1
00:00:04,200 --> 00:00:06,280
[narrator] This is The Americas,

2
00:00:07,120 --> 00:00:11,679
an extraordinary journey
across Earth's great supercontinent.

3
00:00:11,680 --> 00:00:12,879
[yowls]

4
00:00:12,880 --> 00:00:16,359
The widest variety of life on the planet.

5
00:00:16,360 --> 00:00:18,320
[epic orchestral music]

6
00:00:18,800 --> 00:00:22,520
The untold story of our home.

7
00:00:23,000 --> 00:00:25,160
{\an8}[epic orchestral music continues]

8
00:00:26,440 --> 00:00:28,600
{\an8}Tonight on The Americas...

9
00:00:33,080 --> 00:00:35,000
The Frozen North.

10
00:00:37,800 --> 00:00:40,400
An adventure through the vast wilderness

11
00:00:40,840 --> 00:00:43,120
of Alaska and Canada.

12
00:00:44,720 --> 00:00:46,840
Here, winter's beauty

13
00:00:47,360 --> 00:00:50,079
disguises her dangers.

14
00:00:50,080 --> 00:00:52,400
[epic music continues]

15
00:01:00,751 --> 00:01:02,799
[grunts]

16
00:01:02,800 --> 00:01:05,600
But when snow and ice retreat,

17
00:01:06,240 --> 00:01:08,640
the North reveals landscapes

18
00:01:09,360 --> 00:01:11,440
teeming with life.

19
00:01:13,200 --> 00:01:15,160
- [bird chitters]
- [owl hoots]

20
00:01:15,680 --> 00:01:18,440
[epic music]

21
00:01:20,520 --> 00:01:24,240
All animals here must endure or escape

22
00:01:24,920 --> 00:01:27,600
the extreme swing of the seasons

23
00:01:28,440 --> 00:01:33,080
as the North changes before their eyes.

24
00:01:33,800 --> 00:01:35,800
[uplifting music]

25
00:01:36,120 --> 00:01:37,720
[rumbling]

26
00:01:41,040 --> 00:01:45,480
At the top of the continent
lies a frozen frontier,

27
00:01:47,080 --> 00:01:50,120
larger than the rest of the United States.

28
00:01:54,120 --> 00:01:57,399
The night reveals just how few of us

29
00:01:57,400 --> 00:01:58,680
live up here.

30
00:02:00,520 --> 00:02:02,879
From the East Coast to West,

31
00:02:02,880 --> 00:02:05,280
three million square miles

32
00:02:05,800 --> 00:02:07,560
of wilderness.

33
00:02:12,600 --> 00:02:16,840
A late November dawn
in Canada's Hudson Bay.

34
00:02:18,560 --> 00:02:21,520
By now, this place should be frozen solid.

35
00:02:24,280 --> 00:02:27,320
But this year, it's still too warm.

36
00:02:29,760 --> 00:02:31,760
[mysterious music]

37
00:02:33,800 --> 00:02:35,720
And for a polar bear,

38
00:02:38,640 --> 00:02:39,880
that's a problem.

39
00:02:41,160 --> 00:02:43,280
[pensive music]

40
00:02:47,240 --> 00:02:49,040
He's a seal hunter.

41
00:02:50,200 --> 00:02:51,520
But those seals

42
00:02:52,960 --> 00:02:55,440
are way out on the sea ice.

43
00:02:56,520 --> 00:02:57,570
And right now,

44
00:02:59,320 --> 00:03:02,960
the ice still isn't thick enough
to walk on.

45
00:03:04,680 --> 00:03:05,730
[snorts]

46
00:03:06,200 --> 00:03:07,640
[ice crackling]

47
00:03:08,360 --> 00:03:11,720
He's forced to wait
until it really freezes up.

48
00:03:14,480 --> 00:03:16,520
[bird cawing]

49
00:03:17,960 --> 00:03:19,400
[wind gusting]

50
00:03:23,520 --> 00:03:24,570
[sniffing]

51
00:03:26,200 --> 00:03:30,320
A few dead leaves
won't fix an empty stomach.

52
00:03:33,160 --> 00:03:34,640
In just ten years,

53
00:03:34,880 --> 00:03:38,720
the bear population has fallen
by over a third.

54
00:03:40,080 --> 00:03:41,320
Waiting for winter

55
00:03:41,840 --> 00:03:44,519
is becoming a dangerous game.

56
00:03:44,520 --> 00:03:45,720
[sharp exhale]

57
00:03:46,520 --> 00:03:48,320
[wind gusting]

58
00:03:49,280 --> 00:03:51,919
While polar bears occupy the shore...

59
00:03:51,920 --> 00:03:53,560
[wolf howling]

60
00:03:54,240 --> 00:03:56,120
...the forest belongs

61
00:03:57,280 --> 00:03:58,640
to wolves.

62
00:04:03,080 --> 00:04:06,040
Winter is their prime hunting season...

63
00:04:06,760 --> 00:04:08,000
[wolves barking]

64
00:04:08,560 --> 00:04:11,399
...when the deep snow
slows down their prey.

65
00:04:11,400 --> 00:04:13,519
[suspenseful music]

66
00:04:13,520 --> 00:04:17,680
A moose would feed this 17-strong pack.

67
00:04:19,720 --> 00:04:21,720
[suspenseful music continues]

68
00:04:26,200 --> 00:04:28,200
[wolves panting]

69
00:04:34,000 --> 00:04:35,720
[bird cawing]

70
00:04:39,040 --> 00:04:41,600
As a second moose is flushed out,

71
00:04:42,400 --> 00:04:43,800
the pack splits.

72
00:04:45,920 --> 00:04:48,000
It's a costly mistake.

73
00:04:48,600 --> 00:04:50,640
[suspenseful music stops]

74
00:04:51,840 --> 00:04:54,680
Nine out of ten hunts fail.

75
00:04:56,520 --> 00:04:58,480
[somber music]

76
00:05:02,920 --> 00:05:05,599
And with this blizzard rolling in...

77
00:05:05,600 --> 00:05:07,880
[rumbling]

78
00:05:10,120 --> 00:05:12,440
They've missed their chance.

79
00:05:15,240 --> 00:05:16,290
[wolf barks]

80
00:05:16,480 --> 00:05:18,560
[wind whistling]

81
00:05:23,240 --> 00:05:26,800
But that doesn't mean they'll go hungry.

82
00:05:28,680 --> 00:05:29,800
In this weather,

83
00:05:30,320 --> 00:05:35,000
the exposed coastline
will claim casualties.

84
00:05:37,200 --> 00:05:38,280
[wolves panting]

85
00:05:38,480 --> 00:05:40,160
The pack must find them first.

86
00:05:43,040 --> 00:05:45,000
[thrilling music]

87
00:05:49,840 --> 00:05:50,890
They're nervous.

88
00:05:53,440 --> 00:05:54,490
[wolf whimpers]

89
00:05:57,040 --> 00:06:00,640
This is not wolf territory.

90
00:06:01,840 --> 00:06:03,880
[panting]

91
00:06:15,600 --> 00:06:19,920
A dead polar bear is an unexpected feast.

92
00:06:28,000 --> 00:06:29,840
They must feed quickly.

93
00:06:34,000 --> 00:06:36,720
This is no-man's-land.

94
00:06:37,880 --> 00:06:39,040
[snarling]

95
00:06:48,440 --> 00:06:50,680
[suspenseful music]

96
00:06:57,400 --> 00:07:01,039
It's now that Canada's top predators

97
00:07:01,040 --> 00:07:04,280
come face-to-face.

98
00:07:08,760 --> 00:07:10,760
[foreboding music]

99
00:07:13,120 --> 00:07:16,840
As winter descends
on the shoreline of Hudson Bay,

100
00:07:18,360 --> 00:07:20,120
the rulers of the forest

101
00:07:20,560 --> 00:07:23,520
confront a king of the ice.

102
00:07:23,920 --> 00:07:25,920
[tense music]

103
00:07:30,880 --> 00:07:33,399
The wolves have strength in numbers.

104
00:07:33,400 --> 00:07:35,280
[thrilling music]

105
00:07:36,840 --> 00:07:38,880
But at 800 pounds,

106
00:07:39,520 --> 00:07:42,919
this bear has a massive weight advantage.

107
00:07:42,920 --> 00:07:44,759
[wolves barking]

108
00:07:44,760 --> 00:07:46,840
[thrilling music continues]

109
00:07:51,880 --> 00:07:55,640
And this time, that's what counts.

110
00:07:59,680 --> 00:08:01,960
As winters arrive later,

111
00:08:03,400 --> 00:08:05,960
polar bears trapped on the shore

112
00:08:06,400 --> 00:08:08,320
are growing more desperate.

113
00:08:12,920 --> 00:08:14,120
[polar bear growls]

114
00:08:16,640 --> 00:08:19,280
But the fortunes of all who live here

115
00:08:20,680 --> 00:08:22,600
are about to change.

116
00:08:24,840 --> 00:08:27,040
[epic music]

117
00:08:29,880 --> 00:08:30,960
For six months,

118
00:08:31,360 --> 00:08:34,560
winter buries much of the Fr North.

119
00:08:36,600 --> 00:08:38,760
Now the wolves will get their kill.

120
00:08:39,760 --> 00:08:41,760
[epic music continues]

121
00:08:43,760 --> 00:08:45,160
And Hudson Bay

122
00:08:45,880 --> 00:08:48,960
is finally frozen solid.

123
00:08:50,440 --> 00:08:52,440
[calming music]

124
00:08:55,160 --> 00:08:56,400
For polar bears,

125
00:08:57,160 --> 00:08:59,799
the path to seal hunting grounds

126
00:08:59,800 --> 00:09:02,320
is clear, at last.

127
00:09:08,320 --> 00:09:13,440
The North's extreme seasons
are caused by the tilt of the Earth.

128
00:09:16,720 --> 00:09:20,080
For months, the Arctic is plunged

129
00:09:20,760 --> 00:09:22,279
into darkness.

130
00:09:22,280 --> 00:09:25,239
[faint crackling]

131
00:09:25,240 --> 00:09:29,999
But still,
the sun makes its presence felt.

132
00:09:30,000 --> 00:09:32,080
[serene music]

133
00:09:38,040 --> 00:09:40,000
A magical display.

134
00:09:41,320 --> 00:09:43,480
The aurora borealis.

135
00:09:46,840 --> 00:09:49,439
These are the traces of a solar storm

136
00:09:49,440 --> 00:09:51,679
as radiation from the sun

137
00:09:51,680 --> 00:09:55,200
reacts with gases
in the Earth's atmosphere.

138
00:09:58,480 --> 00:10:00,160
Green for oxygen,

139
00:10:00,960 --> 00:10:02,960
purple for nitrogen.

140
00:10:07,280 --> 00:10:09,280
[ethereal music]

141
00:10:15,480 --> 00:10:17,720
[distant cawing]

142
00:10:18,080 --> 00:10:20,400
In Canada's Yukon forest,

143
00:10:20,880 --> 00:10:22,880
temperatures in early February

144
00:10:23,560 --> 00:10:25,320
drop to minus 30.

145
00:10:29,520 --> 00:10:31,480
There's so little food in winter,

146
00:10:32,440 --> 00:10:34,359
you're best to either leave...

147
00:10:34,360 --> 00:10:35,599
[snow pattering]

148
00:10:35,600 --> 00:10:38,440
...or hide away until spring.

149
00:10:46,640 --> 00:10:47,800
Unless...

150
00:10:49,920 --> 00:10:51,920
you're a snowshoe hare.

151
00:10:57,040 --> 00:10:59,960
Wide awake and perfectly at home

152
00:11:00,520 --> 00:11:02,360
here in the frozen forest.

153
00:11:05,200 --> 00:11:06,440
[chitters]

154
00:11:12,080 --> 00:11:14,920
They survive the winter
on nothing more than twigs

155
00:11:15,880 --> 00:11:16,930
and bark.

156
00:11:17,880 --> 00:11:19,080
But they're smart,

157
00:11:19,520 --> 00:11:22,760
only picking plants
that provide the most protein.

158
00:11:23,120 --> 00:11:25,120
[crunches]

159
00:11:26,840 --> 00:11:30,000
He's about as tall as the snow is deep.

160
00:11:31,880 --> 00:11:34,600
But he's got something
that makes living here

161
00:11:35,000 --> 00:11:37,440
seem like a walk in the park.

162
00:11:39,080 --> 00:11:41,119
Enormous webbed feet.

163
00:11:41,120 --> 00:11:42,680
[sprightly music]

164
00:11:45,240 --> 00:11:47,000
They're built-in snowshoes,

165
00:11:48,880 --> 00:11:52,440
so he's always ready for a sprint start.

166
00:11:53,200 --> 00:11:55,120
[sprightly music continues]

167
00:11:58,080 --> 00:11:59,640
And he needs to be.

168
00:12:00,120 --> 00:12:03,760
He's not alone in these woods.

169
00:12:07,760 --> 00:12:09,720
[ominous music]

170
00:12:10,560 --> 00:12:12,960
A Canada lynx.

171
00:12:19,760 --> 00:12:24,160
In winter, a lynx
has one main source of prey.

172
00:12:26,720 --> 00:12:29,040
And he's... it.

173
00:12:31,160 --> 00:12:33,120
[ominous music continues]

174
00:12:35,760 --> 00:12:38,200
His ears rotate independently,

175
00:12:39,600 --> 00:12:42,959
always listening out
for the ominous crunch

176
00:12:42,960 --> 00:12:45,080
of footsteps in the snow.

177
00:12:47,480 --> 00:12:49,280
[suspenseful music]

178
00:12:56,000 --> 00:12:57,260
[distant cawing echoes]

179
00:13:02,440 --> 00:13:04,320
- [bird squawks]
- [chitters]

180
00:13:05,800 --> 00:13:07,800
- Spotted.
- [bird squawks]

181
00:13:08,520 --> 00:13:10,320
[suspenseful music]

182
00:13:17,360 --> 00:13:19,640
Lynx are agile hunters,

183
00:13:22,080 --> 00:13:24,600
though not quite as light on their feet...

184
00:13:28,160 --> 00:13:31,320
which buys the hare precious seconds.

185
00:13:33,720 --> 00:13:35,720
[sinister music]

186
00:13:44,600 --> 00:13:46,720
[dramatic music]

187
00:13:54,840 --> 00:13:56,640
[tense music]

188
00:13:59,840 --> 00:14:04,160
But no hiding place will be safe for long.

189
00:14:05,040 --> 00:14:06,480
[huffing heavily]

190
00:14:10,680 --> 00:14:12,079
Deep in the Yukon,

191
00:14:12,080 --> 00:14:14,719
a snowshoe hare freezes

192
00:14:14,720 --> 00:14:17,000
not from cold, but from fear.

193
00:14:18,800 --> 00:14:22,400
Canada lynx
don't give up on dinner easily.

194
00:14:25,160 --> 00:14:28,640
So escape must be timed to perfection.

195
00:14:30,360 --> 00:14:32,360
[dramatic music]

196
00:14:43,360 --> 00:14:45,200
With the help of those snowshoes,

197
00:14:45,960 --> 00:14:49,280
he can hit a top-speed
of 30 miles per hour.

198
00:14:53,920 --> 00:14:54,970
[music ends]

199
00:14:56,400 --> 00:14:58,200
A clean getaway.

200
00:15:00,680 --> 00:15:03,640
And that's unusual.

201
00:15:04,720 --> 00:15:06,160
[chitters]

202
00:15:06,600 --> 00:15:09,760
Canada lynx rarely miss.

203
00:15:11,520 --> 00:15:15,440
This is one lucky bunny.

204
00:15:18,600 --> 00:15:21,040
When the breeding season arrives,

205
00:15:21,920 --> 00:15:24,920
there will be more hares to take the heat.

206
00:15:27,040 --> 00:15:28,090
Until then,

207
00:15:28,920 --> 00:15:31,200
he'll need to stay on his toes.

208
00:15:36,800 --> 00:15:37,850
[bird caws]

209
00:15:40,480 --> 00:15:42,280
[epic music]

210
00:15:45,040 --> 00:15:49,480
By late winter in Alberta, 12,000 feet up,

211
00:15:50,480 --> 00:15:52,920
the towering mountains of the Rockies

212
00:15:53,560 --> 00:15:56,720
are coated in layer upon layer of snow.

213
00:15:56,840 --> 00:15:58,520
[wind whistling]

214
00:16:00,360 --> 00:16:02,800
In places, more than 20 feet deep.

215
00:16:14,840 --> 00:16:18,639
A playground for millions of visitors
every year.

216
00:16:18,640 --> 00:16:20,880
[rumbles]

217
00:16:23,800 --> 00:16:25,720
[crackles]

218
00:16:27,440 --> 00:16:29,160
But be careful.

219
00:16:29,800 --> 00:16:35,799
The spring sunshine weakens
the vast shelves of mountain snow...

220
00:16:35,800 --> 00:16:37,480
[snapping]

221
00:16:40,600 --> 00:16:45,000
...priming one of nature's
most destructive events.

222
00:16:49,440 --> 00:16:51,200
[loud rumbling]

223
00:16:51,800 --> 00:16:53,760
[dramatic music]

224
00:16:57,760 --> 00:16:58,919
Avalanche.

225
00:16:58,920 --> 00:17:01,000
[dramatic music continues]

226
00:17:22,880 --> 00:17:26,680
A million tons of snow and ice

227
00:17:27,000 --> 00:17:31,599
race downhill at speeds
over 100 miles an hour.

228
00:17:31,600 --> 00:17:33,640
[dramatic music continues]

229
00:17:44,760 --> 00:17:50,600
More than 2,000 avalanches
are reported in the Rockies every year.

230
00:17:52,600 --> 00:17:55,519
Many more go unwitnessed.

231
00:17:55,520 --> 00:17:57,680
[rumbling]

232
00:18:03,400 --> 00:18:05,160
As the planet warms,

233
00:18:05,600 --> 00:18:08,440
avalanches are becoming ever more...

234
00:18:09,080 --> 00:18:10,240
unpredictable.

235
00:18:13,120 --> 00:18:15,240
- [wind whistling]
- [snow pattering]

236
00:18:24,040 --> 00:18:25,760
In the shadow of the Rockies,

237
00:18:26,480 --> 00:18:27,920
even in late April,

238
00:18:28,280 --> 00:18:32,480
snow still falls
across these vast grasslands.

239
00:18:33,560 --> 00:18:35,039
But make no mistake.

240
00:18:35,040 --> 00:18:37,439
Spring has arrived.

241
00:18:37,440 --> 00:18:39,560
[grunting and chirping]

242
00:18:39,880 --> 00:18:43,080
And so have a group of determined dancers.

243
00:18:44,000 --> 00:18:45,520
[squawks]

244
00:18:47,040 --> 00:18:50,599
But will all this be enough
to melt the heart

245
00:18:50,600 --> 00:18:52,240
of an ice queen?

246
00:18:53,440 --> 00:18:54,490
[chirps]

247
00:18:57,520 --> 00:19:00,400
Standing high over the plains of Alberta,

248
00:19:01,360 --> 00:19:05,600
the Rockies channel warm winds
down their eastern flanks,

249
00:19:06,760 --> 00:19:09,759
winds known as "snow eaters."

250
00:19:09,760 --> 00:19:11,480
[wind gusting]

251
00:19:12,440 --> 00:19:14,960
As they descend, they heat up,

252
00:19:14,961 --> 00:19:18,519
raising the temperature
of the plains below

253
00:19:18,520 --> 00:19:21,080
by as much as 20 degrees.

254
00:19:28,000 --> 00:19:29,280
[engine cranks]

255
00:19:29,680 --> 00:19:32,400
Out on the prairies, pretty much everyone

256
00:19:32,800 --> 00:19:34,199
is an early riser.

257
00:19:34,200 --> 00:19:35,560
[engine rumbling]

258
00:19:36,040 --> 00:19:37,600
[radio static humming]

259
00:19:37,601 --> 00:19:41,359
["Gimme Some Lovin'"
by Steve Winwood plays over radio]

260
00:19:41,360 --> 00:19:45,199
None more so than sharp-tailed grouse.

261
00:19:45,200 --> 00:19:47,319
[grouse chirping]

262
00:19:47,320 --> 00:19:51,120
They're here to catch
the very first rays of sunshine,

263
00:19:52,120 --> 00:19:54,920
but they can't resist any spotlight.

264
00:19:56,040 --> 00:19:59,119
- ? Gimme some lovin' ?
- ? Gimme, gimme some lovin' ?

265
00:19:59,120 --> 00:20:01,799
? Gimme some lovin'
Every day ?

266
00:20:01,800 --> 00:20:06,600
The males gather every April
for a mating dance-off.

267
00:20:08,320 --> 00:20:09,759
[grouse chirping]

268
00:20:09,760 --> 00:20:12,319
The females are the judges,

269
00:20:12,320 --> 00:20:13,840
and the prize is...

270
00:20:14,680 --> 00:20:16,920
well, bet you can guess.

271
00:20:22,320 --> 00:20:23,880
[wind gusting]

272
00:20:24,520 --> 00:20:28,320
As dawn breaks, it's show time.

273
00:20:29,080 --> 00:20:30,839
[soft music]

274
00:20:30,840 --> 00:20:32,720
[chirping lightly]

275
00:20:35,240 --> 00:20:38,920
Stomping their feet 20 times per second

276
00:20:39,440 --> 00:20:41,760
with a shake and a shimmy,

277
00:20:42,000 --> 00:20:45,239
it's all about seduction.

278
00:20:45,240 --> 00:20:47,200
[gentle acoustic music]

279
00:20:49,800 --> 00:20:53,120
They look their best at this very moment.

280
00:20:54,640 --> 00:20:55,840
And they know it.

281
00:20:57,520 --> 00:20:59,640
She'll be looking for style.

282
00:21:00,000 --> 00:21:01,760
[grouse chirping]

283
00:21:04,640 --> 00:21:06,080
And stamina.

284
00:21:09,480 --> 00:21:11,400
Very nice.

285
00:21:13,360 --> 00:21:14,639
He's not bad either.

286
00:21:14,640 --> 00:21:16,720
[chirping]

287
00:21:19,120 --> 00:21:21,239
The choice is bewildering.

288
00:21:21,240 --> 00:21:22,520
[chirping continues]

289
00:21:35,920 --> 00:21:37,560
[grouse squawks]

290
00:21:37,880 --> 00:21:39,360
But without a clear winner,

291
00:21:40,280 --> 00:21:42,440
fights break out on the dance floor.

292
00:21:43,120 --> 00:21:44,760
[dramatic music]

293
00:21:46,200 --> 00:21:47,840
[chirping]

294
00:21:49,520 --> 00:21:51,200
[upbeat country music]

295
00:21:53,000 --> 00:21:56,160
With all this testosterone flying around,

296
00:21:57,440 --> 00:21:59,680
she's losing interest.

297
00:22:01,120 --> 00:22:03,120
[upbeat country music continues]

298
00:22:10,600 --> 00:22:14,600
They seem to want the fight
more than the prize.

299
00:22:19,520 --> 00:22:22,840
The males need to up their game.

300
00:22:27,800 --> 00:22:29,720
[wind howling]

301
00:22:30,520 --> 00:22:31,570
By June,

302
00:22:32,480 --> 00:22:35,120
under a sun that no longer sets,

303
00:22:38,040 --> 00:22:41,519
even the most stubborn snow melts away

304
00:22:41,520 --> 00:22:44,519
to reveal lush grasslands.

305
00:22:44,520 --> 00:22:46,600
[gentle music]

306
00:22:49,040 --> 00:22:50,560
[birds chirping]

307
00:22:53,480 --> 00:22:57,560
New life transforms the Frozen North.

308
00:22:58,360 --> 00:23:00,400
[birds chirping]

309
00:23:01,160 --> 00:23:05,000
This is America's largest wildlife refuge,

310
00:23:05,520 --> 00:23:09,280
30,000 square miles of Alaska.

311
00:23:12,600 --> 00:23:15,160
The Arctic Refuge.

312
00:23:16,640 --> 00:23:19,040
[majestic music]

313
00:23:21,160 --> 00:23:25,440
In summer,
one animal dominates these plains.

314
00:23:27,960 --> 00:23:29,040
Caribou.

315
00:23:31,680 --> 00:23:34,240
You might know them as reindeer.

316
00:23:35,360 --> 00:23:36,640
They're nomads,

317
00:23:37,120 --> 00:23:39,439
following the retreating snowmelt,

318
00:23:39,440 --> 00:23:42,080
sometimes for a thousand miles.

319
00:23:42,640 --> 00:23:45,720
The longest land migration in the world.

320
00:23:46,880 --> 00:23:48,880
[birds chirping]

321
00:23:49,800 --> 00:23:51,760
Every summer, for centuries,

322
00:23:52,120 --> 00:23:55,440
caribou have been coming here
to have their calves.

323
00:23:58,240 --> 00:23:59,400
[caribou snorts]

324
00:24:02,160 --> 00:24:05,480
This little male is only three weeks old.

325
00:24:06,920 --> 00:24:11,280
But he can already run faster
than an Olympic sprinter.

326
00:24:11,800 --> 00:24:12,850
[calf bleats]

327
00:24:15,000 --> 00:24:17,000
[soft music]

328
00:24:17,520 --> 00:24:21,599
It's easy to lose track
of whose mom is whose.

329
00:24:21,600 --> 00:24:22,680
[cow snorts]

330
00:24:25,240 --> 00:24:26,290
[calf bleats]

331
00:24:27,440 --> 00:24:28,490
Wanting to explore...

332
00:24:29,760 --> 00:24:32,360
- [bleats]
- ...can get you into trouble around here.

333
00:24:35,600 --> 00:24:37,880
Anyone who can't keep up with the herd

334
00:24:38,960 --> 00:24:40,600
will be left behind.

335
00:24:43,480 --> 00:24:44,530
[calf bleats]

336
00:24:50,520 --> 00:24:51,600
[bleats]

337
00:24:52,880 --> 00:24:55,960
But their unique calls and scent

338
00:24:56,800 --> 00:24:59,000
usually mean they can find each other.

339
00:24:59,520 --> 00:25:00,570
[sucking]

340
00:25:01,880 --> 00:25:05,160
Come wintertime, he will be independent.

341
00:25:07,320 --> 00:25:08,520
But until then,

342
00:25:09,360 --> 00:25:11,560
Mom is his whole world,

343
00:25:12,760 --> 00:25:15,000
whether she likes it or not.

344
00:25:15,440 --> 00:25:16,490
[caribou grunt]

345
00:25:21,120 --> 00:25:24,759
As the herd eat their way
through more than a thousand tons

346
00:25:24,760 --> 00:25:27,320
of tundra grasses every day,

347
00:25:30,120 --> 00:25:33,719
they move further west
across the coastal plains.

348
00:25:33,720 --> 00:25:35,880
[dramatic music]

349
00:25:40,400 --> 00:25:44,079
But hunger is driving them towards danger.

350
00:25:44,080 --> 00:25:46,160
[foreboding music]

351
00:25:48,640 --> 00:25:52,040
The snow that blanketed the Frozen North

352
00:25:53,600 --> 00:25:55,720
now descends from the mountains

353
00:25:56,560 --> 00:25:59,800
as billions of gallons of meltwater,

354
00:26:00,960 --> 00:26:03,640
channeled into raging torrents,

355
00:26:05,120 --> 00:26:07,440
cutting across the caribou's path.

356
00:26:07,880 --> 00:26:09,840
- [tense music]
- [herd grunting]

357
00:26:11,760 --> 00:26:15,800
These rivers are deeper and faster
than ever before.

358
00:26:18,680 --> 00:26:21,840
And the feeding grounds
lie on the other side.

359
00:26:24,720 --> 00:26:25,770
[hard splash]

360
00:26:26,080 --> 00:26:30,080
This crossing is more
than a young calf is ready for.

361
00:26:33,720 --> 00:26:34,770
[grunts]

362
00:26:34,920 --> 00:26:38,440
But survival depends on it.

363
00:26:40,200 --> 00:26:42,800
[dramatic music]

364
00:27:00,640 --> 00:27:04,000
The current takes them by surprise,

365
00:27:05,160 --> 00:27:07,520
sweeping him off his feet.

366
00:27:09,080 --> 00:27:11,080
[dramatic music]

367
00:27:16,080 --> 00:27:17,130
[grunting]

368
00:27:27,240 --> 00:27:29,120
[tense music]

369
00:27:30,800 --> 00:27:32,560
[grunting]

370
00:27:35,520 --> 00:27:38,240
This mother now
has a tough choice to make.

371
00:27:44,640 --> 00:27:46,360
[birds chirping]

372
00:27:47,400 --> 00:27:50,520
On the riverbanks
of Alaska's Arctic Refuge,

373
00:27:52,840 --> 00:27:55,759
this caribou mother scans the water

374
00:27:55,760 --> 00:27:58,320
for any sign of her missing calf.

375
00:28:00,600 --> 00:28:02,600
[somber music]

376
00:28:03,240 --> 00:28:04,290
[grunting]

377
00:28:10,320 --> 00:28:12,240
The herd is moving on.

378
00:28:13,560 --> 00:28:15,720
Her instinct to follow them

379
00:28:16,680 --> 00:28:18,239
is just too strong.

380
00:28:18,240 --> 00:28:20,360
[somber music continues]

381
00:28:32,920 --> 00:28:33,970
Downriver,

382
00:28:34,320 --> 00:28:36,800
the calf is still alive.

383
00:28:38,800 --> 00:28:39,850
[calf grunts]

384
00:28:44,520 --> 00:28:46,600
[calf bleating]

385
00:28:59,000 --> 00:29:01,440
He has a fighting spirit,

386
00:29:04,000 --> 00:29:06,400
but he's exhausted.

387
00:29:09,480 --> 00:29:11,680
Mom's nowhere to be seen.

388
00:29:13,200 --> 00:29:14,480
[calf bleating]

389
00:29:17,040 --> 00:29:19,360
As the herd slows down to feed,

390
00:29:19,920 --> 00:29:24,200
all a lost calf can do is try to catch up.

391
00:29:24,920 --> 00:29:26,720
[melancholy music]

392
00:29:29,160 --> 00:29:31,040
[caribou bleating]

393
00:29:41,680 --> 00:29:45,800
Female caribou rarely adopt
lost or orphaned young.

394
00:29:49,800 --> 00:29:50,850
[caribou bleats]

395
00:29:52,160 --> 00:29:54,040
[melancholy music continues]

396
00:29:56,000 --> 00:29:57,520
[calf bleating]

397
00:30:07,480 --> 00:30:09,120
[bleating]

398
00:30:12,960 --> 00:30:14,010
[caribou snorts]

399
00:30:18,400 --> 00:30:21,999
Mom recognizes a familiar bleating.

400
00:30:22,000 --> 00:30:23,720
[calf bleating]

401
00:30:29,520 --> 00:30:30,720
Reunited.

402
00:30:31,280 --> 00:30:32,330
[cow snorts]

403
00:30:32,560 --> 00:30:34,520
[gentle music]

404
00:30:38,200 --> 00:30:39,480
[cow snorts]

405
00:30:46,440 --> 00:30:49,480
You have to grow up quickly
in the Far North.

406
00:30:54,400 --> 00:30:58,840
These ancient routes will soon
be ingrained in his memory.

407
00:31:04,360 --> 00:31:09,080
His destiny is
to endlessly wander this vast...

408
00:31:09,600 --> 00:31:11,520
American tundra.

409
00:31:22,440 --> 00:31:24,200
As summer warms the North,

410
00:31:25,040 --> 00:31:27,199
hundreds of these swollen rivers

411
00:31:27,200 --> 00:31:30,280
carry soil and nutrients from the land

412
00:31:30,640 --> 00:31:33,200
- to the sea.
- [spouts]

413
00:31:37,760 --> 00:31:38,880
And for some,

414
00:31:39,320 --> 00:31:42,520
this becomes a time of plenty.

415
00:31:45,080 --> 00:31:47,080
[soft music]

416
00:31:48,760 --> 00:31:51,280
[walruses grunting]

417
00:32:02,080 --> 00:32:06,120
In July,
on Alaska's isolated Round Island,

418
00:32:07,720 --> 00:32:11,400
a strange sound is carried on the wind.

419
00:32:12,280 --> 00:32:13,330
Just listen.

420
00:32:14,480 --> 00:32:18,640
[bell-like vocalizing]

421
00:32:27,280 --> 00:32:30,000
This is the surprising song...

422
00:32:30,960 --> 00:32:33,519
[vocalizing continues]

423
00:32:33,520 --> 00:32:35,560
...of male walruses,

424
00:32:37,760 --> 00:32:39,320
known as "chiming."

425
00:32:43,080 --> 00:32:45,960
It's made by pockets of air
in their throats.

426
00:32:48,200 --> 00:32:52,480
Usually, they sing to impress females
during the winter mating season.

427
00:32:55,920 --> 00:32:58,560
But there's no ladies in sight.

428
00:32:59,440 --> 00:33:00,879
[snorts]

429
00:33:00,880 --> 00:33:02,920
[growls]

430
00:33:04,320 --> 00:33:07,920
Which probably suits the ladies just fine.

431
00:33:09,560 --> 00:33:11,999
[walrus bulls chiming]

432
00:33:12,000 --> 00:33:13,400
[snorting]

433
00:33:15,160 --> 00:33:17,319
On Alaska's warm summer evenings...

434
00:33:17,320 --> 00:33:18,639
[snores]

435
00:33:18,640 --> 00:33:22,920
Perhaps this is nothing more
than their very own lullaby.

436
00:33:27,000 --> 00:33:32,680
For walruses,
the short summers are all about downtime.

437
00:33:36,680 --> 00:33:39,359
But in the shallows
of Alaska's mainland...

438
00:33:39,360 --> 00:33:40,760
[mystical music]

439
00:33:41,600 --> 00:33:44,040
...there is no time to rest.

440
00:33:46,840 --> 00:33:48,640
[mystical music continues]

441
00:33:49,320 --> 00:33:52,839
Pink salmon gather
at the starting line of a race

442
00:33:52,840 --> 00:33:55,800
that will test them to their limits.

443
00:33:57,240 --> 00:34:00,240
Driven by an urge they cannot ignore,

444
00:34:00,760 --> 00:34:04,519
salmon arrive at the entrance
of the very same stream

445
00:34:04,520 --> 00:34:06,360
in which they were born.

446
00:34:08,720 --> 00:34:10,479
Now, two years later,

447
00:34:10,480 --> 00:34:12,600
it's their turn to breed.

448
00:34:14,040 --> 00:34:16,560
All 200 million of them.

449
00:34:19,240 --> 00:34:23,400
This female is carrying
at least 2,000 eggs.

450
00:34:25,920 --> 00:34:29,280
Returning to the same spot
in which she was born

451
00:34:29,720 --> 00:34:33,160
will give her offspring
the best chance of survival.

452
00:34:34,280 --> 00:34:35,400
But ahead of her

453
00:34:36,840 --> 00:34:39,520
lies a killer assault course.

454
00:34:40,320 --> 00:34:41,679
[suspenseful music]

455
00:34:41,680 --> 00:34:44,200
[birds calling]

456
00:34:47,840 --> 00:34:49,520
She must succeed...

457
00:34:50,680 --> 00:34:51,920
or die trying.

458
00:34:55,120 --> 00:34:57,560
Prince William Sound, Alaska.

459
00:34:59,280 --> 00:35:00,920
As the tide races out,

460
00:35:02,480 --> 00:35:04,160
countless pink salmon

461
00:35:05,000 --> 00:35:06,050
are waiting.

462
00:35:09,480 --> 00:35:13,360
The scent of their spawning grounds
grows stronger.

463
00:35:14,240 --> 00:35:16,240
[dramatic music]

464
00:35:18,360 --> 00:35:21,240
Now it's a race to cross the shallows

465
00:35:21,680 --> 00:35:24,480
before the tide cuts them off.

466
00:35:34,520 --> 00:35:37,960
One wrong turn and it's game over.

467
00:35:39,280 --> 00:35:41,000
[birds squawking]

468
00:35:45,280 --> 00:35:46,400
For gulls,

469
00:35:47,160 --> 00:35:49,599
the banquet has begun.

470
00:35:49,600 --> 00:35:51,560
[seagulls calling]

471
00:35:54,160 --> 00:35:56,360
They can be picky at this stage...

472
00:35:59,920 --> 00:36:02,919
only selecting the most tender flesh.

473
00:36:02,920 --> 00:36:05,360
[despondent music]

474
00:36:30,040 --> 00:36:33,240
This female has made a serious error

475
00:36:35,160 --> 00:36:37,799
and is now dangerously exposed.

476
00:36:37,800 --> 00:36:40,320
[seagulls calling]

477
00:36:45,040 --> 00:36:47,000
[dramatic music]

478
00:36:53,520 --> 00:36:57,400
Her determination
seems to confuse her attacker.

479
00:37:00,200 --> 00:37:02,000
[ominous music]

480
00:37:04,840 --> 00:37:06,800
[dramatic music]

481
00:37:07,680 --> 00:37:09,760
This is only the beginning.

482
00:37:11,600 --> 00:37:15,439
Every salmon is now on borrowed time.

483
00:37:15,440 --> 00:37:17,520
[menacing music]

484
00:37:21,480 --> 00:37:25,160
From here on out, they barely eat or rest,

485
00:37:25,920 --> 00:37:27,720
as they forge upstream.

486
00:37:33,560 --> 00:37:35,240
[menacing music continues]

487
00:37:35,800 --> 00:37:39,240
This journey takes a grim toll,

488
00:37:41,840 --> 00:37:45,800
as their bodies
begin to shut down and decay,

489
00:37:47,120 --> 00:37:49,000
some faster than others.

490
00:37:51,720 --> 00:37:55,680
Finally, they arrive
at their spawning grounds,

491
00:37:56,880 --> 00:37:58,840
but it's not over yet.

492
00:38:03,840 --> 00:38:07,480
This female
needs to construct a shallow nest,

493
00:38:08,200 --> 00:38:10,240
known as a "redd."

494
00:38:15,040 --> 00:38:17,120
She flicks away fine sediment

495
00:38:17,760 --> 00:38:20,360
to prevent her eggs from being smothered.

496
00:38:31,520 --> 00:38:35,880
She will fiercely defend her nest
from other females.

497
00:38:40,720 --> 00:38:45,480
By now, some males look like
the swimming dead.

498
00:38:47,000 --> 00:38:48,960
They're "zombie" salmon,

499
00:38:52,560 --> 00:38:55,839
desperate to mate before they die.

500
00:38:55,840 --> 00:38:58,000
[dramatic music]

501
00:39:00,080 --> 00:39:01,160
Kind of gross.

502
00:39:01,720 --> 00:39:03,520
[dramatic music continues]

503
00:39:15,000 --> 00:39:16,960
After all she's been through,

504
00:39:17,840 --> 00:39:21,800
she's not going to settle
for anything less than perfect.

505
00:39:22,160 --> 00:39:24,120
[soft somber music]

506
00:39:32,480 --> 00:39:36,280
Males fertilize eggs
in as many redds as possible,

507
00:39:37,240 --> 00:39:40,400
but this will be her only chance.

508
00:39:44,840 --> 00:39:47,960
She will only release her eggs
when she's ready.

509
00:39:50,720 --> 00:39:54,320
It's the moment that will seal her fate.

510
00:39:56,280 --> 00:40:00,400
Spawning and dying
on the same stretch of river as her mother

511
00:40:01,400 --> 00:40:04,600
is a female salmon's destiny.

512
00:40:06,280 --> 00:40:08,280
[dramatic music]

513
00:40:10,440 --> 00:40:12,520
Though their journey ends here,

514
00:40:13,080 --> 00:40:16,119
these salmon leave behind millions of eggs

515
00:40:16,120 --> 00:40:19,440
that will become the next generation.

516
00:40:20,280 --> 00:40:22,240
[dramatic music continues]

517
00:40:30,280 --> 00:40:31,330
Life,

518
00:40:33,480 --> 00:40:35,800
dictated by the seasons.

519
00:40:36,840 --> 00:40:38,840
[soft music]

520
00:40:42,920 --> 00:40:46,360
In just two months, winter returns.

521
00:40:56,520 --> 00:40:58,920
Some begin the long trek south.

522
00:41:03,160 --> 00:41:07,840
Others surrender
to many months in the den.

523
00:41:10,520 --> 00:41:12,480
[soft music continues]

524
00:41:15,800 --> 00:41:18,840
But there are those
who are perfectly at home

525
00:41:19,280 --> 00:41:21,600
in this snowbound world.

526
00:41:27,800 --> 00:41:28,850
A place...

527
00:41:30,160 --> 00:41:31,520
full of magic.

528
00:41:37,200 --> 00:41:40,560
One thing is certain
here in the Frozen North...

529
00:41:44,960 --> 00:41:46,760
nothing stays the same...

530
00:41:48,480 --> 00:41:49,640
for long.

531
00:41:55,040 --> 00:41:57,040
[epic orchestral music]

532
00:41:57,090 --> 00:42:01,640
Repair and Synchronization by
Easy Subtitles Synchronizer 1.0.0.0