1
00:00:06,480 --> 00:00:07,960
[cicadas chirping]
2
00:00:09,600 --> 00:00:10,920
[frogs croaking]
3
00:00:11,680 --> 00:00:13,320
[water sloshing]
4
00:00:13,400 --> 00:00:15,400
[rousing music playing]
5
00:00:18,320 --> 00:00:19,720
[buzzing]
6
00:00:23,200 --> 00:00:25,320
[Cate Blanchett] A hungry hunter...
7
00:00:26,880 --> 00:00:29,120
with his eyes on the prize.
8
00:00:29,200 --> 00:00:30,920
[quirky music playing]
9
00:00:33,240 --> 00:00:34,880
[water burbling]
10
00:00:36,080 --> 00:00:37,240
[slurping]
11
00:00:39,800 --> 00:00:41,680
- [frog croaks]
- [water burbling]
12
00:00:45,280 --> 00:00:46,600
[wings fluttering]
13
00:00:46,680 --> 00:00:47,880
[slurping]
14
00:00:51,760 --> 00:00:56,200
But whatever he tries,
he's just not fast enough.
15
00:00:58,840 --> 00:00:59,840
[croaks]
16
00:01:01,160 --> 00:01:03,160
[playful music playing]
17
00:01:04,880 --> 00:01:05,960
[croaks softly]
18
00:01:09,400 --> 00:01:14,240
It's as if the dragonfly
can see him coming in slow motion.
19
00:01:16,160 --> 00:01:18,040
- [water splashing]
- [croaking]
20
00:01:18,120 --> 00:01:19,200
[wings fluttering]
21
00:01:20,520 --> 00:01:22,480
And maybe he can.
22
00:01:24,560 --> 00:01:26,120
[mysterious music playing]
23
00:01:27,440 --> 00:01:30,600
Dragonflies' food is tiny and quick.
24
00:01:31,560 --> 00:01:33,560
[buzzing]
25
00:01:34,680 --> 00:01:36,600
But unlike the frog...
26
00:01:38,800 --> 00:01:40,880
nine strikes out of ten,
27
00:01:42,080 --> 00:01:43,440
he gets a meal.
28
00:01:44,840 --> 00:01:50,880
Because his visual processors
work five times faster than ours
29
00:01:52,560 --> 00:01:56,120
and effectively slow down time.
30
00:01:56,200 --> 00:01:58,200
[distorted time music playing]
31
00:02:06,240 --> 00:02:07,080
[croaks]
32
00:02:07,160 --> 00:02:09,320
The frog won't stop trying.
33
00:02:11,120 --> 00:02:13,320
[suspenseful music playing]
34
00:02:13,400 --> 00:02:14,400
[croaks]
35
00:02:17,400 --> 00:02:18,600
Close...
36
00:02:19,320 --> 00:02:20,320
but no cigar.
37
00:02:22,400 --> 00:02:24,760
[croaks, trills]
38
00:02:25,920 --> 00:02:30,960
The dragonfly isn't just keeping an eye
on his slow-motion stalker.
39
00:02:34,480 --> 00:02:38,960
He also has to defend
his territory from rivals.
40
00:02:51,200 --> 00:02:53,400
With his eyes on the skies,
41
00:02:53,480 --> 00:02:57,680
he is less likely
to spy someone hiding below.
42
00:02:58,600 --> 00:03:00,880
[tense music playing]
43
00:03:04,400 --> 00:03:06,400
[suspenseful music playing]
44
00:03:12,560 --> 00:03:14,560
[suspenseful music rising]
45
00:03:15,040 --> 00:03:17,040
[slurping]
46
00:03:20,120 --> 00:03:21,120
[frog croaks]
47
00:03:24,600 --> 00:03:28,360
The frog may not have
the dragonfly's lightning moves,
48
00:03:30,800 --> 00:03:34,000
but this time, he's right on cue.
49
00:03:34,840 --> 00:03:36,080
[croaks, munches]
50
00:03:39,000 --> 00:03:41,000
[tranquil music playing]
51
00:03:47,440 --> 00:03:52,600
A sense of timing is crucial to survival
throughout our webs of life.
52
00:03:55,080 --> 00:03:56,960
[birds squawking]
53
00:04:00,080 --> 00:04:05,080
Nature works best when it's in sync
with the planet's rhythms.
54
00:04:06,920 --> 00:04:08,880
- [car horn honks]
- [rhino grunts]
55
00:04:09,360 --> 00:04:14,440
To make the most of it, life must time
its opportunities to perfection.
56
00:04:14,520 --> 00:04:17,800
[howling]
57
00:04:20,080 --> 00:04:22,640
Sometimes in milliseconds.
58
00:04:25,080 --> 00:04:28,280
Sometimes across millennia.
59
00:04:32,800 --> 00:04:36,480
[trilling]
60
00:04:40,440 --> 00:04:43,080
[wildlife calling]
61
00:04:43,160 --> 00:04:44,680
{\an8}[birds chirping]
62
00:04:44,760 --> 00:04:47,520
{\an8}Late afternoon in the Kalahari.
63
00:04:50,760 --> 00:04:52,760
[soft panting]
64
00:04:54,720 --> 00:04:57,960
A lioness has hungry mouths to feed.
65
00:04:59,000 --> 00:05:01,000
[soft growling]
66
00:05:01,680 --> 00:05:07,880
Her growing cubs
need fresh meat every two days.
67
00:05:07,960 --> 00:05:09,960
[wildlife screeching]
68
00:05:13,720 --> 00:05:15,720
[birds squawking]
69
00:05:16,640 --> 00:05:18,600
[lioness grunts softly]
70
00:05:19,320 --> 00:05:21,120
There's food everywhere.
71
00:05:22,640 --> 00:05:24,640
[tense music playing]
72
00:05:29,280 --> 00:05:32,920
But most of her targets
are faster than she is.
73
00:05:33,600 --> 00:05:34,680
[soft growl]
74
00:05:35,960 --> 00:05:38,840
Chase them around under the blazing sun,
75
00:05:39,600 --> 00:05:41,680
and she'll quickly overheat.
76
00:05:41,760 --> 00:05:43,280
[soft growling]
77
00:05:45,520 --> 00:05:48,240
She needs to get close enough
for an ambush.
78
00:05:48,320 --> 00:05:50,320
[tense music rising]
79
00:05:51,800 --> 00:05:54,080
[suspenseful music playing]
80
00:05:56,960 --> 00:05:59,400
Tricky in broad daylight.
81
00:06:04,400 --> 00:06:07,400
Her prey are primed to spot movement.
82
00:06:12,160 --> 00:06:13,160
[lioness growls]
83
00:06:19,360 --> 00:06:21,640
And once her cover is blown,
84
00:06:22,640 --> 00:06:24,720
she's much less of a threat.
85
00:06:28,680 --> 00:06:29,920
[birds chirping]
86
00:06:30,000 --> 00:06:32,440
But she's not fully committed yet.
87
00:06:34,560 --> 00:06:35,960
[bird cawing]
88
00:06:37,680 --> 00:06:42,240
Because she knows
the tables are about to turn.
89
00:06:47,360 --> 00:06:49,360
[bird cawing]
90
00:06:49,840 --> 00:06:55,000
As the sun sets,
the odds shift in her favor.
91
00:06:55,640 --> 00:06:57,640
[owl hooting]
92
00:07:00,800 --> 00:07:02,240
She's harder to spot...
93
00:07:05,160 --> 00:07:07,160
[tense music playing]
94
00:07:07,920 --> 00:07:09,800
...less likely to overheat.
95
00:07:13,120 --> 00:07:15,120
[suspenseful music playing]
96
00:07:15,880 --> 00:07:20,000
And her night vision comes into its own.
97
00:07:21,160 --> 00:07:23,160
[suspenseful music rising]
98
00:07:31,880 --> 00:07:33,280
A herd of buffalo.
99
00:07:37,040 --> 00:07:38,880
[soft growling]
100
00:07:39,400 --> 00:07:40,880
Five times her weight,
101
00:07:41,440 --> 00:07:44,800
these armored giants
are a dangerous target.
102
00:07:46,360 --> 00:07:48,400
[owls hooting]
103
00:07:52,880 --> 00:07:57,560
But if they haven't seen her,
then she has the edge.
104
00:07:58,560 --> 00:08:00,560
[foreboding music playing]
105
00:08:03,720 --> 00:08:04,840
[buffalo bellows]
106
00:08:04,920 --> 00:08:06,360
She targets a calf.
107
00:08:07,320 --> 00:08:09,640
Weaker, less risky.
108
00:08:19,920 --> 00:08:21,920
[suspenseful music playing]
109
00:08:26,760 --> 00:08:29,320
[calf cries]
110
00:08:33,600 --> 00:08:37,080
In the twilight,
she makes it look effortless.
111
00:08:46,040 --> 00:08:49,840
She has already cashed in
on the advantage that dusk brings.
112
00:08:51,800 --> 00:08:54,200
And her cubs will feast tonight.
113
00:09:02,600 --> 00:09:06,160
The sun is always setting
somewhere on Earth,
114
00:09:07,600 --> 00:09:11,320
creating an endless beat
of changing fortunes.
115
00:09:11,400 --> 00:09:13,440
[wildlife calling]
116
00:09:16,160 --> 00:09:20,600
But our ever-spinning planet gives us
more than just day and night.
117
00:09:23,520 --> 00:09:26,560
Because the sun's power
isn't the only force
118
00:09:26,640 --> 00:09:29,000
that holds sway over life on Earth.
119
00:09:32,880 --> 00:09:36,800
The moon carves its own path
through the night sky,
120
00:09:37,720 --> 00:09:41,080
pulling our oceans into a watery waltz.
121
00:09:42,840 --> 00:09:46,440
And sea creatures must dance to its tune.
122
00:09:52,160 --> 00:09:55,760
In Northern Australia, the tide recedes.
123
00:10:01,080 --> 00:10:04,800
Beneath the mangroves,
a new world appears.
124
00:10:06,960 --> 00:10:07,960
[seagulls hoot]
125
00:10:09,720 --> 00:10:13,000
Home to a banana fiddler crab.
126
00:10:16,480 --> 00:10:20,400
He lives his life
in the windows between the high tides.
127
00:10:21,680 --> 00:10:23,920
So he's on a tight schedule.
128
00:10:25,240 --> 00:10:26,720
[jazzy music playing]
129
00:10:26,800 --> 00:10:29,800
Time to feed as fast as he can...
130
00:10:34,120 --> 00:10:38,400
while his female neighbors go double-time.
131
00:10:42,200 --> 00:10:45,840
His banana claw might be
slowing him down now,
132
00:10:46,920 --> 00:10:48,960
but when the moon is right,
133
00:10:50,120 --> 00:10:51,440
his time will come.
134
00:10:58,200 --> 00:11:02,280
The tide turns,
and it's back to his burrow.
135
00:11:06,360 --> 00:11:08,040
[cicadas chirping]
136
00:11:08,560 --> 00:11:10,280
The cycle repeats.
137
00:11:14,320 --> 00:11:15,800
[burbling]
138
00:11:22,920 --> 00:11:27,800
But as the month moves on,
the moon's pull on the ocean weakens.
139
00:11:29,280 --> 00:11:32,320
Each high tide covers less of the beach.
140
00:11:34,600 --> 00:11:39,320
Until eventually... for a few days...
141
00:11:41,960 --> 00:11:44,840
his burrow won't get covered at all.
142
00:11:50,880 --> 00:11:55,520
Now he's got
one of the best spots on the beach.
143
00:11:59,640 --> 00:12:02,680
And another male wants in.
144
00:12:08,880 --> 00:12:10,520
Bananas at the ready.
145
00:12:12,920 --> 00:12:14,400
[tense music playing]
146
00:12:15,280 --> 00:12:16,920
In a shoving contest,
147
00:12:17,720 --> 00:12:19,760
there's not much between them.
148
00:12:21,640 --> 00:12:23,280
But when it comes to the grapple...
149
00:12:26,280 --> 00:12:28,440
our champ's got the upper claw.
150
00:12:32,040 --> 00:12:33,640
Go find your own burrow.
151
00:12:36,680 --> 00:12:40,320
But time and tide wait for no crab.
152
00:12:41,960 --> 00:12:43,600
He's got to find a mate.
153
00:12:46,880 --> 00:12:48,880
[squeaking]
154
00:12:48,960 --> 00:12:52,760
A quick preen and he is ready
to show off his winning claw.
155
00:12:56,640 --> 00:12:58,920
But in which direction?
156
00:12:59,000 --> 00:13:00,680
[quirky music playing]
157
00:13:01,600 --> 00:13:04,880
The beach is covered in crabs.
158
00:13:07,520 --> 00:13:10,320
And he's not great at sizing them up.
159
00:13:12,800 --> 00:13:13,800
How about her?
160
00:13:17,920 --> 00:13:19,120
He's not her type...
161
00:13:21,160 --> 00:13:22,160
of crab.
162
00:13:24,400 --> 00:13:25,400
Ah...
163
00:13:27,400 --> 00:13:29,480
Time to claw back some dignity.
164
00:13:34,080 --> 00:13:35,440
She is more like it.
165
00:13:39,200 --> 00:13:43,600
But now he's got competition
from all sides.
166
00:13:46,120 --> 00:13:48,440
He tries to tempt her with a wave.
167
00:13:52,280 --> 00:13:54,400
But they all know that trick.
168
00:13:56,480 --> 00:13:58,280
What if he goes a bit higher?
169
00:14:00,560 --> 00:14:02,760
[light upbeat music playing]
170
00:14:02,840 --> 00:14:04,120
They do too.
171
00:14:08,640 --> 00:14:12,000
Another and another.
172
00:14:13,360 --> 00:14:16,040
It's turning into quite the beach party.
173
00:14:16,560 --> 00:14:18,680
[fast-tempo, upbeat music playing]
174
00:14:26,400 --> 00:14:28,000
How's a girl to choose?
175
00:14:32,360 --> 00:14:37,280
Finally, she selects
the best banana on the beach.
176
00:14:44,080 --> 00:14:45,640
And only just in time.
177
00:14:49,240 --> 00:14:52,800
He seals her in his burrow
before the tide returns.
178
00:14:54,520 --> 00:14:56,080
[tranquil music playing]
179
00:14:56,160 --> 00:14:59,320
She'll release her larvae
on the next full moon...
180
00:15:01,680 --> 00:15:06,600
when the strongest ebb
will carry them far out to sea.
181
00:15:07,640 --> 00:15:09,200
[soft lapping]
182
00:15:09,280 --> 00:15:11,160
A lucky few will survive.
183
00:15:12,480 --> 00:15:15,960
The rest provide
a pulse of food to the ocean,
184
00:15:16,640 --> 00:15:22,600
connecting whole webs of life
to the never-ending rhythms of the moon.
185
00:15:26,080 --> 00:15:28,480
[birds clucking]
186
00:15:29,960 --> 00:15:35,760
But our planet has another cycle
that shapes nature's networks in a slower
187
00:15:36,280 --> 00:15:38,520
but perhaps more profound way.
188
00:15:41,640 --> 00:15:43,640
The precession of the seasons.
189
00:15:47,480 --> 00:15:51,280
A yearly pulse that life must adapt to.
190
00:15:55,360 --> 00:15:56,640
[birds chirping]
191
00:15:58,240 --> 00:16:02,880
With Earth's longer time scales,
the stakes get higher.
192
00:16:02,960 --> 00:16:04,360
[birdsong]
193
00:16:06,080 --> 00:16:09,960
Because when opportunities
only come around once a year,
194
00:16:10,520 --> 00:16:13,400
you've got to grab them while you can.
195
00:16:13,480 --> 00:16:15,480
[water rushing]
196
00:16:21,120 --> 00:16:22,960
On Norwegian tundra...
197
00:16:23,480 --> 00:16:24,480
[snorts]
198
00:16:24,520 --> 00:16:27,520
...an old warrior watches over the herd.
199
00:16:28,040 --> 00:16:29,600
[lowing]
200
00:16:39,280 --> 00:16:42,720
The females will be in season
for just a few weeks.
201
00:16:43,760 --> 00:16:46,960
His only chance
to father next year's calves.
202
00:16:47,040 --> 00:16:49,040
[soft bellows]
203
00:16:50,800 --> 00:16:52,120
[soft grunts]
204
00:16:56,160 --> 00:16:59,000
Other males will want
to stake their claim.
205
00:17:01,000 --> 00:17:03,000
[birds chirping]
206
00:17:05,200 --> 00:17:07,240
So each year,
207
00:17:07,320 --> 00:17:12,720
this musk ox must face a ritual tournament
to retain his crown.
208
00:17:17,040 --> 00:17:18,520
[growling]
209
00:17:18,600 --> 00:17:19,600
A rival.
210
00:17:22,000 --> 00:17:23,600
[tense music playing]
211
00:17:23,680 --> 00:17:25,080
[low growl]
212
00:17:28,000 --> 00:17:31,160
For the king,
the gauntlet has been thrown down.
213
00:17:37,240 --> 00:17:38,640
He puts up a front.
214
00:17:41,200 --> 00:17:42,480
[low bellowing]
215
00:17:44,560 --> 00:17:46,160
[growling]
216
00:17:47,240 --> 00:17:50,840
It's an old trick
to psych out his opponent.
217
00:17:51,840 --> 00:17:53,880
[snarling]
218
00:17:54,640 --> 00:17:57,000
[low growling]
219
00:17:59,880 --> 00:18:02,400
But the challenger doesn't back down.
220
00:18:08,240 --> 00:18:12,680
They walk in parallel, hoping their size
will scare the other off.
221
00:18:16,520 --> 00:18:17,520
Not this time.
222
00:18:19,360 --> 00:18:21,400
[growls, snarls]
223
00:18:25,000 --> 00:18:26,200
[both roaring]
224
00:18:29,040 --> 00:18:33,600
An airbag beneath their armored horns
cushions them from an impact...
225
00:18:33,680 --> 00:18:34,920
[horns crack]
226
00:18:35,000 --> 00:18:37,520
...as violent as a car crash.
227
00:18:37,600 --> 00:18:39,600
[low growling]
228
00:18:44,720 --> 00:18:48,480
The king is a veteran of many battles.
229
00:18:49,800 --> 00:18:53,200
He uses the slope
to make the most of his weight.
230
00:18:57,480 --> 00:18:59,080
[bellowing]
231
00:19:03,000 --> 00:19:04,920
[low growls]
232
00:19:07,000 --> 00:19:11,960
As he tries to gouge his opponent,
he loses the upper ground.
233
00:19:16,200 --> 00:19:18,200
[low growls]
234
00:19:23,280 --> 00:19:24,280
Not for long.
235
00:19:30,400 --> 00:19:32,760
[growls, exhales forcefully]
236
00:19:33,360 --> 00:19:36,240
This time, experience wins the day.
237
00:19:42,640 --> 00:19:46,600
There will be more jousts to come
in this annual tournament.
238
00:19:48,600 --> 00:19:50,720
And only if he can win them all
239
00:19:50,800 --> 00:19:53,760
will he secure his position
for another year.
240
00:19:55,360 --> 00:19:57,360
[wind gusting]
241
00:20:00,440 --> 00:20:06,440
Now, all across the Northern Hemisphere,
winter closes in.
242
00:20:07,800 --> 00:20:08,800
[wolves whining]
243
00:20:10,280 --> 00:20:11,360
[growls]
244
00:20:12,920 --> 00:20:14,880
In this harshest of seasons,
245
00:20:15,400 --> 00:20:17,880
everyone must bide their time.
246
00:20:21,240 --> 00:20:22,600
[sniffing]
247
00:20:23,120 --> 00:20:25,160
[ice crackling]
248
00:20:25,240 --> 00:20:27,040
Resources freeze.
249
00:20:29,280 --> 00:20:30,760
Temperatures plummet.
250
00:20:32,360 --> 00:20:36,320
And life is held in suspended animation.
251
00:20:36,920 --> 00:20:38,920
[wind howling]
252
00:20:44,600 --> 00:20:50,880
The only certainty of winter
is that in time, it will draw to a close.
253
00:20:50,960 --> 00:20:52,960
[ice crystals crackling]
254
00:20:54,600 --> 00:20:57,400
The earth's yearly journey around the sun
255
00:20:57,920 --> 00:21:02,120
brings the Northern Hemisphere
back into more direct sunlight.
256
00:21:08,360 --> 00:21:10,560
Longer days return.
257
00:21:10,640 --> 00:21:12,000
[bird squawks]
258
00:21:12,080 --> 00:21:16,920
And winter yields to spring.
259
00:21:19,800 --> 00:21:24,160
This is the season
that life makes its own.
260
00:21:24,720 --> 00:21:26,720
[birdsong]
261
00:21:31,000 --> 00:21:33,080
[tranquil music playing]
262
00:21:33,160 --> 00:21:35,280
[birds squawking]
263
00:21:35,360 --> 00:21:39,840
All powered
by the growing warmth of the sun.
264
00:21:44,080 --> 00:21:47,800
Seedlings race for their place
in the strengthening light...
265
00:21:48,520 --> 00:21:50,520
[rousing music playing]
266
00:21:52,720 --> 00:21:56,400
...each with its own strategy to get ahead.
267
00:22:00,000 --> 00:22:02,560
Leaves sprout and unfurl.
268
00:22:08,600 --> 00:22:13,440
Each one, a natural solar panel,
harnessing the sun's energy...
269
00:22:16,080 --> 00:22:22,160
drawing in carbon dioxide
and converting it into food to grow.
270
00:22:27,520 --> 00:22:29,960
So many plants come to life
271
00:22:30,040 --> 00:22:33,120
that the planet
seems to take a deep breath in.
272
00:22:34,920 --> 00:22:37,840
Carbon dioxide levels dip dramatically,
273
00:22:38,440 --> 00:22:42,240
helping bring balance
to the atmosphere we all depend on.
274
00:22:46,000 --> 00:22:50,240
The changing season triggers
countless creatures to move north
275
00:22:51,520 --> 00:22:54,320
as nature's networks spring back to life.
276
00:22:55,520 --> 00:22:57,520
[squawking]
277
00:23:00,320 --> 00:23:04,160
Billions of birds flock
towards distant breeding grounds.
278
00:23:04,240 --> 00:23:06,240
[cawing]
279
00:23:11,000 --> 00:23:15,560
Ocean giants travel
thousands of miles in search of food...
280
00:23:16,320 --> 00:23:17,960
[squealing]
281
00:23:20,800 --> 00:23:24,440
...while huge herds surge
across the waking landscape.
282
00:23:24,520 --> 00:23:26,520
[bleating]
283
00:23:28,080 --> 00:23:29,920
[birds chirping]
284
00:23:30,720 --> 00:23:36,280
To succeed, all of these heroic journeys
must be timed to perfection,
285
00:23:38,160 --> 00:23:41,360
even those of the most
miniature migrators.
286
00:23:43,080 --> 00:23:45,080
[ice crackling]
287
00:23:47,600 --> 00:23:51,160
As the last snow melts deep in the forest,
288
00:23:52,560 --> 00:23:53,960
pools appear.
289
00:23:54,520 --> 00:23:56,400
[birds cawing]
290
00:23:57,800 --> 00:24:01,600
In just a few weeks,
they'll dry out in the heat.
291
00:24:04,800 --> 00:24:08,000
By the time one creature wakes
from her winter sleep...
292
00:24:10,760 --> 00:24:13,320
a countdown has already begun.
293
00:24:17,720 --> 00:24:23,120
This salamander needs to reach her pool
and complete her breeding cycle
294
00:24:23,720 --> 00:24:26,320
before the water disappears.
295
00:24:26,840 --> 00:24:28,840
[cicadas chirping]
296
00:24:30,960 --> 00:24:32,440
The first spring rain...
297
00:24:36,160 --> 00:24:40,600
is the starting gun
for the race of her life.
298
00:24:40,680 --> 00:24:42,680
[rain pattering]
299
00:24:47,160 --> 00:24:48,640
In salamander speed,
300
00:24:50,480 --> 00:24:51,600
she's sprinting.
301
00:24:56,720 --> 00:25:00,400
Her ancestors followed
the same routes through the forest.
302
00:25:03,880 --> 00:25:07,640
But times have changed
since they first walked the Earth.
303
00:25:09,560 --> 00:25:11,560
[car approaching, receding]
304
00:25:22,000 --> 00:25:25,760
In a few hours,
she's almost at the finish line.
305
00:25:27,800 --> 00:25:30,400
The pool where her own life began.
306
00:25:30,480 --> 00:25:32,120
[frogs croaking]
307
00:25:32,960 --> 00:25:38,000
Now she needs to find a mate
as quickly as she can.
308
00:25:41,640 --> 00:25:44,600
Other salamanders
have also raced to this pool.
309
00:25:48,400 --> 00:25:52,560
And they may just have a trick
to help them with their speed dating.
310
00:25:55,680 --> 00:26:00,000
In the forest shadows,
mostly blue light penetrates.
311
00:26:02,600 --> 00:26:05,920
Their vision is particularly sensitive
in the twilight.
312
00:26:08,720 --> 00:26:14,560
And in this blue hue,
their bodies begin to glow.
313
00:26:17,200 --> 00:26:19,200
[contemplative music playing]
314
00:26:27,960 --> 00:26:29,960
[chittering, croaking]
315
00:26:31,600 --> 00:26:33,680
[cicadas chirping]
316
00:26:37,320 --> 00:26:41,080
Scientists have only recently discovered
this phenomenon.
317
00:26:44,000 --> 00:26:47,800
Could it be that it helps
in their race to find a mate?
318
00:26:48,320 --> 00:26:50,320
[crickets chirping]
319
00:26:58,240 --> 00:27:01,240
Now she can lay her fertilized eggs.
320
00:27:10,600 --> 00:27:14,360
But time is already working
against the next generation.
321
00:27:19,720 --> 00:27:22,680
They need to hatch and finish developing...
322
00:27:24,920 --> 00:27:27,240
before their pool disappears.
323
00:27:32,600 --> 00:27:35,440
And it's already started shrinking.
324
00:27:35,520 --> 00:27:37,520
[birdsong]
325
00:27:43,880 --> 00:27:48,960
Every spotted salamander's life is hurried
by the ticking of the seasonal clock.
326
00:27:52,120 --> 00:27:55,520
So too are countless other creatures.
327
00:27:55,600 --> 00:27:56,520
[chirping]
328
00:27:56,600 --> 00:28:01,560
Their lives tied to the rhythms
of the earth, moon, and sun.
329
00:28:02,480 --> 00:28:04,360
[birdsong]
330
00:28:05,000 --> 00:28:10,000
But some mysterious beings dance
to their own beat,
331
00:28:10,560 --> 00:28:15,120
keeping time not in seasons,
but in decades.
332
00:28:15,680 --> 00:28:17,680
[mysterious music playing]
333
00:28:19,800 --> 00:28:25,880
Inside a maple tree, sap flows
for the first time since last fall...
334
00:28:30,680 --> 00:28:32,920
kick-starting new growth.
335
00:28:36,600 --> 00:28:39,120
[birdsong]
336
00:28:40,120 --> 00:28:46,240
But deep below ground,
one creature is using this pulse
337
00:28:46,320 --> 00:28:48,800
to count the passing of the seasons.
338
00:28:52,160 --> 00:28:53,840
A periodical cicada.
339
00:28:57,080 --> 00:29:00,400
She feeds on the tree's sweet sap.
340
00:29:01,280 --> 00:29:06,560
So as it rises each spring,
she can tell that another year has passed.
341
00:29:09,160 --> 00:29:12,200
She burrowed underground 17 years ago.
342
00:29:15,200 --> 00:29:18,360
Now she's tunneled to the surface,
343
00:29:18,880 --> 00:29:21,760
ready for the moment
she's been waiting for.
344
00:29:36,440 --> 00:29:39,480
As darkness cloaks this Indiana woodland,
345
00:29:40,720 --> 00:29:44,200
things are about to get strange.
346
00:29:47,200 --> 00:29:49,200
[intriguing music playing]
347
00:29:51,240 --> 00:29:54,000
Aboveground, she's vulnerable.
348
00:29:54,080 --> 00:29:56,280
[squeaking]
349
00:30:02,080 --> 00:30:05,640
But she's timed her emergence
to perfection.
350
00:30:07,840 --> 00:30:09,640
There's safety in numbers.
351
00:30:13,400 --> 00:30:18,120
Billions of cicadas have synchronized
their 17-year life cycle.
352
00:30:20,760 --> 00:30:22,640
[skittering]
353
00:30:22,720 --> 00:30:26,560
Like a zombie horde, they rise in unison.
354
00:30:31,840 --> 00:30:33,160
Safely off the ground,
355
00:30:34,160 --> 00:30:37,240
they begin the next stage
of their resurrection.
356
00:30:38,320 --> 00:30:39,880
[intriguing music playing]
357
00:30:42,640 --> 00:30:44,920
An eerie transformation
358
00:30:46,160 --> 00:30:47,800
into their adult form.
359
00:30:57,000 --> 00:30:59,000
[cicadas chirping]
360
00:31:00,360 --> 00:31:02,000
[chirping intensifies]
361
00:31:02,080 --> 00:31:05,160
For the first time in 17 years,
362
00:31:05,680 --> 00:31:12,000
dawn breaks to a chorus of cicadas
almost as loud as a chainsaw.
363
00:31:12,080 --> 00:31:14,160
[loud chirping]
364
00:31:15,480 --> 00:31:17,960
The neighbors barely know what's hit them.
365
00:31:18,560 --> 00:31:20,560
[loud buzzing]
366
00:31:22,800 --> 00:31:27,280
The last time these insects appeared
was long before they were born.
367
00:31:27,840 --> 00:31:29,840
[crunching]
368
00:31:32,040 --> 00:31:35,960
It would be terrifying
if they weren't so tasty.
369
00:31:40,080 --> 00:31:45,680
For the next few weeks,
this banquet puts meat on everyone's menu.
370
00:31:47,520 --> 00:31:49,520
[loud chirping]
371
00:31:51,560 --> 00:31:54,920
But with more than a million
in a single acre...
372
00:31:57,200 --> 00:32:00,080
the diners barely make a dent
in the buffet.
373
00:32:02,920 --> 00:32:04,920
[loud buzzing]
374
00:32:06,760 --> 00:32:11,000
So the risen
can finally achieve their purpose.
375
00:32:14,080 --> 00:32:18,400
They mate, and the females lay their eggs.
376
00:32:20,280 --> 00:32:22,320
[dramatic music playing]
377
00:32:22,400 --> 00:32:23,880
It's their final act.
378
00:32:28,880 --> 00:32:34,120
Within a matter of weeks,
all that's left are husks.
379
00:32:35,680 --> 00:32:38,720
A massive dose of fertilizer,
380
00:32:39,360 --> 00:32:44,360
pulsing life back
into nature's underground networks.
381
00:32:44,440 --> 00:32:46,440
[mystical music playing]
382
00:32:53,600 --> 00:32:55,440
Why 17 years?
383
00:32:56,880 --> 00:32:58,920
We still don't really know.
384
00:33:01,840 --> 00:33:05,480
But this pattern evolved deep in the past
385
00:33:06,200 --> 00:33:11,160
when a long life cycle may have helped
to survive more frequent cold snaps.
386
00:33:13,040 --> 00:33:17,560
Because our planet
also has climatic rhythms
387
00:33:17,640 --> 00:33:20,480
that span tens of thousands of years.
388
00:33:22,360 --> 00:33:25,600
Far beyond
any living creature's sense of timing.
389
00:33:25,680 --> 00:33:27,680
[rousing music playing]
390
00:33:30,280 --> 00:33:35,080
But the slowest changes can have
the most profound effects on life.
391
00:33:36,960 --> 00:33:37,960
[croaks]
392
00:33:38,720 --> 00:33:41,480
For better and for worse.
393
00:33:47,760 --> 00:33:52,320
The Sahara Desert,
as large as the United States
394
00:33:52,840 --> 00:33:56,040
and one of the harshest environments
on Earth.
395
00:33:58,680 --> 00:34:03,320
If you're not adapted to the heat,
you won't survive.
396
00:34:03,400 --> 00:34:05,400
[sand gusting]
397
00:34:09,920 --> 00:34:12,040
This light-footed agama lizard
398
00:34:13,320 --> 00:34:15,960
is small enough to find shelter.
399
00:34:22,320 --> 00:34:26,600
And his scaly skin
keeps much-needed moisture locked in.
400
00:34:27,280 --> 00:34:28,600
[skitters]
401
00:34:30,720 --> 00:34:32,400
[soft munching]
402
00:34:32,480 --> 00:34:34,680
But even he needs to drink sometimes.
403
00:34:35,800 --> 00:34:37,800
[suspenseful music playing]
404
00:34:39,320 --> 00:34:43,720
Fortunately for him,
even in this barren wilderness,
405
00:34:44,920 --> 00:34:46,200
there is water.
406
00:34:51,920 --> 00:34:53,920
[intriguing music playing]
407
00:34:56,600 --> 00:35:00,400
A miraculous oasis
for weary desert travelers.
408
00:35:08,840 --> 00:35:09,840
[chirping]
409
00:35:09,920 --> 00:35:13,120
But it might not be
as welcoming as it seems.
410
00:35:13,640 --> 00:35:15,640
[tense music playing]
411
00:35:17,480 --> 00:35:18,480
[skittering]
412
00:35:21,040 --> 00:35:23,040
[ominous music playing]
413
00:35:28,640 --> 00:35:34,320
Incredibly, this pool
is full of crocodiles...
414
00:35:37,880 --> 00:35:39,760
in the middle of the desert.
415
00:35:42,200 --> 00:35:45,760
A hundred miles
from the nearest flowing water.
416
00:35:48,600 --> 00:35:50,600
[low growling]
417
00:35:52,080 --> 00:35:56,280
While their far-flung relatives
swim through lush swamps,
418
00:35:57,920 --> 00:36:00,880
these crocodiles are trapped here.
419
00:36:03,280 --> 00:36:05,880
For them, it's not an oasis,
420
00:36:07,080 --> 00:36:08,280
it's a prison...
421
00:36:09,080 --> 00:36:10,720
[snarls]
422
00:36:13,560 --> 00:36:17,160
...where every inmate
must fight for themselves.
423
00:36:19,040 --> 00:36:20,480
[skittering]
424
00:36:25,520 --> 00:36:28,600
There's fierce competition
for anything that moves.
425
00:36:39,240 --> 00:36:42,040
A migrating honey buzzard stops to drink...
426
00:36:43,000 --> 00:36:45,000
[tense music playing]
427
00:36:47,160 --> 00:36:49,160
...and wades in to cool off.
428
00:36:52,000 --> 00:36:54,000
[sinister music playing]
429
00:37:14,120 --> 00:37:15,680
It won't feed everyone.
430
00:37:21,160 --> 00:37:24,960
If they stay here, they could starve.
431
00:37:28,760 --> 00:37:32,120
But if they make a break for freedom...
432
00:37:32,200 --> 00:37:34,200
[flies buzzing]
433
00:37:36,720 --> 00:37:38,720
[buzzing intensifies]
434
00:37:42,440 --> 00:37:46,400
It's a desperate dilemma
as their world shrinks around them.
435
00:37:51,080 --> 00:37:56,680
But the fact they're here at all is a sign
of a rhythm measured in millennia.
436
00:38:00,720 --> 00:38:03,560
Because it wasn't always like this.
437
00:38:05,360 --> 00:38:07,360
[intriguing music playing]
438
00:38:11,720 --> 00:38:18,080
Just a few thousand years ago,
this desert was green and fertile.
439
00:38:19,600 --> 00:38:22,360
Crocodiles swam in flowing rivers.
440
00:38:25,000 --> 00:38:29,200
Because our spinning planet
has a long-term wobble
441
00:38:30,240 --> 00:38:32,760
that repeats over millennia,
442
00:38:34,240 --> 00:38:39,000
moving its hemispheres closer to
and then further from the sun,
443
00:38:40,400 --> 00:38:42,840
and altering our climate as it goes.
444
00:38:45,920 --> 00:38:50,400
On its current path,
the West African monsoon weakened,
445
00:38:51,480 --> 00:38:54,240
and rain stopped falling in the Sahara.
446
00:38:58,640 --> 00:39:03,480
Within just a few hundred years,
the crocodiles' lush swamps
447
00:39:04,200 --> 00:39:07,200
became one of the planet's
largest deserts.
448
00:39:10,680 --> 00:39:12,680
[birds chirping]
449
00:39:17,480 --> 00:39:20,040
But even in today's searing climate...
450
00:39:22,000 --> 00:39:25,120
there is still an echo
of the long-lost past.
451
00:39:25,960 --> 00:39:28,720
[thunder rumbling]
452
00:39:33,000 --> 00:39:36,600
Just a few precious days
of rainfall each year.
453
00:39:43,680 --> 00:39:48,720
This briefest of wet seasons
lets us travel back in time...
454
00:39:51,680 --> 00:39:56,160
to glimpse what life
was like here 10,000 years ago...
455
00:39:58,800 --> 00:40:00,560
in a green Sahara.
456
00:40:00,640 --> 00:40:02,080
[clucking]
457
00:40:03,080 --> 00:40:05,080
[birds cawing in distance]
458
00:40:06,320 --> 00:40:08,320
[croaking]
459
00:40:13,000 --> 00:40:15,760
[birds cawing]
460
00:40:17,240 --> 00:40:19,240
[squawking]
461
00:40:19,960 --> 00:40:24,880
If the inmates can cling on,
in another 10,000 years or so,
462
00:40:25,560 --> 00:40:28,360
the planetary wobble will run full circle.
463
00:40:31,840 --> 00:40:33,760
Water will flow again,
464
00:40:34,280 --> 00:40:39,000
freeing their distant descendants
to reclaim long-lost rivers.
465
00:40:43,680 --> 00:40:47,120
The creeping pace
of our planet's slowest rhythms
466
00:40:47,200 --> 00:40:49,600
makes them almost impossible to see.
467
00:40:52,840 --> 00:40:58,120
But if these rhythms are interrupted
even by the smallest increment,
468
00:40:58,840 --> 00:41:02,120
we can start
to see things change before our eyes.
469
00:41:04,280 --> 00:41:06,280
[rousing music playing]
470
00:41:09,520 --> 00:41:13,320
Autumn in Oregon's Cascade Mountains.
471
00:41:13,880 --> 00:41:16,120
[chirping]
472
00:41:16,200 --> 00:41:18,200
[breathing intensely]
473
00:41:19,800 --> 00:41:22,800
This hare is trying
to stay out of trouble.
474
00:41:26,720 --> 00:41:28,200
With good reason.
475
00:41:28,280 --> 00:41:29,280
[hawk screeches]
476
00:41:29,360 --> 00:41:32,400
Hares rarely die of old age.
477
00:41:37,480 --> 00:41:41,600
A hunting goshawk
will spot anything that moves.
478
00:41:43,720 --> 00:41:45,160
[birdsong]
479
00:41:45,240 --> 00:41:47,560
So the skittish hare freezes.
480
00:41:49,280 --> 00:41:53,000
Barely even breathing.
481
00:41:57,880 --> 00:42:00,560
Hidden in plain sight.
482
00:42:02,000 --> 00:42:03,280
[screeches]
483
00:42:03,360 --> 00:42:04,440
The hawk moves on,
484
00:42:06,240 --> 00:42:09,080
and the hare can breathe a sigh of relief.
485
00:42:11,600 --> 00:42:16,160
But her home is
about to transform beyond recognition.
486
00:42:20,720 --> 00:42:22,720
[wind howling]
487
00:42:26,720 --> 00:42:29,920
If your best bet
for staying alive is camouflage,
488
00:42:31,760 --> 00:42:35,760
how do you cope when your world
suddenly changes color?
489
00:42:46,160 --> 00:42:48,160
You change too.
490
00:42:51,920 --> 00:42:57,560
As the winter days shorten,
she molts from brown to white.
491
00:42:59,440 --> 00:43:01,200
[sniffing]
492
00:43:01,280 --> 00:43:03,800
An incredible costume change.
493
00:43:06,960 --> 00:43:11,400
Once again, all she has to do is freeze.
494
00:43:11,480 --> 00:43:12,880
[hawk screeching]
495
00:43:12,960 --> 00:43:14,640
And like magic,
496
00:43:16,080 --> 00:43:17,080
she vanishes.
497
00:43:24,680 --> 00:43:26,560
But now, a new threat.
498
00:43:30,680 --> 00:43:34,480
Man-made climate change
means that some winter days
499
00:43:34,560 --> 00:43:40,360
are unseasonably warm,
and snow cover can disappear overnight.
500
00:43:43,720 --> 00:43:45,400
[birdsong]
501
00:43:45,480 --> 00:43:50,360
Her color change is triggered
not by temperature, but by day length.
502
00:43:53,160 --> 00:43:56,480
And these warmer days are still short.
503
00:44:02,200 --> 00:44:06,240
So now, she's desperately
out of sync with her surroundings
504
00:44:07,760 --> 00:44:09,960
and an easy target.
505
00:44:10,600 --> 00:44:12,600
[tense music playing]
506
00:44:18,840 --> 00:44:20,840
[suspenseful music playing]
507
00:44:25,520 --> 00:44:27,520
[suspenseful music rising]
508
00:44:28,280 --> 00:44:29,480
Time for plan B.
509
00:44:30,920 --> 00:44:31,760
[whooshing]
510
00:44:31,840 --> 00:44:32,960
Speed.
511
00:44:42,200 --> 00:44:43,240
She's lost him.
512
00:44:46,560 --> 00:44:52,000
But when you're this conspicuous,
staying hidden isn't an option.
513
00:44:54,400 --> 00:44:56,400
[suspenseful music continues]
514
00:45:06,640 --> 00:45:08,680
[suspenseful music rising]
515
00:45:15,640 --> 00:45:18,320
Next time, she may not be so lucky.
516
00:45:18,880 --> 00:45:20,880
[sniffs]
517
00:45:21,760 --> 00:45:25,240
Mismatched hares
are more likely to be picked off.
518
00:45:28,280 --> 00:45:30,760
And now they're out of step more often.
519
00:45:33,160 --> 00:45:34,760
[bird screeches]
520
00:45:34,840 --> 00:45:38,760
Her kind could still have a future
in this changing world.
521
00:45:43,120 --> 00:45:47,560
This snowshoe hare has adapted
to stay brown all year round.
522
00:45:52,520 --> 00:45:56,720
So his life is easier
when snow is thin on the ground.
523
00:45:59,120 --> 00:46:01,120
[birdsong]
524
00:46:02,680 --> 00:46:07,280
The future of their species
may depend on more guys like him.
525
00:46:08,400 --> 00:46:09,480
[sniffs]
526
00:46:09,560 --> 00:46:10,560
[hawk screeching]
527
00:46:12,360 --> 00:46:13,800
[bird cawing]
528
00:46:16,760 --> 00:46:22,000
Nature works best when life keeps step
with the planet's many rhythms.
529
00:46:23,360 --> 00:46:25,280
[intriguing music playing]
530
00:46:34,920 --> 00:46:39,440
So what happens
when human activity disrupts the tempo?
531
00:46:39,520 --> 00:46:41,200
[distorted music playing]
532
00:46:41,680 --> 00:46:44,000
[wildlife screeching]
533
00:46:47,120 --> 00:46:50,400
As the world changes suddenly
all around us...
534
00:46:53,360 --> 00:46:55,520
can nature survive...
535
00:46:55,600 --> 00:46:56,920
[growls]
536
00:46:58,080 --> 00:46:59,600
...the coming storm?
537
00:47:00,680 --> 00:47:03,040
[epic music playing]
538
00:47:03,960 --> 00:47:05,960
[closing theme music playing]