(light adventurous music) (birds chirping)
We live on an ever moving planet.
It's the driver that brings seasonal change.
(duck quacking)
And as landscapes are altered,
wildlife must march to its rhythm.
(waves crashing)
Performing endless journeys.
As if by magic, they follow a map, built into their DNA,
driven by instinct and the wisdom of thousands
of generations have gone before.
Migration is a phenomenon that wows us
as animals show incredible feats of endurance,
some take to the skies or cross oceans.
But the migrants we know best are the orange aspiring herds
running across our planet,
performing some of the longest journeys on Earth.
Facing endless hurdles and countless dangers,
but nothing can distract them from the nation.
♪ Ooh, ooh, ooh ♪
Stampeding across the planes.
Land migrants provide some of nature's
most dramatic spectacles.
It's a never ending mission to keep herds on the move.
(grass rustling)
(water babbling)
(elephants roaring)
Migrations are like veins running across
the surface of the planet.
(soft dramatic music)
An endless flow of nutrients being spread
and bringing new life.
Cave painting show that these mass movements
of animals have fascinated us since before the dawn of time.
Not least because our ancestors needed to follow
the movement of their food.
Today, the East African March of wildebeest
is perhaps the best known migration,
drawing millions of tourists to a spectacle
they will never forget.
(soft rock music)
(water splashing)
(light music)
The land migrations are undertaken
by just about every kind of animal.
Some are more surprising than others.
(waves crashing)
Christmas Island.
So named because it was discovered on Christmas Day
has become Australian territory.
Even though it lies closest to Indonesia
in the tropical Indian ocean.
It's home to an epic migration.
It's location near the tropics brings an annual wet season.
(soft dramatic music)
(waves crashing)
The pouring rain is like a shot from the starter's gun.
Let the race begin.
These are Christmas Island red crabs.
It's the males who are first off the starting block.
(soft dramatic music)
Their dens are far in land high in the mountains.
But now they must begin a downhill march.
Females and other males magically emerge
at every step of the way to join them.
(whimsical music)
The forest gets the red carpet treatment.
The dedicated crustaceans are working to a deadline.
They must reach the sea
when the moon and tide are just right.
(water bubbling)
(waves crashing)
Somehow the whole process is back timed.
Planned, so that they can get from the mountains mate,
develop eggs and arrive on the coast in perfect time
for the last quarter of the moon on the spring tide.
It requires regimented precision.
As they swarm through the jungle,
they fuel their migrations by hoovering up pretty much
anything they can find.
(sneaky music)
They'll nibble on little insects and snails.
And any carrion they fight.
But fallen leaves and fruit are their main state.
They need all the canneries they can get.
Migrations are difficult for all species,
especially on such tiny legs and some pretty big obstacles
stand in their way.
(birds squaking)
(soft mysterious music)
Kings among crabs, the full kilo coconut crabs
are the largest land invertebrates,
and a giant problem for the red crabs.
(dramatic music)
With claws as strong as alliance jaws,
the coconut crab earned their name
for their nut cracking skills.
But those same tools can be used for murder.
The coconut crabs are not fast.
They lose menacingly in the path of the migration.
The reds must complete their mission,
regardless of the threats.
Not all of them will make it.
One of the traits that defines a migration
is the unstoppable urge to keep going,
even in the face of great danger.
And it affects all migrants regardless of size.
Mammoth bodies require huge amounts of food
and water to survive.
(elephants roaring)
And on the seasonal Plains of Africa,
that is far from guaranteed.
So written into the ancient DNA of these giants is knowledge
and instinct to guide their migrations.
After centuries of hunting,
elephant numbers are much lower than they once were.
This is their last stronghold.
(light adventurous music)
Wisana with over 100,000
has a third of all the elephants in Africa
and the biggest population left on Earth.
The herd spread out and live across the country's planes
and neighboring Zimbabwe and Namibia.
(water splashing)
But as the Plains dry up,
grass is weather and rivers run dry.
The massive animals need to move
to a more reliable water source.
(light adventurous music)
Elephants have a legendary ability to find water,
thanks to huge brains with amazing memories.
They still mental maps.
And to know that three major rivers run
into the North of the country.
Though they are spread out in small groups,
they somehow all know to begin their march.
(birds chirping)
It might be they're changing drying environment
that starts them up,
but it's also possible that they have
a more coordinated approach.
Elephants make low rumbles so low that
they can't be detected by human ears.
(light adventurous music)
They can communicate for several,
perhaps 10 kilometers away.
So they might let neighboring groups
know that they are on the move.
(elephants thumping)
At first it's the small herds, females and their young.
(light music)
Elephant society is matriarchal.
It's the older, wiser females,
that guard and guide the herd.
(elephants roaring)
Adult males are solitary.
(water splashing)
Will hang out in bachelor groups,
roaming from heard to herd
to find opportunities to mate.
But as the migration begins,
other herds seem to magically appear and merge.
(light music)
Their numbers grow.
Knowledge and memory, guide them through the easiest parts,
bypassing difficult and dangerous terrain.
As they travel, knowledge is being passed
from one generation to the next.
Ancient navigators.
The parts made by these giants year after year have created
open roads that humans have taken advantage of for eons,
making travel easier for everyone.
(soft dramatic music)
Their ways are not as regimented as the crabs.
They seem to drift from arid Plains
heading for a lush river basin.
The crabs must rush to make the tides.
The elephants don't follow fixed schedule,
seasonal change and drawing planes triggered the move.
But like the crabs,
they face obstacles along the way.
Dehydration can cause clumsiness
and on rough terrain accidents can happen.
Elephants are famous for their apparent compassion
and empathy for herd mates.
They gather pondering the problem
and offering the fallen moral support.
(birds chirping) (water babbling)
But ultimately, the rigors of migration
claim another victim.
(elephant roaring)
Elephants are among the few animals
well-known for grieving for their dad.
They seem to visit and linger to pay their respects.
They don't have long degree for their comrade.
The march must go on.
(soft music)
Elephants are ecosystem engineers changing
the landscape as they pass through.
Their huge feet can churn the ground,
helping a diverse plant community to establish.
They can literally flattened trees,
creating openings for new plants to get established,
and attracting more plant eating animals.
And like all migrants, they transport nutrients,
redistributing it across the landscape through their dung.
The dung thuds left and the giants weight
or a dinner gone to some grateful residents.
(light music)
It's the trigger for a mini movement of dung beetles
that dashed to the scene.
(sneaky music) (birds chirping)
The cleanup crew row neat and more drivable balls
from the elephants leftovers
that they can steer away to their burrows.
The poop balls will be implanted with beetle eggs,
and will provide them edible nursery for the young
when they hatch.
This shifting of nutrients is
a vital part of healthy ecosystems.
And though areas big enough for migrations
of large animals have diminished,
they were once found on all big land masses.
(soft music)
The vast grasslands and deserts of China,
Mongolia and Russia host lesser known migrations
that are just as spectacular
as those of African Wildebeest.
(light music)
Critically endangered battery in camels,
roam with Mongolian Gazelles,
and once numbered in the millions.
And looking like sci-fi extras,
(soft upbeat music)
the extraordinary floppy nose Saiga antelope once roamed
most of the temperate Northern hemisphere
from the British Isles to Alaska.
Their herds were so huge, they'd carpet the grassland,
as far as the eye can see.
Now just a fraction of their population remains
in several isolated subspecies
They're inflated noses are inbuilt dust filters,
useful adaptations when thousands of tracking together
of a dry Plains and kicking up clouds of choking dust.
(animals thumping)
As keen and travelers as any,
the little goat sized antelope march
1,000 kilometers per year,
to get the best weather and grazing
as harsh seasons roll in around them.
(soft dramatic music)
Migrations can have clear chapters
where conditions alter behavior.
(birds squawking)
As the red crabs get closer
to the shores of Christmas Island,
their behavior radically changes.
The males dig burrows, little love nests.
(mellow music)
The position of the man caves are absolutely vital,
mating success will depend on it.
They have to be close enough to the coast
with the final leg of the journey to be triumphant.
And a surge of hormones triggers some mood swings.
No longer harmonious team players marching on together.
They become fiercely territorial.
All are wrestling for the best spots along the strip,
the migration route,
where they have the best chance to learn a willing mate.
The females have no choice other than to move
through the gangs of males as they show off.
The females carefully select mates.
(soft pleasant music)
And for these crustaceans, lovemaking happens face to face
in a surprisingly tender and grace.
Once the male's handed over his genetic contribution,
his job is done.
He musts his energy and begins to track back up Hill.
But as a departing gift,
he transfers the deeds to his house over to the female.
She'll hide out in the burrow
for a month while her eggs develop.
A brief respite, but her mission is far from over.
(light music)
Migrations have been a part of landscapes and animals lives
since the dawn of time.
For as long as seasons who brought changing conditions,
animals have had to respond,
especially in the extreme latitudes,
with the might of the seasonal change is most felt.
Throughout the Arctic Circle in the habitat known as Tundra,
huge animal journeys take place.
To escape the bleak cold of winter
and to cash in on the productivity of summer's long days.
And no polar migration is more famous than that of caribou.
These deer are made of tough stuff,
eking out a living with few other mammals can survive.
Hundreds of thousands of them band together,
letting no obstacles stand in their way.
(water swishing)
And there are certainly plenty of them.
The harsh Arctic winter has barely loosened its grip.
The snow that once blanketed the Tundra has melted,
but now fuels rivers creating raging torrents.
(water babbling)
Caribou are strong swimmers.
They're broad hooves that serve as snow shoes during winter
help to paddle them through the water.
But in the midst of the herd of this year's carves,
they are only weeks old,
but already undertaking one of the most arduous journeys
that any animal will face.
A true baptism of fire
or in this case water.
As they must fight the icy torrents,
it's an epic battle and not all will succeed.
(animals grunting)
But these deer are born full of fight.
Encouraged by their mothers,
they battled towards the far bank.
They are totally exhausted, but there's no time to rest.
And there's a new hurdle to face.
The banks are steep and slippery,
thanks to the thousands of hooves
that have already turned to mud.
The calves need a breather,
a chance to muster their strength,
but it is not an option.
Arctic some as a short and the herd can't afford to wait.
The mother's bleeding encouragement,
the carves need to keep going.
(animals grunting)
Even now there's no rest for the little ones.
It would be dangerous to be left alone out here to face
predators and the elements.
They must keep up with the herd.
(light dramatic music)
The ultimate nomads,
these animals travel more than 1,000 kilometers.
Twice as far as Wildebeest
in the longest land migration on earth.
The hurdles are endless.
Nothing can stop the march.
Even the great mountain ranges that they move on to cross.
They face other obstacles as well.
Moves are not normally migratory,
but a population that depends on the caribou for food
must move with the herds.
And because they roam constantly throughout the year,
the lanky Arctic wolves actually cover even more ground.
(wolf howling)
The movement of such vast herds of animals
has a massive impact on other life around it,
including humans.
(light dramatic music)
The huge march masses of meat on the move caught
the eye of our ancestors.
Ancient people not only modeled at the migration,
but followed it.
To exploit it as a food source.
It may have been the following of the herds that helps
humans to move North as the ice age retreated.
It was the start of a unique relationship.
In Eurasia, the same species of deer are known as reindeer.
(deer grunting)
People here didn't just hunt the deer.
They lived with them,
migrated with the herds,
getting everything they needed to survive from the animals.
The lies of these two very different species have
become so entwined that reindeer are considered
semi domestic and have been for at least 2,000 years.
Today, half of the world's reindeer population
and some 100,000 people live and migrate together.
The people found the deer for meat, milk, skins for leather.
They even used their bones,
antlers and hooves for tools and building materials.
They ride them and use them to pull sleighs.
Everything they need comes from the deer.
But the reindeer feed themselves marching
in search of the lichens they need to eat.
(deer grunting)
It's not an entirely one sided arrangement.
The presence of people keeps wolves
and other predators from attacking the herds.
The traditional nomadic lifestyle is little altered.
Though, the modus operandi might've changed a bit.
(soft upbeat music)
(snowmobile engine revving)
Humans have massively influenced animal migrations.
As we've spread around the globe,
we've heavily hunted wildlife, especially big game,
sometimes wiping out species
or pushing them to the brink of extinction.
Many great migrations have been lost.
(soft dramatic music)
At one time, bison roamed all across
the Plains of North America from the Gulf of Mexico
to Alaska until 150 years ago,
30 million of them moved in herds that could carpet
the landscape as far as the eye could see.
One herd was measured to cover
an area twice the size of London.
(bison grunting)
The great beasts had to keep on the move
to contend with heavy winters.
(upbeat dramatic music)
Like other migrants, they faced dramatic river crossings.
And attack from predators.
As they traveled,
they were joined by other migrants like agile chrome horns.
They shared their summer range
with great colonies of Prairie dogs.
As they're heavy feet stomped over the grassland,
they churned the ground and their dung fertilized it.
(animal grunting)
Buffalo are ecosystem engineers,
the disturbance and fertilization they give the ground
promote far greater plant diversity.
Even the places they stopped to roll
in the dirt become shallow pits,
known as wallows that can have many environments
for different plant species.
More plants feed a wider variety of insects.
An unhealthy grassland, the bison they're kicking up
so many crickets and other grubs
that birds follow them to pick up the insects.
(birds squawking)
Bison shapes the great grasslands of America.
But from the 1800s, they were slaughtered in droves
by Europeans trying to settle the planes.
(light music)
Only in a few tiny pockets did a handful survive.
Such as this herd.
Now protected by the Yellowstone National Park.
Bison migrations were once so huge
that they wore trails into the ground that were later used
for roads and railways.
And today, the small herds remaining migrate
more than 300 kilometers a year.
A tiny window on a long gone
and glorious migration of the past.
Humans often interfere and get in the way.
Settlements and farming can block, reroute,
or even halt migrations.
All species around the globe are impacted,
as our population continues to grow.
Even the Christmas Island crabs.
There are not many on the tiny Island,
but for years they were enough to kill thousands of crabs.
(truck zooming)
(insects buzzing)
Thankfully, now the crabs are protected
and roads are closed during migration to curb the carnage.
But even now, the crustaceans must tackle
some major changes to their journeys.
Like navigating a golf course.
(upbeat fun music)
Out in the open like this,
they have less shelter from predators
and less plant cover to shield from the hot sun
and risk of dehydration.
Still they soldier on and complete the course.
Even giants experience holdups.
(elephant grunting)
Like the rest of the world,
Africa is being carved up into farmland or mines
and becoming crisscrossed with roads.
(elephant roaring)
Human populations are exploding and need more space.
And to feed their families.
Humans grow crops that they're not willing
to share with wildlife.
(elephant grunting)
Elephants are racing towards extinction.
Hunting has been the major cause of their decline,
the slaughter of thousands for ivory.
(gun blasting)
But loss of habitat is an equally serious threat.
(soft music)
Their reduced population is fragmented
into small protected areas, fenced in to keep them safe,
but preventing any natural migrations from taking place.
Without the ability to roam,
there's a risk of elephants overpopulating and overgrazing
an area which can lead to their own starvation,
and the degradation of the habitat.
The Botswana Zimbabwe population is the last that truly has
space to continue this traditional migratory behavior.
And despite the obstacles,
the elephants finally get through.
(elephants roaring)
(soft dramatic music)
The reward for their efforts,
a vast wetland fed by a major river.
(water splashing)
With water on tap,
it draws thousands of elephants who seem to delight
in the chance to socialize with other groups.
They can't all stay here year round,
they'd soon run out of plants to eat.
So eventually, the return leg of their journeys will begin.
(water splashing)
But for the rest of the dry season, they can relax.
Have a soak in the tub and hang out with friends.
(waves crashing)
The female red crabs on Christmas Island
must also complete their missions.
Their eggs are ready to hatch.
Cautiously, they leave the protection of their burrows.
With incredible coordination,
the females gather in perfect synchrony to spawn together
seeking safety in numbers.
They are land crabs,
no longer capable of life under water.
They need to be weary of the fierce waves
and strong currents and cling to the rocks.
(water rumbling)
Each one, cradling some 100,000 eggs.
(light music)
Hiding in the shadows,
they wait close to the beach until the sunset fades.
Now the timing is perfect.
The leak tide reduces the surge that could sweep them away.
So cautiously at first, they begin to paddle.
Then begin a night of dancing
under the soft glow of the moon.
(twinkling music)
The twerking crustaceans are gyrating
to release the eggs from their undersides.
By working together,
they flood the coastal water with more eggs
than the fish could possibly consume.
To ensure at least someone will survive.
The eggs hatch on contact with water.
For the next month,
the tiny crabs will drift with the plankton.
Migrations are usually return trips,
and now the exhausted mothers,
having completed their missions,
must begin the demanding journey back inland.
(waves crashing)
A month later on Christmas Island
and the beaches are deserted.
There is no sign of the mass gathering.
(water bubbling)
Having matured, the minuscule baby crabs
are ready to come to shore.
By the millions.
(mellow music)
Each one is smaller than a pea.
But there are so many that the great
red tide can be seen from the air.
And amazingly, the magical power of instinct tells
the tiny crustaceans to march.
Despite the dangers in their path,
they will move in land and find habitats where they can grow
and to mature until big enough to return with the adults.
To answer that inescapable urge to join a global phenomenon,
migration.
Migration is a vital part of life on earth.
Animals need space to roam,
to make the most of seasonal changes.
And as they do, and Thai ecosystems can be enriched.
The landscapes of the world have been carved up by humans,
but it doesn't take much effort for us to try
and accommodate the needs of migrants.
Removing fences and closing roads
during peak times are a good start.
And giving up just a little land
to form corridors that the animals can use
to connect their populations and habitat.
We have put ourselves in the path of their migrations
and need to try and allow them to pass through,
to continue their unstoppable march.
(soft music)
(elephant roaring)
(light pleasant music)