1
00:00:15,160 --> 00:00:19,040
Our Moon is
a familiar face in the night sky.

2
00:00:21,600 --> 00:00:25,280
She illuminates the way
for animals on the move.

3
00:00:27,160 --> 00:00:30,119
But even when her light fades,

4
00:00:30,120 --> 00:00:32,839
she has an unseen power,

5
00:00:32,840 --> 00:00:36,800
which guides creatures
across the entire planet.

6
00:00:42,400 --> 00:00:46,319
A humpback whale mum and her new calf

7
00:00:46,320 --> 00:00:50,120
relax in the warm waters
of the Hawaiian archipelago.

8
00:00:53,240 --> 00:00:55,320
It's the perfect nursery.

9
00:01:01,360 --> 00:01:04,040
The calf was born
just a few months ago.

10
00:01:05,360 --> 00:01:08,280
The tropical waters give him warmth.

11
00:01:09,200 --> 00:01:11,440
There's shelter from the waves...

12
00:01:16,720 --> 00:01:20,360
...and from the strong currents
of the open ocean beyond.

13
00:01:21,560 --> 00:01:24,079
But he'll have to face them soon.

14
00:01:24,080 --> 00:01:28,160
He must build his strength,
Mum must rest.

15
00:01:29,480 --> 00:01:32,240
Their journey is about to begin.

16
00:01:34,280 --> 00:01:39,720
They'll need to use the unseen power
of the Moon to find their way.

17
00:01:49,440 --> 00:01:53,800
Our Moon shapes life on Earth
in extraordinary ways.

18
00:01:56,560 --> 00:01:58,840
Creating the swelling tides...

19
00:02:01,160 --> 00:02:03,280
...dictating the length of day...

20
00:02:04,600 --> 00:02:06,720
...summoning the seasons.

21
00:02:08,640 --> 00:02:11,160
She can light the way to love...

22
00:02:12,160 --> 00:02:15,120
...reveal hidden pathways...

23
00:02:17,120 --> 00:02:19,000
...bring times of plenty...

24
00:02:20,880 --> 00:02:24,640
...or strip away chances of survival.

25
00:02:42,400 --> 00:02:44,919
With each phase,

26
00:02:44,920 --> 00:02:47,919
from full moon to new,

27
00:02:47,920 --> 00:02:50,680
less light is reflected to Earth...

28
00:02:51,960 --> 00:02:55,760
...but the more powerful
the Moon becomes.

29
00:02:59,720 --> 00:03:02,559
As the Moon aligns with the sun,

30
00:03:02,560 --> 00:03:05,879
their combined gravitational pull
on our planet

31
00:03:05,880 --> 00:03:07,880
is at its strongest.

32
00:03:09,480 --> 00:03:11,480
This shift in gravity...

33
00:03:13,120 --> 00:03:16,560
...is the signal
to start an ocean odyssey.

34
00:03:19,240 --> 00:03:23,919
This calf has only known the shelter
of these Hawaiian seas

35
00:03:23,920 --> 00:03:25,920
since he was born.

36
00:03:26,720 --> 00:03:31,440
The waters may be calm,
but they are not always safe.

37
00:03:35,280 --> 00:03:37,119
A male.

38
00:03:37,120 --> 00:03:40,160
He's looking
for the chance to impress.

39
00:03:43,720 --> 00:03:48,240
And now he's joined by other males,
who are all searching for a mate.

40
00:04:01,320 --> 00:04:03,079
It's not known why,

41
00:04:03,080 --> 00:04:06,520
but a new moon brings
out their competitive side.

42
00:04:22,760 --> 00:04:26,240
They are keen to show the female
they've got what it takes.

43
00:04:32,080 --> 00:04:36,440
In these displays, they can
accidentally drown a young calf.

44
00:04:43,840 --> 00:04:48,520
The males use the deeper water
to fight for dominance.

45
00:05:07,480 --> 00:05:10,440
Mum takes a chance to slip away.

46
00:05:28,280 --> 00:05:32,480
She has led her calf
to the safety of the shallows.

47
00:05:41,400 --> 00:05:43,479
In a few short months,

48
00:05:43,480 --> 00:05:47,040
he's already doubled in size
drinking mum's rich milk.

49
00:05:52,760 --> 00:05:55,639
But she hasn't eaten in six months.

50
00:05:55,640 --> 00:05:58,759
This nursery comes at a cost.

51
00:05:58,760 --> 00:06:02,000
There's not enough food for mum here.

52
00:06:03,800 --> 00:06:08,159
And their feeding grounds
are 5,000km away

53
00:06:08,160 --> 00:06:10,160
in Northwest Alaska.

54
00:06:13,120 --> 00:06:17,639
It's a journey all the humpbacks
here in Hawaii must take,

55
00:06:17,640 --> 00:06:20,120
and one the calf must learn.

56
00:06:21,240 --> 00:06:25,239
This is the only time
his mother will guide him north.

57
00:06:25,240 --> 00:06:27,640
There's little margin for error.

58
00:06:30,120 --> 00:06:34,599
Set off too early,
and they'll arrive in frozen seas.

59
00:06:34,600 --> 00:06:39,160
Stay too long, and they'll starve
on the long voyage ahead.

60
00:06:42,160 --> 00:06:45,000
The new moon is their signal.

61
00:06:47,600 --> 00:06:51,920
Mum and calf can sense
the greater gravitational pull.

62
00:06:54,800 --> 00:06:58,400
For mum, it's time to head north.

63
00:06:59,840 --> 00:07:02,359
For the calf, this new feeling

64
00:07:02,360 --> 00:07:07,000
is the first lesson
on the unseen power of the Moon.

65
00:07:09,080 --> 00:07:11,039
They'll need to keep on course,

66
00:07:11,040 --> 00:07:13,279
and pinpoint their feeding grounds

67
00:07:13,280 --> 00:07:16,240
among thousands
of kilometres of coastline.

68
00:07:20,520 --> 00:07:25,680
And the Moon's power will guide them
each step of the way.

69
00:07:29,680 --> 00:07:34,960
Every month, the Moon changes
not just her phase, but her position.

70
00:07:36,080 --> 00:07:40,160
Higher in winter,
appearing longer in the night sky...

71
00:07:44,680 --> 00:07:48,239
...lower in summer,
shining for less time,

72
00:07:48,240 --> 00:07:50,400
only skimming the horizon.

73
00:07:53,680 --> 00:07:56,919
It's these changes in phase
and position

74
00:07:56,920 --> 00:08:00,360
which set animal migrations
in motion.

75
00:08:07,080 --> 00:08:09,520
In the lowlands
of Southern England...

76
00:08:11,800 --> 00:08:14,560
...a nightjar rests in the heath.

77
00:08:18,320 --> 00:08:20,480
She's a nocturnal hunter...

78
00:08:23,000 --> 00:08:26,360
...and she's waiting
for the Moon to rise.

79
00:08:36,240 --> 00:08:38,520
In the cool of the night...

80
00:08:39,560 --> 00:08:42,080
...the heath comes alive.

81
00:08:47,120 --> 00:08:50,920
The full moon signals
to the nightjar.

82
00:08:51,800 --> 00:08:55,239
It's time to come out into the light.

83
00:09:05,040 --> 00:09:07,880
She's searching for moths.

84
00:09:09,080 --> 00:09:12,080
They spend these summer nights
looking for a mate.

85
00:09:13,800 --> 00:09:15,719
Using the Moon to navigate,

86
00:09:15,720 --> 00:09:19,720
they'll keep it at a constant angle
as they fly.

87
00:09:20,720 --> 00:09:24,800
But tonight,
the full moon is their downfall.

88
00:09:29,120 --> 00:09:31,599
The nightjar's huge eyes

89
00:09:31,600 --> 00:09:35,280
drink in every photon of light
the Moon provides.

90
00:09:36,320 --> 00:09:38,439
Tonight's bright full moon

91
00:09:38,440 --> 00:09:42,400
helps her pick out insects
silhouetted against the dark sky.

92
00:09:48,960 --> 00:09:50,799
Under a full moon,

93
00:09:50,800 --> 00:09:54,360
nightjars are twice as effective
at catching prey.

94
00:09:56,480 --> 00:10:00,560
And she must catch
as many moths as she can.

95
00:10:14,000 --> 00:10:16,439
Packed with protein,

96
00:10:16,440 --> 00:10:18,760
insects are the ideal fuel.

97
00:10:29,480 --> 00:10:33,120
But this Moon is
more than a hunting aid.

98
00:10:38,720 --> 00:10:42,360
It's a countdown
to the start of her migration.

99
00:10:43,640 --> 00:10:45,799
In late summer,

100
00:10:45,800 --> 00:10:50,640
the low full moon will only stay
above the horizon for a short while.

101
00:10:52,800 --> 00:10:57,600
Nightjars' lives are tuned
to the phase and light of the Moon.

102
00:11:01,360 --> 00:11:03,880
And she won't be alone
on this journey.

103
00:11:05,680 --> 00:11:09,559
Nightjars all across Europe
will start their migration

104
00:11:09,560 --> 00:11:13,480
ten days after this low full moon
of late summer.

105
00:11:16,160 --> 00:11:18,319
Using the Moon as a clock,

106
00:11:18,320 --> 00:11:21,039
they can synchronise their departure,

107
00:11:21,040 --> 00:11:25,240
ensuring there's safety in numbers
on their long journey ahead.

108
00:11:29,480 --> 00:11:33,640
Thousands of nightjars
will head to Central Africa...

109
00:11:34,600 --> 00:11:37,520
...chasing an endless summer.

110
00:11:46,240 --> 00:11:51,160
The changing height and phase
are both clock and calendar...

111
00:11:52,400 --> 00:11:56,920
...a seasonal signal
and a call to arms.

112
00:12:04,160 --> 00:12:06,959
Beneath the glow
of a high winter moon

113
00:12:06,960 --> 00:12:08,600
in Southern Australia...

114
00:12:10,040 --> 00:12:13,400
...a transformation is underway.

115
00:12:17,560 --> 00:12:21,519
Every year, spider crabs must moult
their spiky armour

116
00:12:21,520 --> 00:12:23,840
in order to grow.

117
00:12:28,440 --> 00:12:31,840
But it'll take days
for their new shell to harden.

118
00:12:34,440 --> 00:12:36,680
So they're vulnerable.

119
00:12:43,640 --> 00:12:48,039
Long legs help this crab travel
around seven kilometres

120
00:12:48,040 --> 00:12:51,720
from the rocky depths to the cool,
calm shallows.

121
00:12:52,760 --> 00:12:55,719
He's searching
for a safe place to moult,

122
00:12:55,720 --> 00:12:58,200
and needs to find it fast.

123
00:12:59,440 --> 00:13:03,199
His body has already started
to transform,

124
00:13:03,200 --> 00:13:05,200
it can't be stopped.

125
00:13:10,840 --> 00:13:14,320
The Moon has triggered others
to migrate here to moult...

126
00:13:16,520 --> 00:13:18,799
...but they've been followed.

127
00:13:22,240 --> 00:13:25,640
A three-metre-long broad ray.

128
00:13:32,840 --> 00:13:35,440
With no place
for the crabs to hide...

129
00:13:41,840 --> 00:13:44,560
...a lone crab is defenceless...

130
00:13:46,320 --> 00:13:48,200
...and delicious.

131
00:13:55,840 --> 00:13:58,720
They pin them to the sea floor.

132
00:14:06,200 --> 00:14:09,760
Port Jackson sharks mop up
the stragglers.

133
00:14:16,640 --> 00:14:20,000
The Moon draws more crabs
out of the deep.

134
00:14:23,200 --> 00:14:26,840
In winter,
the water is calm and cold...

135
00:14:27,680 --> 00:14:30,120
...the perfect conditions to moult.

136
00:14:32,320 --> 00:14:36,039
The full moon allows
thousands of crabs

137
00:14:36,040 --> 00:14:38,880
to co-ordinate their march
to the shallows.

138
00:14:43,000 --> 00:14:46,840
And as they gather,
they begin to band together.

139
00:14:53,800 --> 00:14:55,799
To shed his shell,

140
00:14:55,800 --> 00:14:59,800
this crab needs to find
the safety of the swarm.

141
00:15:01,520 --> 00:15:03,760
He can't drop his guard.

142
00:15:10,800 --> 00:15:13,440
He's no heavyweight...

143
00:15:14,400 --> 00:15:16,600
...but can still pack a pinch.

144
00:15:19,960 --> 00:15:22,960
Nipping at the ray's
soft undersides...

145
00:15:24,560 --> 00:15:27,960
...is just enough to put it off.

146
00:15:40,160 --> 00:15:43,800
The safety of a huge mound
is in sight.

147
00:16:05,640 --> 00:16:08,000
It's a lucky escape.

148
00:16:15,800 --> 00:16:20,080
Now he has an army
who's got his back.

149
00:16:41,960 --> 00:16:45,840
The mountain of crabs
should make an easy meal.

150
00:16:48,600 --> 00:16:52,920
But the mound is now
a sea of spines and claws...

151
00:16:54,080 --> 00:16:56,160
...which sways and shifts.

152
00:17:06,280 --> 00:17:09,280
So the ray can't grip
even a single crab.

153
00:17:15,280 --> 00:17:20,400
There are as many as 20,000 crabs
in this small sandy bay.

154
00:17:22,800 --> 00:17:25,599
And with this sheer force of numbers,

155
00:17:25,600 --> 00:17:28,480
they create an impenetrable fortress.

156
00:17:38,520 --> 00:17:42,519
Surrounded by his band of brothers,

157
00:17:42,520 --> 00:17:47,119
he'll moult, transforming in safety,

158
00:17:47,120 --> 00:17:49,960
until his new armour hardens.

159
00:17:50,760 --> 00:17:55,840
The crabs will disappear back
into the depths until next year...

160
00:17:57,040 --> 00:18:02,680
when the high winter moon signals
the army to rise up once more.

161
00:18:08,240 --> 00:18:13,640
The full Moon is 400,000 times
less bright than the Sun.

162
00:18:14,800 --> 00:18:17,080
But it's no pale imitation.

163
00:18:19,080 --> 00:18:24,440
She can extend the day
and open up new opportunities.

164
00:18:31,280 --> 00:18:36,000
And there's no more important time
than when raising a family.

165
00:18:38,520 --> 00:18:42,520
In the lush forests
of Kyushu Island, Japan...

166
00:18:47,480 --> 00:18:51,679
...a red shield bug guards
her tiny babies,

167
00:18:51,680 --> 00:18:54,040
tucked into the leaf litter.

168
00:18:57,200 --> 00:19:00,360
This is the only brood
she'll ever have.

169
00:19:01,320 --> 00:19:04,039
Shield bugs' lives are short.

170
00:19:04,040 --> 00:19:07,320
Being a mum is
the last thing she'll do.

171
00:19:10,120 --> 00:19:14,559
To ensure they can get
the best start in life,

172
00:19:14,560 --> 00:19:18,080
she must leave them
in search of food.

173
00:19:20,840 --> 00:19:24,040
Among the tangle of vines
and trees...

174
00:19:24,920 --> 00:19:28,520
...she's searching
for a special type of ripe fruit.

175
00:19:33,840 --> 00:19:39,679
She keeps an eye on the pattern
of light and shade in the canopy,

176
00:19:39,680 --> 00:19:42,080
which will guide her home.

177
00:19:51,280 --> 00:19:53,799
She's locked on to a scent.

178
00:19:58,440 --> 00:20:01,520
The fruit of the Boro Boro tree.

179
00:20:15,800 --> 00:20:17,840
But the light is fading...

180
00:20:20,040 --> 00:20:22,560
...and her map has gone.

181
00:20:24,680 --> 00:20:27,480
She can't find her way
back to her babies.

182
00:20:38,600 --> 00:20:44,280
A dark forest is a dangerous place
for a lost little bug.

183
00:20:51,360 --> 00:20:53,920
But the Moon is here to help.

184
00:20:58,760 --> 00:21:01,800
It reilluminates the canopy.

185
00:21:03,600 --> 00:21:05,999
It may not be as bright as the Sun,

186
00:21:06,000 --> 00:21:09,599
but the contrast
between the moonlight and dark

187
00:21:09,600 --> 00:21:11,879
creates a clearer pattern.

188
00:21:11,880 --> 00:21:15,960
The little bug can read these
like points on a map.

189
00:21:20,400 --> 00:21:24,839
So she's able to take the most direct
route home to her babies

190
00:21:24,840 --> 00:21:27,480
in minutes, not hours.

191
00:21:32,000 --> 00:21:34,119
It's these full moon nights

192
00:21:34,120 --> 00:21:37,440
which give her
valuable extra foraging time.

193
00:21:45,320 --> 00:21:49,079
Tomorrow,
the Moon will shine less bright,

194
00:21:49,080 --> 00:21:51,999
the canopy map dimmer,

195
00:21:52,000 --> 00:21:56,120
harder to read,
less time to feed her babies.

196
00:21:58,040 --> 00:22:01,639
But tonight,
it won't set until dawn,

197
00:22:01,640 --> 00:22:05,239
so she must make the most
of this extended opportunity

198
00:22:05,240 --> 00:22:09,840
to find food on this long,
moonlit night.

199
00:22:25,480 --> 00:22:28,519
On the nights after the full moon,

200
00:22:28,520 --> 00:22:32,040
the amount of reflected light
fades fast.

201
00:22:34,720 --> 00:22:37,360
A crescent moon is barely visible...

202
00:22:38,320 --> 00:22:42,960
...but even a silver sliver
can keep animals on track.

203
00:22:48,080 --> 00:22:50,359
African savannah elephants

204
00:22:50,360 --> 00:22:54,400
take the definition
of a midnight snack to the extreme.

205
00:22:55,440 --> 00:22:57,999
They can spend 16 hours eating,

206
00:22:58,000 --> 00:23:01,960
and consume over 100kg of food a day.

207
00:23:04,000 --> 00:23:06,639
They'll spend so much time eating,

208
00:23:06,640 --> 00:23:09,439
that they're awake nearly all night.

209
00:23:09,440 --> 00:23:14,160
And all that food
has predictable consequences.

210
00:23:20,520 --> 00:23:25,440
Life in the shadow of giants
is a dangerous game.

211
00:23:28,600 --> 00:23:31,760
This little beetle
could easily be crushed.

212
00:23:37,400 --> 00:23:41,880
But it's a risk he must take
if he's to win a mate.

213
00:23:44,880 --> 00:23:49,319
For this beetle,
dung is a prized possession.

214
00:23:49,320 --> 00:23:54,079
A big ball of dung is exactly
what a female beetle is looking for

215
00:23:54,080 --> 00:23:56,640
to lay her eggs in.

216
00:23:57,720 --> 00:24:01,640
And this pile has
already attracted other males.

217
00:24:05,640 --> 00:24:08,680
To beat the competition,
he needs to be quick.

218
00:24:11,280 --> 00:24:13,800
It's time to get dirty.

219
00:24:21,120 --> 00:24:23,439
Using his strong legs,

220
00:24:23,440 --> 00:24:26,560
he sculpts a ball
five times his size.

221
00:24:32,520 --> 00:24:36,760
He needs the moonlight
to make a clean getaway.

222
00:24:38,720 --> 00:24:41,400
A straight line is the fastest way.

223
00:24:43,400 --> 00:24:46,079
But which way to go?

224
00:24:49,080 --> 00:24:52,319
The small amount of light
from a crescent moon

225
00:24:52,320 --> 00:24:55,280
is scattered by particles
in the atmosphere.

226
00:24:58,920 --> 00:25:02,880
And this creates lines of light
in the night sky...

227
00:25:03,840 --> 00:25:06,839
...known as polarised light.

228
00:25:14,000 --> 00:25:16,839
Even head down and facing backwards,

229
00:25:16,840 --> 00:25:20,000
he can follow these lines of light.

230
00:25:33,240 --> 00:25:36,999
But beware the thief in the night.

231
00:25:40,840 --> 00:25:42,799
With such a big ball,

232
00:25:42,800 --> 00:25:45,600
stopping to check
your position can be risky.

233
00:25:59,480 --> 00:26:03,680
Equally matched,
it's now a battle of stamina.

234
00:26:05,040 --> 00:26:07,400
he needs to stay on top.

235
00:26:12,320 --> 00:26:16,600
Losing the higher ground
could mean it's game over.

236
00:26:19,080 --> 00:26:21,360
But he won't give up.

237
00:26:28,680 --> 00:26:32,160
With the chance
of other dung-ball bandits nearby...

238
00:26:34,760 --> 00:26:38,520
...he pushes on,
following the polarised light.

239
00:26:47,000 --> 00:26:50,439
Finally, his new ball of dung

240
00:26:50,440 --> 00:26:53,880
brings him
the female attention he desires.

241
00:27:02,960 --> 00:27:07,120
The ball will become home
for their new brood.

242
00:27:08,600 --> 00:27:10,759
He'll keep pushing,

243
00:27:10,760 --> 00:27:14,800
until he finds soil soft enough
to bury the ball.

244
00:27:16,040 --> 00:27:19,120
His moonlight guided great escape...

245
00:27:20,920 --> 00:27:22,920
...finally complete.

246
00:27:30,200 --> 00:27:34,280
Moonlight offers a visible guide
to animals on the move.

247
00:27:37,480 --> 00:27:40,359
But the Moon has an unseen,

248
00:27:40,360 --> 00:27:43,960
and even more powerful way
to guide navigators.

249
00:27:45,400 --> 00:27:48,079
The Moon's proximity to Earth

250
00:27:48,080 --> 00:27:53,799
means her gravitational pull
helps power an immense force.

251
00:27:59,040 --> 00:28:01,199
Under the Earth's crust,

252
00:28:01,200 --> 00:28:04,440
the iron-rich rock is molten.

253
00:28:05,280 --> 00:28:09,599
Just as the Moon's
gravitational pull acts on the tides,

254
00:28:09,600 --> 00:28:14,760
it also tugs on the swirling rock
deep underground.

255
00:28:17,880 --> 00:28:21,919
This movement adds
electromagnetic energy,

256
00:28:21,920 --> 00:28:25,320
creating powerful magnetic fields.

257
00:28:29,040 --> 00:28:32,640
These fields align
and oppose each other...

258
00:28:33,760 --> 00:28:37,120
...creating our North and South Poles.

259
00:28:44,160 --> 00:28:48,640
When charged particles from space
strike this magnetic field...

260
00:28:49,920 --> 00:28:53,439
...it causes the atmosphere to glow,

261
00:28:53,440 --> 00:28:56,720
and it becomes visible as an aurora.

262
00:29:00,480 --> 00:29:02,919
An ever-present power,

263
00:29:02,920 --> 00:29:07,240
felt all across the entire planet.

264
00:29:14,880 --> 00:29:20,319
Even in the middle of the world's
largest ocean, the Pacific.

265
00:29:20,320 --> 00:29:24,639
155 million square kilometres

266
00:29:24,640 --> 00:29:26,680
of endless blue.

267
00:29:29,920 --> 00:29:33,679
Its sheer size means storms
and strong currents

268
00:29:33,680 --> 00:29:36,440
swirl across it uninterrupted.

269
00:29:40,240 --> 00:29:43,280
Our humpback mum
and her young calf...

270
00:29:44,200 --> 00:29:46,760
...are 2,000km from land.

271
00:29:47,760 --> 00:29:52,200
In the open ocean, they could
easily be knocked off course.

272
00:29:53,160 --> 00:29:57,679
The calf sticks close to mum,
riding her slip stream,

273
00:29:57,680 --> 00:30:00,119
saving valuable energy.

274
00:30:00,120 --> 00:30:02,159
But mum is now burning through

275
00:30:02,160 --> 00:30:04,720
hundreds of thousands
of calories a day.

276
00:30:05,760 --> 00:30:10,760
Make a mistake in navigation now,
and it could cost them their lives.

277
00:30:20,360 --> 00:30:25,559
As they journey, the visible Moon
will change phase and position,

278
00:30:25,560 --> 00:30:28,400
so it can't be relied upon
as a guide.

279
00:30:30,400 --> 00:30:34,840
But the magnetic field is
an all-pervasive power.

280
00:30:39,280 --> 00:30:41,399
Inside their brains,

281
00:30:41,400 --> 00:30:45,119
mum and calf both have
tiny iron particles,

282
00:30:45,120 --> 00:30:47,799
called magnetite.

283
00:30:47,800 --> 00:30:50,879
These align with the magnetic field,

284
00:30:50,880 --> 00:30:53,200
triggering a cellular reaction.

285
00:30:54,000 --> 00:30:58,160
It lets them sense how steep
and how strong the field is.

286
00:31:00,480 --> 00:31:03,439
From this,
they can work out their position,

287
00:31:03,440 --> 00:31:05,800
and in what direction to swim.

288
00:31:08,880 --> 00:31:12,000
Their own biological map
and compass.

289
00:31:16,320 --> 00:31:21,280
So mum can find her way across
this seemingly featureless ocean.

290
00:31:23,360 --> 00:31:27,320
And now the calf is learning
how to use this sense...

291
00:31:28,200 --> 00:31:32,360
...for a life
as a long-distance ocean voyager.

292
00:31:41,440 --> 00:31:45,639
The magnetic field touches
every part of the planet,

293
00:31:45,640 --> 00:31:47,760
from the deepest oceans...

294
00:31:49,240 --> 00:31:51,760
...to high mountain peaks.

295
00:31:53,240 --> 00:31:56,480
From the largest animals
on the longest migrations...

296
00:31:57,320 --> 00:32:01,440
...to the smaller, but no less mighty.

297
00:32:05,560 --> 00:32:08,440
Deep in a European forest...

298
00:32:12,840 --> 00:32:17,280
...the spring sunshine stirs
a sleepy Alpine newt.

299
00:32:20,720 --> 00:32:23,439
After a year in the woods,

300
00:32:23,440 --> 00:32:26,560
instinct now drives him
to find water.

301
00:32:31,720 --> 00:32:33,880
He's looking for a mate.

302
00:32:39,760 --> 00:32:44,799
This finger length newt is too small
to see which way to go.

303
00:32:44,800 --> 00:32:49,120
He'll need to rely on his superpower
to find his pond.

304
00:32:52,360 --> 00:32:55,279
But he's not alone.

305
00:33:00,800 --> 00:33:02,759
A grass snake,

306
00:33:02,760 --> 00:33:06,240
energised by the sun, is on the hunt.

307
00:33:12,960 --> 00:33:16,439
The snake relies
on its speed and strength

308
00:33:16,440 --> 00:33:19,480
to chase down and strangle its prey.

309
00:33:41,360 --> 00:33:44,360
Little legs struggle
in the dense forest.

310
00:33:52,080 --> 00:33:56,760
But for a tiny newt,
there are plenty of places to hide.

311
00:34:15,840 --> 00:34:18,960
The setting sun is a sign it's safe.

312
00:34:20,080 --> 00:34:22,960
A grass snake can't hunt in the dark.

313
00:34:24,720 --> 00:34:27,599
But now disorientated from the hunt,

314
00:34:27,600 --> 00:34:31,080
he needs to work out
which way his pond is.

315
00:34:33,720 --> 00:34:36,439
He, too, has magnetite in him.

316
00:34:36,440 --> 00:34:41,280
His superpower, which allows him
to sense the magnetic field.

317
00:34:42,480 --> 00:34:44,719
Just like following a compass,

318
00:34:44,720 --> 00:34:49,120
he's keeping his whole body aligned
to the angle of the field...

319
00:34:49,920 --> 00:34:54,680
...and can head in the direction
of the pond he left a year ago.

320
00:35:05,240 --> 00:35:07,840
A spring storm
doesn't bother him, either.

321
00:35:09,480 --> 00:35:12,800
The magnetic force flows
whatever the weather.

322
00:35:16,880 --> 00:35:19,159
With his internal compass,

323
00:35:19,160 --> 00:35:23,400
this tiny newt can travel
as far as four kilometres.

324
00:35:31,760 --> 00:35:34,559
As the dense forest thins out,

325
00:35:34,560 --> 00:35:38,439
the newt can now smell
that water is close.

326
00:35:45,480 --> 00:35:48,160
Finally, his pond.

327
00:35:53,440 --> 00:35:57,520
Time for a well-earned dip.

328
00:36:00,040 --> 00:36:05,240
But he can't rest,
it's time to find a mate.

329
00:36:16,960 --> 00:36:19,959
As the season turns to summer,

330
00:36:19,960 --> 00:36:22,399
he'll return to the forest,

331
00:36:22,400 --> 00:36:26,079
but next spring,
wherever he is in the woods,

332
00:36:26,080 --> 00:36:28,799
he'll find his way back to this pond,

333
00:36:28,800 --> 00:36:34,160
using the lunar-charged
magnetic field to point the way.

334
00:36:43,320 --> 00:36:46,919
As the magnetic field wraps
around the planet,

335
00:36:46,920 --> 00:36:49,160
its angle changes.

336
00:36:50,600 --> 00:36:53,439
At the poles, it's vertical.

337
00:36:53,440 --> 00:36:57,519
At the equator,
it's parallel to the surface,

338
00:36:57,520 --> 00:37:00,440
creating a map
for those who can read it.

339
00:37:11,000 --> 00:37:13,599
Where the waters
of the vast Atlantic

340
00:37:13,600 --> 00:37:15,600
meet the Congo jungle,

341
00:37:16,400 --> 00:37:19,279
the coastline is one
of the few places in the world

342
00:37:19,280 --> 00:37:23,480
suitable...
for ocean giants to emerge.

343
00:37:26,000 --> 00:37:28,240
Four kilometres of sand...

344
00:37:29,040 --> 00:37:33,840
...just soft enough,
the beach not too steep.

345
00:37:41,040 --> 00:37:43,799
This Leatherback turtle

346
00:37:43,800 --> 00:37:48,240
touches land
for the first time in three years.

347
00:37:49,960 --> 00:37:53,279
The Moon has gifted her a high tide,

348
00:37:53,280 --> 00:37:55,960
helping her part of the way.

349
00:37:58,080 --> 00:38:02,360
She'll need all the energy she has
to haul herself up the beach.

350
00:38:06,480 --> 00:38:08,839
Using a Moon-powered map,

351
00:38:08,840 --> 00:38:12,279
she's travelled
from her feeding grounds in Brazil,

352
00:38:12,280 --> 00:38:14,439
six thousand kilometres away,

353
00:38:14,440 --> 00:38:17,600
back to the place
she first hatched...

354
00:38:19,960 --> 00:38:23,320
...on the coast of equatorial Africa.

355
00:38:32,920 --> 00:38:37,320
This time,
she's here to lay eggs of her own.

356
00:38:45,520 --> 00:38:49,320
Her eggs will be incubated
in the warm sand...

357
00:38:50,200 --> 00:38:53,320
...where they'll develop
a super-sense.

358
00:39:08,720 --> 00:39:11,040
Mum has done all she can.

359
00:39:16,440 --> 00:39:20,920
She's leaving her eggs
in the care of the Moon.

360
00:39:32,880 --> 00:39:35,119
As the eggs develop,

361
00:39:35,120 --> 00:39:39,079
the lunar charged magnetic field
courses through them,

362
00:39:39,080 --> 00:39:41,080
deep in the sand.

363
00:39:55,600 --> 00:39:59,879
The hatchlings have particles
of magnetite within them,

364
00:39:59,880 --> 00:40:03,520
and can also sense
the angle of the magnetic field.

365
00:40:05,560 --> 00:40:09,239
So each one is born
with a magnetic imprint

366
00:40:09,240 --> 00:40:11,440
of this stretch of coastline.

367
00:40:15,800 --> 00:40:20,320
This beach is their first mark
on their magnetic map.

368
00:40:26,720 --> 00:40:30,680
But it's the visible Moon
which guides their first steps.

369
00:40:33,400 --> 00:40:35,639
Instinctively, they head out

370
00:40:35,640 --> 00:40:38,680
to the brightest part
of their new world...

371
00:40:39,600 --> 00:40:42,439
...moonlight reflected on the sea.

372
00:41:04,360 --> 00:41:07,920
They'll ride the ocean currents
in search of food.

373
00:41:13,800 --> 00:41:18,120
As they travel, the angle
of the magnetic field will change.

374
00:41:21,040 --> 00:41:25,199
They'll add new markers
on their internal map -

375
00:41:25,200 --> 00:41:28,120
the key to long-distance navigation.

376
00:41:32,360 --> 00:41:34,760
From the shores of central Africa...

377
00:41:38,440 --> 00:41:40,760
...a whole ocean awaits.

378
00:41:50,560 --> 00:41:53,639
The Moon has had influence
over the Earth

379
00:41:53,640 --> 00:41:55,640
for billions of years...

380
00:41:57,640 --> 00:42:01,040
...creating profound physical changes
to our planet.

381
00:42:01,880 --> 00:42:06,279
These allow animals on the final
stretch of their long migration

382
00:42:06,280 --> 00:42:09,000
to home in with amazing accuracy.

383
00:42:14,320 --> 00:42:19,520
The gravitational pull of the Moon
strains the Earth's thin crust.

384
00:42:24,520 --> 00:42:28,079
This has helped create
volcanic peaks,

385
00:42:28,080 --> 00:42:31,120
and vast canyons, even underwater.

386
00:42:32,440 --> 00:42:35,759
Such are the scale
of these formations,

387
00:42:35,760 --> 00:42:39,879
their huge mass alters
the gravity on Earth,

388
00:42:39,880 --> 00:42:43,039
slightly stronger
where there are mountains,

389
00:42:43,040 --> 00:42:46,919
slightly weaker in deep canyons.

390
00:42:56,320 --> 00:43:01,360
These are gravitational signposts
for those who can feel it.

391
00:43:12,960 --> 00:43:18,079
Mum and calf can sense
the slight change in gravity

392
00:43:18,080 --> 00:43:21,760
caused by the mountains
and canyons on the ocean floor.

393
00:43:44,400 --> 00:43:46,359
They've made it,

394
00:43:46,360 --> 00:43:49,559
across 5,000km of open ocean

395
00:43:49,560 --> 00:43:52,120
to the cool Alaskan waters.

396
00:43:56,400 --> 00:44:00,320
The calf now has a thick layer
of blubber to keep him warm.

397
00:44:03,880 --> 00:44:06,519
But mum has lost
nearly half her bodyweight

398
00:44:06,520 --> 00:44:09,320
since she left these shores
seven months ago.

399
00:44:13,640 --> 00:44:15,919
These green seas

400
00:44:15,920 --> 00:44:19,640
are a sign her fasting
will soon be over.

401
00:44:27,920 --> 00:44:32,279
Plankton-rich waters have drawn
in millions of herring,

402
00:44:32,280 --> 00:44:36,920
and this is why mum
and calf have come so far.

403
00:44:40,680 --> 00:44:43,959
Weeks of travelling with the Moon
as their guide,

404
00:44:43,960 --> 00:44:47,920
they've arrived at the right place
and at the right time.

405
00:44:49,240 --> 00:44:54,000
And there's one final skill
the calf can learn.

406
00:44:57,640 --> 00:45:00,360
How to work as part of a pod...

407
00:45:02,560 --> 00:45:05,040
...and master the art of the hunt.

408
00:45:09,040 --> 00:45:13,560
The males put their fighting aside,
and now work together.

409
00:45:15,440 --> 00:45:18,840
Each humpback in the group
has a role to play.

410
00:45:20,280 --> 00:45:22,999
One releases air,

411
00:45:23,000 --> 00:45:26,920
whilst swimming in a circular pattern
towards the surface.

412
00:45:29,960 --> 00:45:34,280
As the bubbles rise,
they form vertical curtains...

413
00:45:39,440 --> 00:45:41,760
...forcing the fish together.

414
00:45:48,080 --> 00:45:51,360
Calls from the others
further concentrate the shoal...

415
00:45:54,280 --> 00:45:57,640
...and then, a co-ordinated surge.

416
00:46:04,720 --> 00:46:10,199
The bubble-net size,
shape and amount of air is adjusted,

417
00:46:10,200 --> 00:46:13,360
depending on the type of prey.

418
00:47:00,960 --> 00:47:03,479
Not all humpbacks catch food
this way.

419
00:47:03,480 --> 00:47:07,440
it's unique
to only a few groups in Alaska.

420
00:47:12,400 --> 00:47:16,320
This calf is part
of a special community of whales.

421
00:47:31,360 --> 00:47:35,160
He'll need to spend the summer
finding his place in the pod.

422
00:47:38,120 --> 00:47:42,600
After a well-earned feed,
it's time to play.

423
00:47:56,160 --> 00:47:59,080
But there's another reason
for his breaching.

424
00:48:02,720 --> 00:48:05,559
It's now thought the young humpback

425
00:48:05,560 --> 00:48:08,560
is also resetting his senses.

426
00:48:12,120 --> 00:48:15,759
As he freefalls back into the water,

427
00:48:15,760 --> 00:48:19,279
he's calibrating
to the gravity signposts

428
00:48:19,280 --> 00:48:22,559
of the underwater mountains
and canyons

429
00:48:22,560 --> 00:48:24,560
at these rich feeding grounds.

430
00:48:47,520 --> 00:48:51,559
Once autumn arrives
and the herring leave,

431
00:48:51,560 --> 00:48:56,320
the calf will join his mum
on the return back to Hawaii.

432
00:49:03,840 --> 00:49:06,919
The next time he travels
back to these waters,

433
00:49:06,920 --> 00:49:09,000
he'll do so alone.

434
00:49:11,440 --> 00:49:16,800
On his long journey
triggered by the Moon phase...

435
00:49:18,160 --> 00:49:21,200
...kept on course
by the magnetic field...

436
00:49:22,040 --> 00:49:24,040
...and guided by gravity.

437
00:49:31,280 --> 00:49:36,679
The Moon's
all-pervasive power and influence

438
00:49:36,680 --> 00:49:40,360
will be with him
every step of the way.

439
00:49:52,280 --> 00:49:56,159
To film the lunar lives
of leatherback turtles in Gabon,

440
00:49:56,160 --> 00:50:00,320
the team partnered with a local NGO
devoted to their survival.

441
00:50:21,400 --> 00:50:24,920
Didier doesn't have to go far
to reconnect.

442
00:50:26,720 --> 00:50:29,999
Only ten kilometres
from the capital Libreville

443
00:50:30,000 --> 00:50:32,319
is Pongara National Park,

444
00:50:32,320 --> 00:50:35,799
one of the world's
most important nesting beaches

445
00:50:35,800 --> 00:50:38,000
for endangered leatherback turtles.

446
00:52:54,600 --> 00:52:59,520
Adult turtles can get tangled
and drown in discarded fishing nets.

447
00:53:01,440 --> 00:53:04,159
And Pongara's proximity
to the capital

448
00:53:04,160 --> 00:53:06,160
brings a greater threat.

449
00:53:08,080 --> 00:53:10,759
Timber from Gabon's vast forests

450
00:53:10,760 --> 00:53:13,960
is taken by sea to sawmills
in the capital.

451
00:53:15,040 --> 00:53:17,360
Not all the huge trees make it.

452
00:54:02,720 --> 00:54:06,679
Leatherbacks have existed
since the time of the dinosaurs,

453
00:54:06,680 --> 00:54:10,559
and it's down to the hard work
of Didier and his team

454
00:54:10,560 --> 00:54:14,359
to help them survive the pressures
of the modern world,

455
00:54:14,360 --> 00:54:18,639
and ensure Pongara remains
a vital nesting ground -

456
00:54:18,640 --> 00:54:23,720
critical not only for Gabon,
but of global importance.

457
00:54:46,000 --> 00:54:50,000
Subtitles by Sky Access Services
www.skyaccessibility.sky