibernation underweight.
0:21:28 > 0:21:31By 30,000 years ago, this was a species
0:21:31 > 0:21:35teetering on the edge as more and more bears died in hibernation.
0:21:37 > 0:21:42Within a few thousand years, the European cave bear was extinct.
0:21:52 > 0:21:57Europe's woodland gave way to ever more open landscapes,
0:21:57 > 0:22:00putting forest species under extreme stress.
0:22:04 > 0:22:08But this harsh new world wasn't a total disaster.
0:22:08 > 0:22:12It presented a great opportunity for one feisty giant...
0:22:15 > 0:22:19..a two-ton eating and fighting machine.
0:22:21 > 0:22:24An animal you might have thought
0:22:24 > 0:22:27would be more at home in the Tropics.
0:22:27 > 0:22:32Its remains crop up in the most unlikely of places.
0:22:38 > 0:22:42Under the North Sea lies a vast Ice Age plain.
0:22:45 > 0:22:48Today, it's a rich fishing ground,
0:22:48 > 0:22:50and the trawlers' nets often dredge up
0:22:50 > 0:22:52a lot more than just cod or haddock.
0:22:59 > 0:23:04Sometimes, the remains of woolly rhinoceros.
0:23:12 > 0:23:16Hundreds of rhino remains have been discovered
0:23:16 > 0:23:19between Birmingham and Vladivostok.
0:23:23 > 0:23:27And just recently, a new specimen,
0:23:27 > 0:23:30superbly preserved by the permafrost,
0:23:30 > 0:23:32has been discovered in Siberia.
0:23:37 > 0:23:42I'm going to Yakutsk, the coldest city on Earth, to see it.
0:23:46 > 0:23:50In winter, temperatures seldom creep above minus 40.
0:23:56 > 0:24:00And it's thanks to this unforgiving climate that we can see
0:24:00 > 0:24:04exactly what a real Ice Age rhino was like.
0:24:11 > 0:24:16A 20-year-old female woolly rhino was found in a mine
0:24:16 > 0:24:18just outside the city.
0:24:33 > 0:24:38I can't believe that she died 40,000 years ago!
0:24:56 > 0:24:59This is an incredibly rare
0:24:59 > 0:25:04and precious thing - it's the almost complete carcass of a woolly rhino,
0:25:04 > 0:25:09the most complete that has ever been found.
0:25:09 > 0:25:13When you touch it, you expect the skin to give a little
0:25:13 > 0:25:14under your fingers.
0:25:14 > 0:25:17And of course it doesn't - it's still frozen,
0:25:17 > 0:25:20so it feels like a cold, hard stone.
0:25:24 > 0:25:27This is an animal which was perfectly adapted
0:25:27 > 0:25:31to living on the steppe in Siberia.
0:25:31 > 0:25:35She was covered in this woolly, furry coat to keep her warm.
0:25:35 > 0:25:39There's a little bit of it still clinging on, on the back feet.
0:25:45 > 0:25:49A woolly rhino was about the same size as a modern African rhino.
0:25:50 > 0:25:53But it had a double-layered coat of wool
0:25:53 > 0:25:56to shield it from the brutal cold.
0:25:58 > 0:26:03Long hairs formed an outer protective layer,
0:26:03 > 0:26:06shorter hairs formed a downy thermal layer underneath.
0:26:09 > 0:26:14Its ears and tail were smaller than an African rhino's
0:26:14 > 0:26:18to prevent heat loss in temperatures as low as minus 60.
0:26:24 > 0:26:28And her whole body shape, this massive stocky body
0:26:28 > 0:26:33with short legs, is a very good way of keeping warm in cold climates.
0:26:37 > 0:26:39Their most striking feature, the horn,
0:26:39 > 0:26:44was about twice the size of an African rhino's.
0:26:45 > 0:26:50Just the thing for settling territorial disputes.
0:26:54 > 0:26:58With two males competing over the same precious territory,
0:26:58 > 0:27:01it's going to end in a showdown.
0:27:19 > 0:27:23The woolly rhinoceros was an impressive creature.
0:27:23 > 0:27:27But its very presence reveals something quite odd
0:27:27 > 0:27:30about the Ice Age in Europe and Siberia.
0:27:33 > 0:27:35To fuel its large body,
0:27:35 > 0:27:39a rhino needs to spend virtually all day eating.
0:27:43 > 0:27:46It simply couldn't exist in a place
0:27:46 > 0:27:50where its food is always getting covered in snow.
0:27:54 > 0:27:58And this is the great paradox of the Ice Age.
0:27:58 > 0:28:02In the freezing wastes of Europe and Siberia,
0:28:02 > 0:28:07one thing that was thin on the ground was snow!
0:28:16 > 0:28:20Temperatures were colder, but with so much of the planet's water
0:28:20 > 0:28:26locked up as ice, this meant that the climate was also drier.
0:28:26 > 0:28:30So under clear blue skies, there was plenty of sun in the summer
0:28:30 > 0:28:33for grass to grow, and in the winter,
0:28:33 > 0:28:35hardly any snow to cover it up.
0:28:40 > 0:28:45Huge as they were, rhinos weren't the largest eating machines
0:28:45 > 0:28:48to benefit from these cold, dry plains.
0:28:49 > 0:28:55There's one giant without which the Ice Age story would be incomplete.
0:29:04 > 0:29:09Winter. Woolly mammoths make their yearly migration across Siberia.
0:29:21 > 0:29:25Over the past hundred years, the Siberian permafrost
0:29:25 > 0:29:30has yielded some truly amazing specimens.
0:29:30 > 0:29:33And this is the most captivating of them all.
0:29:38 > 0:29:41This is one of the most famous mammoth finds of recent years.
0:29:41 > 0:29:45She's called Lyuba and she's a little baby mammoth,
0:29:45 > 0:29:47probably just a month old.
0:29:47 > 0:29:52She was found in 2007, and she is amazingly well preserved,
0:29:52 > 0:29:54so that we have her skin, her soft tissues
0:29:54 > 0:29:57and we even have the contents of her gut.
0:29:59 > 0:30:03Specimens like this one reveal that the inside
0:30:03 > 0:30:07of a woolly mammoth is even more impressive than the outside.
0:30:09 > 0:30:14Like the rhino, a woolly mammoth had a double-layered coat of wool
0:30:14 > 0:30:17to shield it from the brutal cold.
0:30:17 > 0:30:22But under the skin coursed antifreeze blood.
0:30:23 > 0:30:26Inside the red blood cells, the haemoglobin -
0:30:26 > 0:30:29the oxygen-carrying component of blood -
0:30:29 > 0:30:33operated efficiently in sub-zero conditions.
0:30:34 > 0:30:38In other words, mammoths actually PREFERRED the cold.
0:30:46 > 0:30:51But the real mystery of both woolly mammoths and rhinos
0:30:51 > 0:30:54isn't how they survived appalling cold,
0:30:54 > 0:30:57but what these giants found to eat.
0:30:58 > 0:31:05These were animals that needed up to 200 kilos of food a day.
0:31:11 > 0:31:14And this was nothing like the Serengeti,
0:31:14 > 0:31:17or the jungles of Borneo where elephants live today.
0:31:19 > 0:31:22How could a freezing Ice Age environment
0:31:22 > 0:31:26provide enough food for these mighty giants?
0:31:31 > 0:31:3530,000 years ago, mammoths ranged over a vast area.
0:31:38 > 0:31:42Thanks to lower sea levels, Britain was joined to Europe,
0:31:42 > 0:31:49and Siberia to Alaska, north of America's great ice sheet,
0:31:49 > 0:31:54which meant mammoths could have walked an unbroken belt
0:31:54 > 0:31:58all the way from Britain to the Canadian Yukon.
0:32:12 > 0:32:16Today, it's in this far-flung corner of the mammoths' world -
0:32:16 > 0:32:21the Yukon - that their lost habitat is uniquely well preserved.
0:32:33 > 0:32:36Mammoth remains were first identified in the Yukon
0:32:36 > 0:32:40when they were discovered by miners of the Klondike gold rush.
0:32:50 > 0:32:55A century on, and things are a bit more organised.
0:32:55 > 0:32:59The territory now has its own official palaeontologist.
0:33:02 > 0:33:05What we have here is a woolly mammoth molar.
0:33:05 > 0:33:06This is a typical iconic
0:33:06 > 0:33:09Ice Age fossil that's found
0:33:09 > 0:33:13from the Yukon, Alaska, Siberia, all over the north.
0:33:13 > 0:33:17The grinding surface on the top of a woolly mammoth tooth
0:33:17 > 0:33:19is very indicative of a large grazer,
0:33:19 > 0:33:22something that eats a lot of grass.
0:33:22 > 0:33:24But sometimes with the palaeontological record,
0:33:24 > 0:33:25you have to look beneath that.
0:33:25 > 0:33:29You have to look at some of the smaller guys that lived here, too.
0:33:29 > 0:33:31They can actually provide us with a lot more information
0:33:31 > 0:33:34in terms of the whole ecosystem, and how it functioned,
0:33:34 > 0:33:36how it was structured during the Ice Age.
0:33:46 > 0:33:50When you look out on these valleys here, this is a mammoth playground.
0:33:50 > 0:33:55This is a huge, huge Serengeti of large mammals during the Ice Ages.
0:33:58 > 0:34:01Today, in the search for gold,
0:34:01 > 0:34:05the ground, still frozen since the Ice Age,
0:34:05 > 0:34:08is broken up with high-pressure hoses...
0:34:12 > 0:34:16..giving Grant a brief chance to hunt for clues
0:34:16 > 0:34:20left behind by one very special Ice Age character.
0:34:23 > 0:34:27Well, we're always looking for these bales of grass heaps.
0:34:27 > 0:34:31These look like little hay bales. But it's just grassy material.
0:34:31 > 0:34:33When we see that in the outcrop
0:34:33 > 0:34:35we know we're dealing with squirrel nests.
0:34:38 > 0:34:42These are the traces of an Ice Age animal,
0:34:42 > 0:34:49one that is still with us today - arctic ground squirrels.
0:34:49 > 0:34:54These endearing rodents once lived under the feet of mammoths.
0:34:54 > 0:34:56Today, they still thrive in the Yukon
0:34:56 > 0:34:59alongside a couple of other Ice Age survivors.
0:35:03 > 0:35:07The reason that the ground squirrel is so useful to Grant
0:35:07 > 0:35:10is that it's one of nature's collectors.
0:35:20 > 0:35:24In the brief summer, the race is on for this male ground squirrel.
0:35:27 > 0:35:31Before he settles down to hibernate, he must eat enough
0:35:31 > 0:35:36to double his bodyweight, collect plants for his bedding,
0:35:36 > 0:35:40and make a cache of seeds, ready for when he wakes up in the spring.
0:35:55 > 0:36:00When winter finally arrives, he goes underground to hibernate.
0:36:02 > 0:36:05This is the most dangerous time of year.
0:36:05 > 0:36:10There's no guarantee that he'll survive the winter.
0:36:10 > 0:36:14Back in the Ice Age, death in hibernation was common.
0:36:16 > 0:36:22Thousands of years later, the frozen remains of ground squirrels
0:36:22 > 0:36:27along with what they collected, are an Ice Age time capsule.
0:36:29 > 0:36:33I think we have a dead squirrel in this nest.
0:36:33 > 0:36:36Oh, yeah, for sure. Oh, wow.
0:36:38 > 0:36:40Look at that.
0:36:40 > 0:36:44Wow. We've got ourselves a whole Arctic ground squirrel skeleton in this nest.
0:36:44 > 0:36:48This guy died during the Ice Age and never made it through hibernation.
0:36:48 > 0:36:50Very interesting.
0:36:52 > 0:36:56Within a few feet of space, there's three squirrel nests,
0:36:56 > 0:37:00this is literally a colony of ground squirrels here during the Ice Age.
0:37:01 > 0:37:06This is a great one. There's some really nice seeds preserved in here.
0:37:15 > 0:37:19The plant remains in the ground squirrel nests
0:37:19 > 0:37:22hold the secret to the woolly mammoth's success.
0:37:31 > 0:37:36I'm seeing here a number of plant species that we typically find
0:37:36 > 0:37:40in Arctic ground squirrel nests. There's a number of buttercups
0:37:40 > 0:37:44and poppy seeds, things like wild rye grass, some bluegrass,
0:37:44 > 0:37:47and these are all the types of plant species
0:37:47 > 0:37:49that really love cold settings,
0:37:49 > 0:37:55so places like mountain tops, and ridge tops, grassland environments.
0:37:55 > 0:37:59It's not just grass, but a wide variety of species,
0:37:59 > 0:38:02creating a robust and productive habitat -
0:38:02 > 0:38:06plenty for mammoths and rhinos to feast on.
0:38:06 > 0:38:10It's not a good place today to be a mammoth in the north
0:38:10 > 0:38:13because there's essentially nothing to eat, but if we go back
0:38:13 > 0:38:15where there's grass everywhere
0:38:15 > 0:38:19and small flowers, very few trees and very few shrubs,
0:38:19 > 0:38:22it's a feeding frenzy for grazing mammals,
0:38:22 > 0:38:25and if you can imagine that sort of grassland environment
0:38:25 > 0:38:29spread all the way from northern Canada, here in the Yukon,
0:38:29 > 0:38:30all the way to England.
0:38:35 > 0:38:40This lost grassland is known as the Mammoth steppe...
0:38:46 > 0:38:48..a source of food for mammoths
0:38:48 > 0:38:52and woolly rhinos that wrapped round half the world.
0:39:02 > 0:39:05Autumn on the European steppe.
0:39:05 > 0:39:08Mammoths mingle with a huge herd of bison
0:39:08 > 0:39:12making their way to winter grazing grounds in France.
0:39:29 > 0:39:30A cave lion waits
0:39:30 > 0:39:33to pick off the weak and the old.
0:39:37 > 0:39:40But there's only one predator
0:39:40 > 0:39:43that is a real threat to the mammoth,
0:39:43 > 0:39:48and it makes the lion look like, well, a pussycat.
0:39:52 > 0:39:55This Ice Age creature was a giant of its kind,
0:39:55 > 0:39:58and it preyed on giants.
0:40:00 > 0:40:04Science has probed it more than any other Ice Age species,
0:40:04 > 0:40:07right down to its genetic makeup.
0:40:09 > 0:40:12Supremely successful hunters and scavengers,
0:40:12 > 0:40:17intelligent, with a huge geographic range,
0:40:17 > 0:40:20one of the largest apes -
0:40:20 > 0:40:24our very own cousins, Neanderthals.
0:40:32 > 0:40:36Neanderthals, with their long, low heads, pronounced brow ridges
0:40:36 > 0:40:40and stocky frames, were better adapted to the cold
0:40:40 > 0:40:44and had already survived several Ice Ages.
0:40:48 > 0:40:53But, for Neanderthals, this Ice Age was to prove more challenging
0:40:53 > 0:40:55than any that had gone before.
0:40:59 > 0:41:04In one site, on the edge of Europe, there is compelling evidence
0:41:04 > 0:41:06that in their struggle to survive,
0:41:06 > 0:41:11Neanderthals turned to the biggest beasts of the steppes.
0:41:12 > 0:41:16It's a cave - La Cotte de Saint-Brelade, on Jersey.
0:41:26 > 0:41:31Matt Pope of University College London wants to show me
0:41:31 > 0:41:35what it looked like 30,000 years ago.
0:41:42 > 0:41:46We're getting a perspective here that Neanderthals would have had approaching it from the bay.
0:41:46 > 0:41:50This would have all been dry land, and you can see, it absolutely dominates this bay
0:41:50 > 0:41:52and it would have dominated the skyline
0:41:52 > 0:41:55out there on the hunting grounds on the plains surrounding this site.
0:41:55 > 0:41:59And these cliffs, which have always been a feature of the Jersey coast
0:41:59 > 0:42:02for the past several hundred thousand years, would have
0:42:02 > 0:42:06just been rising up of this relatively flat, open landscape.
0:42:13 > 0:42:17Excavations spanning nearly a century have revealed
0:42:17 > 0:42:22that generation upon generation of Neanderthals used this cave.
0:42:25 > 0:42:28Now this has got to be one of the most famous Neanderthal sites
0:42:28 > 0:42:30anywhere in the British Isles,
0:42:30 > 0:42:33so what types of animal bones have been found here?
0:42:33 > 0:42:39Well, bone preserves fairly poorly at the site, but it's dominated by abundant amounts
0:42:39 > 0:42:43of mammoth and rhinoceros bone, and we know this isn't just a natural accumulation of animal bone
0:42:43 > 0:42:48because on the bones are clear marks from stone tools.
0:42:51 > 0:42:54And we know exactly what those tools those were.
0:43:00 > 0:43:03This is a hand axe, or a bi-face.
0:43:03 > 0:43:05It's a large symmetrical tool,
0:43:05 > 0:43:08but where they really come into their own
0:43:08 > 0:43:10is where they become an incredible meat knife,
0:43:10 > 0:43:14where just using a rotational hand grip, which kind of picks up
0:43:14 > 0:43:17the tissue, it picks up meat, and then it slices through.
0:43:17 > 0:43:20So having with you a very portable,
0:43:20 > 0:43:23very useable butchery knife is a survival tool in itself.
0:43:23 > 0:43:26That makes sense, especially when we think about earlier ancestors
0:43:26 > 0:43:29who'd have competed with all sorts of formidable predators,
0:43:29 > 0:43:32to be able to cut a carcass up, to be able to take pieces of meat away quickly.
0:43:32 > 0:43:37A tool as simple as this extends any kind of human range.
0:43:37 > 0:43:41It's a technology that extends the abilities of our basic anatomy.
0:43:49 > 0:43:52Before the Neanderthals could butcher a mammoth,
0:43:52 > 0:43:54they had to kill one.
0:43:54 > 0:43:58So how did they hunt these five-tonne behemoths?
0:44:01 > 0:44:06An early theory was that they chased mammoths over the edge of the cliff here.
0:44:06 > 0:44:09But Matt thinks this an unlikely strategy.
0:44:17 > 0:44:20LOUD TRUMPETING
0:44:25 > 0:44:30He's got another theory, based on the shape of the landscape here.
0:44:38 > 0:44:41During Neanderthal occupation,
0:44:41 > 0:44:44with sea levels far lower than today,
0:44:44 > 0:44:48the cave was at the head of a narrow gorge,
0:44:48 > 0:44:49a dead end.
0:44:50 > 0:44:55If you bring a small herd of mammoth within that dead-end valley,
0:44:55 > 0:44:58you stand a good chance of being able to isolate individuals,
0:44:58 > 0:45:01isolate a group of them and kill them through a different way,
0:45:01 > 0:45:04using technology and the Neanderthals' robust physique
0:45:04 > 0:45:06to kill them at close quarters.
0:45:15 > 0:45:20A woolly mammoth, searching for water, follows the path of the gorge.
0:45:23 > 0:45:28He has no idea that he's walked straight into a trap.
0:46:09 > 0:46:12But despite their prowess as hunters,
0:46:12 > 0:46:16Neanderthals were a species threatened with extinction.
0:46:18 > 0:46:21In the north, the great ice sheet was growing,
0:46:21 > 0:46:23locking up more and more water.
0:46:33 > 0:46:39The land began to dry out, and across Eurasia, deserts formed.
0:46:39 > 0:46:44Their dust was scooped up by strong winds and blown westward.
0:46:46 > 0:46:49In the cave in Jersey, above the Neanderthal remains,
0:46:49 > 0:46:54archaeologists discovered a thick layer of this dust.
0:46:54 > 0:46:57Around 35,000 years ago,
0:46:57 > 0:47:01the Neanderthals' cave was suffocated by it.
0:47:08 > 0:47:13Shortly afterwards, Neanderthals disappeared from Jersey.
0:47:16 > 0:47:18Their species now clung on
0:47:18 > 0:47:22in just a few refuges around the Mediterranean.
0:47:26 > 0:47:30As the ice sheet neared its greatest extent,
0:47:30 > 0:47:33there was one final mighty glacial pulse.
0:47:33 > 0:47:39It sent armadas of icebergs out into the North Atlantic.
0:47:42 > 0:47:46As they melted, the ocean cooled.
0:47:46 > 0:47:49This time, the continent was plunged
0:47:49 > 0:47:52into the coldest period of this last Ice Age.
0:47:57 > 0:48:02Average global temperature plunged to 12 degrees below that of today.
0:48:11 > 0:48:17By now, Neanderthals had become yet another Ice Age species to go extinct.
0:48:26 > 0:48:29The climate was partly to blame.
0:48:29 > 0:48:33But it's also very likely that it had something to do
0:48:33 > 0:48:37with the arrival of some new immigrants.
0:48:46 > 0:48:50Our own species, homo sapiens, began colonising Europe
0:48:50 > 0:48:55just 20,000 years before the peak of the last Ice Age.
0:48:55 > 0:49:00Our ancestors didn't have the physical adaptations of Neanderthals
0:49:00 > 0:49:04and they weren't proven Ice Age survivors.
0:49:05 > 0:49:12So how come our ancestors survived while the Neanderthals died out?
0:49:15 > 0:49:20During the Ice Age, modern humans spread right across Europe and Asia,
0:49:20 > 0:49:22right up to the coast of the Arctic Ocean.
0:49:22 > 0:49:25But as the last glacial maximum approached
0:49:25 > 0:49:28and conditions worsened, they sought refuge in the south.
0:49:28 > 0:49:32Even there, though, the climate was harsh,
0:49:32 > 0:49:34but they found ways of surviving.
0:49:34 > 0:49:37Using the natural resources available to them,
0:49:37 > 0:49:40they eked out a living in the challenging environment
0:49:40 > 0:49:44of central Europe and southern Siberia.
0:49:53 > 0:49:56Evidence of their survival skills has been found here,
0:49:56 > 0:50:01in the town of Zaraysk, on the banks of the Osyotr River, in Russia.
0:50:04 > 0:50:09A mediaeval fortress now stands on this spot, but excavations show
0:50:09 > 0:50:14that humans were making their home here 20,000 years ago.
0:50:20 > 0:50:25And there are clues as to how they survived the Ice Age.
0:50:30 > 0:50:32Those ancient hunter-gatherers used
0:50:32 > 0:50:35whatever material they could lay their hands on,
0:50:35 > 0:50:38and there was one material in particular that was to be found
0:50:38 > 0:50:43in great abundance across swathes of Europe and Asia at the time,
0:50:43 > 0:50:46and that was the remains of woolly mammoths -
0:50:46 > 0:50:48their bones and their tusks.
0:51:01 > 0:51:03Sergey Lev leads the project.
0:51:30 > 0:51:34Trees were scarce during the Ice Age,
0:51:34 > 0:51:39and mammoth bones, teeth and tusks offered an alternative fuel.
0:51:45 > 0:51:50200,000 artefacts have already been found here,
0:51:50 > 0:51:55some of which suggest an ingenuity not known in Neanderthals.
0:51:56 > 0:52:00This is a really beautiful example of something that would have been used
0:52:00 > 0:52:03probably for piercing or for drilling.
0:52:03 > 0:52:06Some kind of material, probably quite hard material,
0:52:06 > 0:52:10and we can tell just from the lovely slender shape and the fact
0:52:10 > 0:52:13that there's all this wear around the top,
0:52:13 > 0:52:17they've shaped it very carefully to begin with
0:52:17 > 0:52:20and then we have additional wear on top of that.
0:52:20 > 0:52:24- So that's been used to drill through something?- It could be ivory.
0:52:24 > 0:52:27- You think it's for ivory working? - Yeah, it could be ivory.- Yeah.
0:52:31 > 0:52:33The archaeologists have discovered
0:52:33 > 0:52:36some really ingenious uses for mammoth remains.
0:52:43 > 0:52:47Tusks were driven into the ground to form a frame.
0:52:53 > 0:52:57Sergey believes that traces of organic material suggest
0:52:57 > 0:53:01that hides were stretched over the top, to form a roof.
0:53:09 > 0:53:12These semi-subterranean pit dwellings
0:53:12 > 0:53:16are some of the very first houses ever built.
0:53:20 > 0:53:27Our ancestors had been using Ice Age giants to survive.
0:53:34 > 0:53:39The technology used by these people, surviving in extreme conditions,
0:53:39 > 0:53:43during the peak of the last Ice Age, is a fantastic example
0:53:43 > 0:53:46of the ingenuity and adaptability of our species.
0:53:46 > 0:53:51But it wasn't just about building shelters and making stone tools.
0:53:51 > 0:53:54The archaeologists here at Zaraysk have uncovered
0:53:54 > 0:53:59some truly beautiful and enigmatic objects.
0:54:10 > 0:54:14Many of them speak to us of the close relationship
0:54:14 > 0:54:20that our ancestors had with the Ice Age giants, whose world they shared.
0:54:27 > 0:54:31This bison, carved from mammoth ivory, represents an animal
0:54:31 > 0:54:34that must have been key to the survival of the people
0:54:34 > 0:54:37who lived here during the Ice Age.
0:54:37 > 0:54:42It takes time and effort to carve something this beautifully,
0:54:42 > 0:54:44and I would love to know what it meant
0:54:44 > 0:54:48to the person who made it and to his or her community.
0:54:48 > 0:54:52Was it an object of great ritual significance?
0:54:52 > 0:54:55An object that was perhaps revered?
0:54:55 > 0:54:58Was it something used to teach children
0:54:58 > 0:55:01about the animals that they would hunt when they grew up?
0:55:01 > 0:55:05There are some things that we will never know.
0:55:05 > 0:55:10But how wonderful to have this intimate connection
0:55:10 > 0:55:12to those Ice Age hunters.
0:55:25 > 0:55:30For our ancestors, these animals were sources of food,
0:55:30 > 0:55:33clothing, and building materials.
0:55:33 > 0:55:36They may even have worshipped them.
0:55:48 > 0:55:55These images of lions, bison, woolly rhino,
0:55:55 > 0:55:58woolly mammoths
0:55:58 > 0:56:03and cave bears are from Chauvet cave in southern France.
0:56:09 > 0:56:13Animals which, along with our own species,
0:56:13 > 0:56:15battled against the Ice Age.
0:56:18 > 0:56:20Right across the Northern Hemisphere,
0:56:20 > 0:56:24in Eurasia and North America, the temperatures plummeted
0:56:24 > 0:56:28to the lowest they'd been for thousands of years.
0:56:28 > 0:56:32The changing climate and environment put large numbers of species
0:56:32 > 0:56:38under enormous pressure, driving many to the brink of extinction.
0:56:39 > 0:56:43But many species survived through the peak of the last Ice Age,
0:56:43 > 0:56:47and what's really surprising is that it wasn't those years,
0:56:47 > 0:56:52those millennia of intense cold, that finally finished them off -
0:56:52 > 0:56:56it was what happened next as the world began to warm up
0:56:56 > 0:57:01and the great ice sheets of the north started to melt.
0:57:15 > 0:57:17Join me next time as I revisit
0:57:17 > 0:57:20the Ice Age landscapes of the Northern Hemisphere.
0:57:29 > 0:57:34I'll discover what it took to survive the Ice Age...
0:57:36 > 0:57:42..and find out why so few of the megafauna are still with us today.
0:57:50 > 0:57:54It's been a mystery for over a hundred years,
0:57:54 > 0:57:57but new discoveries tell a surprising story
0:57:57 > 0:58:02of what finally killed off the Ice Age giants.
0:58:32 > 0:58:35Subtitles by Red Bee Media Ltd