Growing Up Animal

Canada's Great Bear Rainforest.

Twenty-five thousand square miles of wilderness.

Home to a young female

grizzly bear called Fern.

At five years old, she can take care of herself.

But everything is about to change.

Fern's going to become a mom for the very first time.

Growing inside her, not one, but two baby bears...

Lulu...

and Joey.

Witness the wonder, as these cubs explore their new world.

Taking their first steps

towards independence.

But for this new mom, the pace of life is fast.

Fern only has six months

to prepare Lulu and Joey before winter returns.

The pressure is on...

...as they take on the challenge of Growing Up Animal.

Fern's having a tough day.

She's been fishing for salmon since dawn.

And only had a couple of bites.

While she might be fully grown,

she's still a little inexperienced.

Fern only left her mom two summers ago.

But she knows

she's gotta make the most of this salmon run.

Winter is in eight weeks.

Food will be hard to come by,

and she'll need to hibernate for six months.

With just a few hours of daylight left...

Fern won't give up easily.

She may be young...

but she's a fighter.

This year for the first time,

it's not just her own survival at stake.

Inside Fern, is the promise of new life.

Not one, but two precious spheres of cells called blastocysts.

The beginnings of two baby bears.

But their development is on hold.

A miraculous evolutionary trick,

to ensure a bear's young, aren't born at the start of winter.

They won't progress further, and implant in her womb

until she's eaten enough fat from salmon to sustain all three of them.

To do that, Fern must find just the right spot to fish.

But she's not the only hungry bear on this river.

Powerful males, much larger than her dominate areas

where it's easiest to catch salmon.

Rain or shine, there's one who rules this stretch of river.

Rocky.

With a swipe from his three-inch claws...

the salmon don't stand a chance.

His appetite is massive.

He devours the equivalent of a small deer every day.

Fern knows this guy well.

Four months ago, in spring, they mated.

But she knows that won't win her any favors.

Rocky will never share his stretch on the river.

Not everyone wants to be a hands-on dad.

She's gonna have to do this all on her own.

Time to move on where there's less competition.

Another female has had the same idea.

Blondie's an experienced mom, with three cubs.

Her boys are a year old, and can now catch their own dinner.

Well, most of the time.

This looks like a momma Fern could learn from.

If she's here, then it must be a good place to fish.

Fern settles on a spot. Now, the game begins.

She just needs one fish to pass within reach.

So she can pluck it from the water.

First catch of the day.

Each one is packed with five thousand calories,

double our daily intake.

And for Fern...

every mouthful is crucial.

The amount she eats will determine whether the blastocysts implant...

and Fern's journey to motherhood can begin.

As the salmon run finishes, the rivers calm.

The forests grow quieter...

...and fall comes to an end.

Snowfall rarely takes hold here in the Great Bear Rainforest...

but it will transform the mountains above.

It’s time Fern took the arduous climb

up into these peaks to make her den.

She’s bulked up to the max

and done all she can to trigger the start of her pregnancy.

Only when she wakes from hibernation in six months' time,

will she discover if she has done enough to become a grizzly mom.

By December, Fern's mountain retreat is gripped by winter.

Up here, two thousand feet above sea level,

temperatures can drop below zero Fahrenheit.

Quiet and isolated. It's perfect for Fern's den.

Fern is ten weeks into her six-month hibernation.

She's in and out of consciousness, living her life in slow motion.

Her metabolism has dropped by half.

And her heart rate has plummeted from 70 beats per minute,

to just ten.

Fern is surviving only on stored body fats.

She may appear completely inactive,

but inside her, something miraculous is happening.

All that fishing means...

...not one, but two cubs are successfully growing.

Lulu and Joey.

At four weeks into their eight-week journey,

each is just the size of an apple.

Their umbilical cords fuel them with protein and carbohydrates.

They're growing quickly, and could quadruple in size

over the next month.

Their shoulders and forearms are building muscle.

Claws have broken through.

They'll need those to crawl up Fern's sleeping chest

to nurse when they're born.

Outside Fern's den, winter grows even colder.

There's no escape from the harsh conditions.

Winds become gale force.

And the mercury drops to minus eight Fahrenheit.

The bitter cold strips the heat from every animal it touches.

Fern is protected from it and sleeps on in comfort.

Her thick winter coat traps air. Providing insulation...

and saving as much energy as possible for her rapidly growing cubs.

Lulu and Joey are doing really well.

They've made it to six weeks.

And a delicate layer of fur has started to grow.

Almost fully formed, they can now survive if born early.

Their most vital asset is developing...

their incredible sense of smell.

Two thousand times greater than ours.

The cubs will use it to find food,

communicate, and learn about their new world.

Glands have even developed in their feet that leave their scent with every step.

And their claws are almost primed and ready for action.

Equipped with these essential tools, the cubs simply increase in size

until the day they're born.

By February, winter reaches its peak.

This far north, even waterfalls are frozen in time.

Fern sleeps through it all.

But deep under the snow,

something truly magical has happened.

Lulu and Joey have arrived.

Each the size of a newborn puppy, weighing around one pound.

Completely blind and totally vulnerable.

Safe with their mom at last.

Soaking up her scent and mouthfuls of milk.

Fern's milk contains almost three times the calories of ours.

Packed with antibodies, it builds up their immune systems.

Fern can sense them as Lulu and Joey feed,

grow, and bond with their mom.

Safe and snug for the next two months, in their den sanctuary.

Throughout winter, these slopes have given the family isolation and peace.

But by April, temperatures are rising...

and the mountains begin to stir.

The hard-packed snowdrifts start to weaken.

An avalanche.

Ten thousand tons of snow,

traveling up to 100 miles per hour.

It pays to choose your den site carefully in these mountains.

Beneath the snow...

the family is safe.

Fern is finally awake...

...and meets her babies for the very first time.

It's got to be the best surprise in the world.

Lulu and Joey have been piling on the pounds.

They are now 20 times bigger than when they were born,

and a whole lot hungrier.

Fern hasn't eaten in over six months.

So, it's time this new mom showed Lulu and Joey

the world beyond their den.

Outside...

winter is losing its grip on the mountains.

And the cubs get their first glimpse of daylight.

It's a lot to take in.

Lulu and Joey's world...

just got a whole lot bigger.

But there's no time to stop.

Fern has lost almost half her body weight.

She's gotta get her cubs down from the mountains.

A journey she can make with ease.

But now there's little legs to think of.

And the pace of life here is fast.

Fern has to set them up for survival

before winter returns in six months.

She's never done it before, and the clock is ticking.

Far below, the Great Bear Rainforest looks like a different world.

It's May.

Spring breathes new life into the inlets.

The forests are singing...

...and the meadows are in bloom.

It's taken two weeks for Fern and her cubs to get down here.

A sight for sore eyes.

After a long journey, the first thing that Fern needs is a decent meal.

On the springtime menu...

fresh greens.

Sedge.

It might seem a surprising choice for a bear,

but this type of grass is packed with protein.

Fern desperately needs to rebuild muscle and fat reserves after her pregnancy.

She's gotta eat over 60 pounds a day,

spending every hour of daylight grazing.

There never seems to be enough time,

especially with two hungry cubs.

Lulu and Joey still get all their nutrition from her.