大熊的國度｜完整的紀錄片 - Planet Doc 完整的紀錄片。 (The Land of Giant Bears | Full Documentary - Planet Doc Full Documentaries)

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I’m going to die.
Time is running out for me, and for my companions;
my brothers of the river who, like me, were born in these waters four years ago.
Our lives are coming to an end after a long, dangerous journey.
But we have made it here, to the place where we first emerged into the world,
the place we have chosen to die.
Our beloved Alaska.
It is a harsh, wild place.
A land of dense forests and cold tundras,
crossed by innumerable rivers that are born in the distant mountains of the interior
and come to die here, on these frozen coasts.
We left these waters some time ago, when we were still young
and now, we have returned to swim from the sea back up our rivers.
An epic journey, plagued with dangers.
But that is part of our destiny, part of our greatness.
In a land as harsh as this, which gives you no second chances,
our arrival is the key to the continuity of life.
Before we die, we will leave behind, on the river bed,
the seed of future generations of salmon.
And at the end of our long journey, our old but nutritious bodies
will serve as food for the large animals of this land,
fattening them up, giving them the reserves they need to survive the terrible Arctic winter.
Yes, I’m going to die,
but allow me, in these final minutes, to tell you the story of our lives,
our odyssey in the distant land of the giant bears.
In the far north-west of the American continent
stretches a land some one and a half million square kilometres in size.
Only six hundred thousand people inhabit this region where the frozen tundra,
the coniferous forests and the mountains dominate a landscape
which, in some places, has never been trodden by man.
It is an inhospitable region, where life must make the maximum advantage of the few warm months,
after which the cold and the snow will once more take over the land.
And nonetheless, such is the natural wealth of Alaska
that over 50% of all the protected territory of the United States of America can be found here.
Its waters are full of krill, the small crustaceans that forms the basic diet of many marine animals.
Such a delicious feast that every summer the hunchback whales
travel over three thousand miles from the warm waters of Hawaii
in order to eat their fill.
And only the cold forces them to return to the south.
They are not the only summer visitors.
In a land dominated by ice few species can survive the hardships of winter.
When the cold sets in, food becomes scarce, and hibernation or emigration are the only possible alternatives.
The only thing that grows in the winter are the glaciers high up in the mountains.
The snows feed the glacier valleys and their gigantic tongues of ice
can advance a few more centimetres on their slow descent to the sea.
For thousands of years they were the real masters of Alaska.
The entire land was covered in ice, allowing no life to enter its domains.
Today, however, this supremacy has been challenged,
and each spring the ice it´s once more defeated.
Little by little the surface of the land is covered in blocks of ice
which began their slow journey towards the sea over a thousand years ago.
The start of the melt announces the resurgence of life in Alaska.
At the feet of the giant the seals doze in the sun before diving into the freezing cold waters in search of food.
Nature forges her way ahead at the very gates of the titan of ice.
From this time on the land undergoes a rapid transformation
With the increase in temperature, the layer of snow that had covered the landscape shrinks back
and the vegetation begins a race against the clock to complete its life cycle
in the few available months.
With the vegetation, food returns, and the largest of Alaska’s land carnivores,
the grizzly bear, awakes from its winter sleep.
Five months spent in the darkness in his den
Five months of fasting which are now coming to an end.
For the first time in many months, precipitation falls in the form of rain,
announcing the change of season, and the new-grown prairies fill with hungry bears.
They have spent the winter breastfeeding their cubs while themselves observing a strict fast.
Summer is short and it is essential to regain those lost kilos
if they hope to survive another year.
In Alaska, svelte figures don’t last for long.
The grizzly bear belongs to the same species as the European brown bear,
but its better diet enables it to grow much bigger.
A Pyrenean bear weighs around 300 kilos and stands two metres tall,
while on Kodiak island some bears can weigh almost 1,000 kilos and measure 3 metres.
The cubs remain with their mother for three years, after which their life of solitude begins.
From that time on, they will receive neither protection nor help,
and the companions they had played with up to now will become their rivals.
The grizzlies are solitary animals, and at the start of spring hunger makes them even more dangerous.
So, when an adult male approaches a group of young bears,
they know it’s time to stop their games and make a rapid getaway.
In times of hunger the adult bears are capable of killing and eating young of their own species,
so it’s probably best to take no chances.
The climate has also determined the vegetation of Alaska.
Wherever temperatures permit, the land is covered with coniferous forest.
Their small leaves, the needles, are not shed in the winter,
which permits them to take advantage of the warmer months from the very first day.
And this they do so effectively they block out almost all the light.
Except for the moss that covers the forest floor,
few plants are capable of living in their shade
The trees with deciduous leaves, less well adapted to the cold,
have to take refuge along the shores of the rivers and in the more protected areas,
and that is where the large herbivores go in search of them.
The spring brings fresh vegetation, an irresistible feast for any moose.
Like the bears, they are solitary animals.
The only groups outside the mating season are mothers with their young,
and these are precisely the most dangerous because the mother will allow no one,
not even one of her own species,
to get close to her young.
An absent-minded moose has come to drink at the same pool, unaware of her presence.
The calf doesn’t seem to mind the intruder, but its mother does not exactly welcome visitors
and it’s not long before she approaches the stranger to make her position clear.
There have been cases of female moose killing people who got too close to her young.
In a land of bears and wolves, the most dangerous animals of all are, paradoxically, the moose.
The unwitting intruder knows this, and moves off in search of quieter pastures.
No one, not even the large males, would dare challenge a mother,
and even less for a bit of water or a few willow leaves.
The deciduous plants, in contrast to the conifers, shed their leaves during the winter,
and in a land as cold as this that creates real problems.
When warmer weather arrives they have to waste precious time growing new leaves,
which reduces their summer to the minimum.
And that without counting the herbivores or the most feared enemy of all,
the leaf-eating caterpillars.
Hidden by the leaf itself, the tiny caterpillars feed on the internal tissue,
robbing the plant of its food factories, the photosynthetic cells.
With luck, the birch will lose only part of its foliage,
but if the attack is widespread it will die.
The good weather does not last long enough to produce new leaves to replace the damaged ones.
The same climatic conditions that give the conifers a considerable advantage over the deciduous trees
are also a determining factor in Alaska’s animal life
Many species, such as this bald eagle, have given birth to their young during the spring
and have to make sure they complete their development before the winter freeze returns.
To achieve this in so little time, the fauna needs a source of food the land is simply unable to give them.
But what Alaska doesn’t have it receives every year, just at the right time, from the sea.
As the summer advances, the grizzly bears leave the pasture
to visit the shores where this manna from heaven is about to arrive.
With all the calm in the world they walk along the river bank, examining it for food.
But this year, the gift from the sea is a little late in coming.
For the time being the only food around is algae and the odd dead fish.
Nothing vaguely interesting for their empty stomachs.
After sniffing around in the sand for something to eat,
the male understands it’s still early.
It might be a long wait,
so the best thing you can do is make yourself comfortable and dig yourself a good seat in the soft sand.
And now all that’s required is a little patience.
He was the first to arrive, but he’s not the only that comes to the coast.
Soon, he will be joined by another adult male with similar intentions,
and the disputes will begin to determine who gets the best spot along the shore.
The loser doesn’t have to move far.
Just a few metres away, he goes back to padding around in search of food.
It won’t be long before these two are accompanied by other bears who,
like them, have abandoned the grasslands, and now impatiently examine the water.
All of them are waiting for the salmon to arrive, their only hope in this cold, hostile land.
Each year thousands of salmon return to the rivers where they were born,
providing the local wildlife with the food they need to build up the reserves necessary
to survive the long, harsh winter.
They are manna from the sea, the reserves of protein and fat everyone is waiting for.
The salmon, quite simply, are life.
The role of the salmon is so important that even those species that don’t eat them are affected by the phenomenon.
These are sea otters, one of the few sea mammals that remain along the coast of Alaska all year round.
They are relatives of the river otter, but unlike them, the sea otters spend 90% of their lives in the water.
There, they eat, sleep, reproduce, and even give birth to their young.
The air trapped in their fur helps them to float,
but it also provides insulation against the cold, essential this far north.
Thanks to this, they can float on their backs,
their favourite posture, while they eat, sleep or simply play.
They have been a protected species for many years,
but still their numbers are now declining, due in part to the salmon.
Salmon are not the basic diet of the otters,
but they do attract the seals and sea lions, which come to Alaska every year.
And they, in turn are the favourite food of the largest predator in the ocean: the orca.
So, when salmon are scarce, the seals and sea lions have fewer young,
and when there are not many seals, sea lions and salmon around,
the orcas have to find an alternative source of food:
the otters.
The habitats of Alaska are both complex and fragile,
the result of the extreme conditions and thousands of years of evolution.
And any change, however small it may appear, can cause irreparable damage.
This delay in the arrival of the salmon can, itself, bring severe consequences.
It’s now the end of June, the salmon have still not arrived, and many animals are starting to get impatient.
Day after day they enter the estuaries of the rivers in the hope of seeing the tireless travellers.
And day after day they return to their rocks empty-handed.
Alongside them, on a tiny nearby island, the colony of puffins seems much calmer.
They too have specialised in fishing,
but their prey is much smaller than the salmon.
For them, the herring are their own particular feast
and this year fishing will be plentiful.
While the puffins are hard at work fishing,
on the neighbouring island the seals and sea lions continue their wait.
Both species arrived at the start of the summer in order to reproduce.
They came with plenty of fat reserves, because the males don’t eat during the breeding season
and the females have to breastfeed their young, which is an additional drain on their resources.
For them, the arrival of the salmon means an incredible source of energy just at the time they most need it.
The low temperature of the water means they need a layer of fat to protect them from the cold.
But, if food is scarce, the sea lions, like the seals,
will be forced to stop breastfeeding their young and return to their winter habitats.
The pups acquire this layer of fat during lactation,
so if their mothers have to return early they will not be ready to face the journey and will die.
This problem has already arisen in Alaska, and has forced the law courts to place a ban on trawl net fishing in the area
in order to save these colonies of marine mammals.
At last, there is a sign from the sea: orcas.
For once, their worst enemies are a reason to rejoice, as they come in pursuit of the salmon.
Still, it would be a good idea to wait a little longer before diving into the banquet.
The orcas are still in the vicinity
and if they spot the sea lions they might just decide it’s time to change the menu and try a little meat instead of fish.
After several years out in the ocean, the five species of salmon that live in the rivers of Alaska return home.
Millions of them approach the coast, heading for the same watercourse in which they were born,
in order to carry out their final mission to perpetuate the species.
The seals watch the orcas move off while the salmon begin their journey upriver.
The first ones are the most fortunate
they have a little time while the seals make sure there is no danger before diving into the water.
The salmon hunting season has begun.
The passage is very narrow, so it’s very easy for the seals.
All they have to do is wait near the entrance for lunch to arrive.
For the salmon their own personal Calvary has just begun..
The water is teeming with fish, and the predators hardly need make an effort.
But it is precisely their sheer numbers that enable the salmon to survive
for every one caught, hundreds of others manage to slip past and into the river.
Finally, after the terror, the first rest.
Protected by the narrowness of the entrance, the salmon remain at the river mouth while they adapt to this new medium.
In a few days, they will make the transition from salt water to fresh water,
and in order to be able to tolerate this change, which would kill any other fish,
their bodies have to undergo profound physiological transformations.
Their nutritious bodies are also eagerly awaited inland,
and when they arrive thousands of birds gather at the river mouths.
The salmon have finally reached the land they originally came from,
but their odyssey has just begun.
Now, they have to face seagulls, eagles, otters, and above all the great predator of Alaska,
the largest land carnivore in the world
the grizzly
Hundreds of bears will take up their places along the river banks,
eagerly awaiting the nutritious salmon.
For weeks, they have been feeding on grasses and berries, waiting for them to arrive.
The time of abundance has finally arrived and they will be sure to make the most of it.
The first days are the most intense.
The fishing territories are not yet established and everyone wants the best place.
Hunger and strength will decide who gets first choice.
In just a few days the rivers are full of salmon and hungry bears in search of food.
The large males have taken up the best positions, but the young ones are not so fortunate,
and a group of them decides to try its luck in a nearby stream.
It would seem to be the ideal place, and there’s no competition.
But there is one problem
there are no salmon in the water.
They appear to have chosen the wrong stream.
Sure enough, there are no salmon.
Each individual salmon returns to the same river in which it was born,
and the proximity of two streams doesn’t mean there will be salmon in both of them.
Until they arrive, the young bears will have to feed on crustaceans,
larvae or other small animals hiding among the rocks on the bed of the stream.
While the young bears continue to search for food,
three new hungry mouths arrive at the nearby river
a mother, accompanied by her two cubs.
The bear cubs don’t seem to be very interested in fishing.
They’ve never known hard times.
They’ve spent the entire winter feeding on their mother’s milk and their stomachs have never experienced hunger.
The mother, in contrast, has spent months feeding her young and needs to regain her strength for the coming winter.
With so much available food, the bears become less aggressive,
but an adult male is always dangerous.
Especially when there are cubs around.
The mother has smelt him and immediately goes on the alert.
The stranger is heading directly towards them, so the female decides to move off,
and when the male makes a sharp movement she flees with her offspring.
They will have to find a quieter river.
The flow of salmon is influenced by the tides.
At low tide, the current becomes stronger at the river mouth and this, combined with the reduced depth,
means it is not the best time to enter the water.
There are fewer salmon, and the predators take advantage to snooze or play on the beach revealed by the outgoing tide.
Six hours later the process is reversed,
and the sea returns to reclaim the land.
With the conditions in their favour, the indefatigable travellers again set off on their journey home.
A long time has passed since they descended these same waters on their way to the ocean.
Today, they are finally returning to their origins, to once again complete the cycle of life.
Thanks to their chemical receptors, the equivalent of the sense of smell in humans,
while still out at sea they detected the waters of their own rivers,
much like people differentiate one perfume from another.
And, guided by this, thousands of salmon dispersed across the Pacific Ocean
again gather at the same place they left years ago,
the river where they first came into the world.
Their bodies have now made the necessary changes.
Now, they can live in fresh water and are ready to face the next test,
the ascent up the river.
The jaws of the males have grown longer and have developed sharp, ferocious teeth
which they will use to fight for the females.
In some species, they have also acquired a characteristic hump.
But the most important change is that in their gonads, their sexual glands.
They have grown so much that they press against the stomach wall and prevent them from eating.
They will have to conquer the rapids, leap up waterfalls and escape from their predators without eating a single thing.
In the river they will have virtually no rest.
Even along the calmest stretches the current drags back any who do not struggle against it, so constant effort is required.
With no possibility of feeding, every lost minute reduces their precious reserves a little more.
And so the journey upriver becomes a race against time.
Along the river the salmon will establish their spawning grounds.
Some of them will spawn near the river mouth,
but others will have to travel hundreds of kilometres against strong currents
before they reach their destination.
And throughout the journey there will be predators trying to prevent them from ever reaching their goal.
The salmon are Alaska’s particular staff of life, on which all other wildlife, directly or indirectly, depends.
Marine mammals, birds and land predators
rely on this torrent of proteins and carbohydrates which every year sweeps across the land.
Their enormous reserves, accumulated in order to survive for weeks without eating,
will pass directly to the bodies of their assassins.
Their only hope lies in sheer numbers.
While the predator is occupied with one victim,
others are able to escape and continue on their way.
This incredible nutrition explains why the bears here are the largest in the world.
Even within Alaska, those bears that live in the interior of the state and don’t have access to this manna are much smaller.
Not every attempt is successful.
But at this time of year it’s no problem if a salmon manages to escape.
After the first desperate days, and with their stomachs now full,
the bears have become much more choosy, and carefully select their prey.
The females, for example, are full of tasty eggs, and a real delicacy.
As the days advance, they reject more and more potential prey
and will accept only the most exquisite morsels offered by the river.
No one is more grateful for this attitude than the seagulls.
Their food is served up on a plate, without them having to make the slightest effort.
The number of dead bodies scattered along the river bank keeps on mounting,
but the bears, seemingly oblivious, continue the massacre.
As long as there are salmon in the river, they will not move far from the banks,
and at each high tide they again come down to fish.
Along the upper reaches, the shallower waters make fishing easier,
but the best places are those close to the river mouth.
Here, the salmon arrive in their prime, their bodies full of nutritious fat.
The bears know this, and so they concentrate downstream.
The upper reaches are left for the younger ones, who can’t compete against the adults.
On occasions, a brave young bear decides to try his luck alongside the adults
but here each one has his own territory and anyone who tries to invade it is quickly repelled.
It doesn’t make much sense to fight with so much food around,
and the intruder does not put up much resistance.
But he’s not resigned to leaving empty-handed.
When no one is looking, he grabs a fish that has been thrown aside,
and finally is able to enjoy a fat, juicy salmon.
Though the bears continue to feed on the salmon, at this time of summer, fishing has become almost a game
and they don’t even eat the majority of those they catch.
The salmon that have been discarded then have a second chance,
if they can manage to get back to the water.
When he is almost there, the predator stops him.
After mutilating the salmon, he lets it go and sets off in search of another victim,
who will probably receive the same treatment.
The wounded salmon will have virtually no chance of fulfilling their mission of procreating.
The majority flap around in the river, exhausting what little strength they have left,
in a vain attempt to reach their goal.
And within days they will die at the hands of another bear or some other predator that crosses their path.
A few weeks after they arrived, the rivers are like the scene of some terrible battle.
Along the riverbanks float hundreds of dying salmon,
and the bodies of those who were unable to survive this demanding test.
he bears kill thousands of the incoming salmon.
And many of them are simply discarded, without even taking a bite out of them.
It would appear to be a senseless massacre.
But in Alaska nothing goes to waste.
Thousands of smaller predators and scavengers depend on the bears in order to be able to get at this source of energy
brought by the sea every year.
The salmon also benefit from this natural selection.
The fact this test is so demanding means only the fittest will make it to the end.
Moreover, the number of salmon that come to these coasts every year is such that,
if they all reached their final destination, the rivers would be saturated.
The last to arrive destroy eggs previously laid by others, and prepare their own nests right there.
The population needs to be controlled, and that is precisely the role the predators perform .
Slowly, the travellers continue on their way upriver.
They have left behind the majority of their enemies.
Now, they are not constantly under attack from the bears,
but the current becomes stronger and stronger, and they are increasingly weak.
Any calm stretch comes as a relief to their tired bodies.
They have been days without eating, struggling against the current.
Now that they are weak, the seagulls become more daring, and mercilessly attack them.
But they don’t defend themselves, all their energy is concentrated on continuing the journey,
reaching the longed-for destination, and procreating.
The majority of the rivers of Alaska subject the salmon to one final test.
Those that don’t spawn near the river mouth, but swim inland against the current
are more than likely to face the greatest obstacle: the waterfalls.
After swimming along fast-flowing waters for days or weeks,
the salmon now have to leap up falls which in some cases can be three metres high.
Very few manage it.
Exhausted by the effort, the majority are barely able to jump half the required height.
But if they don’t manage it, they will die in the attempt.
Little by little, new arrivals reach the bottom of the waterfall,
and soon it is full of salmon trying to make the tremendous leap
Their parents managed it the year before, so it is an obstacle that can be overcome.
The further inland, the more exhausted the salmon will be,
but Mother Nature compensates for this.
Those salmon that spawn along the upper reaches arrive at the coast with more fat,
and so more reserves, than those that remain at the river mouths.
Thanks to this, they will still have the strength to once again overcome the harsh trials to which Alaska faces them with.
Finally, after many hardships, the salmon make it to their respective spawning grounds.
For some, however, it is too late.
The constant effort has exhausted their strength and they have died just as success was within their grasp.
Their companions are not in a much better state,
but hey still have a mission to fulfil, and time is running out.
After choosing a suitable place, the salmon prepare their nests.
This consists of a small hollow which the female digs with strong movements of her tail.
Behind her, a male has just chosen her as his mate,
and is anxiously waiting for her to deposit the eggs, so he can fertilise them.
There are constant challenges from competitors, and every few seconds the male has to fight them off.
Meanwhile, the female has to contend with others trying to lay claim to her nest.
Each member of the couple sees off those of its same sex.
Funguses already cover their emaciated bodies, like a warning of approaching death.
Their time is coming to an end.
When the nest is ready, the female deposits over four thousand eggs in the river bed.
As she does so, the male follows behind and, with compulsive movements, covers them with semen.
It’s all over.
Thousands of miles and innumerable obstacles in order to reach this point.
And once they have achieved their objective,
the salmon die.
Yes, I’m going to die, but I’m one of the lucky ones.
I fulfilled my dream and the river bed is already pulsing with the life of new salmon
who will carry my blood.
And they too, my children, will one day seek their destiny.
And that day we, the salmon, will again sacrifice our lives for this land.
The land of our ancestors.
The land in which the giant bears live.