1
00:00:02,752 --> 00:00:05,005
[NBC chime]

2
00:00:07,381 --> 00:00:10,635
NARRATOR: The story
of life on Earth...

3
00:00:10,676 --> 00:00:12,387
[roars]

4
00:00:13,513 --> 00:00:15,140
...has been marked by a series

5
00:00:15,181 --> 00:00:17,684
of catastrophic
extinction events.

6
00:00:18,726 --> 00:00:21,980
Natural disasters, which have
threatened to wipe out

7
00:00:22,021 --> 00:00:25,483
many of the creatures
that call our planet home.

8
00:00:25,858 --> 00:00:28,320
But after each brush with death,

9
00:00:28,361 --> 00:00:33,492
life has come back
even stronger.

10
00:00:33,533 --> 00:00:35,619
[majestic music]

11
00:00:35,660 --> 00:00:39,206
One such event occurred
two and half million years ago,

12
00:00:39,247 --> 00:00:41,207
in the Americas.

13
00:00:42,041 --> 00:00:46,797
Up until then, North and South
America had been separated

14
00:00:46,838 --> 00:00:48,089
by ocean.

15
00:00:48,881 --> 00:00:50,050
[trumpeting]

16
00:00:50,550 --> 00:00:53,803
But then, the seabed rose up,

17
00:00:54,262 --> 00:00:56,264
and a land bridge formed.

18
00:00:56,848 --> 00:00:58,850
[snarling]

19
00:00:58,891 --> 00:01:00,727
♪♪♪

20
00:01:00,768 --> 00:01:02,562
For the first time,

21
00:01:02,603 --> 00:01:06,650
animals and plants from these
two completely different worlds

22
00:01:06,691 --> 00:01:07,734
would face off.

23
00:01:09,193 --> 00:01:10,779
[squawks]

24
00:01:11,154 --> 00:01:13,448
Many were driven to extinction.

25
00:01:13,489 --> 00:01:15,033
-[growling]
-[screeching]

26
00:01:15,074 --> 00:01:19,037
But for others,
it was a whole new beginning.

27
00:01:19,078 --> 00:01:20,622
-[trumpeting]
-[screeching]

28
00:01:21,831 --> 00:01:23,166
[growling]

29
00:01:23,207 --> 00:01:24,459
[trumpeting]

30
00:01:26,085 --> 00:01:30,131
[majestic music]

31
00:01:30,882 --> 00:01:32,133
[low grunting]

32
00:01:33,426 --> 00:01:38,181
It changed life
in the Americas forever.

33
00:01:39,182 --> 00:01:43,269
[theme music]

34
00:01:52,195 --> 00:01:54,447
[wind gusts howl]

35
00:01:56,282 --> 00:01:59,869
[reverent music]

36
00:02:03,873 --> 00:02:07,169
NARRATOR: Long after the time
of the dinosaurs,

37
00:02:07,210 --> 00:02:08,920
and more than two million years

38
00:02:08,961 --> 00:02:11,381
before modern humans
walk the earth,

39
00:02:12,506 --> 00:02:15,593
the world is becoming
drier and cooler.

40
00:02:18,137 --> 00:02:19,639
In Central America,

41
00:02:19,680 --> 00:02:21,641
the climate shift is extreme.

42
00:02:23,809 --> 00:02:28,356
A punishing drought has gripped
these lands for six months.

43
00:02:29,815 --> 00:02:34,905
♪♪♪

44
00:02:34,946 --> 00:02:36,323
To survive here,

45
00:02:36,364 --> 00:02:39,159
it takes a special
kind of animal.

46
00:02:41,202 --> 00:02:42,328
[snuffling]

47
00:02:42,745 --> 00:02:45,582
Like these majestic
Gomphotheres.

48
00:02:45,623 --> 00:02:47,876
[low, rumbling grunts]

49
00:02:47,917 --> 00:02:50,420
Descended from
ancient elephant species

50
00:02:50,461 --> 00:02:53,131
that originally migrated
out of Africa,

51
00:02:53,172 --> 00:02:56,676
these creatures have made
North America their home.

52
00:02:56,717 --> 00:02:58,928
[trumpeting]

53
00:02:59,428 --> 00:03:01,723
Today, they are celebrating.

54
00:03:01,764 --> 00:03:03,683
[trumpeting]

55
00:03:05,017 --> 00:03:08,771
A little female calf,
only hours old.

56
00:03:09,855 --> 00:03:12,067
[trumpeting]

57
00:03:12,108 --> 00:03:14,944
Her mom is the 40-year-old
matriarch.

58
00:03:15,611 --> 00:03:18,364
She is the leader of this herd.

59
00:03:19,407 --> 00:03:21,326
[trumpeting]

60
00:03:21,367 --> 00:03:22,577
[grunting]

61
00:03:23,494 --> 00:03:25,080
She doesn‘t have the strength

62
00:03:25,121 --> 00:03:26,664
to join the celebration.

63
00:03:27,373 --> 00:03:33,087
♪♪♪

64
00:03:33,421 --> 00:03:35,006
[trumpeting]

65
00:03:35,715 --> 00:03:38,009
Exhausted after giving birth,

66
00:03:38,050 --> 00:03:40,887
she looks for a place
to be alone.

67
00:03:44,890 --> 00:03:45,975
[screeching]

68
00:03:47,560 --> 00:03:49,729
As matriarch, she is key

69
00:03:49,770 --> 00:03:52,565
to the whole herd‘s survival,

70
00:03:53,941 --> 00:03:56,361
so it is not surprising
her behavior

71
00:03:56,402 --> 00:03:58,321
is starting to make
them anxious.

72
00:03:59,822 --> 00:04:02,992
Something extremely rare
has happened.

73
00:04:04,410 --> 00:04:06,871
[high-pitched trumpeting]

74
00:04:08,372 --> 00:04:12,168
[gentle music]

75
00:04:12,209 --> 00:04:15,672
The matriarch
has given birth to a twin.

76
00:04:17,089 --> 00:04:20,927
♪♪♪

77
00:04:21,344 --> 00:04:23,096
[trumpeting]

78
00:04:23,512 --> 00:04:26,099
Brother and sister meet.

79
00:04:26,140 --> 00:04:28,393
It is a moment of pure joy.

80
00:04:28,434 --> 00:04:32,563
[high-pitched trumpeting]

81
00:04:37,193 --> 00:04:40,113
The entire herd
is elated with the arrival

82
00:04:40,154 --> 00:04:41,865
of its newest members.

83
00:04:41,906 --> 00:04:45,285
[herd trumpeting]

84
00:04:48,079 --> 00:04:51,958
[tense music]

85
00:04:53,000 --> 00:04:56,462
When night comes,
the mood changes.

86
00:05:05,638 --> 00:05:07,807
Despite an exhausting day,

87
00:05:07,848 --> 00:05:10,685
it is the new mom
who bravely stands guard

88
00:05:10,726 --> 00:05:13,438
while the rest
of the herd sleeps.

89
00:05:14,814 --> 00:05:17,067
As an experienced matriarch,

90
00:05:17,108 --> 00:05:19,944
one of her duties
is to keep the others safe.

91
00:05:20,986 --> 00:05:24,657
♪♪♪

92
00:05:24,698 --> 00:05:26,368
And it‘s a good thing,

93
00:05:26,409 --> 00:05:29,287
because tonight,
there is danger,

94
00:05:29,328 --> 00:05:32,332
lurking in the darkness.

95
00:05:33,165 --> 00:05:35,835
[snarling growls]

96
00:05:42,383 --> 00:05:44,344
Smilodon.

97
00:05:48,347 --> 00:05:50,725
Ruthless sabretooth cats,

98
00:05:50,766 --> 00:05:53,353
as big as jaguars.

99
00:05:54,270 --> 00:05:58,942
♪♪♪

100
00:05:58,983 --> 00:06:01,819
They’ve picked up the scent
of the new calves.

101
00:06:03,612 --> 00:06:09,911
♪♪♪

102
00:06:15,541 --> 00:06:21,756
[tense music builds]

103
00:06:30,723 --> 00:06:32,559
At three and a half tons,

104
00:06:32,600 --> 00:06:37,063
these adult Gomphotheres are too
big for Smilodon to take down.

105
00:06:37,104 --> 00:06:39,524
[snarling]

106
00:06:39,565 --> 00:06:41,859
But with a surprise attack...

107
00:06:42,234 --> 00:06:44,863
they could separate
one of the calves,

108
00:06:44,904 --> 00:06:46,739
and go in for the kill.

109
00:06:48,199 --> 00:06:50,701
[clattering]

110
00:06:52,036 --> 00:06:54,080
[birds cawing]

111
00:06:54,121 --> 00:06:56,791
[trumpeting]

112
00:07:01,086 --> 00:07:02,297
[snarling]

113
00:07:02,338 --> 00:07:05,550
Well, it‘s no longer a surprise.

114
00:07:06,091 --> 00:07:07,927
[roars]

115
00:07:07,968 --> 00:07:11,389
Changing tactics,
they go straight for the herd.

116
00:07:11,430 --> 00:07:14,934
[dramatic music]

117
00:07:14,975 --> 00:07:18,604
-[trumpeting]
-[snarling]

118
00:07:23,484 --> 00:07:25,111
If they cause enough chaos,

119
00:07:25,152 --> 00:07:27,363
one of the babies
will be exposed.

120
00:07:27,404 --> 00:07:28,948
[high-pitched trumpeting]

121
00:07:28,989 --> 00:07:32,577
-[roaring]
-[trumpeting]

122
00:07:37,957 --> 00:07:41,210
Led by the matriarch,
the adults hold the line...

123
00:07:42,628 --> 00:07:43,963
for now.

124
00:07:45,464 --> 00:07:49,135
But the sabretooths
have got all night.

125
00:07:51,053 --> 00:07:55,725
-[roaring]
-[trumpeting]

126
00:08:03,482 --> 00:08:06,152
It‘s rare for twin
calves to both survive

127
00:08:06,193 --> 00:08:08,613
their first year
in this harsh land.

128
00:08:09,154 --> 00:08:13,284
But can they even survive
their first night?

129
00:08:13,325 --> 00:08:14,577
[roaring]

130
00:08:17,454 --> 00:08:21,042
[tense music]

131
00:08:21,083 --> 00:08:23,378
NARRATOR: The moon sets
over Central America,

132
00:08:23,419 --> 00:08:25,713
two and a half
million years ago.

133
00:08:25,754 --> 00:08:28,424
♪♪♪

134
00:08:28,465 --> 00:08:31,719
It is a land gripped
by a severe drought.

135
00:08:33,387 --> 00:08:34,556
[snarling]

136
00:08:34,597 --> 00:08:35,682
During the night,

137
00:08:35,723 --> 00:08:37,183
a herd of American elephants

138
00:08:37,224 --> 00:08:40,395
have been targeted
by sabretooth predators,

139
00:08:40,436 --> 00:08:43,648
drawn by the smell
of newborn twin calves.

140
00:08:43,689 --> 00:08:46,025
[high-pitched trumpeting]

141
00:08:46,066 --> 00:08:48,069
[trumpeting]

142
00:08:48,402 --> 00:08:49,946
[snarling]

143
00:08:51,405 --> 00:08:56,077
[gentle music]

144
00:08:58,120 --> 00:08:59,872
NARRATOR: In the morning light,

145
00:08:59,913 --> 00:09:02,709
the matriarch
triumphantly reveals

146
00:09:02,750 --> 00:09:05,962
all the members
of her herd survived.

147
00:09:06,462 --> 00:09:10,383
[gentle music]

148
00:09:10,424 --> 00:09:13,761
Most importantly,
her two babies.

149
00:09:14,887 --> 00:09:19,809
♪♪♪

150
00:09:22,019 --> 00:09:23,938
They didn‘t go unscathed.

151
00:09:26,398 --> 00:09:28,443
Both the little male,

152
00:09:28,484 --> 00:09:31,195
and his mother were injured.

153
00:09:33,614 --> 00:09:35,616
But there‘s no time to rest.

154
00:09:38,619 --> 00:09:41,956
The drought makes
our matriarch‘s top priority

155
00:09:41,997 --> 00:09:44,125
to find water for the herd.

156
00:09:45,292 --> 00:09:47,462
[dramatic music]

157
00:09:47,503 --> 00:09:50,423
She knows a place
where her own mother

158
00:09:50,464 --> 00:09:52,049
took her, decades ago.

159
00:09:58,305 --> 00:10:01,893
It might seem dry,
but if you know where to look,

160
00:10:01,934 --> 00:10:04,645
there are underground springs.

161
00:10:05,729 --> 00:10:10,276
[suspenseful music]

162
00:10:21,829 --> 00:10:23,831
There’s barely a trickle.

163
00:10:25,332 --> 00:10:27,960
[low grunting]

164
00:10:28,001 --> 00:10:29,962
She is distressed.

165
00:10:30,003 --> 00:10:32,632
Her home range has failed her,

166
00:10:32,673 --> 00:10:35,343
and she has failed her herd.

167
00:10:35,384 --> 00:10:37,219
She must find water.

168
00:10:38,387 --> 00:10:41,641
[reverent music]

169
00:10:41,682 --> 00:10:45,353
It is all down to the very land
she is standing on.

170
00:10:50,858 --> 00:10:52,318
Before now,

171
00:10:52,359 --> 00:10:54,946
the continents
of North and South America

172
00:10:54,987 --> 00:10:57,532
were completely separate
land masses.

173
00:10:57,573 --> 00:11:00,201
♪♪♪

174
00:11:00,242 --> 00:11:02,370
But continental drift
has been pushing them

175
00:11:02,411 --> 00:11:06,040
on a collision course
over millions of years.

176
00:11:08,000 --> 00:11:10,461
Now, they are almost touching.

177
00:11:11,712 --> 00:11:14,966
♪♪♪

178
00:11:15,007 --> 00:11:18,219
Ocean currents are rerouting,

179
00:11:18,260 --> 00:11:20,930
and the climate
in Central America

180
00:11:20,971 --> 00:11:23,891
is getting steadily drier.

181
00:11:24,892 --> 00:11:27,186
[wind gusts howl]

182
00:11:27,227 --> 00:11:29,814
As the dry seasons get longer,

183
00:11:29,855 --> 00:11:32,608
reliable water sources
disappear,

184
00:11:32,649 --> 00:11:34,860
and animals suffer.

185
00:11:37,279 --> 00:11:41,450
These Gomphotheres can normally
survive for days without water.

186
00:11:42,117 --> 00:11:44,120
But with two calves to feed,

187
00:11:44,161 --> 00:11:47,832
this new mother needs
to find a solution, fast.

188
00:11:47,873 --> 00:11:49,125
[high-pitched trumpeting]

189
00:11:50,375 --> 00:11:52,128
Another mother
in the herd has already

190
00:11:52,169 --> 00:11:54,130
lost her calf to this drought.

191
00:11:54,171 --> 00:11:57,091
[babies trumpeting]

192
00:11:57,841 --> 00:11:59,969
Staying here, with no water,

193
00:12:00,010 --> 00:12:02,972
would mean certain death
for her two babies.

194
00:12:03,013 --> 00:12:06,559
[trumpeting]

195
00:12:06,600 --> 00:12:09,479
But then, our matriarch
feels something

196
00:12:09,520 --> 00:12:10,813
in the ground.

197
00:12:13,941 --> 00:12:16,235
Through thick pads on her feet,

198
00:12:16,276 --> 00:12:18,779
she can sense vibrations.

199
00:12:21,281 --> 00:12:24,869
From experience,
she knows what this is.

200
00:12:26,078 --> 00:12:28,080
Distant thunderstorms.

201
00:12:28,121 --> 00:12:32,543
[joyful music]

202
00:12:32,584 --> 00:12:36,923
The promise of rain pushes
her to take a huge risk.

203
00:12:36,964 --> 00:12:39,467
[trumpeting]

204
00:12:40,092 --> 00:12:41,469
[thud, echoes]

205
00:12:42,094 --> 00:12:44,138
[low grunting]

206
00:12:45,097 --> 00:12:48,518
[majestic music]

207
00:12:48,559 --> 00:12:51,896
She decides to leave
her ancestral lands,

208
00:12:51,937 --> 00:12:53,981
and lead her herd south.

209
00:12:55,983 --> 00:13:00,529
These American elephants can
walk over 100 miles in a day,

210
00:13:01,613 --> 00:13:04,492
but they are traveling
into the unknown.

211
00:13:05,534 --> 00:13:08,287
The lands to the south
are even more inhospitable

212
00:13:08,328 --> 00:13:10,331
than their home territory.

213
00:13:10,372 --> 00:13:13,459
♪♪♪

214
00:13:13,500 --> 00:13:17,630
Even the creatures they meet
will be alien to them.

215
00:13:18,589 --> 00:13:21,676
The gamble she‘s taking
could be disastrous

216
00:13:21,717 --> 00:13:25,805
for her new babies,
and for the whole herd.

217
00:13:25,846 --> 00:13:27,264
[high-pitched trumpeting]

218
00:13:27,931 --> 00:13:29,475
[trumpeting]

219
00:13:32,811 --> 00:13:36,858
[reverent music]

220
00:13:36,899 --> 00:13:39,569
NARRATOR: The matriarch
of a herd of Gomphotheres

221
00:13:39,610 --> 00:13:42,530
has decided to migrate
in search of water.

222
00:13:44,865 --> 00:13:48,619
Desperate, she is leading
her herd further south

223
00:13:48,660 --> 00:13:51,997
than any American elephants
have ever been.

224
00:13:53,373 --> 00:13:57,253
And so far,
it is only getting drier.

225
00:13:58,629 --> 00:14:05,177
[suspenseful music]

226
00:14:07,304 --> 00:14:10,933
When the matriarch‘s young son
wanders away from the herd,

227
00:14:11,600 --> 00:14:15,020
he encounters something
he‘s never seen before.

228
00:14:17,189 --> 00:14:18,900
-[grunting]
-[trumpeting]

229
00:14:18,941 --> 00:14:21,277
[braying]

230
00:14:22,527 --> 00:14:25,281
An armored Glyptotherium.

231
00:14:26,031 --> 00:14:28,576
Definitely not a creature
from around here.

232
00:14:29,451 --> 00:14:33,331
In fact,
he‘s from another world...

233
00:14:33,372 --> 00:14:36,292
the island continent
of South America.

234
00:14:37,501 --> 00:14:39,128
[trumpets]

235
00:14:40,879 --> 00:14:45,509
[whimsical music]

236
00:14:46,885 --> 00:14:49,305
Somehow, he‘s crossed
into the north.

237
00:14:51,765 --> 00:14:53,392
[grunting]

238
00:14:53,433 --> 00:14:54,685
[braying]

239
00:14:55,185 --> 00:14:56,729
He doesn‘t smell dangerous.

240
00:14:56,770 --> 00:14:58,981
[trumpeting]

241
00:15:00,983 --> 00:15:02,902
Maybe this odd-looking animal

242
00:15:02,943 --> 00:15:04,194
could be a playmate.

243
00:15:06,655 --> 00:15:08,115
[trumpeting]

244
00:15:08,865 --> 00:15:10,326
[high-pitched trumpeting]

245
00:15:13,161 --> 00:15:14,455
[screeching]

246
00:15:14,496 --> 00:15:17,583
[low trumpeting]

247
00:15:18,834 --> 00:15:20,962
The mother who lost her own baby

248
00:15:21,003 --> 00:15:22,338
comes to the rescue.

249
00:15:24,006 --> 00:15:25,091
[baby screeching]

250
00:15:25,132 --> 00:15:26,508
[dramatic music]

251
00:15:27,968 --> 00:15:29,762
[braying]

252
00:15:31,013 --> 00:15:33,057
[low trumpeting]

253
00:15:34,266 --> 00:15:36,727
It‘s nice to be part of a herd.

254
00:15:38,186 --> 00:15:40,522
[trumpeting]

255
00:15:40,897 --> 00:15:43,442
The little one is a bit bruised,

256
00:15:43,483 --> 00:15:45,569
but his instincts were right.

257
00:15:50,198 --> 00:15:53,744
The herd has nothing to fear
from these strangers.

258
00:15:53,785 --> 00:15:58,666
[whimsical music]

259
00:15:59,541 --> 00:16:01,794
[braying]

260
00:16:01,835 --> 00:16:04,005
Although, the Glyptotherium
aren‘t used

261
00:16:04,046 --> 00:16:07,633
to creatures powerful enough
to turn them on their backs.

262
00:16:09,217 --> 00:16:10,511
[braying]

263
00:16:13,513 --> 00:16:17,726
For them, this new,
dry world is proving tough.

264
00:16:20,062 --> 00:16:23,858
[dramatic music]

265
00:16:23,899 --> 00:16:27,111
The desperate herd
is also struggling.

266
00:16:29,988 --> 00:16:32,408
They haven‘t drunk now for days.

267
00:16:33,784 --> 00:16:36,620
But our matriarch
is sticking with her plan,

268
00:16:37,079 --> 00:16:39,498
so she steps up the pace.

269
00:16:39,873 --> 00:16:41,166
[bird screeching]

270
00:16:46,838 --> 00:16:48,924
They persevere for days.

271
00:16:48,965 --> 00:16:55,097
♪♪♪

272
00:16:58,475 --> 00:17:01,311
Perhaps this was a mistake.

273
00:17:03,146 --> 00:17:06,608
For the new calves,
the pace is punishing,

274
00:17:07,359 --> 00:17:10,154
but something
even worse is happening.

275
00:17:11,113 --> 00:17:12,865
[low grunting]

276
00:17:13,949 --> 00:17:16,869
Their mother‘s wound
is badly infected,

277
00:17:16,910 --> 00:17:19,747
and she is growing weaker
with every step.

278
00:17:21,289 --> 00:17:28,297
♪♪♪

279
00:17:33,468 --> 00:17:36,472
She made the decision
to take them south,

280
00:17:36,513 --> 00:17:39,934
but now, exhaustion
and her infected wound

281
00:17:39,975 --> 00:17:43,353
are making it impossible
for this matriarch to lead.

282
00:17:45,105 --> 00:17:46,648
She can barely walk.

283
00:17:47,774 --> 00:17:52,321
[solemn music]

284
00:18:00,745 --> 00:18:02,790
She knows her time has come.

285
00:18:03,415 --> 00:18:06,668
[herd trumpeting]

286
00:18:15,051 --> 00:18:18,973
Her herd try to help
their leader back to her feet.

287
00:18:19,014 --> 00:18:23,519
♪♪♪

288
00:18:23,560 --> 00:18:26,188
But she’s reached the end
of her journey.

289
00:18:28,106 --> 00:18:29,900
[trumpeting]

290
00:18:32,194 --> 00:18:36,240
And her death could
mean the death of her twins.

291
00:18:36,823 --> 00:18:40,494
[herd trumpeting]

292
00:18:45,332 --> 00:18:51,213
♪♪♪

293
00:18:55,008 --> 00:18:59,888
NARRATOR: The next morning,
the herd has no leader.

294
00:19:01,223 --> 00:19:04,518
But then, something
remarkable happens.

295
00:19:05,977 --> 00:19:10,024
The mother who lost
her own calf still has milk.

296
00:19:10,065 --> 00:19:13,235
[poignant music]

297
00:19:14,361 --> 00:19:16,446
[grunting]

298
00:19:18,240 --> 00:19:19,491
[high-pitched trumpeting]

299
00:19:20,450 --> 00:19:23,579
She is now the new matriarch.

300
00:19:24,871 --> 00:19:27,749
And following in the footsteps
of her predecessor,

301
00:19:29,084 --> 00:19:32,087
she starts to lead
the herd south again.

302
00:19:32,128 --> 00:19:36,925
♪♪♪

303
00:19:38,760 --> 00:19:42,723
Finally, rolling clouds
on the horizon.

304
00:19:44,849 --> 00:19:47,644
It looks like our old
matriarch was right.

305
00:19:49,187 --> 00:19:52,858
Her legacy will be
the herd‘s survival.

306
00:19:52,899 --> 00:19:57,780
♪♪♪

307
00:19:57,821 --> 00:20:00,616
There‘s the smell
of water in the air.

308
00:20:03,660 --> 00:20:07,373
But it’s not like any water
they’ve smelled before.

309
00:20:07,414 --> 00:20:12,169
[majestic music]

310
00:20:12,210 --> 00:20:13,629
It’s the ocean.

311
00:20:14,963 --> 00:20:18,926
This is where the Atlantic
meets the Pacific.

312
00:20:20,552 --> 00:20:23,138
For the last 50 million years,

313
00:20:23,179 --> 00:20:25,849
this would have been the end
of their journey.

314
00:20:26,850 --> 00:20:30,312
Now, as the American
continents collide,

315
00:20:31,146 --> 00:20:35,442
there is the promise of a
whole new land on the horizon.

316
00:20:35,483 --> 00:20:37,903
[waves splashing]

317
00:20:37,944 --> 00:20:42,366
But the journey there will test
this herd to its limits.

318
00:20:42,407 --> 00:20:43,784
[dramatic music]

319
00:20:49,706 --> 00:20:52,001
NARRATOR:
After an epic migration

320
00:20:52,042 --> 00:20:54,211
the new matriarch
has brought her herd

321
00:20:54,252 --> 00:20:57,047
to the southern most tip
of North America.

322
00:20:57,881 --> 00:21:00,717
Before them lies South America

323
00:21:01,760 --> 00:21:03,846
a continent
that has been isolated

324
00:21:03,887 --> 00:21:07,140
for the last 50 million years.

325
00:21:14,647 --> 00:21:18,527
In between stretches miles
of shallow sea,

326
00:21:18,568 --> 00:21:20,571
crisscrossed with sand banks

327
00:21:20,612 --> 00:21:23,407
and deep channels
in all directions,

328
00:21:24,741 --> 00:21:28,412
Here, they face an ocean
for the first time.

329
00:21:28,453 --> 00:21:30,748
[Gomphotheres grunting]

330
00:21:30,789 --> 00:21:34,418
The new environment
makes the herd nervous.

331
00:21:36,419 --> 00:21:40,090
For the innocent calves,
it’s a fun day at the beach.

332
00:21:42,133 --> 00:21:47,806
[Gomphotheres squeaking
and grunting]

333
00:21:58,525 --> 00:22:01,570
Their new leader can tell
the water isn’t drinkable.

334
00:22:01,611 --> 00:22:04,198
[Gomphothere growling]

335
00:22:04,239 --> 00:22:07,868
Then, she picks up
the unmistakable scent

336
00:22:07,909 --> 00:22:12,247
of lush vegetation floating
on a southerly breeze.

337
00:22:12,288 --> 00:22:17,085
Ahead, lies the island continent
of South America.

338
00:22:18,461 --> 00:22:21,590
Except, it’s no longer
an island.

339
00:22:23,675 --> 00:22:26,387
2.5 million years ago,

340
00:22:26,428 --> 00:22:30,557
continental drift is pushing
it so close to North America

341
00:22:30,598 --> 00:22:34,811
that a series of new islands
are forming a strip of land.

342
00:22:37,564 --> 00:22:39,191
To find fresh water,

343
00:22:39,232 --> 00:22:42,819
all the matriarch has
to do is follow her nose.

344
00:22:43,695 --> 00:22:46,114
So, she continues
the journey south.

345
00:22:57,584 --> 00:23:02,214
But she is unaware
the land bridge they are on

346
00:23:02,255 --> 00:23:04,633
only exists at low tide.

347
00:23:04,674 --> 00:23:06,802
[dramatic music]

348
00:23:16,686 --> 00:23:19,815
Now, the tide is coming in.

349
00:23:25,278 --> 00:23:29,032
The herd is trapped,
surrounded by water.

350
00:23:32,660 --> 00:23:35,831
[Gomphotheres groaning]

351
00:23:36,748 --> 00:23:40,585
Gomphotheres are
naturally good swimmers,

352
00:23:42,045 --> 00:23:44,882
but fighting tides and
unpredictable currents

353
00:23:44,923 --> 00:23:47,759
is much harder
than crossing a river.

354
00:23:57,018 --> 00:23:59,688
They all struggle
to stay together.

355
00:24:09,572 --> 00:24:12,576
The little female calf
is pulled by the tide.

356
00:24:12,617 --> 00:24:14,286
[calf crying]

357
00:24:14,327 --> 00:24:17,372
The new matriarch
can do nothing to help her.

358
00:24:17,413 --> 00:24:22,127
[Gomphotheres crying]

359
00:24:31,886 --> 00:24:35,015
[Gomphotheres groaning]

360
00:25:01,874 --> 00:25:05,295
NARRATOR:
Exhausted and disoriented,

361
00:25:05,336 --> 00:25:08,965
they find themselves
on a new continent:

362
00:25:10,466 --> 00:25:12,010
South America.

363
00:25:15,805 --> 00:25:17,974
But at what cost?

364
00:25:26,816 --> 00:25:31,279
[Gomphothere trumpeting]

365
00:25:47,170 --> 00:25:50,382
A miracle arrives
on the high tide.

366
00:25:53,009 --> 00:25:55,095
It‘s his sister!

367
00:25:56,554 --> 00:26:00,642
In her young life
she‘s overcome so much already.,

368
00:26:00,683 --> 00:26:04,938
And now she‘s even managed
to survive the rough sea.

369
00:26:04,979 --> 00:26:08,024
[Gomphotheres trumpeting]

370
00:26:21,537 --> 00:26:24,874
Finally, a new world.

371
00:26:38,554 --> 00:26:42,726
This part of South America is
less affected by the drought,

372
00:26:42,767 --> 00:26:46,396
with plenty of fresh water
and dense vegetation.

373
00:26:48,690 --> 00:26:51,693
Yet, for the herd
and their matriarch,

374
00:26:51,734 --> 00:26:54,070
nothing is familiar here.

375
00:26:55,613 --> 00:26:58,283
New scents hang in the air.

376
00:26:58,324 --> 00:27:02,078
There are strange
varieties of fruits.

377
00:27:06,249 --> 00:27:09,002
Even the birdsongs
are new to their ears.

378
00:27:20,054 --> 00:27:23,558
Here, they are the aliens

379
00:27:24,726 --> 00:27:28,897
and they have no idea
who they‘ll encounter.

380
00:27:35,445 --> 00:27:38,114
[animal growling]

381
00:27:39,866 --> 00:27:44,287
This ancient land has been
isolated for so long,

382
00:27:44,328 --> 00:27:46,748
[bird squawking]

383
00:27:46,789 --> 00:27:48,417
it has had plenty of time

384
00:27:48,458 --> 00:27:52,420
to evolve
its own terrifying predators.

385
00:27:59,093 --> 00:28:00,637
NARRATOR:
The herd of gomphotheres

386
00:28:00,678 --> 00:28:04,391
have made the impossible journey
across the tidal isthmus

387
00:28:04,432 --> 00:28:07,435
that connects North
and South America.

388
00:28:09,312 --> 00:28:11,523
Everything is new to them.

389
00:28:12,982 --> 00:28:15,152
These are
the sights and sounds

390
00:28:15,193 --> 00:28:17,779
of a completely
unfamiliar world.

391
00:28:17,820 --> 00:28:19,072
[birds trilling]

392
00:28:19,113 --> 00:28:22,659
[animals growling]

393
00:28:22,700 --> 00:28:27,414
Almost immediately, a strange
call echoes around them.

394
00:28:29,707 --> 00:28:33,044
It comes from
an enormous creature.

395
00:28:37,215 --> 00:28:40,635
Luckily, he‘s only
interested in the fruit.

396
00:28:42,261 --> 00:28:44,556
A Giant sloth.

397
00:28:45,348 --> 00:28:47,642
One of the wonders
of South America

398
00:28:47,683 --> 00:28:50,603
two and a half
million years ago.

399
00:28:52,730 --> 00:28:55,317
Even bigger
than the gomphotheres,

400
00:28:55,358 --> 00:28:57,736
they evolved during
the continent‘s

401
00:28:57,777 --> 00:29:00,321
50 million years of isolation.

402
00:29:04,367 --> 00:29:08,205
The matriarch leads them
deeper into this new world.

403
00:29:08,246 --> 00:29:10,707
Her role is to protect
the herd

404
00:29:10,748 --> 00:29:14,919
but she has no idea
who‘ll they‘ll meet next.

405
00:29:18,256 --> 00:29:21,968
For now, there is
no sign of predators.

406
00:29:23,928 --> 00:29:26,431
A herd of toxodons.

407
00:29:31,143 --> 00:29:35,440
Thousands of these one-ton
beasts graze these plains.

408
00:29:37,233 --> 00:29:39,528
And with so much
vegetation around,

409
00:29:39,569 --> 00:29:42,447
they have no problem sharing.

410
00:29:43,322 --> 00:29:47,202
So far, South America
seems like paradise.

411
00:29:51,205 --> 00:29:53,416
[bird trilling]

412
00:29:54,375 --> 00:29:59,047
Suddenly, a piercing call sends
the toxodons into a panic.

413
00:30:01,799 --> 00:30:06,596
[birds squawking]

414
00:30:11,309 --> 00:30:14,729
South America‘s Terror Bird.

415
00:30:16,480 --> 00:30:18,650
These seven-foot
super-predators

416
00:30:18,691 --> 00:30:21,611
can run at over
25 miles an hour.

417
00:30:32,496 --> 00:30:34,541
They start
to flush out the weak.

418
00:30:39,128 --> 00:30:40,839
[Gomphothere trumpeting]

419
00:30:40,880 --> 00:30:45,385
Until, they spot
unexpected visitors.

420
00:30:51,807 --> 00:30:57,355
[bird squawking]

421
00:31:00,149 --> 00:31:03,528
[Gomphothere groaning]

422
00:31:04,278 --> 00:31:08,366
Our matriarch knows
it‘s time for her to step up.

423
00:31:08,407 --> 00:31:10,743
[Gomphothere trumpeting]

424
00:31:12,828 --> 00:31:15,874
The birds assess
these new creatures.

425
00:31:17,083 --> 00:31:20,795
They have never seen
an elephant of any kind before.

426
00:31:27,635 --> 00:31:32,265
But, in this land,
everything is prey to them.

427
00:31:33,391 --> 00:31:35,226
[Gomphothere grunting]

428
00:31:40,898 --> 00:31:42,025
[bird squawking]

429
00:31:42,066 --> 00:31:44,110
They select their target.

430
00:31:53,953 --> 00:31:56,122
[Gomphothere trumpeting]

431
00:31:57,999 --> 00:31:59,292
[bird squawking]

432
00:32:00,501 --> 00:32:02,045
[Gomphothere trumpeting louder]

433
00:32:02,086 --> 00:32:04,380
[bird squawking]

434
00:32:14,348 --> 00:32:18,770
[bird crying]

435
00:32:20,187 --> 00:32:21,522
[bones snapping]

436
00:32:23,691 --> 00:32:25,610
[bird squawking]

437
00:32:26,318 --> 00:32:27,862
Not today.

438
00:32:39,790 --> 00:32:44,629
Our new matriarch secured her
place as leader of the herd.

439
00:32:48,799 --> 00:32:51,636
And stamped her mark
on this new continent.

440
00:32:53,345 --> 00:32:55,139
They‘ve finally made it.

441
00:32:55,973 --> 00:32:59,811
In a land where no predators
can threaten the adults,

442
00:32:59,852 --> 00:33:03,231
the gomphotheres’
future looks bright.

443
00:33:06,942 --> 00:33:09,696
But this is only the beginning.

444
00:33:14,158 --> 00:33:16,119
More species are moving south

445
00:33:16,994 --> 00:33:18,955
and it is not
just the herbivores

446
00:33:18,996 --> 00:33:21,332
discovering this new continent.

447
00:33:22,666 --> 00:33:27,047
Predators from the north
have also made the crossing

448
00:33:27,088 --> 00:33:31,634
and are about to change
this land forever.

449
00:33:31,675 --> 00:33:34,262
[growling]

450
00:33:40,434 --> 00:33:42,312
NARRATOR: Over the course
of hundreds

451
00:33:42,353 --> 00:33:44,439
of thousands of years,

452
00:33:44,480 --> 00:33:46,232
the movement of the continents

453
00:33:46,273 --> 00:33:50,361
continue to push North and
South America closer together.

454
00:33:52,446 --> 00:33:54,699
A new permanent land
bridge grows

455
00:33:54,740 --> 00:33:56,993
at what will
one day be Panama.

456
00:34:01,539 --> 00:34:04,084
Thousands of species
of plant and animal

457
00:34:04,125 --> 00:34:07,378
move both north and south.

458
00:34:08,671 --> 00:34:11,716
It is one of the largest
rapid mixings of plant

459
00:34:11,757 --> 00:34:14,635
and animal species
in Earth‘s history.

460
00:34:17,596 --> 00:34:20,808
And as these vastly
different species collide,

461
00:34:21,684 --> 00:34:25,772
they forge a new future
for the Americas.

462
00:34:37,324 --> 00:34:39,536
One million years later,

463
00:34:39,577 --> 00:34:43,873
life in South America has
gone through a seismic shift.

464
00:34:46,667 --> 00:34:49,379
During the great
Clash of Species,

465
00:34:49,420 --> 00:34:52,257
many went extinct.

466
00:34:52,298 --> 00:34:56,511
But out of the melting pot,
new ones have evolved.

467
00:35:03,100 --> 00:35:06,104
Now, at the top
of the food chain,

468
00:35:06,145 --> 00:35:10,399
sits the giant
South American sabretooth.

469
00:35:12,026 --> 00:35:14,487
Four times the weight
of the sabretooths

470
00:35:14,528 --> 00:35:16,405
that crossed
over from the North,

471
00:35:17,156 --> 00:35:21,661
this is one of the largest
cats that ever lived.

472
00:35:26,874 --> 00:35:29,585
The gomphotheres
are also thriving.

473
00:35:31,003 --> 00:35:35,091
Tens of thousands now
roam these grassy plains.

474
00:35:41,847 --> 00:35:45,602
And a large herd of
gomphotheres is perfect

475
00:35:45,643 --> 00:35:47,770
for a hungry sabretooth.

476
00:35:53,442 --> 00:35:56,362
[sabretooth growling]

477
00:35:56,403 --> 00:35:57,822
[Gomphothere trumpeting]

478
00:36:05,996 --> 00:36:08,249
Unlike his Northern cousins,

479
00:36:08,290 --> 00:36:10,710
this predator hunts alone

480
00:36:12,503 --> 00:36:16,841
and is easily large enough to
take down a gomphothere calf.

481
00:36:33,357 --> 00:36:37,445
[Gomphothere trumpeting]

482
00:36:52,293 --> 00:36:55,463
[frantic music]

483
00:36:56,797 --> 00:36:59,300
[Gomphothere trumpeting]

484
00:36:59,341 --> 00:37:01,469
[sabretooth growling]

485
00:37:02,386 --> 00:37:04,430
[gomphothere grunting]

486
00:37:05,848 --> 00:37:07,808
A bull gomphothere.

487
00:37:09,310 --> 00:37:11,437
[gomphothere growling]

488
00:37:11,478 --> 00:37:13,773
Pumped full of testosterone,

489
00:37:16,859 --> 00:37:19,487
the little guy
is part of a herd.

490
00:37:20,529 --> 00:37:22,907
[animals growling]

491
00:37:22,948 --> 00:37:27,787
And even apex predators
know when to run from a fight.

492
00:37:36,503 --> 00:37:38,965
[gomphothere trumpeting]

493
00:37:42,468 --> 00:37:46,764
[gomphothere trumpeting]

494
00:37:50,642 --> 00:37:53,021
From their origins in Africa,

495
00:37:53,062 --> 00:37:56,441
the elephant family have now
claimed a fifth continent

496
00:37:56,482 --> 00:37:57,817
as their home.

497
00:38:06,784 --> 00:38:10,288
A million years after
the Americas unite,

498
00:38:10,329 --> 00:38:13,958
there’s been
an explosion in biodiversity.

499
00:38:17,795 --> 00:38:19,213
The continent will go on

500
00:38:19,254 --> 00:38:22,300
to support 32 different
types of mammals

501
00:38:22,341 --> 00:38:24,760
that weigh over a ton.

502
00:38:28,889 --> 00:38:32,310
It‘s the greatest
diversity of mega-mammals

503
00:38:32,351 --> 00:38:34,937
in Earth‘s history.

504
00:38:54,123 --> 00:38:57,210
The impact of the joining
of the Americas

505
00:38:57,251 --> 00:38:59,211
can still be seen today.

506
00:39:07,678 --> 00:39:12,725
NARRATOR: But more recently, it
is humans that have kickstarted

507
00:39:12,766 --> 00:39:15,269
an even bigger clash of species.

508
00:39:16,395 --> 00:39:20,691
After some 110 million years
of separation,

509
00:39:20,732 --> 00:39:25,780
the arrival of Columbus marked
a new continental collision.

510
00:39:29,116 --> 00:39:32,119
Living things from
Africa and Eurasia

511
00:39:33,078 --> 00:39:35,706
met with those
of the Americas.

512
00:39:37,458 --> 00:39:41,379
Everything from
livestock and insects

513
00:39:41,420 --> 00:39:43,423
to vegetables and viruses

514
00:39:43,464 --> 00:39:47,134
moved both ways
across the Atlantic.

515
00:39:49,386 --> 00:39:52,640
The consequences of our
re-connecting the continents

516
00:39:52,681 --> 00:39:54,350
have been profound:

517
00:39:56,560 --> 00:39:59,688
Some species’
populations are exploding,

518
00:40:02,483 --> 00:40:05,069
while others’ go extinct.

519
00:40:08,906 --> 00:40:10,908
Humans have
impacted the environment

520
00:40:10,949 --> 00:40:12,493
in countless ways,

521
00:40:13,327 --> 00:40:16,622
but the way our activities
are now mixing species

522
00:40:16,663 --> 00:40:18,374
on a global scale

523
00:40:20,501 --> 00:40:23,754
is perhaps our biggest legacy

524
00:40:24,922 --> 00:40:30,052
to the future shape
of life on Earth.