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At the northernmost point of our world lies a land of ice and snow - a land of darkness
and light - where strange creatures have made peculiar adaptations to the harsh conditions.
Despite the bitterly cold winters, life flourishes in the short, cool summers, making this fragile
ecosystem a remarkable one.
Come explore the Arctic, one of the most remote and beautiful places on earth.
Because of the tilt of Earth's axis, the Arctic gets a great deal of sunlight in the summer,
and very little in the winter.
As spring turns to summer, the days become longer and longer, until finally there comes
a day when the sun does not set at all.
When daylight lingers all through the night, it is called the Midnight Sun, something which
occurs in the days surrounding the summer solstice.
As fall turns into winter the days get shorter and shorter, until finally there comes a day
when the sun does not rise and darkness lasts a full 24 hours.
This is called Polar Night.
The polar night may be long, but there is a light in the darkness, and its name is aurora.
The aurora borealis, also known as the Northern Lights, is a display of lights in the night
sky that is only visible near the north pole.
Although they may occur at any time, they can only be seen at night, as they are too
faint to be seen in the light of the sun.
The Northern Lights have fascinated people for thousands of years!
Some people once thought they were spirits dancing in the sky; others thought they were
the flames of dragons.
Today's scientists have learned that the auroras are caused by charged particles from the sun
that interact with Earth's magnetosphere, exciting the gases of the atmosphere until
it glows.
Auroras will also occur in the skies surrounding the South Pole, where they are called the
Southern Lights.
Any place on earth far enough north that it has at least one night where the sun does
not set and one day where the sun does not rise is considered to be inside the Arctic
Circle.
The Arctic Circle is an imaginary line that encircles the North Pole at about 66 degrees
North Latitude.
The Arctic is mostly ocean, but it also includes parts of Greenland, Canada, the United States,
Russia, Norway, Finland, Sweden, and Iceland.
Lands at the southern edges of the Arctic Circle are generally covered by tundra.
The tundra is vast, and for the most part, treeless.
The short Arctic summers are too cool and too brief to allow trees to flourish here,
but there is another barrier as well: permafrost.
Beneath a thin active layer of soil that thaws and re-freezes every year, the ground is permanently
frozen.
The plants that survive - mostly grass, moss, and shrubs,
grow close to the ground and have shallow roots.
Although there is little rain on the tundra, summer is very wet.
The frozen upper layer of soil thaws out, but water cannot sink into the ground past
the frozen barrier of the permafrost.
Since temperatures there rarely climb higher than 54 degrees fahrenheit or 12 degrees celsius,
very little of the water evaporates.
Instead, it sits on top of the permafrost layer, forming lakes and marshes that will
turn to ice as soon as temperatures sink below freezing once more.
Many birds, especially waterfowl, will migrate north to these cool summer wetlands to breed.
One bird that does this is the trumpeter swan, with some flying from wintering grounds as
far south as Texas or Mexico.
With adults frequently reaching weights of 30 lbs or 13.6 kg, it is the heaviest bird
living that is native to North America.
It is also the largest species of waterfowl in the world, with a wingspan that can surpass
10 feet or 3 meters.
The Arctic wetlands provide an important habitat for the trumpeter swan - a refuge from hunters
that decimated populations in Canada and the northern United States near the beginning
of the 20th century.
By 1933, only a few dozen wild trumpeters could be found in these southern areas, and
people feared they would become extinct.
Then, a second population of trumpeter swans was discovered up in Alaska: thousands of
them.
Some of the Alaskan swans were carefully introduced to the areas where trumpeters had been overhunted,
allowing the populations to recover.
Waterfowl are not the only animals to make their home on the tundra.
Fish like salmon and cod migrate to the waterways there each year.
The fish, in turn, attract predators like bear and eagles.
Wolverine and fox live here, too, as well as musk ox and caribou.
Caribou, or reindeer, are one of the world's great migrators.
In the winter, they travel south to snowy pine forests.
They cannot survive farther north, where the snow is too deep, because they must dig through
the snow to eat the moss and lichens beneath it.
In the spring, they migrate north again to take advantage of the plants growing on the
tundra and birth their calves.
Some North American caribou have the longest migration of any land mammal in the world,
up to 3,000 miles or 5,000 kilometers.
Animals attempting to survive in the Arctic need every advantage they can get, and some
have found it by changing their appearance.
In a land of ice and snow, it is sometimes helpful to be white yourself.
Some animals, like the snowy owl, keep white feathers year round.
Others, like the arctic fox, wear brown or gray fur in the summer and only turn white
in the winter.
Another color changer is the ptarmigan.
Covered in patchy brown and white feathers in the summer, they begin to change their
plumage as the days shorten.
Both male and female ptarmigans will go through the winter in a coat of nearly pure white
feathers.
Once the snow begins to melt, bright white birds can easily be spotted by predators,
and so they change back.
The female regains her brown camouflage first, when spring comes, which offers her some protection
from predators while she sits on her eggs.
The males, on the other hand, keep their white feathers for a while to stand out and attract
a female - and to prove that they are smart and quick enough to avoid being eaten in showy
feathers.
The puffin is another Arctic bird - with a very different tactic for camouflaging itself.
Puffins are seabirds.
They only return to land to breed, nesting in burrows dug in clifftops.
They prefer to breed on islands, where risk from land predators is much lower.
Puffins spend months at a time out on the open ocean, and it is out at sea that their
coloring comes in handy.
They have black feathers on their backs, and white feathers on their stomachs.
This color pattern is called countershading, and it helps them blend in to the dark ocean
water when seen from above, or the bright sky when seen from below.
Although they can fly, puffins are awkward in the air and typically move around by paddling
their webbed feet as they sit on the water's surface.
To catch fish, they dive, moving along by flapping their wings underwater, much as penguins
do.
The rich feeding grounds of the northern oceans attract larger animals than puffins - much
larger.
Humpback whales travel north in the spring to feed on the krill and small fish abundant
in the frigid waters.
Although humpbacks are often solitary, they sometimes form small groups - especially when hunting.
A group of humpback whales together can use a special method called bubble netting to
trap fish and krill.
The whales will surround and circle a school of fish.
Then, other whales begin blowing a ring of bubbles to trap them.
Once the fish are trapped close together, the whales will come up from beneath them,
mouths wide open, scooping up huge quantities of fish like a net.
Their baleen plates allow them to strain the tiny creatures from the seawater.
The humpbacks must eat massive amounts of food in the spring and summer months to build
up their fat stores.
When the weather turns cold, they will migrate to warmer tropical waters, and they will not
eat again until the spring.
It is in these warmer waters that they mate and give birth: newborn calves could not survive
the freezing temperatures near the poles.
It is important for the adults to have successful summer hunts, so that they can survive their
yearly migration.
As we travel farther north, we come to areas where the snow and ice never completely melt,
in a place called the High Arctic.
Even here, there is life.
Instead of tundra, the high arctic has polar barrens.
Far fewer plants survive here, mainly moss and lichens.
As a result, most food chains do not rely on land-growing plants.
Instead, they begin in the sea.
The walrus is at home on the land, in the water, or on the ice.
They sleep and rest on beaches or on ice shelves.
They prefer to live near shallow waters.
Walrus cannot dive as deeply as their relatives, the harp seals, and must be able to reach
the sea floor to find their favorite foods: clams, mollusks, and oysters.
They may look peculiar, but walruses are well-adapted to their icy habitat.
Their wrinkled skin is nearly 4 inches or 10 cm thick in places, and the layer of fatty
blubber beneath it is even thicker: nearly 6 inches or 15 cm.
The purpose of both is the same - to allow walruses to stay warm in freezing Arctic waters.
Thick skin and thick blubber contribute to the walrus's massive size: adult males often
weigh more than 2000 lbs or 900 kg, and some even weigh double that.
By far their most recognizable trait, however, is their tusks.
Both male and female walruses grow tusks.
Tusks are enlarged teeth that can grow about 3 feet or a meter in length.
Walruses use their tusks like ice picks, to help pull themselves out of the water onto
sheets of ice.
They also use their tusks to clear breathing holes when ice covers too much of the water's surface.
Finally, tusks provide some defense against the only animals that prey on walruses: killer
whales, and polar bears.
Because of their harsh Arctic habitat, polar bears rely more on meat than any other bear.
They eat mostly seals, waiting at breathing holes in the ice for them to pop their noses
through the surface of the water and then dragging them up onto the ice.
Sometimes they will catch beluga, narwhal, or young walruses this way, but larger prey
of this kind is much more difficult to manage.
Polar bears are the largest land predators in the world, but they are also excellent
swimmers, sometimes swimming for days at a time to move between hunting grounds.
Like the walrus, polar bears are well adapted to their harsh Arctic habitat.
Thick white fur serves as camouflage as well as insulation, and a layer of blubber underneath
provides extra warmth.
Their paws are extra wide, to help them distribute their weight and allow them to walk on top
of snow or thin ice without breaking through, and their thick, strong claws help polar bears
grab onto slippery prey as well as better grip the slippery ice.
The Arctic is a harsh, forbidding land, but it is far from lifeless.
Plants and animals live and grow and flourish in the conditions they are adapted for.
Many species depend on the cold and the ice and would not be able to survive if it was
gone.
Because the Arctic climate is so unwelcoming to humans, much of it has gone untouched and
undeveloped, but we can still disturb the delicate balance these creatures depend on.
Hunting... pollution...and gathering natural resources may cause changes that upset the
network supporting life in the northernmost reaches of our planet.
I hope you learned a lot today about the Arctic, the land of the midnight sun.
Goodbye till next time!