Polar Bears

- We have a complex relationship to polar bears.

One of the most loved creatures in the world,

we see them as cute and funny,

but at the same time,

as dangerous top predators,

one of the few that might hunt us

They are the ultimate icons of polar wilderness.

And figureheads for climate change and conservation.

The lives of polar bears and nothing short of remarkable.

Winter in the Arctic.

This is a no man's land, literally.

For half the year,

this vast area is locked in ice and devoid of sunlight.

Even plants can't make it.

The temperatures plummeting to minus 40 for weeks on end,

this really is the toughest place to make a living.

But there are a few incredible creatures who not only live,

but thrive in the cold

Seals are wrapped in blubber

to buffer against the freezing water.

The incredibly hardy mammals spend almost all

of winter beneath the frozen layer of ice,

using their teeth and claws to dig breathing holes

on which they depend.

They have to come up for air every 15 minutes or so.

It's not an option for them.

Like us, they must breathe,

but this basic necessity for life can put them

in grave danger.

The seal weighs as much as an average human,

but the bear carries it off like a box of pizza.

Gulls are waiting in the wings.

They can only survive here thanks to scraps from the bear.

And they're not the only ones.

Tiny foxes often shadow the great bears.

Scavenging from the giants is one of the few things

that enable Arctic foxes to make it through winter.

Like the bears, their pale coats helps them to blend in.

The polar bears are the true kings out here,

top predators on which the entire community depends.

How does this master of the ice survive?

With its lethal temperatures and five months of darkness,

the Arctic winter tests, any forms of life,

but survival is possible thanks to just one thing, fat.

When he can, the bear eats nothing but seal blubber,

this incredible fat blankets its body,

protecting it against the elements.

It means the fortunes of bears and seals

are inextricably entwined.

The bears fatty body is double wrapped

by its famous white fur,

another layer so that the giant can maintain

an average mammalian body temperature of 37 degrees.

The same as ours,

even when the Arctic hits all time lows close to minus 70.

The male polar bears are outside

and active throughout winter.

They are the undisputed lords of the ice.

Incredibly tough animals,

but the females are even tougher.

While the males are roaming in the dark,

gorging on seal blubber,

the females are in dens in the snow.

For the entire five months of winter,

she will have no food or water.

But at Christmas time,

this one gave birth to three guinea-pig-sized babies

and has been nurturing them ever since.

The cubs were blind, toothless,

and totally dependent on her.

They're growing fast

and it's all because she's keeping them topped up

with fatty milk.

Cow's milk has just over 3% fat.

Her milk is 31%.

She rapidly loses weight herself to produce milk

For a female bear, winter is a test of endurance,

but despite the difficulties,

all her focus will be on caring for her cubs.

She's the ultimate supermum, girl power in the extreme

and the true queen of the ice.

She and her family have been entombed for months,

but outside things are slowly changing.

The icy North Pole didn't see any sunlight at all

for 11 weeks.

But for the last few weeks,

it has been based in an eerie twilight

until finally a low sun breaks on the horizon.

The first glimmer that winter is loosening its grip.

At first, the sun is only visible for a few minutes.

It barely breaks the horizon,

but each day it rises a little higher

and is seen a little longer.

Spring comes late,

but the mother bear wastes no time in greeting it.

She digs an exit

and for the first time in five months smells fresh air.

For their first three months of life,

all these cubs have known is the dark interior of the den.

For the first time,

they can feast their eyes on a bigger world.

The bright, reflective snow couldn't contrast more

with their dingy nursery.

One is a little hesitant,

but the others are keen to get out and explore.

Mum can't wait for a good stretch after being cooped up

She has a snow bath using it to clean her fur.

Polar bears spend a great deal of time cleaning

because wet and dirty fur will not keep them warm.

It's a vital task,

but it momentarily distracts her from her cubs.

The cautious little one is ready

to leave the den, but slips.

He's in a tight spot and can't grip the compacted snow.

His siblings play fighting outside don't notice at first.

Then they hear his plaintiff calls.

The others treat it like a game of hide and seek,

but the little one's getting worried.

Eventually mum notices she's one cub short and moves in

to give it a hand.

To help them move on ice,

the bears have dinner-plate-sized paws

and rubber soles for grip.

It doesn't take her long to dig him out.

Shaken up, the little male is reluctant to let go.

To calm her panicked clan down,

she offers up some warm milk.

Now with the whole family mobile,

she leads them off to explore.

She's not the only mum guiding her babies through

their first steps.

Arctic seals also give birth in early spring,

out on the ice.

Two Arctic specialist seals have the dubious honor

of being most important to polar bears as food.

Though similar in appearance,

they have very different ways of raising their young.

Both time their births for late winter,

just as the first cracks appear in the sea ice.

But when there will be ice floes long enough

for them to raise pups.

Harp seals live life in the fast lane.

Born onto the ice the pup's thick white fur protects it

against the elements.

Cute and vulnerable, the little ones need to get ready

for a life of fending for themselves.

They only have the benefit

of their mother's milk for 12 days.

Fortunately, the milk is so fatty

that they gain two and a half kilos a day,

but then less than two weeks from their birth,

their mothers head back to sea.

The pups will stay on the ice alone,

living off their fat reserves until their fluffy coats molt,

and they are ready to swim.

Six whole weeks alone.

Ring seals take a slightly different approach.

Using her claws and teeth,

the mother seal digs a nesting chamber into the ice floe.

Concealed in the icy igloo,

her pup can hide out while its mum continues to forage.

She'll suckle her little one for two months

until it's ready to leave the ice.

The pump will be super-sized,

growing four or five times in weight during

that short period.

Because the ice floes are covered in plump

and not very independent seal pups,

it's the perfect time for bears to raise their own young.

The mother bear leads her cubs out onto the sea ice

for the first time.

She picks up a seal's scent.

But there's another bear that's beaten her to it.

The young male.

Male bears are the main threat to her cubs.

They will kill Cubs to try and secure mating rights

with the mother or even, very rarely,

if they are desperate enough for food.

So the mother watches as it moves in,

targeting the seal pup.

Mother seals sees it coming and dives for cover,

But the naive pub is torn.

He's never been in the sea

and is dependent on his dry fur to keep him warm.

It's almost too late when instinct kicks in.

He's exhausted.

Running, the bears expend twice as much energy

as average for mammals.

Their temperature rises quickly

and they consume more oxygen.

Even walking uses 13 times more energy than just resting,

which is why the bears prefer to sit

and wait by a seal hole and pounce.

They spend half their lives hunting.

Only 2% are successful.

They need an absolute minimum