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Our Moon is
a familiar face in the night sky.

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She illuminates the way
for animals on the move.

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But even when her light fades,

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she has an unseen power,

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which guides creatures
across the entire planet.

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A humpback whale mum and her new calf

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relax in the warm waters
of the Hawaiian archipelago.

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It's the perfect nursery.

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The calf was born
just a few months ago.

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The tropical waters give him warmth.

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There's shelter from the waves...

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...and from the strong currents
of the open ocean beyond.

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But he'll have to face them soon.

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He must build his strength,
Mum must rest.

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Their journey is about to begin.

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They'll need to use the unseen power
of the Moon to find their way.

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Our Moon shapes life on Earth
in extraordinary ways.

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Creating the swelling tides...

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...dictating the length of day...

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...summoning the seasons.

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She can light the way to love...

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...reveal hidden pathways...

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...bring times of plenty...

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...or strip away chances of survival.

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With each phase,

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from full moon to new,

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less light is reflected to Earth...

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...but the more powerful
the Moon becomes.

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As the Moon aligns with the sun,

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their combined gravitational pull
on our planet

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is at its strongest.

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This shift in gravity...

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...is the signal
to start an ocean odyssey.

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This calf has only known the shelter
of these Hawaiian seas

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since he was born.

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The waters may be calm,
but they are not always safe.

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A male.

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He's looking
for the chance to impress.

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And now he's joined by other males,
who are all searching for a mate.

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It's not known why,

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but a new moon brings
out their competitive side.

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They are keen to show the female
they've got what it takes.

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In these displays, they can
accidentally drown a young calf.

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The males use the deeper water
to fight for dominance.

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Mum takes a chance to slip away.

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She has led her calf
to the safety of the shallows.

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In a few short months,

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he's already doubled in size
drinking mum's rich milk.

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But she hasn't eaten in six months.

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This nursery comes at a cost.

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There's not enough food for mum here.

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And their feeding grounds
are 5,000km away

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in Northwest Alaska.

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It's a journey all the humpbacks
here in Hawaii must take,

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and one the calf must learn.

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This is the only time
his mother will guide him north.

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There's little margin for error.

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Set off too early,
and they'll arrive in frozen seas.

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Stay too long, and they'll starve
on the long voyage ahead.

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The new moon is their signal.

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Mum and calf can sense
the greater gravitational pull.

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For mum, it's time to head north.

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For the calf, this new feeling

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is the first lesson
on the unseen power of the Moon.

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They'll need to keep on course,

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and pinpoint their feeding grounds

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among thousands
of kilometres of coastline.

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And the Moon's power will guide them
each step of the way.

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Every month, the Moon changes
not just her phase, but her position.

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Higher in winter,
appearing longer in the night sky...

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...lower in summer,
shining for less time,

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only skimming the horizon.

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It's these changes in phase
and position

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which set animal migrations
in motion.

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In the lowlands
of Southern England...

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...a nightjar rests in the heath.

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She's a nocturnal hunter...

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...and she's waiting
for the Moon to rise.

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In the cool of the night...

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...the heath comes alive.

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The full moon signals
to the nightjar.

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It's time to come out into the light.

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She's searching for moths.

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They spend these summer nights
looking for a mate.

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Using the Moon to navigate,

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they'll keep it at a constant angle
as they fly.

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But tonight,
the full moon is their downfall.

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The nightjar's huge eyes

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drink in every photon of light
the Moon provides.

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Tonight's bright full moon

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helps her pick out insects
silhouetted against the dark sky.

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Under a full moon,

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nightjars are twice as effective
at catching prey.

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And she must catch
as many moths as she can.

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Packed with protein,

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insects are the ideal fuel.

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But this Moon is
more than a hunting aid.

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It's a countdown
to the start of her migration.

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In late summer,

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the low full moon will only stay
above the horizon for a short while.

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Nightjars' lives are tuned
to the phase and light of the Moon.

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And she won't be alone
on this journey.

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Nightjars all across Europe
will start their migration

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ten days after this low full moon
of late summer.

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Using the Moon as a clock,

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they can synchronise their departure,

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ensuring there's safety in numbers
on their long journey ahead.

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Thousands of nightjars
will head to Central Africa...

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...chasing an endless summer.

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The changing height and phase
are both clock and calendar...

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...a seasonal signal
and a call to arms.

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Beneath the glow
of a high winter moon

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in Southern Australia...

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...a transformation is underway.

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Every year, spider crabs must moult
their spiky armour

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in order to grow.

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But it'll take days
for their new shell to harden.

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So they're vulnerable.

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Long legs help this crab travel
around seven kilometres

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from the rocky depths to the cool,
calm shallows.

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He's searching
for a safe place to moult,

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and needs to find it fast.

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His body has already started
to transform,

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it can't be stopped.

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The Moon has triggered others
to migrate here to moult...

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...but they've been followed.

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A three-metre-long broad ray.

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With no place
for the crabs to hide...

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...a lone crab is defenceless...

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...and delicious.

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They pin them to the sea floor.

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Port Jackson sharks mop up
the stragglers.

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The Moon draws more crabs
out of the deep.

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In winter,
the water is calm and cold...

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...the perfect conditions to moult.

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The full moon allows
thousands of crabs

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to co-ordinate their march
to the shallows.

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And as they gather,
they begin to band together.

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To shed his shell,

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this crab needs to find
the safety of the swarm.

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He can't drop his guard.

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He's no heavyweight...

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...but can still pack a pinch.

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Nipping at the ray's
soft undersides...

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...is just enough to put it off.

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The safety of a huge mound
is in sight.

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It's a lucky escape.

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Now he has an army
who's got his back.

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The mountain of crabs
should make an easy meal.

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But the mound is now
a sea of spines and claws...

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...which sways and shifts.

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So the ray can't grip
even a single crab.

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There are as many as 20,000 crabs
in this small sandy bay.

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And with this sheer force of numbers,

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they create an impenetrable fortress.

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Surrounded by his band of brothers,

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he'll moult, transforming in safety,

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until his new armour hardens.

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The crabs will disappear back
into the depths until next year...

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when the high winter moon signals
the army to rise up once more.

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The full Moon is 400,000 times
less bright than the Sun.

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But it's no pale imitation.

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She can extend the day
and open up new opportunities.

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And there's no more important time
than when raising a family.

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In the lush forests
of Kyushu Island, Japan...

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...a red shield bug guards
her tiny babies,

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tucked into the leaf litter.

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This is the only brood
she'll ever have.

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Shield bugs' lives are short.

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Being a mum is
the last thing she'll do.

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To ensure they can get
the best start in life,

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she must leave them
in search of food.

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Among the tangle of vines
and trees...

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...she's searching
for a special type of ripe fruit.

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She keeps an eye on the pattern
of light and shade in the canopy,

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which will guide her home.

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She's locked on to a scent.

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The fruit of the Boro Boro tree.

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But the light is fading...

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...and her map has gone.

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She can't find her way
back to her babies.

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A dark forest is a dangerous place
for a lost little bug.

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But the Moon is here to help.

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It reilluminates the canopy.

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It may not be as bright as the Sun,

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but the contrast
between the moonlight and dark

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creates a clearer pattern.

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The little bug can read these
like points on a map.

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So she's able to take the most direct
route home to her babies

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in minutes, not hours.

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It's these full moon nights

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which give her
valuable extra foraging time.

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Tomorrow,
the Moon will shine less bright,

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the canopy map dimmer,

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harder to read,
less time to feed her babies.

196
00:21:48,260 --> 00:21:51,850
But tonight,
it won't set until dawn,

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00:21:51,860 --> 00:21:55,450
so she must make the most
of this extended opportunity

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00:21:55,460 --> 00:22:00,060
to find food on this long,
moonlit night.

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00:22:15,700 --> 00:22:18,730
On the nights after the full moon,

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the amount of reflected light
fades fast.

201
00:22:24,940 --> 00:22:27,580
A crescent moon is barely visible...

202
00:22:28,540 --> 00:22:33,180
...but even a silver sliver
can keep animals on track.

203
00:22:38,300 --> 00:22:40,570
African savannah elephants

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take the definition
of a midnight snack to the extreme.

205
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They can spend 16 hours eating,

206
00:22:48,220 --> 00:22:52,180
and consume over 100kg of food a day.

207
00:22:54,220 --> 00:22:56,850
They'll spend so much time eating,

208
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that they're awake nearly all night.

209
00:22:59,660 --> 00:23:04,380
And all that food
has predictable consequences.

210
00:23:10,740 --> 00:23:15,660
Life in the shadow of giants
is a dangerous game.

211
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This little beetle
could easily be crushed.

212
00:23:27,620 --> 00:23:32,100
But it's a risk he must take
if he's to win a mate.

213
00:23:35,100 --> 00:23:39,530
For this beetle,
dung is a prized possession.

214
00:23:39,540 --> 00:23:44,290
A big ball of dung is exactly
what a female beetle is looking for

215
00:23:44,300 --> 00:23:46,860
to lay her eggs in.

216
00:23:47,940 --> 00:23:51,860
And this pile has
already attracted other males.

217
00:23:55,860 --> 00:23:58,900
To beat the competition,
he needs to be quick.

218
00:24:01,500 --> 00:24:04,020
It's time to get dirty.

219
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Using his strong legs,

220
00:24:13,660 --> 00:24:16,780
he sculpts a ball
five times his size.

221
00:24:22,740 --> 00:24:26,980
He needs the moonlight
to make a clean getaway.

222
00:24:28,940 --> 00:24:31,620
A straight line is the fastest way.

223
00:24:33,620 --> 00:24:36,290
But which way to go?

224
00:24:39,300 --> 00:24:42,530
The small amount of light
from a crescent moon

225
00:24:42,540 --> 00:24:45,500
is scattered by particles
in the atmosphere.

226
00:24:49,140 --> 00:24:53,100
And this creates lines of light
in the night sky...

227
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...known as polarised light.

228
00:25:04,220 --> 00:25:07,050
Even head down and facing backwards,

229
00:25:07,060 --> 00:25:10,220
he can follow these lines of light.

230
00:25:23,460 --> 00:25:27,210
But beware the thief in the night.

231
00:25:31,060 --> 00:25:33,010
With such a big ball,

232
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stopping to check
your position can be risky.

233
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Equally matched,
it's now a battle of stamina.

234
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he needs to stay on top.

235
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Losing the higher ground
could mean it's game over.

236
00:26:09,300 --> 00:26:11,580
But he won't give up.

237
00:26:18,900 --> 00:26:22,380
With the chance
of other dung-ball bandits nearby...

238
00:26:24,980 --> 00:26:28,740
...he pushes on,
following the polarised light.

239
00:26:37,220 --> 00:26:40,650
Finally, his new ball of dung

240
00:26:40,660 --> 00:26:44,100
brings him
the female attention he desires.

241
00:26:53,180 --> 00:26:57,340
The ball will become home
for their new brood.

242
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He'll keep pushing,

243
00:27:00,980 --> 00:27:05,020
until he finds soil soft enough
to bury the ball.

244
00:27:06,260 --> 00:27:09,340
His moonlight guided great escape...

245
00:27:11,140 --> 00:27:13,140
...finally complete.

246
00:27:20,420 --> 00:27:24,500
Moonlight offers a visible guide
to animals on the move.

247
00:27:27,700 --> 00:27:30,570
But the Moon has an unseen,

248
00:27:30,580 --> 00:27:34,180
and even more powerful way
to guide navigators.

249
00:27:35,620 --> 00:27:38,290
The Moon's proximity to Earth

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00:27:38,300 --> 00:27:44,010
means her gravitational pull
helps power an immense force.

251
00:27:49,260 --> 00:27:51,410
Under the Earth's crust,

252
00:27:51,420 --> 00:27:54,660
the iron-rich rock is molten.

253
00:27:55,500 --> 00:27:59,810
Just as the Moon's
gravitational pull acts on the tides,

254
00:27:59,820 --> 00:28:04,980
it also tugs on the swirling rock
deep underground.

255
00:28:08,100 --> 00:28:12,130
This movement adds
electromagnetic energy,

256
00:28:12,140 --> 00:28:15,540
creating powerful magnetic fields.

257
00:28:19,260 --> 00:28:22,860
These fields align
and oppose each other...

258
00:28:23,980 --> 00:28:27,340
...creating our North and South Poles.

259
00:28:34,380 --> 00:28:38,860
When charged particles from space
strike this magnetic field...

260
00:28:40,140 --> 00:28:43,650
...it causes the atmosphere to glow,

261
00:28:43,660 --> 00:28:46,940
and it becomes visible as an aurora.

262
00:28:50,700 --> 00:28:53,130
An ever-present power,

263
00:28:53,140 --> 00:28:57,460
felt all across the entire planet.

264
00:29:05,100 --> 00:29:10,530
Even in the middle of the world's
largest ocean, the Pacific.

265
00:29:10,540 --> 00:29:14,850
155 million square kilometres

266
00:29:14,860 --> 00:29:16,900
of endless blue.

267
00:29:20,140 --> 00:29:23,890
Its sheer size means storms
and strong currents

268
00:29:23,900 --> 00:29:26,660
swirl across it uninterrupted.

269
00:29:30,460 --> 00:29:33,500
Our humpback mum
and her young calf...

270
00:29:34,420 --> 00:29:36,980
...are 2,000km from land.

271
00:29:37,980 --> 00:29:42,420
In the open ocean, they could
easily be knocked off course.

272
00:29:43,380 --> 00:29:47,890
The calf sticks close to mum,
riding her slip stream,

273
00:29:47,900 --> 00:29:50,330
saving valuable energy.

274
00:29:50,340 --> 00:29:52,370
But mum is now burning through

275
00:29:52,380 --> 00:29:54,940
hundreds of thousands
of calories a day.

276
00:29:55,980 --> 00:30:00,980
Make a mistake in navigation now,
and it could cost them their lives.

277
00:30:10,580 --> 00:30:15,770
As they journey, the visible Moon
will change phase and position,

278
00:30:15,780 --> 00:30:18,620
so it can't be relied upon
as a guide.

279
00:30:20,620 --> 00:30:25,060
But the magnetic field is
an all-pervasive power.

280
00:30:29,500 --> 00:30:31,610
Inside their brains,

281
00:30:31,620 --> 00:30:35,330
mum and calf both have
tiny iron particles,

282
00:30:35,340 --> 00:30:38,010
called magnetite.

283
00:30:38,020 --> 00:30:41,090
These align with the magnetic field,

284
00:30:41,100 --> 00:30:43,420
triggering a cellular reaction.

285
00:30:44,220 --> 00:30:48,380
It lets them sense how steep
and how strong the field is.

286
00:30:50,700 --> 00:30:53,650
From this,
they can work out their position,

287
00:30:53,660 --> 00:30:56,020
and in what direction to swim.

288
00:30:59,100 --> 00:31:02,220
Their own biological map
and compass.

289
00:31:06,540 --> 00:31:11,500
So mum can find her way across
this seemingly featureless ocean.

290
00:31:13,580 --> 00:31:17,540
And now the calf is learning
how to use this sense...

291
00:31:18,420 --> 00:31:22,580
...for a life
as a long-distance ocean voyager.

292
00:31:31,660 --> 00:31:35,850
The magnetic field touches
every part of the planet,

293
00:31:35,860 --> 00:31:37,980
from the deepest oceans...

294
00:31:39,460 --> 00:31:41,980
...to high mountain peaks.

295
00:31:43,460 --> 00:31:46,700
From the largest animals
on the longest migrations...

296
00:31:47,540 --> 00:31:51,660
...to the smaller, but no less mighty.

297
00:31:55,780 --> 00:31:58,660
Deep in a European forest...

298
00:32:03,060 --> 00:32:07,500
...the spring sunshine stirs
a sleepy Alpine newt.

299
00:32:10,940 --> 00:32:13,650
After a year in the woods,

300
00:32:13,660 --> 00:32:16,780
instinct now drives him
to find water.

301
00:32:21,940 --> 00:32:24,100
He's looking for a mate.

302
00:32:29,980 --> 00:32:35,010
This finger length newt is too small
to see which way to go.

303
00:32:35,020 --> 00:32:39,340
He'll need to rely on his superpower
to find his pond.

304
00:32:42,580 --> 00:32:45,490
But he's not alone.

305
00:32:51,020 --> 00:32:52,970
A grass snake,

306
00:32:52,980 --> 00:32:56,460
energised by the sun, is on the hunt.

307
00:33:03,180 --> 00:33:06,650
The snake relies
on its speed and strength

308
00:33:06,660 --> 00:33:09,700
to chase down and strangle its prey.

309
00:33:31,580 --> 00:33:34,580
Little legs struggle
in the dense forest.

310
00:33:42,300 --> 00:33:46,980
But for a tiny newt,
there are plenty of places to hide.

311
00:34:06,060 --> 00:34:09,180
The setting sun is a sign it's safe.

312
00:34:10,300 --> 00:34:13,180
A grass snake can't hunt in the dark.

313
00:34:14,940 --> 00:34:17,810
But now disorientated from the hunt,

314
00:34:17,820 --> 00:34:21,300
he needs to work out
which way his pond is.

315
00:34:23,940 --> 00:34:26,650
He, too, has magnetite in him.

316
00:34:26,660 --> 00:34:31,500
His superpower, which allows him
to sense the magnetic field.

317
00:34:32,700 --> 00:34:34,930
Just like following a compass,

318
00:34:34,940 --> 00:34:39,340
he's keeping his whole body aligned
to the angle of the field...

319
00:34:40,140 --> 00:34:44,900
...and can head in the direction
of the pond he left a year ago.

320
00:34:55,460 --> 00:34:58,060
A spring storm
doesn't bother him, either.

321
00:34:59,700 --> 00:35:03,020
The magnetic force flows
whatever the weather.

322
00:35:07,100 --> 00:35:09,370
With his internal compass,

323
00:35:09,380 --> 00:35:13,620
this tiny newt can travel
as far as four kilometres.

324
00:35:21,980 --> 00:35:24,770
As the dense forest thins out,

325
00:35:24,780 --> 00:35:28,650
the newt can now smell
that water is close.

326
00:35:35,700 --> 00:35:38,380
Finally, his pond.

327
00:35:43,660 --> 00:35:47,740
Time for a well-earned dip.

328
00:35:50,260 --> 00:35:55,460
But he can't rest,
it's time to find a mate.

329
00:36:07,180 --> 00:36:10,170
As the season turns to summer,

330
00:36:10,180 --> 00:36:12,610
he'll return to the forest,

331
00:36:12,620 --> 00:36:16,290
but next spring,
wherever he is in the woods,

332
00:36:16,300 --> 00:36:19,010
he'll find his way back to this pond,

333
00:36:19,020 --> 00:36:24,380
using the lunar-charged
magnetic field to point the way.

334
00:36:33,540 --> 00:36:37,130
As the magnetic field wraps
around the planet,

335
00:36:37,140 --> 00:36:39,380
its angle changes.

336
00:36:40,820 --> 00:36:43,650
At the poles, it's vertical.

337
00:36:43,660 --> 00:36:47,730
At the equator,
it's parallel to the surface,

338
00:36:47,740 --> 00:36:50,660
creating a map
for those who can read it.

339
00:37:01,220 --> 00:37:03,810
Where the waters
of the vast Atlantic

340
00:37:03,820 --> 00:37:05,820
meet the Congo jungle,

341
00:37:06,620 --> 00:37:09,490
the coastline is one
of the few places in the world

342
00:37:09,500 --> 00:37:13,700
suitable...
for ocean giants to emerge.

343
00:37:16,220 --> 00:37:18,460
Four kilometres of sand...

344
00:37:19,260 --> 00:37:24,060
...just soft enough,
the beach not too steep.

345
00:37:31,260 --> 00:37:34,010
This Leatherback turtle

346
00:37:34,020 --> 00:37:38,460
touches land
for the first time in three years.

347
00:37:40,180 --> 00:37:43,490
The Moon has gifted her a high tide,

348
00:37:43,500 --> 00:37:46,180
helping her part of the way.

349
00:37:48,300 --> 00:37:52,580
She'll need all the energy she has
to haul herself up the beach.

350
00:37:56,700 --> 00:37:59,050
Using a Moon-powered map,

351
00:37:59,060 --> 00:38:02,490
she's travelled
from her feeding grounds in Brazil,

352
00:38:02,500 --> 00:38:04,650
six thousand kilometres away,

353
00:38:04,660 --> 00:38:07,820
back to the place
she first hatched...

354
00:38:10,180 --> 00:38:13,540
...on the coast of equatorial Africa.

355
00:38:23,140 --> 00:38:27,540
This time,
she's here to lay eggs of her own.

356
00:38:35,740 --> 00:38:39,540
Her eggs will be incubated
in the warm sand...

357
00:38:40,420 --> 00:38:43,540
...where they'll develop
a super-sense.

358
00:38:58,940 --> 00:39:01,260
Mum has done all she can.

359
00:39:06,660 --> 00:39:11,140
She's leaving her eggs
in the care of the Moon.

360
00:39:23,100 --> 00:39:25,330
As the eggs develop,

361
00:39:25,340 --> 00:39:29,290
the lunar charged magnetic field
courses through them,

362
00:39:29,300 --> 00:39:31,300
deep in the sand.

363
00:39:45,820 --> 00:39:50,090
The hatchlings have particles
of magnetite within them,

364
00:39:50,100 --> 00:39:53,740
and can also sense
the angle of the magnetic field.

365
00:39:55,780 --> 00:39:59,450
So each one is born
with a magnetic imprint

366
00:39:59,460 --> 00:40:01,660
of this stretch of coastline.

367
00:40:06,020 --> 00:40:10,540
This beach is their first mark
on their magnetic map.

368
00:40:16,940 --> 00:40:20,900
But it's the visible Moon
which guides their first steps.

369
00:40:23,620 --> 00:40:25,850
Instinctively, they head out

370
00:40:25,860 --> 00:40:28,900
to the brightest part
of their new world...

371
00:40:29,820 --> 00:40:32,650
...moonlight reflected on the sea.

372
00:40:54,580 --> 00:40:58,140
They'll ride the ocean currents
in search of food.

373
00:41:04,020 --> 00:41:08,340
As they travel, the angle
of the magnetic field will change.

374
00:41:11,260 --> 00:41:15,410
They'll add new markers
on their internal map -

375
00:41:15,420 --> 00:41:18,340
the key to long-distance navigation.

376
00:41:22,580 --> 00:41:24,980
From the shores of central Africa...

377
00:41:28,660 --> 00:41:30,980
...a whole ocean awaits.

378
00:41:40,780 --> 00:41:43,850
The Moon has had influence
over the Earth

379
00:41:43,860 --> 00:41:45,860
for billions of years...

380
00:41:47,860 --> 00:41:51,260
...creating profound physical changes
to our planet.

381
00:41:52,100 --> 00:41:56,490
These allow animals on the final
stretch of their long migration

382
00:41:56,500 --> 00:41:59,220
to home in with amazing accuracy.

383
00:42:04,540 --> 00:42:09,740
The gravitational pull of the Moon
strains the Earth's thin crust.

384
00:42:14,740 --> 00:42:18,290
This has helped create
volcanic peaks,

385
00:42:18,300 --> 00:42:21,340
and vast canyons, even underwater.

386
00:42:22,660 --> 00:42:25,970
Such are the scale
of these formations,

387
00:42:25,980 --> 00:42:30,090
their huge mass alters
the gravity on Earth,

388
00:42:30,100 --> 00:42:33,250
slightly stronger
where there are mountains,

389
00:42:33,260 --> 00:42:37,130
slightly weaker in deep canyons.

390
00:42:46,540 --> 00:42:51,580
These are gravitational signposts
for those who can feel it.

391
00:43:03,180 --> 00:43:08,290
Mum and calf can sense
the slight change in gravity

392
00:43:08,300 --> 00:43:11,980
caused by the mountains
and canyons on the ocean floor.

393
00:43:34,620 --> 00:43:36,570
They've made it,

394
00:43:36,580 --> 00:43:39,770
across 5,000km of open ocean

395
00:43:39,780 --> 00:43:42,340
to the cool Alaskan waters.

396
00:43:46,620 --> 00:43:50,540
The calf now has a thick layer
of blubber to keep him warm.

397
00:43:54,100 --> 00:43:56,730
But mum has lost
nearly half her bodyweight

398
00:43:56,740 --> 00:43:59,540
since she left these shores
seven months ago.

399
00:44:03,860 --> 00:44:06,130
These green seas

400
00:44:06,140 --> 00:44:09,860
are a sign her fasting
will soon be over.

401
00:44:18,140 --> 00:44:22,490
Plankton-rich waters have drawn
in millions of herring,

402
00:44:22,500 --> 00:44:27,140
and this is why mum
and calf have come so far.

403
00:44:30,900 --> 00:44:34,170
Weeks of travelling with the Moon
as their guide,

404
00:44:34,180 --> 00:44:38,140
they've arrived at the right place
and at the right time.

405
00:44:39,460 --> 00:44:44,220
And there's one final skill
the calf can learn.

406
00:44:47,860 --> 00:44:50,580
How to work as part of a pod...

407
00:44:52,780 --> 00:44:55,260
...and master the art of the hunt.

408
00:44:59,260 --> 00:45:03,780
The males put their fighting aside,
and now work together.

409
00:45:05,660 --> 00:45:09,060
Each humpback in the group
has a role to play.

410
00:45:10,500 --> 00:45:13,210
One releases air,

411
00:45:13,220 --> 00:45:17,140
whilst swimming in a circular pattern
towards the surface.

412
00:45:20,180 --> 00:45:24,500
As the bubbles rise,
they form vertical curtains...

413
00:45:29,660 --> 00:45:31,980
...forcing the fish together.

414
00:45:38,300 --> 00:45:41,580
Calls from the others
further concentrate the shoal...

415
00:45:44,500 --> 00:45:47,860
...and then, a co-ordinated surge.

416
00:45:54,940 --> 00:46:00,410
The bubble-net size,
shape and amount of air is adjusted,

417
00:46:00,420 --> 00:46:03,580
depending on the type of prey.

418
00:46:51,180 --> 00:46:53,690
Not all humpbacks catch food
this way.

419
00:46:53,700 --> 00:46:57,660
it's unique
to only a few groups in Alaska.

420
00:47:02,620 --> 00:47:06,540
This calf is part
of a special community of whales.

421
00:47:21,580 --> 00:47:25,380
He'll need to spend the summer
finding his place in the pod.

422
00:47:28,340 --> 00:47:32,820
After a well-earned feed,
it's time to play.

423
00:47:46,380 --> 00:47:49,300
But there's another reason
for his breaching.

424
00:47:52,940 --> 00:47:55,770
It's now thought the young humpback

425
00:47:55,780 --> 00:47:58,780
is also resetting his senses.

426
00:48:02,340 --> 00:48:05,970
As he freefalls back into the water,

427
00:48:05,980 --> 00:48:09,490
he's calibrating
to the gravity signposts

428
00:48:09,500 --> 00:48:12,770
of the underwater mountains
and canyons

429
00:48:12,780 --> 00:48:14,780
at these rich feeding grounds.

430
00:48:37,740 --> 00:48:41,770
Once autumn arrives
and the herring leave,

431
00:48:41,780 --> 00:48:46,540
the calf will join his mum
on the return back to Hawaii.

432
00:48:54,060 --> 00:48:57,130
The next time he travels
back to these waters,

433
00:48:57,140 --> 00:48:59,220
he'll do so alone.

434
00:49:01,660 --> 00:49:07,020
On his long journey
triggered by the Moon phase...

435
00:49:08,380 --> 00:49:11,420
...kept on course
by the magnetic field...

436
00:49:12,260 --> 00:49:14,260
...and guided by gravity.

437
00:49:21,500 --> 00:49:26,890
The Moon's
all-pervasive power and influence

438
00:49:26,900 --> 00:49:30,580
will be with him
every step of the way.

439
00:49:42,500 --> 00:49:46,370
To film the lunar lives
of leatherback turtles in Gabon,

440
00:49:46,380 --> 00:49:50,540
the team partnered with a local NGO
devoted to their survival.

441
00:50:11,620 --> 00:50:15,140
Didier doesn't have to go far
to reconnect.

442
00:50:16,940 --> 00:50:20,210
Only ten kilometres
from the capital Libreville

443
00:50:20,220 --> 00:50:22,530
is Pongara National Park,

444
00:50:22,540 --> 00:50:26,010
one of the world's
most important nesting beaches

445
00:50:26,020 --> 00:50:28,220
for endangered leatherback turtles.

446
00:52:44,820 --> 00:52:49,740
Adult turtles can get tangled
and drown in discarded fishing nets.

447
00:52:51,660 --> 00:52:54,370
And Pongara's proximity
to the capital

448
00:52:54,380 --> 00:52:56,380
brings a greater threat.

449
00:52:58,300 --> 00:53:00,970
Timber from Gabon's vast forests

450
00:53:00,980 --> 00:53:04,180
is taken by sea to sawmills
in the capital.

451
00:53:05,260 --> 00:53:07,580
Not all the huge trees make it.

452
00:53:52,940 --> 00:53:56,890
Leatherbacks have existed
since the time of the dinosaurs,

453
00:53:56,900 --> 00:54:00,770
and it's down to the hard work
of Didier and his team

454
00:54:00,780 --> 00:54:04,570
to help them survive the pressures
of the modern world,

455
00:54:04,580 --> 00:54:08,850
and ensure Pongara remains
a vital nesting ground -

456
00:54:08,860 --> 00:54:13,940
critical not only for Gabon,
but of global importance.