1
00:00:04,805 --> 00:00:07,774
21st century, North America,

2
00:00:09,842 --> 00:00:13,712
where people have reached even
the remotest corners of the continent

3
00:00:13,812 --> 00:00:17,382
and pushed back the boundaries
of modern technology.

4
00:00:33,161 --> 00:00:37,531
But it isn't so long since
humans first set foot here,

5
00:00:37,598 --> 00:00:40,233
about 14,000 years ago.

6
00:00:40,500 --> 00:00:45,071
And back then North America
belonged to other creatures

7
00:00:45,137 --> 00:00:49,574
of the size to match
this vast land.

8
00:00:50,208 --> 00:00:55,112
Giants whose lives are now
lost in the shadows.

9
00:01:20,866 --> 00:01:23,735
Imagine if we could
travel back in time

10
00:01:23,835 --> 00:01:26,137
to the end
of the last Ice Age,

11
00:01:26,237 --> 00:01:29,740
long before the first
city was born

12
00:01:36,545 --> 00:01:40,715
to look through the eyes
of the very first people

13
00:01:47,321 --> 00:01:52,492
and experience a wild new world.

14
00:02:07,270 --> 00:02:11,373
In this series we will take you
on a journey back into the past

15
00:02:11,473 --> 00:02:15,677
to build a picture of how things
were at the end of the last Ice Age,

16
00:02:15,744 --> 00:02:18,679
14 thousand years ago.

17
00:02:31,556 --> 00:02:34,826
By searching for evidence
that still survives today

18
00:02:34,926 --> 00:02:37,761
we reconstruct the landscape
and the wildlife

19
00:02:37,828 --> 00:02:40,764
of prehistoric North America.

20
00:02:56,076 --> 00:02:58,078
During the last Ice Age

21
00:02:58,144 --> 00:03:01,947
massive glaciers covered
half of North America.

22
00:03:10,187 --> 00:03:12,489
But to the far north west

23
00:03:12,589 --> 00:03:15,858
there was a land
that remained free of ice.

24
00:03:16,959 --> 00:03:19,728
This land was called Beringia

25
00:03:19,795 --> 00:03:24,132
and it ranged from what we now know
as the Canadian Yukon and Alaska

26
00:03:24,199 --> 00:03:27,268
across to Siberia
in the west.

27
00:03:29,436 --> 00:03:34,273
NA was only colonized
by people around 14,000 years ago.

28
00:03:34,540 --> 00:03:37,443
And Beringia is believed
to be the starting point

29
00:03:37,509 --> 00:03:40,478
from which they spread out
across the continent.

30
00:03:53,622 --> 00:03:58,126
In this programme we'll go back
to where it all began.

31
00:03:58,593 --> 00:04:01,929
What was this wild
new world really like

32
00:04:01,996 --> 00:04:06,566
when it was still
the Land of the Mammoth?

33
00:04:27,483 --> 00:04:30,452
These mountain glaciers
in the Canadian Yukon

34
00:04:30,518 --> 00:04:32,387
are relics of the great ice sheets

35
00:04:32,453 --> 00:04:36,790
that reached their peaks
some 20,000 years ago.

36
00:04:42,828 --> 00:04:46,231
The Yukon and its neighbour,
modern day Alaska,

37
00:04:46,331 --> 00:04:50,101
were once part of the land
that was Beringia.

38
00:04:56,273 --> 00:04:58,941
Stunning though
this region is today,

39
00:04:59,008 --> 00:05:01,643
it's just a shadow of the world
that was encountered

40
00:05:01,710 --> 00:05:03,979
by the first Americans.

41
00:05:04,679 --> 00:05:07,615
Underground, the soil is frozen solid

42
00:05:07,682 --> 00:05:10,184
as it has been ever since the Ice Age.

43
00:05:15,955 --> 00:05:18,023
Locked within this permafrost,

44
00:05:18,090 --> 00:05:23,294
are vital clues to help us recreate
the ancient wildlife of Beringia.

45
00:05:32,335 --> 00:05:39,340
Even today Alaska's rivers wash intriguing
traces of the past out of the permafrost.

46
00:05:45,612 --> 00:05:49,482
So who did this titanic tusk belong to?

47
00:05:54,986 --> 00:05:57,388
Beringia's largest resident

48
00:05:57,455 --> 00:05:59,023
- the woolly mammoth.

49
00:06:07,063 --> 00:06:09,131
Weighing six tonnes or more,

50
00:06:09,198 --> 00:06:13,635
the woolly mammoth was about the
size of a bull African elephant today

51
00:06:15,369 --> 00:06:18,972
and it had equally impressive
Ice Age neighbours,

52
00:06:19,039 --> 00:06:22,475
some of which survive
here almost unchanged,

53
00:06:22,775 --> 00:06:26,312
and some of which
can still be found elsewhere.

54
00:06:32,917 --> 00:06:37,821
Although 14,000 years is long enough
to see enormous climate changes,

55
00:06:37,988 --> 00:06:42,124
in evolutionary terms
it's just the blink of an eye.

56
00:06:45,927 --> 00:06:52,299
Beringia was a world where familiar
North American  animals lived
alongside prehistoric giants.

57
00:07:21,456 --> 00:07:28,261
Of all these creatures, the woolly
mammoth  is the undisputed symbol of
the Ice Age.

58
00:07:31,531 --> 00:07:35,167
But what do we really know
about how this giant lived?

59
00:07:35,234 --> 00:07:39,003
How did it use
its massive spiral tusks?

60
00:07:47,443 --> 00:07:51,280
Modern day elephants,  who are
mammoths' closest living relatives,

61
00:07:51,346 --> 00:07:53,782
may provide some answers.

62
00:07:54,382 --> 00:07:59,453
They use tusks to break and lever
branches in their search for food,

63
00:08:03,289 --> 00:08:05,591
and also to dig for minerals,

64
00:08:05,658 --> 00:08:09,361
which all leaves telltale
scratches on their tusks.

65
00:08:09,428 --> 00:08:14,298
Similar marks found on mammoth tusks
suggest they, too, were used as tools.

66
00:08:14,398 --> 00:08:16,267
But these tusks are huge.

67
00:08:16,367 --> 00:08:18,101
They reach 4 metres long

68
00:08:18,168 --> 00:08:22,438
and can weigh more than 80 kilos,
equal to a full-grown man.

69
00:08:22,505 --> 00:08:25,908
So why were
mammoth tusks so big?

70
00:08:48,025 --> 00:08:50,894
Bull elephants fight
for the right to mate.

71
00:08:50,961 --> 00:08:53,730
The strongest males
win access to the females

72
00:08:53,797 --> 00:08:55,898
and pass on their genes.

73
00:08:57,933 --> 00:09:00,569
It was the same
for mammoth bulls.

74
00:09:00,669 --> 00:09:05,706
And over time this competition led
to the development of ever larger tusks.

75
00:09:07,608 --> 00:09:11,044
Sheer size didn't save
the mammoth from extinction.

76
00:09:11,578 --> 00:09:15,848
But another of Beringia's woolly
beasts  is still around today:

77
00:09:18,216 --> 00:09:20,818
the musk ox.

78
00:09:27,090 --> 00:09:29,158
Like other Ice Age survivors,

79
00:09:29,425 --> 00:09:33,562
musk oxen have hardly
changed in 14 millennia.

80
00:09:44,070 --> 00:09:47,840
Every autumn males compete
to father young

81
00:09:47,907 --> 00:09:51,943
until a single dominant bull
emerges in the herd.

82
00:10:00,984 --> 00:10:03,286
An Ice Age drama unfolds

83
00:10:03,353 --> 00:10:06,455
as rivals thrash out
threat displays.

84
00:10:19,999 --> 00:10:22,435
The two bulls size
one another up

85
00:10:22,501 --> 00:10:25,637
by walking
in ritualised circles.

86
00:10:50,123 --> 00:10:51,558
A brief chase

87
00:10:51,691 --> 00:10:54,160
and the matter is resolved.

88
00:11:07,638 --> 00:11:10,006
The winner takes all.

89
00:11:19,781 --> 00:11:23,384
While the musk ox still
survives in North America,

90
00:11:23,484 --> 00:11:26,986
many of Beringia's other
Ice Age mammals are now extinct.

91
00:11:27,120 --> 00:11:28,821
But like the mammoth,

92
00:11:28,888 --> 00:11:32,391
they left clues locked
within the permafrost.

93
00:11:39,730 --> 00:11:42,999
Gold miners in Alaska
use high-powered water jets

94
00:11:43,066 --> 00:11:46,235
to thaw the permafrost
in search of gold.

95
00:11:46,302 --> 00:11:47,670
But every now and then

96
00:11:47,836 --> 00:11:50,572
they hit another kind of treasure.

97
00:11:56,010 --> 00:11:59,579
In one remarkable
discovery, recreated here,

98
00:11:59,646 --> 00:12:03,416
the head and hide
of a large carcass was exposed,

99
00:12:03,549 --> 00:12:08,053
a unique opportunity to scientists
to tap some Ice Age secrets.

100
00:12:14,958 --> 00:12:18,294
The remains were of an
extinct steppe bison,

101
00:12:18,361 --> 00:12:22,331
along the horned relative
of the North American bison of today,

102
00:12:22,731 --> 00:12:24,833
an adult bull
that must have died

103
00:12:24,900 --> 00:12:26,568
being immersed in silt

104
00:12:26,634 --> 00:12:30,771
and mummified by the cold
for thousands of years.

105
00:12:31,872 --> 00:12:34,574
Thick fat deposits found under the skin

106
00:12:34,641 --> 00:12:37,910
suggested that the bison
did not starve to death,

107
00:12:37,977 --> 00:12:42,514
and deep wide scratch marks
hinted at a violent end.

108
00:12:42,681 --> 00:12:45,516
An Ice Age predator
killed the bison.

109
00:12:45,916 --> 00:12:47,384
But which one?

110
00:12:49,152 --> 00:12:53,189
Wolves are the bison's major
predators in North America today

111
00:12:53,289 --> 00:12:56,325
and they were certainly
around during the Ice Age.

112
00:12:56,592 --> 00:12:58,827
Could they have
been responsible?

113
00:13:08,768 --> 00:13:11,804
Wolves hunt in packs surrounding prey

114
00:13:11,871 --> 00:13:15,841
and gradually exhausting it
through constant hurrying and nipping.

115
00:13:15,907 --> 00:13:19,543
But there's no way
they could have made these marks.

116
00:13:25,248 --> 00:13:27,250
What about the grizzly bear,

117
00:13:27,350 --> 00:13:31,687
another meat-eater that was around
in prehistoric North America?

118
00:13:51,136 --> 00:13:53,804
The grizzly can be
an impressive hunter,

119
00:13:55,472 --> 00:14:01,377
but during the Ice Age
there was another, even bigger, bear -

120
00:14:07,048 --> 00:14:09,884
the Giant Short-Faced Bear -

121
00:14:09,984 --> 00:14:13,187
the biggest bear that ever lived.

122
00:14:14,321 --> 00:14:18,357
So could a bear have made the
scratch marks on the goldmine bison?

123
00:14:25,530 --> 00:14:27,465
Bears have long claws,

124
00:14:27,531 --> 00:14:30,300
but they get worn down
by the daily grind

125
00:14:31,034 --> 00:14:34,037
moving around
and rooting for food.

126
00:14:34,137 --> 00:14:38,040
They're just not sharp enough
to rip into the bison's hide.

127
00:14:43,811 --> 00:14:47,648
To solve this puzzle
we need to look to Africa.

128
00:14:47,814 --> 00:14:52,251
African buffalo are similar
in size to the extinct steppe bison.

129
00:14:52,485 --> 00:14:55,320
So what is
their foremost predator?

130
00:14:58,923 --> 00:15:00,858
The lion.

131
00:15:02,159 --> 00:15:04,128
Lions, unlike bears,

132
00:15:04,194 --> 00:15:06,496
have their claws sheathed
most of the time

133
00:15:06,563 --> 00:15:09,065
to keep them razor-sharp.

134
00:15:10,266 --> 00:15:11,533
But when they strike

135
00:15:11,600 --> 00:15:15,537
their claws extend to get
a good grip on the victim's hide.

136
00:15:15,603 --> 00:15:21,141
This often leaves deep gauges just
like those found on the mummified bison.

137
00:15:30,782 --> 00:15:32,550
And there's a second clue:

138
00:15:32,851 --> 00:15:37,421
the most efficient way
to kill large prey is suffocation.

139
00:15:37,521 --> 00:15:43,192
Lions typically clamp their jaws around
the victim's muzzle in a deadly bite.

140
00:15:44,827 --> 00:15:48,663
Our Ice Age bison had a set
of puncture marks on its snout,

141
00:15:48,730 --> 00:15:51,132
around 9 cm apart,

142
00:15:51,199 --> 00:15:54,701
the blueprint of a lion's bite.

143
00:15:55,502 --> 00:15:59,706
The third and final clue was found
embedded in the bison's hide,

144
00:15:59,806 --> 00:16:03,275
a tiny fragment of lion tooth.

145
00:16:07,812 --> 00:16:10,381
So it seems the king
of the savannah

146
00:16:10,447 --> 00:16:14,984
once roamed the cold expanses
of Ice Age America.

147
00:16:22,557 --> 00:16:24,892
These long-lost lions of Beringia

148
00:16:24,959 --> 00:16:28,662
were close relatives
of those we find in Africa today,

149
00:16:28,729 --> 00:16:31,631
but they were up
to 25 percent bigger,

150
00:16:31,698 --> 00:16:35,701
amongst the largest lions
that ever walked the Earth.

151
00:16:36,135 --> 00:16:39,037
Thanks to the bison herds
and other big game

152
00:16:39,104 --> 00:16:42,373
they could flourish
in the freezing north.

153
00:16:42,573 --> 00:16:45,843
But the lion's family tree
begins in Africa.

154
00:16:46,076 --> 00:16:48,778
so how did they
end up here?

155
00:16:52,114 --> 00:16:57,185
The answer lies in the effects of
North America's immense
and fluctuating ice sheets.

156
00:16:57,252 --> 00:16:58,419
As they grew,

157
00:16:58,486 --> 00:17:00,288
they locked up so much water

158
00:17:00,354 --> 00:17:03,090
that the sea levels began to fall.

159
00:17:07,260 --> 00:17:11,830
The Bering Sea between Asia
and North America began to drain away,

160
00:17:11,897 --> 00:17:15,133
leaving a bridge of land exposed,

161
00:17:15,900 --> 00:17:17,935
the Bering Land Bridge,

162
00:17:18,035 --> 00:17:20,570
roughly a thousand miles wide

163
00:17:20,637 --> 00:17:24,140
and covering an area twice that
of modern Texas.

164
00:17:24,507 --> 00:17:26,609
This was the route by which lions,

165
00:17:26,675 --> 00:17:32,146
woolly mammoths and other creatures
colonised the American continent.

166
00:17:49,060 --> 00:17:53,630
During the last Ice Age
the Bering Land Bridge formed once more

167
00:17:53,730 --> 00:17:57,133
and this time it allowed
a different colonist across,

168
00:17:57,233 --> 00:18:02,304
one that would have a huge and
permanent effect upon the continent.

169
00:18:02,638 --> 00:18:05,240
This is one
of their first known haunts -

170
00:18:05,373 --> 00:18:07,975
the Mesa site
in northern Alaska,

171
00:18:08,075 --> 00:18:11,144
a key point on the Ice Age map.

172
00:18:17,883 --> 00:18:21,052
Beautifully crafted
spear points found here

173
00:18:21,119 --> 00:18:24,956
are known to date back
almost 14,000 years

174
00:18:25,056 --> 00:18:28,125
and tell us that the first people
to cross the land bridge

175
00:18:28,225 --> 00:18:31,894
were skilled sophisticated hunters.

176
00:18:49,876 --> 00:18:53,245
But what were they doing
on this particular spot?

177
00:18:53,345 --> 00:18:54,980
The climate was harsh,

178
00:18:55,046 --> 00:18:58,182
the location extremely exposed.

179
00:18:58,282 --> 00:19:01,418
It's not a place you choose
to make a campsite.

180
00:19:02,419 --> 00:19:04,254
But if you were a hunter

181
00:19:04,554 --> 00:19:06,589
what you need it was a view.

182
00:19:06,689 --> 00:19:09,258
The Mesa was the perfect
lookout point

183
00:19:09,358 --> 00:19:13,094
with panoramas
of surrounding land and game.

184
00:19:14,162 --> 00:19:17,631
These early hunters had spread
all the way from Asia.

185
00:19:17,698 --> 00:19:21,968
What did they find
on the other side of the Bering Bridge?

186
00:19:25,404 --> 00:19:27,272
This is Alaska today -

187
00:19:27,873 --> 00:19:33,444
a wetland of forests,
boggy tundra, lakes and rivers;

188
00:19:38,081 --> 00:19:43,485
rivers that still churn out
fresh clues to the Ice Age past.

189
00:19:46,354 --> 00:19:48,890
This is a brick-size tooth.

190
00:19:48,956 --> 00:19:51,158
And it belonged
to a woolly mammoth.

191
00:19:51,959 --> 00:19:53,794
Its narrow ridges of enamel

192
00:19:53,860 --> 00:19:56,629
tell us more about
how mammoth lived.

193
00:19:58,164 --> 00:20:04,102
Studies of modern elephants suggest
that  the more grassy weed, the more
ridges you need,

194
00:20:04,202 --> 00:20:09,206
and mammoth tooth had even more
ridges than those of any elephants.

195
00:20:10,807 --> 00:20:14,610
It seems that mammoths
fed almost exclusively on grass,

196
00:20:14,677 --> 00:20:17,246
they were gargantuan grazers.

197
00:20:27,554 --> 00:20:31,857
Fossil bones help draw a picture
of another well known grazer,

198
00:20:31,924 --> 00:20:34,026
a kind of horse.

199
00:20:37,896 --> 00:20:40,564
Wild horses live in small herds

200
00:20:40,631 --> 00:20:46,069
and Beringia would have been the scene of
vicious battles between rival stallions.

201
00:21:23,532 --> 00:21:26,268
But Beringia's horses
are now gone.

202
00:21:26,368 --> 00:21:32,439
Today their closest living relatives
roam the open steppes of Central Asia.

203
00:21:32,506 --> 00:21:36,409
Like mammoths, horses are
predominantly grazers.

204
00:21:51,822 --> 00:21:54,591
The fact that both horses
and mammoths were here

205
00:21:54,657 --> 00:21:57,159
suggests these forests weren't.

206
00:21:57,293 --> 00:22:00,195
It seems that 14,000 years ago

207
00:22:00,262 --> 00:22:04,866
Beringia was a huge expanse
of open grassland.

208
00:22:12,372 --> 00:22:15,908
This unique habitat
of cold dry grasslands

209
00:22:15,974 --> 00:22:19,177
is known as mammoths' steppe.

210
00:22:20,678 --> 00:22:23,581
But that's not
how the region looks today.

211
00:22:23,647 --> 00:22:26,383
So why is it so different?

212
00:22:31,454 --> 00:22:33,322
14,000 years ago

213
00:22:33,489 --> 00:22:39,527
the climate here was heavily influenced
by the vast blankets of ice to the east.

214
00:23:56,956 --> 00:24:01,960
At its maximum the ice covered
nearly 6 million square miles

215
00:24:02,026 --> 00:24:06,330
and in places it was up
to two miles thick.

216
00:24:12,001 --> 00:24:16,705
The ice blanket was punctuated
only by occasional islands of rock,

217
00:24:16,772 --> 00:24:20,341
the peaks of the very
highest mountains.

218
00:24:39,023 --> 00:24:42,926
Though Beringia itself
remained largely ice-free

219
00:24:42,993 --> 00:24:46,128
it still felt the effects
of the ice sheets -

220
00:24:46,195 --> 00:24:49,264
cold dry air flowed
down the glaciers

221
00:24:49,331 --> 00:24:52,233
and out across surrounding lands.

222
00:24:54,835 --> 00:24:57,871
The freezing dry winds
blasting off the ice

223
00:24:57,938 --> 00:25:03,409
created conditions in which only grasses
and other small plants could flourish.

224
00:25:06,545 --> 00:25:08,580
There were advantages:

225
00:25:08,713 --> 00:25:11,716
the wind also prevented
snow from building up

226
00:25:11,782 --> 00:25:15,218
so grass remained accessible
throughout the year.

227
00:25:15,319 --> 00:25:17,120
In such cold temperatures

228
00:25:17,187 --> 00:25:22,324
this was a lifeline for the mammoths,
bison and other grazers,

229
00:25:25,760 --> 00:25:30,798
which in turn sustained
other beasts of Beringia.

230
00:25:42,574 --> 00:25:46,744
Another widespread Beringian animal
that depended on the Ice Age wind

231
00:25:46,811 --> 00:25:48,845
was the Dall sheep.

232
00:25:49,780 --> 00:25:53,850
Dall sheep needed the snow to be
blown clear from their winter grazing

233
00:25:53,916 --> 00:25:56,151
and today they have
the same priority.

234
00:25:56,819 --> 00:26:01,589
They're found only on the most exposed
and windswept mountain slopes.

235
00:26:07,627 --> 00:26:12,431
In the autumn Dall rams,
like the mammoths and the musk oxen,

236
00:26:12,498 --> 00:26:14,900
become focused
on their urge to mate.

237
00:26:24,908 --> 00:26:27,076
The male flicks
the air with his tongue

238
00:26:27,143 --> 00:26:29,645
to test if
the ewe is receptive.

239
00:26:29,945 --> 00:26:32,948
The next stage of courtship
is not so subtle -

240
00:26:33,281 --> 00:26:34,916
he gives her a kick.

241
00:26:47,759 --> 00:26:50,262
At this highly
charged time of year

242
00:26:50,395 --> 00:26:53,764
skirmishes can easily erupt
between the rams,

243
00:27:06,541 --> 00:27:10,578
especially if they both have
the same ewe in their sights.

244
00:27:35,264 --> 00:27:37,633
But though there was
food in Beringia,

245
00:27:37,700 --> 00:27:41,169
it was still cold, bitterly cold.

246
00:27:41,436 --> 00:27:42,604
For much of the year

247
00:27:42,704 --> 00:27:47,841
temperatures would have remained
below freezing 24 hours a day.

248
00:27:47,908 --> 00:27:52,745
How did the Ice Age animals
survive in such a harsh world?

249
00:27:55,447 --> 00:27:58,650
The more hair the better
for a start.

250
00:27:59,217 --> 00:28:04,054
Musk oxen can stay warm in
temperatures of -50 degrees centigrade.

251
00:28:04,121 --> 00:28:06,890
thanks to their chill proof
woolly coats.

252
00:28:06,990 --> 00:28:10,860
In fact, they have
the warmest fur of any mammal.

253
00:28:11,026 --> 00:28:13,462
They have an extremely
long outer layer

254
00:28:13,628 --> 00:28:17,465
over another very dense
fine wool layer beneath,

255
00:28:17,532 --> 00:28:19,433
a combination so effective

256
00:28:19,500 --> 00:28:25,305
that even in winter the musk ox
can overheat if it runs too far.

257
00:28:26,272 --> 00:28:28,173
From frozen mammoth remains

258
00:28:28,274 --> 00:28:31,209
we know they had
a very similar fur coat

259
00:28:31,309 --> 00:28:35,112
made up of strands of hair
up to a metre long.

260
00:28:41,885 --> 00:28:45,387
Small ears also help
to minimize heat loss,

261
00:28:45,554 --> 00:28:51,692
the opposite effect of those huge heat
dispersing  ears of their relatives,
African elephants.

262
00:28:53,227 --> 00:28:58,331
Other Beringian animals had more than
a fur coat to help them cope with cold.

263
00:29:07,605 --> 00:29:12,142
This skull belongs to the bizarre
looking Saiga antelope,

264
00:29:14,744 --> 00:29:18,614
one of the less familiar faces
of the Ice Age scene.

265
00:29:27,955 --> 00:29:29,556
Like the musk ox,

266
00:29:29,623 --> 00:29:35,227
Saiga have a thick winter coat
of hollow hairs for extra insulation.

267
00:29:40,498 --> 00:29:43,768
But they have another
adaptation all of their own -

268
00:29:43,868 --> 00:29:47,370
an enormous bulbous nose.

269
00:29:53,776 --> 00:29:58,213
The nose is shaped
like this because it contains large

270
00:29:58,313 --> 00:30:01,148
which pre-warm cold air
while breathing in

271
00:30:01,215 --> 00:30:05,285
and retain pressure's moisture
before breathing out.

272
00:30:06,052 --> 00:30:11,256
So Saiga, too, were well equipped to
live in a cold dry climate of Beringia.

273
00:30:13,925 --> 00:30:17,995
Today, they're only found
in another bleak environment -

274
00:30:18,062 --> 00:30:20,464
the steppes of Central Asia.

275
00:30:26,268 --> 00:30:31,306
Some Ice Age animals took a totally
different approach to surviving in
winter.

276
00:30:32,307 --> 00:30:35,176
Arctic ground squirrels
feed up in autumn

277
00:30:35,242 --> 00:30:37,644
building up as much
body fat as possible,

278
00:30:37,744 --> 00:30:39,713
almost doubling their weight.

279
00:30:40,813 --> 00:30:42,915
As the first snows fall

280
00:30:43,049 --> 00:30:45,417
they retreat
to their underground burrows

281
00:30:45,517 --> 00:30:48,386
and bypass the winter entirely.

282
00:30:59,095 --> 00:31:02,898
Arctic ground squirrels hibernate
like other small mammals,

283
00:31:02,998 --> 00:31:05,066
but with a unique twist -

284
00:31:05,333 --> 00:31:11,038
they can lower their body temperature
right down to almost -3 degrees
centigrade.

285
00:31:11,171 --> 00:31:14,307
But thanks to our biochemical
supercooling process

286
00:31:14,407 --> 00:31:16,742
they don't actually freeze.

287
00:31:25,783 --> 00:31:30,387
Every few weeks they warm up
temporarily through bouts of shivering,

288
00:31:30,487 --> 00:31:34,890
which probably helps to ward off
permanent brain damage from the cold.

289
00:31:39,694 --> 00:31:43,897
This deep sleep tactic helps the
ground squirrels to conserve energy,

290
00:31:43,997 --> 00:31:45,699
but it's a high risk strategy.

291
00:31:45,799 --> 00:31:47,901
and some just don't wake up.

292
00:31:48,001 --> 00:31:51,670
30,000 year old frozen
ground squirrels have been discovered

293
00:31:51,737 --> 00:31:54,806
still preserved
in their underground tombs.

294
00:32:04,080 --> 00:32:08,851
Every inhabitant of Beringia had to
have its own way of dealing with the
cold

295
00:32:08,918 --> 00:32:14,222
and that included those first people who
arrived across the Bering Land Bridge.

296
00:32:14,455 --> 00:32:18,358
They knew how to make weapons
and cooperate to hunt for food.

297
00:32:18,425 --> 00:32:21,227
They made weather proof
clothing out of animal hides

298
00:32:21,327 --> 00:32:23,930
and had fire
to keep them warm.

299
00:32:24,130 --> 00:32:29,668
Without these skills they couldn't
have survived the endless winters.

300
00:32:47,448 --> 00:32:50,451
But spring bought easier times

301
00:32:50,518 --> 00:32:53,420
and excellent
hunting opportunities.

302
00:33:03,862 --> 00:33:08,399
Spring was when Beringia's
big game gave birth to their young.

303
00:33:20,975 --> 00:33:25,446
For these baby animals it was a race
to go up over the brief summer

304
00:33:25,546 --> 00:33:28,448
to be tough enough
to face the winter.

305
00:33:50,666 --> 00:33:53,502
One young animal that died
in its first winter

306
00:33:53,602 --> 00:33:57,071
was discovered in the permafrost
of an Alaskan goldmine.

307
00:34:01,341 --> 00:34:08,013
Recreated here are the best mummified
remains  of this animal ever found in
North America.

308
00:34:13,084 --> 00:34:15,319
It's a baby woolly mammoth

309
00:34:15,553 --> 00:34:19,556
and from its size we know
it was less than a year old.

310
00:34:19,623 --> 00:34:21,424
But did it starve to death

311
00:34:21,557 --> 00:34:23,726
or was taken by a predator?

312
00:34:26,395 --> 00:34:29,631
Perhaps young elephants
provide some clues.

313
00:34:29,897 --> 00:34:33,367
They stick close to their mothers'
side for more than a year.

314
00:34:33,567 --> 00:34:35,535
And they also have backup -

315
00:34:35,635 --> 00:34:39,839
a family group of very
protective sisters and aunts.

316
00:34:40,873 --> 00:34:44,876
Even lions will think twice
about approaching adult elephants.

317
00:34:44,976 --> 00:34:47,145
And with the babies
so well guarded

318
00:34:47,211 --> 00:34:50,014
they really get
a chance to strike.

319
00:35:04,292 --> 00:35:06,860
Starvation during
its first bitter winter

320
00:35:06,927 --> 00:35:09,696
is more likely to have killed
our baby mammoth.

321
00:35:09,763 --> 00:35:13,332
Perhaps its mother could not
provide enough warm milk.

322
00:35:15,034 --> 00:35:17,202
Only part of the body remains.

323
00:35:17,269 --> 00:35:19,237
The hindquarters were eaten.

324
00:35:19,437 --> 00:35:23,674
There were plenty of scavengers
around 14,000 years ago.

325
00:35:26,176 --> 00:35:27,811
There were foxes,

326
00:35:28,778 --> 00:35:30,346
wolves

327
00:35:30,680 --> 00:35:33,148
and grizzly bears.

328
00:35:38,886 --> 00:35:42,322
But back then
they had serious competition

329
00:35:42,422 --> 00:35:45,692
from the Giant Short-Faced Bear.

330
00:35:47,059 --> 00:35:49,161
The Short-Faced Bear's bone chemistry

331
00:35:49,228 --> 00:35:51,363
reveals it was a carnivore,

332
00:35:51,430 --> 00:35:58,035
at up to a tonne probably the largest
meat-eating mammal that ever walked
the Earth.

333
00:36:03,339 --> 00:36:10,145
On its long legs it ranged great
distances  across the open steppes in
search of food.

334
00:36:10,211 --> 00:36:12,180
We also know from fossils

335
00:36:12,246 --> 00:36:16,583
that it had broad nostrils
and an acute sense of smell.

336
00:36:18,785 --> 00:36:21,587
But with its powerful
bone crunching jaws

337
00:36:21,654 --> 00:36:24,456
it's now believed
the Giant Short-Faced Bear

338
00:36:24,523 --> 00:36:26,925
was primarily
a specialist scavenger

339
00:36:26,992 --> 00:36:28,459
rather than a predator,

340
00:36:28,526 --> 00:36:32,663
feeding on the victims
of this unforgiving world.

341
00:36:47,708 --> 00:36:48,942
The Short-Faced Bear

342
00:36:49,009 --> 00:36:54,147
was just one of the many extraordinary
beasts that roamed the Ice Age steppes.

343
00:36:54,280 --> 00:36:57,483
Clues in the landscape
and the wildlife of today

344
00:36:57,616 --> 00:37:02,353
have given us an insight into
what that long-lost land was like.

345
00:37:04,121 --> 00:37:08,558
Now imagine that we can really
travel back 14,000 years

346
00:37:08,658 --> 00:37:11,694
and stand with those first
hunters on the Mesa.

347
00:37:11,794 --> 00:37:14,096
Look out on that Ice Age world

348
00:37:14,163 --> 00:37:17,999
and experience a day
in the life of Beringia.

349
00:37:18,099 --> 00:37:21,002
This is what it might
have been like.

350
00:37:29,842 --> 00:37:33,378
Beneath us the steppes
stretch away to the mountains.

351
00:37:33,445 --> 00:37:34,713
It's only winter

352
00:37:34,779 --> 00:37:36,447
and a time to feed up

353
00:37:36,514 --> 00:37:39,650
ready for the long
cold months ahead.

354
00:37:42,686 --> 00:37:49,491
Bison, Saiga antelope and other
grazers throng the flats below the Mesa.

355
00:38:15,679 --> 00:38:20,182
Musk oxen and Arctic hares
are well insulated against the cold

356
00:38:20,283 --> 00:38:25,887
as are the largest grazers of them all
- the woolly mammoths.

357
00:38:38,797 --> 00:38:40,232
This herd is regrouping,

358
00:38:40,299 --> 00:38:44,769
ready for a long day feeding
on the grasses beneath the snow.

359
00:38:46,871 --> 00:38:50,640
Mothers need to keep milk
flowing for their young.

360
00:38:51,875 --> 00:38:54,610
This baby will need
all the care that he can get

361
00:38:54,710 --> 00:38:58,213
to make it through
his first Beringian winter.

362
00:38:59,214 --> 00:39:02,650
Despite the cold,
there is still food available.

363
00:39:02,950 --> 00:39:05,519
The high winds stop
the snow from building up

364
00:39:05,619 --> 00:39:07,721
and keep the grass exposed -

365
00:39:07,821 --> 00:39:11,657
a lifeline for
all Beringia's grazers.

366
00:39:30,706 --> 00:39:32,207
Away from the herd

367
00:39:32,307 --> 00:39:36,977
the dominant male mammoth
is distracted from his usual routine.

368
00:39:37,478 --> 00:39:41,081
Today he has a more urgent
priority than food -

369
00:39:46,619 --> 00:39:50,255
a younger challenger
that wants to take his place.

370
00:39:53,958 --> 00:39:58,461
This ritual clash of tusks
will decide the future for them both.

371
00:39:58,561 --> 00:40:00,863
The rival may
be young and fit,

372
00:40:00,963 --> 00:40:05,534
the old bull has experience
on his side.

373
00:40:21,747 --> 00:40:25,216
This time experience wins.

374
00:40:37,793 --> 00:40:40,662
The biting winter winds
that clear the snow

375
00:40:40,729 --> 00:40:44,332
produce a windshield
that would kill most mammals.

376
00:40:44,465 --> 00:40:46,533
But musk oxen are made for this,

377
00:40:46,633 --> 00:40:49,836
cocooned in double layered coats.

378
00:41:05,582 --> 00:41:10,386
But cold is not the only
danger in this windswept land.

379
00:41:28,434 --> 00:41:30,869
The herd reacts

380
00:41:33,438 --> 00:41:36,507
and runs for higher ground.

381
00:41:42,578 --> 00:41:45,514
They huddle and turn
to face the threat -

382
00:41:48,283 --> 00:41:51,686
a Giant Short-Faced Bear.

383
00:42:15,705 --> 00:42:17,807
Faced by a wall of horns,

384
00:42:17,940 --> 00:42:22,110
the bear moves on to sniff out
a less daunty meal.

385
00:42:33,820 --> 00:42:39,124
Occasional blizzards are another
harsh reality of living in Beringia.

386
00:42:39,824 --> 00:42:44,295
But the drifting snow may at least
provide a hunter with some cover.

387
00:43:04,878 --> 00:43:08,281
Saiga antelope can run
at 40 miles an hour

388
00:43:08,381 --> 00:43:12,851
and so far this lion isn't
close enough to cause too much alarm.

389
00:43:17,188 --> 00:43:20,891
As long as they can keep it
in their sights they are safe.

390
00:43:34,668 --> 00:43:38,305
Eventually the sky clears
and the blizzard stops.

391
00:43:38,338 --> 00:43:44,543
Then ravens announce that the weather
has taken its toll.

392
00:43:44,610 --> 00:43:48,713
This old mammoth has succumbed
to starvation and cold.

393
00:43:48,813 --> 00:43:52,082
With its meat
will help keep others warm.

394
00:43:55,418 --> 00:43:59,588
The hunting lion homes in
with another member of the pride.

395
00:44:02,457 --> 00:44:04,793
They can soon
see off the ravens.

396
00:44:04,993 --> 00:44:06,427
But they're weary -

397
00:44:06,527 --> 00:44:11,598
a fresh carcass may have attracted
other, more substantial competition.

398
00:44:36,084 --> 00:44:41,622
One Giant Short-Faced Bear
is more than a match for two lions.

399
00:44:48,361 --> 00:44:50,263
But in this bitter climate

400
00:44:50,329 --> 00:44:54,032
lions can't afford to go
without a meal for long.

401
00:44:56,267 --> 00:44:58,703
A mammoth calf
in its first winter

402
00:44:58,803 --> 00:45:01,205
is a tempting sight.

403
00:45:04,541 --> 00:45:06,776
But mammoths are attentive mothers

404
00:45:06,843 --> 00:45:09,244
and they have the backup
of their herd.

405
00:45:09,311 --> 00:45:12,847
The calf is ringed
by vigilant relatives.

406
00:45:25,791 --> 00:45:28,527
The lions try
to find a loophole.

407
00:45:38,835 --> 00:45:42,771
The mammoths' matriarch,
the oldest female, takes control

408
00:45:42,838 --> 00:45:47,775
and she has sixty years' experience
of putting lions in their place.

409
00:46:18,634 --> 00:46:22,336
In the bosom of its close knit family
the calf is safe,

410
00:46:22,437 --> 00:46:24,838
from predators at least.

411
00:46:29,876 --> 00:46:32,578
The lions will have
to try elsewhere.

412
00:46:42,753 --> 00:46:45,722
Could a bison be
a more realistic prospect?

413
00:46:53,595 --> 00:46:56,364
The wind whips up
again offering cover.

414
00:46:56,431 --> 00:47:00,434
and the hunters focus on a target
on the fringes of the herd.

415
00:47:41,367 --> 00:47:44,169
Before long, the carcass freezes

416
00:47:44,269 --> 00:47:46,471
and becomes difficult to eat.

417
00:47:46,571 --> 00:47:49,640
Abandoned, it is buried
by the elements,

418
00:47:49,740 --> 00:47:51,975
preserved until the day
it will emerge

419
00:47:52,075 --> 00:47:55,445
to tell the story
of another Ice Age death.

420
00:47:55,545 --> 00:47:58,047
Just one of many pieces
of evidence

421
00:47:58,113 --> 00:48:02,750
which together have built up
a picture of this remarkable world.

422
00:48:03,618 --> 00:48:09,122
But now, another unforgiving
winter's night falls on Beringia,

423
00:48:09,189 --> 00:48:12,125
Land of the Mammoth.

424
00:48:14,273 --> 00:48:17,773
Visit www.mvgroup.org
Written & synchr. by m06166