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This is the land of the midnight sun, the very top of the world. At this time of year,
early August, there's sunlight all day and all night, followed by a fall and winter of
increasing darkness until by December here along the East Coast of Greenland, there's no sunlight
at all. The Arctic. It's been called a cold desert, a white hell, but the Arctic is full
of surprises, home for a startling variety of wildlife that live both above and below the ice.
Much of the Arctic area is ocean, including the North Pole, and it's frozen solid for all or part
of the year. This week, we focus on the marine animals that live here. Like the land animals,
they're beautifully adapted to their cold environment. And at the very top of the food
chain, there is a marine mammal, the magnificent polar bear.
With a sensitive nose for sniffing out prey, excellent eyesight,
sharp hearing, thick fur to keep out the intense cold, and claws as sharp as a tiger's,
the polar bear is the largest carnivore in the world.
An adult male weighing half a ton with a shoulder height of five feet is a formidable predator.
In the kingdom of the ice bear, it is March. Daylight has returned after three months darkness,
but as yet, the sun provides little warmth, and it's 40 degrees below zero.
The polar bears roam the frozen seas of all the Arctic nations, Russia, Alaska, Canada,
Greenland, and here in Norwegian Svalbard. Throughout the winter, male bears have hunted
the ice for seals, but the pregnant females have spent their time in dens beneath the snow.
In November, driven by the new life within them, the females wander away from the sea ice into the
coastal hills and valleys to find places where the shifting snow creates drifts. Here, they dug
their maternity dens. Their design is similar to an Eskimo igloo with a tunnel leading to a living
chamber. The females have been insulated below the snow for the past four months until now,
when the March daylight encourages them to surface.
In the depth of winter, protected in her den, this female has given birth to cubs,
but she will not reveal them until she's had some exercise herself,
which on the first occasion is usually at night.
She's confined to an icy hole for four months. Her limbs are stiff. Her first outings are very brief.
In March, the most northerly islands on our globe are still surrounded by vast expanses of ice.
The open sea freezes each year to a depth of up to 10 feet.
Further north, around the pole, lies the permanent ice of the Arctic Ocean.
But there are some areas which don't freeze all winter. They're called pollinias.
Pollinias are kept open by strong ocean currents, often where the sea is shallow.
With each new tide, sheets of ice break off from the edge before they can fully form.
Bears visit pollinias to hunt seals and walrus, which take advantage of the open water. With a
thick layer of fat, polar bears are immune to the cold and able to swim long distances.
They're true marine mammals.
The distinct drum-like underwater song of an adult male walrus is thought to proclaim an area of sea as his own,
and to attract females to mate with.
Rival males sing from other areas, each one with a distinctive rhythm of his own.
In late March, different calls bring an echo
of spring to the islands of the high Arctic. Black-legged kittywakes arrive from the coasts
of Europe to inspect the cliffs where eventually they will nest.
Throughout the month, millions of sea birds, northern fulmers, dovkeys, meres, and many others
migrate to their traditional nesting areas, attracting a resident arctic fox.
The breeding season is short, so the birds arrive in plenty of time to pair up.
Competition for nest sites is intense, even when the ledges are still covered in ice.
A mer will make a welcome meal for a fox, which has survived the winter on small scraps of food.
A high slope above the sea ice is a relatively safe position for a bear's maternity den.
Large males who sometimes disturb a mother bear avoid these steeper places,
but she's still wary. At first, she makes only short journeys.
Initially, the cub stays within the entrance, watching its mother loosen up her body.
Polar bears have one to three cubs, or rarely four. Twins are most common. Weighing a mere one and a half pounds at their birth around Christmas,
they've grown rapidly, nourished by their mother's rich milk. But she herself has not eaten since November.
Having lived only on her fat reserves, she's now extremely thin and hungry.
In contrast, this large male has obviously caught plenty of seals during his winter on the sea ice.
A few days after opening the den, the mother bear takes the cubs on short outings, strengthening their legs for longer journeys across the sea ice.
A third, smaller cub has surfaced, but it's too nervous to join its larger siblings.
On this first trip outside, however, the attentive mother will not take them far from the safety of the den.
The large male bears can pose a threat to the mother and her cubs.
Black gillimots, early arrivals from Europe, perform the courtship routines of spring,
while still in winter plumage. And the pollinia is shared by a resident ringed seal, favorite prey of polar bears.
Early April, and throughout the Arctic, families of polar bears are on the move.
Usually, 10 to 14 days are spent near the safety of the den, but eventually a mother's increasing hunger forces her to go looking for food, even though the littlest cub is still not very strong.
The sea ice, where a mother must hunt for seals, is a dangerous place, and speed is her best defense against competitive male bears twice her size.
If they're not feeding in a pollinia, walruses must keep a hole in the ice open permanently, and they spend much of the day lying near it while they digest their food.
Both sexes have ivory tusks, which are used in social displays to establish dominance, or as weapons.
An adult bull can weigh as much as a ton. The cows are always smaller.
A mustache of sensitive bristles helps them feel along the muddy seabed when they dive for food.
Walruses feed on the bottom, grubbing around in the gloom for shellfish.
A large walrus might eat several thousand clams in a day, but the cold Arctic sea is very productive, and under the ceiling of ice, marine life flourishes.
Jellyfish swim in water teeming with microscopic animals.
And comb jellies, sometimes in great numbers, drift along in the current.
From March on, enough sunlight filters through the ice for a layer of greenish-brown algae to grow under the surface.
These simple plants form the basis of the food chain in the Arctic Ocean.
Many tiny creatures graze this marine pasture. The most obvious are the shrimp-like amphipods, which reproduce in profusion.
Polar and Arctic cod, small fish adapted to withstand the cold, feed exclusively on amphipods, and in turn are preyed upon by other resident carnivores, like the ringed seal.
To survive most of the year under the ice, a ringed seal must keep open several breathing holes.
Through constant use and by scraping with their claws, a funnel-shaped opening to the air is kept free from ice, and is hidden under a hard crust of surface snow.
With their acute sense of smell, polar bears can find the hidden spots and sometimes crash through to grab a seal as it comes up for air.
Their heavily-ferred feet allow them to move almost silently on the ice.
But seals are sensitive to the tiniest vibration from above, and will swim to other holes if they suspect danger.
Early June, and a growing cub is learning quickly from its mother how to survive on the still-frozen sea. But on cloudless days, there can now be 24 hours of sunlight.
Temperatures rise to above freezing, and where currents are strong, the ice weakens and begins to move.
Following a late winter decline, autosol anger
The sheer cliffs of Prince Leopold Island and Canada's high Arctic rise 1,300 feet
above the broken ice of Lancaster Sound.
More than half a million pairs of seabirds nest on these ledges each summer, and throughout
the Arctic there are thousands of similar colonies.
The total number of breeding birds that migrate to such remote northern cliffs runs to many
millions and shows how plentiful food is below the ice of the Arctic Ocean.
On Prince Leopold Island, most of the nesting birds are black-legged kittywakes and these
thick-billed merres, but also there are a thousand or more northern fulmers sharing
the crowded ledges.
By July, most of the birds are sitting on their eggs, and for merres, the moment when
the parents swap brooding duty is the most dangerous time.
Locust gulls patrol the cliffs and are quick to swoop down on unguarded eggs.
Parents who lose their eggs soon after laying might try again, but the brief Arctic summer
will last only another five or six weeks, and chicks that hatch late are likely to perish
in the returning blizzards of autumn.
But for now, conditions are benign, and in good weather, merres often fly 30 miles or
more to find the best feeding areas.
Most popular is the flow edge, where the sea ice meets the open ocean to the south.
Flowing from beneath the frozen surface, the tides break off chunks of ice, some very small,
others the size of a skating rink.
In this way, fresh marine pastures constantly are being brought within diving range of the
ice.
But seals also come to the flow edge each summer.
They've journeyed from as far south as Newfoundland to feed here on amphipods and polar fish.
Another visitor to the ice edge is one of the Arctic Ocean's strangest animals.
The unicorn of the sea, the narwhal.
Only males have the characteristic single tusk, an elongated tooth believed to be used
for sexual displays.
Like the seals and sea birds, narwhals are attracted here in great numbers to feed on
the bounty of the flow edge.
Another toothed whale and a close relative of the narwhal, the beluga, is even more numerous
in the plankton-rich sea near the ice edge.
Marine mammals communicate using a variety of underwater sounds.
The predominant noises here are made by the lugus.
Walrus and bearded seal are in the background.
In July, fog banks hang over the sea ice and temperatures sometimes well above freezing.
Now, the bears are forced to stalk the ringed seals.
No longer restricted to the breathing holes, they surface in many open cracks or pools.
Inevitably, some seals do get caught, on this occasion by a young male.
He appears to be three years old.
This is his first hunting season without the help of his mother.
At this age, he's in danger of losing his meal to a larger bear.
For some reason, the bigger male is more interested in pursuing the younger one, but the smell
of seal attracts a mother bear and her cub.
Although ringed seals escape to the water to avoid danger, at this time of the year,
they spend much of their day basking, motionless on the ice.
At a distance, it would be difficult for the bears to tell that a seal lying on the ice
is already dead.
So this female bear, thinking the dead seal will notice her, slips quietly into the water
and begins a stealthy journey toward her supposedly alert prey.
In its first summer on the ice, the cub learns to hunt by example.
Several feet away now, and still the seal hasn't moved.
Only at the last moment does the mother realize that all her stealth was unnecessary, but
at least the cub may have learned more about stalking seals, and there's a good meal to
be had at the end of the lesson.
At this age, the cub hardly knows where to start, while the mother first checks that
no other bears are near enough to endanger her cub or their meal.
Invariably, locus gulls arrive within a few seconds to clear up the scraps.
Poor bears consume the vitamin and energy-rich blubber and skin first, possibly to get the
Cubs must learn from their mothers the various ways a polar bear can catch a seal, such as
ambushing, stalking, and crashing through the snow crust above a winter breathing hole.
Polar bears can live to the age of 30, but cubs don't become independent until they're
two and a half years old.
It's midnight in July.
Gradually, the seasonal ice sheets thaw and split, and glaciers weaken where they meet
weakness.
The ice caps and glaciers and the central core of the Arctic Ocean circling the North
Pole remain permanently frozen. But around the fringes of the polar basin, the ice breaks
up each year. By early August, large areas of sea are dotted with loose pieces of ice.
Music
The walruses now digest their huge seafood meals while basking on ice flows.
And like this full-grown male, sometimes use the rough surface to remove dead skin.
Normally they're social creatures, and if a flow is large enough, several will try to
fit on it together. Immature animals up to two years old, three or four cows, and a single
adult bull make up this walrus group.
Music
Swalbard, Norway, and on the seabird cliffs an annual late summer event is about to occur.
High on the nesting ledges, young birds prepare their feathers for flight.
Unlike kitty-wake chicks, mer fledglings with their stubby wings are not good fliers.
When the moment comes to cast themselves off the cliffs, they will attempt to glide across a half-moon.
When the moment comes to cast themselves off the cliffs, they will attempt to glide across a half-mile
of loose rock and shoreline to reach the sea.
During just a few days in early August, all the chicks will follow their parents and take the plunge.
Many young merres reach the sea in safety, but as more and more attempt the journey,
arctic foxes arrive.
Having shed their heavy white winter coats, a young merre is ready to mate.
The birds are given a chance to hunt and hunt.
Having shed their heavy white winter coats,
they now blend in better with the rocky terrain of summer.
Sooner or later, some of the merchants will misjudge the angle of the glide.
Putting themselves at terrible risk.
The
During the peak of the Exodus,
hundreds of birds are in the air at once.
So many crash land that the foxes hardly know which way to run.
Glockus gulls also take their toll.
Grounded chicks continue toward the sea on foot,
trying to avoid the predators,
which by now have caught as many as they can handle.
Once in the sea, maintaining contact with a parent is important.
An isolated fledgling is more vulnerable to attack by gulls.
Within four or five days, most of the merres have reached the water.
But autumn storms add to the difficulties facing an exhausted youngster.
Gathering in groups, the merres from Svalbard start to drift south.
After only two months of summer, late August temperatures drop sharply.
The ice begins to form once more.
Each winter, millions of blue duties take on the ice.
Their
The great white bear, able to crush the skull of a seal
in a single blow, proves capable of more gentle behavior.
In early November, when the sea ice becomes strong enough to support the immense weight of a polar bear,
they spread out across the bay to hunt for seals. In the meantime, among the males, these playful tests of strength continue.
In the kingdom of the ice bear, the last of the
sunset of autumn draws to a close. For the next six months, the cold will be intense.
Darkness will settle over the far north, until the female bears emerge once more from their dens to bring out their cubs into the sunshine of a new Arctic spring.
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Thank you.