Original subtitles

(gentle music)

- [Narrator] Antarctica, a vast icy desert.

In terms of rainfall, it's the driest place on earth.

And yet, the Antarctic holds

more than 2/3rds of the planet's fresh water.

With plunging temperatures and powerful winds

our southernmost landmass is an unrelenting habitat.

But life persists

and thrives.

Once part of a connected southern supercontinent,

Antarctica is now isolated by a current so powerful

it creates undersea highways

back to each and every continent.

Where extraordinary lifeforms answer the call of the seasons

on icy islands and on a land frozen by time.

(soaring music)

This is the "Wildest Antarctic."

The Antarctic continent itself

holds about 29 million cubic kilometers of ice

or 90% of all ice on the planet.

Deep in the center

conditions are so extremely cold that few forms of life,

beyond the microscopic, survive.

Even on the coast seals and penguins

need to enter water to warm up.

And most flee when Antarctica

is plunged into 24 hour darkness each winter.

The sheer inhospitable nature of the continent itself

means the icy islands that surround it

play a vital role.

They are the refuges that allow polar species to survive,

places that are cold enough to support their food sources

but warm enough to nourish their young.

For some wildlife the breeding and feeding rage

extends far into the south Atlantic Ocean,

into the Subantarctic.

Antarctic and Subantarctic islands

are separated by the convergence zone.

This is an area of deep, cold upwelling water

completely encircling the continent.

It forms a temperature barrier

and since it first arose about 20 million years ago,

very few fish and smaller marine organisms pass through it.

However, many of the Antarctic's largest species,

birds, land, and sea mammals,

cross this border from season to season.

Some return to the cold continental waters with their young.

More than half the species

never set foot on the mainland itself

and make permanent homes in the scattered surrounds.

In the Antarctic zone itself

the islands are continental fragments of blasting winds

and little vegetation.

In these far flung outcrops of ice and volcanic rock

are the nurseries

for some of Antarctica's most iconic animals.

Within the Antarctic zone the South Shetland archipelago

lies about 150 kilometers north of the Antarctic Peninsula.

Made up of 11 major islands and several smaller ones

about 90% of the land is permanently glaciated.

From early April to December

the surrounding seas are also frozen over.

But as the summer melt begins and the ocean liquefies

some of the coastlines become ice free.

Barrientos Island sits in the heart of the Shetlands group.

Just 1 1/2 kilometers across

the coastline is dominated by steep cliffs,

some rising more than 70 meters from the ocean.

The cliffs graduate to beaches of black rock and sand,

testament to the area's volcanic origins,

as are the tall spires of basalt

the South Shetlands are renowned for.

Carpets of moss and lichen cover these icy islands.

Nearly 20 species are found nowhere else.

(midtempo music)

At the Barrientos spire's base

elephant seals lounge amidst gentoo penguins.

The seals could easily be mistaken for the dark,

sea weathered boulders that line these beaches.

At this time of the year

they are less active than they are in breeding season.

The elephant seals have returned to these beaches

for a second annual event

and this one requires them to conserve energy.

(elephant seals roaring)

Elephant seals are the largest of the seal species.

Males exceed weights of 4,000 kilograms.

They can't rise up on all four flippers

so must undulate their enormous bodies

to move about on land.

They spend most of their lives at sea

but in mid-March of each year

elephant seals haul ashore on islands like Barrientos

near the mainland

to islands north of Drake Passage,

such as South Georgia.

The elephant seals left these very beaches

several weeks ago.

They spent the warmer months here

in enormous, active congregations to mate,

fight,

and birth young.

(somber music)

After heading back to the ocean to feast

and recover blubber stores

depleted by their energetic summer

the seals have returned to the islands one last time

before winter sets in.

They are here to undergo a process

called a catastrophic molt.

Most animals slowly shed skin, fur, or feathers

as the top layer of cells die

and make way for the new ones growing underneath.

Catastrophic molting is a very rapid variation.

The elephant seals molt just once a year,

shedding the entire outer layer of skin in a month.

First the brown outer layer splits

and begins to come away in patches.

Underneath, a new, smooth, grayer coat is revealed.

It slowly darkens to brown again

before the seals reenter the ocean.

Elephant seals have evolved to molt

in this dramatic fashion

because they can't afford to lose their top layer

whilst in the water.

To stay in such freezing conditions for long durations

the seals restrict blood flow to the outer layers.

They then dedicate these few weeks each year

to ascend ashore

and send blood to the outer layers

to grow healthy new skin.

The islands become a final flurry of activity

before winter arrives.

The weeners of the breeding season a few months earlier

are still honing their swimming

and hunting skills in the shallows

before the winter exodus.

Females and sub-adults arrive first.

The biggest, oldest male bulls

will join the molt last.

They'll all engage in a number of techniques

to ease the itch

and protect the emerging skin from sunburn:

cooling in meltwater streams,

wallowing in pools of mud,

or creating sand baths in the dark beaches and stream banks.

The elephant seals fast the entire month they're on land.

The raw skin is too sensitive

to the ocean's cold temperatures

so they're unable to hunt for squid and fish.

At the molting month's end

the beaches will finally be emptied for winter.

Islands close to the Antarctic continent,

like Barrientos, will freeze over,

along with the top layer of salt water surrounding it.

The entire elephant seal colony will leave.

They'll spend winter at the edge of the sea ice,

usually several thousand kilometers

away from their beach colonies.

The colder months will be spent feeding

and replenishing enough blubber stores

to support them for their return

and the next year of breeding and molting to come.

These polar marine mammals and birds

choose the same sites year after year

to haul ashore for breeding and molting.

One such location a little further south,

in the Shetland Archipelago

is an unusual fusion of fire and ice.

(mystical music)

Deception Island is a horseshoe shaped structure

that sits atop one of the Antarctic's

two remaining active volcanoes.

The volcano first exploded 10,000 years ago,

spreading molten rock for kilometers.

Subglacial eruptions have occurred in the last century,

events where lava slowly rises,

melting the surrounding ice on the seafloor

and creating steam.

The volcanic ejection produce large amounts of rock,

called scoria and pumice.

On this island the unusual conditions,

extreme heat forced into extreme cold,

caused a reaction

that turned the lava rock blood red in many places.

(playful music)

For the resident chinstrap penguins

it means a telltale red stain

on the chests of those that have been on nesting duty

amid the pumice stone.

Chinstraps are the Antarctic's most prolific penguin.

And the South Shetland Archipelago

has the largest colonies inside the Antarctic zone.

Hundreds of thousands of breeding pairs

return at winter's end,

after the thick layer of sea ice around the islands

has melted.

The chinstraps first task ashore

is to find their breeding mate from the previous season.

Chinstraps are faithful to their pair bonds

most of the time.

When they see each other again each year

they perform a greeting ritual of circling and preening.

But if their partner hasn't returned

they'll find a new one.

Chinstrap layers puff out their chests,

throw their head back and loudly call,

(penguin squawking)

drawing attention to the size of their beaks.

The larger the beak,

the more effective it is as a weapon

to ward off nest intruders.

(calm music)

The rookeries on Baily Head are about two kilometers

above the pumice stone shores.

Here mating pairs incubate and raise two chicks

in nests of volcanic rocks,

collected from the banks of nearby meltwater streams.

The red pumice stains the rookeries pink,

as well as the penguin waste

which has a large amount of the pumice

ground up and digested within it.

(penguin cooing)

Chinstraps have a signature high-pitched cry

woven through their loud calls.

(penguin crying)

These penguins have a reputation

for being prone to arguments.

(penguins squawking)

Such large colonies lead to territorial spats.

This species concentrates their feeding times

around noon and midnight.

(exciting music)

Each morning the streams of meltwater

from Deception Island's glaciers

become superhighways

for penguins descending to the shoreline.

To reach the blooms of krill just offshore

they must first traverse the surf zone.

This requires the skill and judgment

of seasoned surfers.

Waves of penguins watch the sets roll in

and time their entry before the next barrage hits the shore.

The timing isn't always precise.

The art of duck diving a breaking wave

is another acquired skill.

Offshore the chinstraps

dive in and out of the water in shallow arcs

in a technique called porpoising.

It helps confuse predators like orca and leopard seals

lurking in the deeper drop offs

and helps the penguins to swim longer distances

with less energy.

They'll also use this technique

to negotiate the surf zone back onto land.

If they time it perfectly

the shore break does the work for them,

delivering the penguins right back

into the midst of beach aggregation.

(playful music)

Roughly 1,500 kilometers northeast of the South Shetlands

macaroni penguins clamor ashore another island beach.

A resident gentoo briefly tries to claim territorial rights.

(penguins squawking)

But the amassing flocks of macaronis are too numerous

and noisy.

Macaronis are one of the crested penguin species.

Named for a 19th century style

of outlandish European fashion,

these penguins are loud and bold.

As they ascend the island slopes

the engage in bill jousting with each other

and announce their presence to any other seal or bird

on the South Georgia Island shorelines.

(melodic music)

South Georgia Island's position

on the northern fringe of Drake Passage

makes it a dense landing pad for most Subantarctic species,

penguins, sea birds, and seals.

South Georgia sits in the southern Atlantic,

capturing the outflow of the Antarctic Circumpolar Current

as it passes through Drake Passage.

It's almost the same distance from the Antarctic continent

as it is from the southern tip of South America.

The vegetation on this island

shares characteristics of both continents.

South Georgia's mountain ranges

are nearly 3,000 meters in height

and permanently covered in snow and glaciers.

At the lower altitudes around the bays

giant kelp forests flourish.

The foreshore flora is considerably richer

than the icy Antarctic islands.

Slightly warmer air temperature

allows lush gardens of herbs to bloom.

These flowering herbs have evolved to take advantage

of the rare sunlight opportunities

in this perennially cloud covered region.

The macaroni penguins continue their noisy climb

to the cliffs overlooking South Georgia Island's bays.

The breeding colonies here are enormous,

over a million mated pairs.

They arrive in droves from each October

to breed in the warmer months,

often seeking out their mate from the previous season.

Single eggs are laid

and chicks are reared amongst rudimentary nests

around tussock grass.

By late November the penguins share their nurseries

with the first arrival

of the island's fur seal pups.

(sweet music)

Antarctic fur seals are generally more solitary

than their relatives in Australia and New Zealand,

apart from this time of year.

It's thought 95% of the Antarctic

and Subantarctic fur seal population

chooses this island to breed and rear young.

Here they walk amongst bleached whale bones

and the dilapidated remains of whaling stations

abandoned in the 1960s.

The fur seals too were once hunted here.

Their numbers have recovered healthily.

But it's believed some survivors

had a particular genetic trait

that is rarely seen beyond this island,

blonde fur seals.

These are seals with a condition called leucism.

It's a partial loss of skin pigmentation,

causing light colored fur or feathers.

In other parts of the world

this difference would be enough for the fur seals

to be cast out from their colony.

On South Georgia the trait is so common

these seals are treated no differently.

Also nesting in the tussock,

a southern giant petrel.

This seabird only comes to land to breed and nest.

It's developed a tube-like passage on its beak

to help expel excess salt.

The name petrel comes from the biblical story of Saint Peter

who walked on water.

These birds appear to run across the surface

until they've built up enough speed for takeoff.

The southern giant petrel has an impressive wingspan

of some two meters

(tense music)

which it uses to full effect not just for gliding,

but in battle.

While giant petrel females tend to prefer

hunting for live fish and krill at sea

the males are more inclined to scavenge carrion.

On prolific breeding island sites like this one

small carcasses are common.

Male giant petrels will gather about

and aggressively posture to claim their feeding rights.

With wings on full display

a petrel about to attack will assume a threat position,

head forward, tail raised and fanned.

A number of dominant males

will result in several demands for respect.

If the birds are similarly sized it usually ends

in a clash.

The sharp, hooked beaks of a giant petrel

are designed for tearing into seal flesh and bone

and can inflict hideous damage

if an aggressor refuses to give way.

These displays of competitive carnage can continue for hours

as the scavengers fight over any small remains

left on land or sea.

With the nearest continents more than 1,000 kilometers away

these island residents leave little to waste

in the breeding and feeding months on land.

(bright music)

For many, the end of the breeding season

means a very long journey back to feeding grounds.

(whales singing)

For humpback whales this is

a 5,000 plus kilometer return migration to Antarctic waters.

These family pods have spent the southern winter

in warm climes around the Southern Hemisphere,

like the islands and shore

of Australia's Great Barrier Reef,

birthing and fattening up newborns on milk.

The pods leave the tropical island behind

with young calves in tow

to spend the next six months

around the islands of the icy Antarctic.

The adults have not fed

for the half year they have been away.

In summer, as the sea ice

around the Antarctic Peninsula islands thaws and melts,

and freshwater icebergs are set adrift,

it sets in motion an underwater ecosystem

ripe for planktonic bloom.

And that means an abundance of krill.

Krill are shrimp-like crustaceans

that feed on plant matter, or phytoplankton,

which blooms as nutrients are released by the ice.

Each tiny animal lives for five to seven years.

They school in extremely dense numbers for protection,

often under the melting bergs.

But the schooling method of protection is no defense

against the enormous gape of a whale.

Like blue whales, humpbacks are baleen feeders.

Orca and some whales have teeth,

but humpback mouths have

a system of thin plates made from keratin,

the same material that makes up human fingernails

or rhinoceros horn.

Up to 35 throat grooves run from the whale's chin to navel.

These expand,

allowing the mammals to take in huge volumes of water

and entire schools of small fish or krill

in a single gulp.

The plates strain the food

and the whale expels the water.

These tightly packed plates

and inner throats the size of a grapefruit

mean baleen feeders can only small prey whole.

When the humpbacks reach Antarctic waters

they'll start actively feeding again

for 22 hours of the day.

They've lost weight in the breeding season

and the feeding season has begun in earnest.

But the absence of teeth

doesn't make these whales sedate foragers.

They are hunters

and Antarctica is one of the very few places on earth

where they've learned a specialized technique

for group hunting,

bubble-net feeding.

(ominous music)

This hypnotic spiral are a visual cue

that these humpbacks are using

a highly sophisticated herding method below the surface.

When a humpback pod locates a large school of krill

near one melting berg

the leader will cue the start of the hunt.

The whale takes a breath of air from the surface

and dives down deep below the school.

It then begins a slow ascent in a wide circle underneath it,

tightening each loop as it rises up through the water.

The whale constantly blows a stream of bubbles

through its blowhole all the while.

The effect is a type of net.

The bubbles create a shimmering wall around the krill.

Other whales circle outside the rising bubble spiral,

emitting an eerie high-pitched noise.

The curtain of bubbles, circling giant shadows,

and piercing wails panic the small prey,

they won't cross the bubble wall.

The spiral draws them closer together

and herds them to the surface.

Another humpback signals it's time to plunder the net

and sounds a feeding call.

The whales swim upward into the school,

mouths agape, and consume tons of the corralled crustaceans

in a single mouthful.

Bubble-net hunting requires a high degree

of intelligence and cooperation.

But not all humpback whales know how to do it.

It appears to be a behavior that has been learned

by certain family pods in very specific areas of the world.

In the Northern Hemisphere some unrelated groups

fish in this way for herring.

It's unsure how both groups learned the technique.

Humpback groups rarely cross the equator.

In Antarctica it's a means to maximize a krill school

and feed many mouths at once.

The bubble-net technique

is handed down to the next generation.

For the humpback calves that made their first trek

to the southern feeding waters from the tropics

it's a lesson that they will in turn

begin to practice in years to come.

(quiet music)

The area considered to be the Subantarctic zone

extends far north of the Antarctic convergence

into the southern region of South America.

Nearly 500 kilometers east from the tip

lies the Falkland Islands.

These islands are continental crust fragments,

left over from the breakup

of the southern supercontinent Gondwana,

the scattered remains from a reef

that formed the south Atlantic ocean

130 million years ago.

The Falklands is now made up of two large islands

separated by a deep channel

and several hundred smaller surrounding islands.

One such island in the northwest of the archipelago

is Carcass Island.

Strong westerly winds limit tree growth.

Instead, the average temperature of five degrees

encourages dense scrub and tussock grass.

The hillside is pocked with deep burrows.

Inside, nesting pairs of the Falkland's very own penguin,

the Magellanic.

(playful music)

This is the largest of the warm weather penguins.

Close relatives are found in South America,

the Galapagos Islands and Africa.

Like the African penguin,

the Magellanic has a pink gland above its eye

to help regulate body heat.

Though the high winds of Falklands create a unique problem,

one that has been solved

by digging burrows into the hillside.

Unlike most penguins that head north to fish for winter,

Magellanics return to these colder islands from the north

where they've spend the season fishing for anchovy

and sardines off the South American coast.

A male will return to the same burrow year after year

and await his female breeding companion

to return and join him.

She's able to recognize her partner by call alone.

Magellanic are strict carnivores,

fishing off the shoreline and among the kelp beds.

These algal gardens offer up another unusual sight,

(bright music)

ducks and geese that prefer to live and feed in salt water

rather than inland freshwater ponds.

Carcass Island is a nesting site for many marine waterfowl.

These two geese look markedly different

but are actually the same species,

male and female.

They're kelp geese, entirely herbivorous.

Their diet is made up of sea lettuce,

algae from rock pools accessed at low tide.

The kelp goose female builds a nest

just above the tidal zone

and lines it with a warm inner lining of down,

plucked from her own breast feathers,

to keep her eggs warm.

Her mottled plumage camouflages her

while she's undertaking the important task of incubating.

The male's stark white feathers allow him to stand out.

He has the task of lookout and defender

and needs to be an obvious bodyguard

to deter other birds.

He'll stay close by his mate for the next month

until the hatchlings emerge.

(birds peeping)

When the goslings arrive

the male begins his watch anew,

this time over a large brood

as the mother teaches her young chicks how to forage.

They'll begin with the smaller algae species

until tiny beaks learn to peck

and webbed feet learn to grip the slippery rocks.

The family will spend the three months of summer

together on the foreshore

until the chicks are ready to leave.

On Carcass Island

downy chicks nestling into barnacled rocks

is a common sight.

(cheery music)

Upland geese have a similar male/female color variation

but prefer to forage in the grasslands above the foreshore.

These families spend the summer teaching their young

to pick seeds and insects from the damp vegetation.

On the beaches

an island subspecies of the Patagonian crested duck

negotiates the waves alongside

a mother steamer duck teaching her chicks to dabble.

Dabbling is the name given to

a waterfowl's surface feeding technique,

paddling on water with the head below,

dipping down to pick up small fish

or invertebrates in the shallows.

These steamer ducks are flightless.

Ducklings will spend the summer

building up strength in their legs

to powerfully cycle in the water,

much like the steamer paddle boats their named for.

Their beaks will become powerful enough

to crack open mussels and crabs in the foreshore rocks.

Once again the male steamer is tasked with

guarding the family as they complete their morning lessons.

(somber music)

To the south of this Falklands island

towering cliffs overlook a deep channel.

The Devil's Nose is the name given to these sandstone cliffs

of West Point Island.

It's the feeding ground for carrion scavengers,

large birds that will pick off the young,

injured, or dead of other species.

The striated caracara is a large South American raptor

with exceptional color vision,

superior to that of mammals.

It allows the caracara to specifically hone in

on the color red from a great height.

The formidable turkey vulture,

found throughout the Americas,

also inhabits the Falklands.

It makes fast works of any remains on the shores.

West Point Island is a significant

southern giant petrel nesting site.

At breeding times the predatory petrels

have their own young to feed.

Fights between all these scavenging species are common.

The unforgiving cliffs of the Devil's Nose

provide plenty of opportunity for the carrion scavengers.

Covered in algae and dauntingly steep

it's a terrain only suited to the most sure of foot.

(playful music)

One penguin has adapted

to the cliffs of Subantarctic islands like no other.

The rockhopper penguin has

a spiky crest of yellow and black feathers

and can be distinguished by red eyes

and bright orange beaks.

Talon-tipped pink feet are the lifelines

that hold them steadfast to uneven and slippery surfaces.

Unlike most penguins,

these island dwellers have learned to hop.

They can leap bounds of nearly two meters.

The barnacle capped slopes of the Devil's Nose

are particularly perilous, even for a rockhopper.

These are the only penguins

known to leap into the ocean feet first.

Come the summer breeding season

rockhoppers won't seek out the quiet shelter of bays,

they carefully ascend the cliffs

and congregate right in the path

of the Falklands unimpeded Roaring Forty winds.

Nests are simple bowls scraped from the ground

and rookeries are extremely dense.

The close living quarters sees

a number of territorial arguments break out each day.

Rockhoppers are notorious for constant bickering

and infighting, especially around nests.

Though two eggs are usually laid,

like many penguin species,

only the strongest will survive to fledge.

When the chicks reach about three weeks of age

they're huddled into creches

to allow their parents to return to sea in shifts

to feed their rapidly growing young.

The adults left in charge of the Devil's Nose creches

must be hypervigilant.

(tense music)

These cliffs are teaming with birds

looking for easy targets.

The bloodstained beak of a giant petrel

announces it has already been successful

at least once today.

It brazenly attempts another attack.

The penguin's distress cries

attract a hungry hoard,

ready to take advantage of any scraps.

The giant petrel aggressively

spreads its wings in a threat posture

as it moves in once again

but this brood mother is fierce in her defense.

Her ferocity is matched by the petrel's patience

and need to feed her own young.

These standoffs can last for hours.

Eventually the petrel moves on,

in search of an easier target.

(cheery music)

Further south along the island cliffs

a new black-browed albatross mother

feeds her young chick.

The Devil's Nose is an unlikely place

for such an extensive nursery

but summers sees

every available inch of clifftop real estate

dedicated to nesting.

Each year the southern ocean albatross

will return to the same cliff and the exact same nest.

These precisely engineered pods

are built to last for years,

high, smooth pillars of mud, guano, and grass.

The nests are built for one,

the albatross have a single chick each season,

but also to withstand strong katabatic winds

that rush from the clifftops down the slopes.

The albatross themselves

are also perfectly engineered for these winds.

(majestic music)

Though the smallest of the albatross family,

black-brows still have an impressive wingspan

that can reach over two meters tip to tip.

They perform highly aerodynamic maneuvers,

looping and riding it for hundreds of meters.

These birds are constantly studied

for their efficient use of air currents.

Like sailors they'll tack back and forth

to make the most of the wind

without the need to expend energy with flapping.

And though the black-browed albatross is found

right down to Antarctica itself

they stay loyal to their home nesting site.

These chicks will learn to glide

and fish from the cliffs of West Point Island.

In years to come they'll return to

precisely the same nest if they can

and find a mate for life.

(gentle music)

Right across the southern oceans

many other animals returning from winters offshore

make their way back to summer homes

below the convergence zone.

The islands of the Antarctic play a vital role

in the cycle of breeding and feeding.

They are nurseries and sanctuaries.

They are the touchstones for entire populations

to annually meet, socialize,

and learn the traditional pathways, places,

and techniques that are unique to them.

The feeding season begins

and for these few months of the year

the sun shines on Antarctica,

in some areas for weeks on end.

This vast tract of ice, rock, and snow

is undoubtedly inhospitable

and requires an unyielding resilience

of the lifeforms that live here.

And yet the terrain is surprisingly varied,

breathtaking in both its beauty and alien nature.

Antarctica remains the least explored continent

but it was once the center of our southern world.

Today it continues to influence the entire planet

through the currents, winds, and wandering wildlife

of the "Wildest Antarctic."

(sweeping music)