Bears on Top of the World Natural World

The Arctic - an icy ocean on the top of the world.

Polar bears' lives are getting harder.

The ice cap is shrinking.

But that's not the whole story.

Birds and animals are heading north to take advantage of this warming world.

Another bear is there, too - the grizzly.

On the same shores,

there are families from the two different worlds.

How will bears, brown and white, rear their cubs in a changing Arctic?

The ice of the Arctic Ocean is skirted by tundra.

There are a few towns,

old hunting outposts or new oil installations.

But man's main impact is on the climate.

It's autumn. The cold has come late this year.

After a good summer feeding,

a pregnant grizzly heads for her den.

There's a tunnel leading to a chamber dug in the frozen earth.

She'll live on her fat reserves and won't re-emerge until spring.

She'll have her cubs around Christmas - the solstice,

winter's low point.

BEAR SNORES

Grizzlies and polar bears share this coast,

but with opposite perspectives.

One is at the start of the sea.

The other is at the end of the land.

Only pregnant polar bears stay on land.

They find a place to settle and let the snow cover them.

As soon as the sea freezes, the rest of the polar bears set off.

Hibernation's out of the question. This is the hunting season.

For the males and mothers with yearlings,

darkness and blizzards are everyday life.

The cubs of both bears are born in December.

Polar bear cubs are tiny compared to their mother.

She's the largest of all the bears.

But her cubs are no bigger than a guinea pig.

Both polar bears and grizzlies can have up to four cubs at a time.

But twins are more normal.

Polar bear mothers are thinner than they used to be,

and cubs are less likely to survive.

One of these cubs has a very short life.

The surviving twin now has sole access

to the richest milk in the whole bear family.

Scattered in the ice are breathing holes.

Polar bears stand motionless for days sometimes

waiting for a seal to pop up.

Underneath, in a cathedral of ice, seals are wary.

ICE CREAKS

Nothing else could muster the patience or tolerate the cold.

It was the cold, in fact, that created polar bears.

They were born

out of climate change.

A few hundred thousand years ago, this shore was a forest.

It wasn't so long ago that there weren't any polar bears.

Only brown bears, like grizzlies.

Bears were the most successful of the hunters,

mainly because they weren't just hunters.

Bears can run and hunt. But like us, they can eat what they find -

delicate morsels of seafood, or roots and berries, or insects,

or anything to be scavenged, like a washed-up whale.

To help find hidden food, a nose.

Bears have a better sense of smell even than a bloodhound.

It's the most sensitive nose in the world.

They became clever and powerful,

probably the largest predators since the dinosaurs.

They were adaptable. They could hunt anywhere.

Even underwater.

Then the climate changed.

The Ice Ages began and the trees disappeared.

The landscape went from green to brown to white.

As the cold drove other life south, some bears stayed put.

Another world had formed around them

and they found they could adapt to it.

These bears looked to the north,

where the frozen sea stretched out like newly-created land.

Out on the sea were big, blubbery prey fit for a bear.

Seals hunted fish under the ice and emerged to breathe and rest.

These ice grizzlies changed.

They blended in. They got bigger. They ate only meat.

They became polar bears.

Polar bears took to the cold. They gave up hibernating.

They turned the seasons upside down and hunted all winter.

Problem was, the seals got better at escaping.

Bears are great opportunists and they'll have a go at almost anything.

This one has found some beluga whales.

This one's trying to bring down a walrus,

an animal four times his size.

But bearded and ringed seals alone remained 95% of a polar bear's diet.

This is an animal of seals and ice.

10,000 years ago, the Ice Age ended,

but enough of the ice caps stayed frozen

for polar bears to keep their Ice Age lives.

As the Arctic now lurches into an unnatural and untimely meltdown,

what will the polar bear mother face

as she emerges into the new March sun?

The mother hasn't eaten properly for nine months

and the cub has been draining the last of her reserves.

She has to check for danger.

He may be the father. But that means nothing to polar bears.

Or their cubs.

Bears occasionally eat each other if they're hungry enough.

A cub's life is fragile.

Each year, fewer than 5,000 polar bear cubs emerge

and most die in their first year.

It takes a few weeks of short practice walks

and then the two of them are ready to head for the frozen ocean

and the seals.

Survival depends on the springtime ice, having good hunting there

and avoiding other polar bears.

Some polar seals give birth straight under the ice.

Bearded and ringed seal pups need the solid ice to breathe,

suckle and sleep.

They can swim, but they would soon die

if they had to stay in the water.

One of the tricks seals use to outsmart polar bears

is to fashion dens for the pups that can be reached only from underwater.

Polar bears, in turn, have learned to recognise a very faint pup smell

seeping up through the ice.

The mother's nose leads her to the den,

and all she needs to do is break through.

All the pup or mother seal needs to do

is dive and swim to one of its other dens.

Not all is lost.

The cub is learning something about hunting.

But the mother is racing the spring, the growing seal pups and the melting ice.

April, and the pole tilts a little towards the sun.

Ice reflects sunlight away.

Land, though, absorbs the warmth.

Along the coast are grizzlies.

The grizzly mother and her two cubs are a month behind their white cousins.

These grizzlies are called barren-ground brown bears.

They're descended from the ancient brown bears that stayed on land.

They're not winter animals.

There's no point in leaving the den until the spring thaw is under way.

Spring starts earlier.

The world's changing, and the cubs should feel the benefit.

These snow geese are better off.

Millions of them fly up from California to feed on the tundra.

Most years, they're flying earlier and in greater numbers.

Other birds, bald eagles, fight over fish taken from rivers further north.

She's produced milk for them for three months inside the den

and kept out the cold.

Now it's warmer outside than inside.

Anyway, the grizzly cubs need the freedom to move,

to run around and explore.

It's the first few weeks of learning about their world.

When they're strong enough, she takes them a little further afield.

The snow and ice melt,

and little streams become raging rapids to a cub.

Grizzlies have claws like pitchforks

and the same subtle sense of smell that helps polar bears find seals.

Through earth and ice,

a grizzly can sniff out insects, plant bulbs, pine cones -

anything a grizzly can eat, which is almost anything.

The grizzly's digging creates insect and rodent refugees,

which a coyote is happy to hang around for.

COYOTE HOWLS

For days at a time, he'll follow the bear family,

profiting from the grizzly's nose and claws.

It's as though the family has acquired a friend.

The coyote's certainly no threat to the cubs, but tree-climbing practice

is a good idea anyway, in case of wolves or other grizzlies.

What a mother can't show, they learn by trial...

and error.

There's a lot to learn.

A mother bear teaches by example,

and one of the hardest lessons is catching ground squirrels.

The rodents are maddeningly quick

and have the ability to vanish from one place and pop up in another.

If you ever see a grizzly dancing on a hillside,

they're probably chasing ground squirrels.

Finally the mother does what her mother probably taught her to do,

corner the squirrel in its burrow and quickly dig it out.

It's a lot of effort for a mouthful of fur and bones,

but at least the cubs are copying her,

chasing their own imaginary ground squirrels.

The pole tilts further towards the sun.

The days are longer, and it should be peak hunting for polar bears.

Seal numbers may be down this year, or they may have moved,

but pups have been hard to find.

Other bears can lead the family to seals.

The mother has no instinct toward sociability.

Those bears would kill the cub before they'd share.

Big brothers don't even share with each other if they can help it.

In the cold, clear air of the Arctic spring, the mother bear can smell

everything that's happening, even over the horizon.

The mother is focused on one smell.

A few seal pups are hiding around here.

Gone.

It's important to find seals and the cub is keen to help.

She breaks into another den and watches another seal swim away.

Her mother taught her where to find seals a generation ago,

but they are not there any more.

It can be frustrating.

At least the cub won't go hungry.

The mother will provide milk for another year if she can.

She should average catching a seal about once every five days.

A seal is a big meal,

much more than a grizzly can get,

grubbing for roots and dancing around with ground squirrels.

It's time to move on,

and find another colony less wary of polar bears.

They walk past Arctic islands and icy coasts

in the constant search for seals.

He struggles to keep up.

A mother has to wait if a cub gets a little footsore.

Throughout May, the days get longer,

and by June, the sun never completely sets.

The ice breaks up around the Arctic Ocean and Hudson Bay.

The seals have finished pupping.

It's late June, and the cub would dwarf a grizzly of the same age.

They've had three months of hunting and now it's over.

There's never been so much ice-free water at this time of year.

In the endless summer days

birds such as guillemots fly in to feed and court.

Polar bears aren't the only ones affected by the rising temperatures.

The winners in the Arctic now, generally, are the land animals.

Where there was white, there's green.

Grass, bushes, even trees are spreading north.

With summer grass come grazers - caribou, also known as reindeer.

They should be benefiting.

But caribou are creatures of routine and confused by change.

With time, they'll adapt.

Where their numbers increase, wolves and bears should profit, too.

Caribou know how to keep their distance.

It's easier to go back to digging out ground squirrels.

The grazers everywhere are feeding on new growth.

And if you can't eat them, join them!

Bears can eat grass.

It's not very digestible.

The cubs try it, but they need protein.

Down by the water are limpets and barnacles.

This bear's mother showed her and now she's showing her cubs.

They're like little family secrets.

There are opportunities when the caribou are at a disadvantage,

wading through a freezing river, for example.

The cubs aren't quite ready for this lesson.

She'll save the river crossing for next year.

The cubs, and the caribou, are safe.

It's back to the barnacles.

Beyond the shore,

many polar bears are far north, deeper into the Arctic Ocean.

The ice cap has retreated away from the land.

In midsummer, the distance between the ice and the shore of northern Canada used be about 50 miles.

Now it's over 200 miles.

Climate change has been happening for 20 years,

and it's now a different world.

Some animals don't seem to be bothered.

Narwhals prefer the broken ice.

And guillemots can only live in open water.

It's hard for polar bears to catch anything from a swimming start.

Seals in the water are much too fast,

yet frustratingly close.

Guillemots can fly after fish, but there's a new problem.

Fishing boats can get in now too, and have stolen the birds' food.

Commercial trawlers affect whales, such as belugas, who also eat fish.

On the other hand,

there's less danger from polar bears at their breathing holes.

Midsummer has passed, and polar bears have to make a choice.

The cub needs a solid surface for sleeping and suckling.

Should they head north to the permanent ice or swim south to land?

Many biologists believe they should be classed as marine mammals, like seals.

Polar bears can close their nostrils and have webbed paws.

Even cubs are at home in the water.

But how could they know how far it is this year to solid ice, or land?

Most head south to land.

The marathon swims are testing polar bears to the limit.

They face strong currents.

A bad storm, and they'll both drown.

Aerial surveys find floating white corpses.

Cubs wash up on the Arctic shore, dead.

Those that make it are now safe, at least from drowning.

They're exhausted, and they won't find much food here.

In the past, they wouldn't have needed food.

It's summer, the polar bears' off-season,

and they'd do a summer version of hibernation,

sleeping, and living off their fat.

Sleeping hidden away was safer, too.

Most of the Arctic coast is grizzly country.

Parts of Hudson Bay and Greenland are the same latitude as Scotland,

but bleaker.

Here, hunger will drive them inland,

and be more like grizzlies in summer, awake and trying to find food.

Trouble is, they appear to have forgotten how to be like grizzlies.

She may know kelp is edible, but she overlooks the shellfish.

It may help that food on the tundra is increasing as the climate warms,

but will she find it?

The Arctic in summer has always been rich,

thanks largely to continuous daylight.

Now, though, the permafrost is melting and the land is even richer.

But the melting releases millions of tons of carbon dioxide,

so the planet gets even warmer,

and the ice shrinks.

While polar bears need to branch out,

grizzlies do what they've always done,

following traditions passed down the generations.

At the end of a long hike

is a salmon river.

It's July and the fishing season.

Many bears have arrived early to stake a claim.

Heading upstream to breed are the salmon.

It's a dangerous place for a mother to bring her cubs.

It's packed with hungry and frustrated bears.

She needs to find a fishing spot,

but even the poorer places are taken by the younger bears.

The cubs are bigger by now and need a lot of milk.

If she has to fight for a fishing spot, she'll fight.

The cubs are confused and can't keep up.

Bigger grizzlies arrive.

Claws rip flesh. A mother couldn't risk injuries like these.

So when life along the river gets too violent,

she leads her cubs down the beach,

and gives them a lesson in the peaceful and delicate art of digging clams.

Clams are still good food,

and finding and opening them takes just as much skill and education.

The intelligence of bears has been a revelation to scientists.

Their memory, knowing when, where and how to find food,

is very impressive.

By August, the fish have reached the high lakes at the top of the rivers.

They've spawned and are slowly dying and sinking.

Bears can swim well, of course,

but the bonanza of food lying on the bottom rotting seems out of reach.

That is, if you assume grizzly bears don't dive.

From the surface, it's an impressive lesson for the cubs.

Diving for salmon continues for a week or two,

until the fish get too rotten.

By now, it's early September,

the last days of summer.

Polar bears are wandering miles inland in their search for food.

They haven't found much.

They missed the salmon season because they didn't know about it.

It's a pity.

The mother would have been a match for any of the grizzlies.

Polar bears in the summer are spread out over impossibly vast distances.

It's hard for us to keep track of what they're doing,

but it's certain many are travelling further and looking for food.

It's much easier for grizzlies

with their well-worn paths and their seasonal food.

August was salmon, September is berries.

Right down to the Arctic Ocean is a carpet of bushes,

bilberries, bog cranberries,

bunchberries, crowberries, loganberries, cloudberries.

A grizzly can eat 14,000 a day.

Polar bears eat berries, too,

and it's at berrying time that they're most likely to meet.

It was thought that the two bears hardly ever saw each other,

much less had any closer contact.

It's certainly true that mother bears would avoid each other.

As for the possibility of a male of one species

and a female of the other mating in the wild -

no, scientists thought it unlikely.

Bears are wary of each other.

There's no room for a mistake like that in the wild.

There are some very pale grizzlies,

but that's always been considered a normal colour variation.

Then, in 2006, a hunter named James Martell

shot a white bear with brown markings.

It seemed worth checking its DNA.

Its mother was a polar bear, its dad a grizzly.

It has a name now, a Pizzly.

Or if you prefer, a Growler.

They can breed successfully with either grizzlies or polar bears.

But cubs learn only from their mothers.

There's little scope for a halfway bear.

The polar bear nose leads them both into trouble.

As far as she's concerned

she's found one of the best feeding spots since coming ashore.

At night, people burn their rubbish,

partly in an effort to keep the bears away.

The bears come anyway.

From hunting in a clean, frozen world,

they now scavenge in a hellish inferno of our own making.

Polar bears don't stop at night raids on rubbish dumps.

People in Arctic towns and oil installations

worry that bears are targeting houses and even people.

The bigger towns put out bear traps.

A bear goes for the meat, and ends up...

in bear jail.

It's kept in custody until the sea freezes again.

For a mother and cub in this alien and changing world,

staying out of trouble is the hard part of finding food.

The grizzly family is coming to the end of a good summer.

They're full and sleepy.

The cubs have done well on their Arctic education

and try different foods on their own now.

She'll slowly cut down their milk supply.

These northerly grizzlies could benefit from climate change,

with vast new territories opening up.

But what opens up for bears also opens up for us,

with our hunger for oil and increasing need for farmland.

The land is being fenced

and these "dangerous" bears are being driven out and killed.

If we want the land,

they are as helpless and vulnerable as polar bears.

By mid-September, the polar bears have made their way to the shore.

They're waiting for the sea to freeze.

Soon the first autumn snows make the landscape at least look right for polar bears.

They gather at the places where the sea freezes first.

The young males pass the time play-fighting.

They're working out who's the best fighter.

Later, on the ice, defending food or females,

it helps to know when to pick your fights.

The freshwater lakes freeze first.

The bears carefully test the ice.

Long before the sea freezes, the grizzly family head home.

In the past five months, the cubs have learnt grizzly traditions from their mother.

It now guides them back to their den.

Only pregnant polar bears don't wait on the shore.

They lie down in the hills and let the snow cover them.

In the past, when she emerged with cubs in spring, there would have been ice and seals,

but nothing seems certain any more.

The hills are soon covered by a blanket of snow

with the bears lying snugly under it.

Sleep is eking out calories collected from seals and salmon and berries and rubbish.

The polar bears on the shore wait.

It may be January before the sea freezes.

For a cub that has made it through so much,

it may be too late.

A mother who's lost her cub has no choice but to start again.

Since the winter and the ice have both been shrinking, fewer cubs are surviving.

But some are.

He has survived,

perhaps in part because he is a lone cub.

Eventually, the sea freezes.

The polar bears' world reappears in midwinter...

..and the family head out to hunt seals.

His story has really only just begun.

And what happens next?

Who knows?

Subtitles by Red Bee Media Ltd

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