Life in the Freezer (1993) s01e05 Episode Script

Winter in Antarctica.
The temperature has dropped
to minus 70 degrees centigrade,
and winds of 120 miles an hour
blow across the desolate icescape.
The centre of Antarctica
is in continuous darkness.
Only its fringes see the bleak winter light.
The sea freezes over for hundreds of miles,
effectively doubling the size of the continent.
In winter, the Antarctic is a very lonely place.
As the temperature plummets
and the sea ice forms,
most of the wildlife that came down here
to take advantage of the brief summer season
is forced to retreat north again.
Practically nothing stays.
To survive in the deep south
at its most bitterly hostile
requires a very special animal
with very special adaptations.
Such a creature is the Weddell seal.
No other mammal lives throughout the year
as far south as this.
These seals
are just 800 miles from the pole,
and they stay here winter and summer.
Like all Antarctic seals,
they have a thick layer of blubber
to insulate them from the cold.
But the real key
to their success in surviving here
is their ability to keep open holes in the ice
so that they have
access to the sea the year round.
These holes are the only things
that break the white monotony
over hundreds of square miles of sea ice.
The seals, with no escape to the open ocean,
are forced to stay near the holes.
Each is a gateway
to and from the underwater world
in which the seals hunt and find shelter.
Underwater, the temperature
never drops below minus 1.8 degrees.
The seals retreat down here
during the worst winter storms
and so keep comparatively warm.
When you dive beneath the ice,
you enter, within seconds,
a totally different world.
Here, within a foot or so
of the gale-swept,
savagely cold wilderness above,
illuminated only by the dim blue
light filtering through the ice,
there is stability, peace,
and an eerie, unforgettable beauty.
Animals need special adaptations
to live in water that is below zero centigrade.
Most fish would explode
if they touched this glacier wall.
Crystals would immediately form in their cells.
These survive because their tissues
are loaded with anti-freeze.
Life beneath the ice,
compared with the white desert above,
is extraordinarily rich.
There are all kinds of invertebrates,
including giant jellyfish.
It's a very sheltered place,
for the permanent sea ice overhead
provides year-round protection
from waves and storms.
But food is scarce,
and many of these creatures
have become scavengers.
These starfish make a meal of seal faeces.
Weddell seals can dive
to 750 metres, possibly more,
in search of food.
At these depths, in permanent darkness,
they encounter a world
dominated by stalk sponges.
Growing extremely slowly in the cold,
the Antarctic invertebrates become giants.
Returning from depths
where a human would be crushed,
seals surface suffering none
of the effects of deep diving
that can cripple human swimmers.
October in the far south.
Female Weddell seals haul out
on the sea ice to give birth.
Imagine the shock of leaving a womb
at plus 37 degrees centigrade
and being dropped on the ice
into a world of minus 20.
The pup has to suckle
and build a layer of blubber
as fast as possible.
It usually doubles its weight in ten days,
for Weddell milk is 60% fat,
one of the richest produced by any mammal.
Remarkably, after one week,
the pup is ready for a swim.
(MOTHER LOWS TO HER PUP)
The mother is anxious to get her pup
accustomed to the water
before the weather deteriorates.
At this time, more than any other,
breathing holes are jealously guarded.
Weddells have an especially wide gape
and long canine and incisor teeth,
which enable them to scrape away the ice
that is constantly forming
and threatens to close their breathing holes.
Their teeth aren't impervious
to this wear and tear
and are gradually worn down,
so that eventually the seal can't eat.
As a consequence,
Weddells die at about 20 years,
half the age of other Antarctic seals.
A male defends an underwater territory
and mates with all the females
that use his breathing holes.
It's an effective way of acquiring a harem,
because females must have
a refuge below the ice
from the extremes of the winter weather.
It might seem that there could not be
a more harsh existence than this,
but the environment here
is comparatively constant
and these seals are adapted to it -
protected by a coat of dense hair
and insulated by blubber
immediately beneath the skin.
Indeed, Weddells do far better
than most other seals.
If they are sufficiently fattened
in the six weeks before they wean,
95% of pups will survive.
These seals,
the most southerly in the world,
live in the shadow
of the largest active volcano
in Antarctica - Mount Erebus.
Erebus is a mountain of extremes.
In the crater, molten lava bubbles
away at 600 degrees centigrade,
and yet, on the summit,
temperatures rarely rise
above minus 45 degrees.
Even here, there is life.
The heat of the volcano produces steam
that rises to the rim
and melts the snow and ice,
leaving bare patches of rock -
home to heat-loving bacteria and algae.
Another extraordinary example
of how life can survive in the most
extreme conditions on Earth.
Behind Mount Erebus,
the trans-Antarctic mountains
stretch in a long broad band.
They are the most extensive range
on the continent,
running for some 2,000 miles
and separating
the great east and west ice caps.
Although many of the peaks
are over 4,000 metres high,
most of the range is blanketed
by vast glaciers which fill the valleys.
Hidden among the trans-Antarctic mountains
is one of the continent's greatest surprises -
the dry valleys.
Here is the largest area
of bare rock in Antarctica.
It's so arid
that falling snow soon evaporates
and never builds up.
The valley below me is the driest place on Earth.
It hasn't snowed or rained here for centuries.
In winter, the temperature falls
to minus 52 degrees centigrade
and the ground is permanently frozen
to a depth of half a mile.
Conditions are so extreme
that when scientists came to design
a vehicle to work on the surface of Mars,
they brought it to this valley
in order to test it.
A clue to the factor
that creates these conditions
lies in the extraordinary shape
of these boulders.
Although they are solid granite,
they have been carved by savage winds
that scream down off the ice cap.
These winds are so dry
that they instantly absorb
any moisture in the air,
and by doing so desiccate
and preserve organic tissues.
This mummified crabeater seal,
70 miles from the sea,
has probably been lying here
for 3,000 years or more.
You might suppose
that a place that can freeze-dry
seals' bodies for centuries
would be totally without life.
But even in these extreme conditions,
life does exist.
Pick the right sort of rock -
this is a light porous sandstone -
give it a hit
and there, a millimetre
beneath the surface,
within the actual fabric of the rock,
a band of green, the colour of life.
It is lichen that has managed
to penetrate and colonise
the microscopic spaces between
the grains of the porous rock.
It's the only place where it can survive
in these arid, desert-like conditions.
Above the dry valleys,
held back by the trans-Antarctic mountains,
stretches the ice cap itself.
This is the Antarctic plateau,
3,000 metres high.
There can be no more forbidding,
hostile, desolate places to be
than up here on the Antarctic plateau.
It's not just that human life
here seems insignificant -
it seems totally irrelevant.
A few spots of lichens
may grow on boulders
to within 200 miles of the South Pole,
and, in the summer,
maybe one or two
particularly adventurous snow petrels
will come up here to try and nest.
But come the winter,
absolutely nothing living
moves up here on the Antarctic plateau.
Even in summer, it is always winter here,
with temperatures averaging minus 30.
1.5 times the size of Australia,
this is the largest area
of lifeless wilderness in the world.
Snow petrels,
brief visitors here in summer,
are forced to spend the winter
hundreds of miles
to the warmer north,
at the edge of the frozen sea.
This is the frontier
between life in the ocean
and a desert of ice
where almost no animals dare go.
But one creature has to cross it -
the Emperor penguin.
In May, when the freezing waters
and cold winter temperatures
force other animals
to retreat to the warmer north,
Emperor penguins head south.
They make their way to a number
of traditional nesting sites.
In this one alone, there may be 25,000 birds.
Emperors are unique.
They are the only birds
to lay their eggs directly on ice.
Just hours after the female
has produced her single egg,
the male takes it over.
The transfer has to be quick
if the egg is not to freeze.
The male manoeuvres it
into a brood pouch lined with blood vessels
that keep the egg 80 degrees
warmer than the outside temperature.
There, under a flap of skin,
it's sealed away for the winter.
When the egg is safely
inside the male's pouch,
the females are free to go,
and they start the long trek back
across the sea ice, to the open ocean,
leaving their partners to face
the coldest conditions on Earth.
With temperatures of 70 below,
and in terrible storms,
the penguins huddle tightly together for warmth.
No other adult penguins
are so tolerant of one another,
but for Emperors this is the key to survival.
The co-operation is not random.
Those most exposed on the windward side
move around the huddle
to the more sheltered side.
So every bird gets a fair share
of the warmth in the middle
and takes its turn in enduring
the brunt of the Antarctic weather.
As midwinter approaches,
the sun disappears below the horizon
for the last time this season.
A month of total darkness lies ahead.
Above the huddle, the Southern Lights -
the Aurora Australis -
blaze across the winter sky.
These spectacular displays occur
as subatomic particles,
travelling through space,
enter the Earth's magnetic field.
As winter recedes,
the huddles begin to break up,
and heat that was trapped
within them for so long escapes.
These males,
who have not eaten for 115 days,
are close to death by starvation.
(SQUAWKING)
As the sun returns
to the southern hemisphere,
the female Emperors,
sleek and fat from months of feeding at sea,
begin the long march back to the rookery.
The sea ice is now at its fullest extent,
and they may have to walk 100 miles
to reach their colony.
By now the eggs have hatched
and the tiny chicks
are awaiting their first feed.
Each female times her return
to coincide with the hatching of her chick.
A male, having starved for so long,
can give the chick only one meal -
no more than a milky secretion
from his gut wall.
If his partner doesn't return
within ten days of the chick hatching,
he will have to abandon it and head
to the sea to find food for himself.
(TREMENDOUS DIN)
It's a noisy time in the colony.
The courtship calling
that took place before winter
now brings its reward.
After a separation of over three months,
a bird can still recognise its partner's call.
(VARl0US CALLS)
When they find one another,
the pair perform their greeting ritual
to ensure there hasn't been
a case of mistaken identity.
Then the female gives their chick
its first proper meal -
half-digested fish.
She's very eager to take charge of the chick,
but the male, having cared for it
for so long, is reluctant to give it up.
She has literally to push him back
to get him to release it.
The transfer is a tricky manoeuvre
that must be done fast.
A chick left on the ice
for only two minutes will die.
The males, after their four-month ordeal,
near to starvation and desperate to feed,
have to walk 100 miles or so
back to the open sea.
Mothers and chicks spend the next few weeks
learning each other's call
and establishing a strong bond
that ensures they will recognise
one another in the months ahead
when she returns from feeding trips.
It's early spring
and the weather is still variable.
(HOWLING GALE)
Severe storms are a real threat
to the chick's survival.
An abandoned one seeks shelter
from passing adults.
One of them seems interested,
but the vital bond between
parent and chick isn't there
and eventually the adult walks off.
In fact, the adults do have
a strong instinct to protect chicks.
So much so that birds
that have not managed to breed
will try to take possession
of a stray or abandoned chick.
But this fostering never succeeds
because the adult has no partner
to help in rearing the waif.
These desperate unpartnered penguins
will sometimes fight over a chick
and crush it to death.
Mortality is high.
Many eggs don't hatch,
and of those that do,
25% die in the first few months.
Those that survive
have to grow fast and fledge
before the sea ice on which they live
breaks up beneath them.
These chicks take five months to rear.
Only by incubating the eggs
through the harsh winter,
so that the chicks hatch
at the very beginning of the short summer,
is it possible for the Emperors
to breed every year.
It was to collect
an Emperor penguin's egg like this
that men made the first-ever land journey
in the bitter cold darkness
of the Antarctic winter.
Bill Wilson, the naturalist
on Captain Scott's expedition,
was fascinated
by the evolutionary origin of birds
and was convinced
that the embryo in an egg like this
would provide conclusive evidence of the link
between the feathers of birds
and the scales of reptiles.
So, on 12 June, 1911,
in the middle of winter,
he and two companions
left Captain Scott's hut here on Cape Evans
and set out for the Emperor penguin colony
on the other side of Mount Erebus,
65 miles away.
It was a trip
that became known with some justice
as the worst journey in the world.
The weather was abominable.
Their clothes and harnesses froze solid
and all three suffered terrible frostbite
as they hauled their sledges
over heavily-crevassed terrain.
On the return journey, they lost
their tent in a violent storm.
By a miracle, they found it again
and made it back to the hut alive.
They brought back three eggs
and three Emperor penguin skins,
one of which is still here in Scott's hut,
preserved by the Antarctic cold.
Although the connection between
birds and reptiles is no longer in doubt,
the eggs did not provide the evidence
that Wilson thought they would.
Even so, the journey remains
one of the great epic stories
in the annals of polar exploration.
In the next programme,
we'll look at the history
of Antarctic exploration in more detail
and also see how people today
survive life in the freezer.