Great White Bear
Introduction

The polar bear rules the north. To the hardy native people who settled the harsh lands of the Arctic, the powerful hunter with the ghostly white coat is known as the “lonely roamer.” But most of us know the huge mammal as the polar bear. And the story of how the world’s largest land predator prospers in one of Earth’s harshest environments is the subject of the NATURE program Great White Bear.

In extraordinary scenes collected across the top of the world, Great White Bear shows that polar bears are prodigious roamers indeed. Single bears have been known to trek and swim as far as 3,000 miles across icy seas and mossy, treeless tundra in search of food. Typically, however, studies suggest the bears stay within a home range that is just a few hundred square miles. Still, polar bears, by far, range over the largest territories of any bear.

The reason for the huge territories, scientists believe, is the unpredictable availability of their favorite food: ringed seals. As Great White Bear shows, populations of this common, four-foot long arctic seal can build up and melt away mysteriously, much like the ice sheets the sleek swimmers often inhabit. In good years, the bears may not have to travel far to find a seal meal. But in bad years the dark, cream-spotted animals are few and far between.

Though polar bears are excellent swimmers — their scientific name, Ursus maritimus, means “sea bear” — they usually aren’t fast enough to catch a seal in open water. Instead, in winter, the bears creep within striking distance of one of the breathing holes the seals have made in the ice. When a seal pops its head out of the hole to catch a breath, as it must do every ten minutes or so, the bear leaps and yanks the unsuspecting bather out of the water.

Sometimes, however, bears take a more direct route: as Great White Bear shows, they will crash through the top layer of the ice itself in an effort to trap the seals that may be resting in the hollow space below.

Ringed seals are a staple of the polar bear diet. In early summer, when the seals like to bask in the warming sun, hunting bears must use a different strategy. They wait until the seals are asleep and then creep close, freezing in place when the snoozers periodically open an eye to check for danger. Eventually, if the seals don’t spot the stalker, the bear gets close enough to make a powerful pounce.

More often than not, however, the seals escape: some studies have shown that bears outwit their prey less than five percent of the time.

But when the hunting is good, bears can be finicky eaters. They will easily polish off a 100-pound meal consisting of the seal’s energy-packed skin and blubber, or fat layer. But they commonly will leave much of the less nutritious muscle behind. Young bears will sometimes devour the leftovers, but it is often another Arctic inhabitant — an Arctic fox or gull — that rushes in to claim a free meal.

It can take a lot of seals to satisfy a polar bear. Males can be ten feet tall and weigh 1,500 pounds, while females are smaller, topping the scales at about 550 pounds. Remarkably, however, the huge animals can withstand lengthy periods without food. Male bears, for instance, are routinely forced to go without a major meal for three or four months each summer, when melting ice prevents them from hunting seals. And pregnant females apparently go without food for eight months — a record among mammals. Mothers even keep fasting for some weeks after their one-pound cubs, usually twins, are born between late November and January. By the time the cubs have left her care one to three years later, however, the mother has rebuilt her energy stores and is ready for another litter.

To survive their forced diets, polar bears burn a thick layer of reserve fat. In some cases, this layer can be up to five inches thick. But the blubber doesn’t just store energy: in winter, it also provides an excellent insulating blanket in temperatures that can plunge to 40 degrees below zero. Other adaptations, such as a small tail and ears and two layers of specialized heat-trapping fur, also help the bears conserve heat. In addition, each hair of a polar bear’s coat is hollow and transparent, helping to draw the sun’s rays toward the bear’s black skin. But when things get too cold, even polar bears must seek shelter, digging out snow caves in which they curl up like giant furry balls.

In summer, however, that same fat can present a problem. Polar bears can easily overheat when they run — which probably explains why they spend much of their time loping across the landscape at such a leisurely pace. In the southern part of their range, where summer temperatures can rise to levels downright blistering for bears, they may even take to the water simply to stay cool. Such strategies have allowed polar bears, which can live for 30 years, to prosper for at least 200,000 years in a challenging Arctic landscape that is by winter enveloped in icy darkness and by summer bathed by a never-setting sun.

But hunting and environmental changes, such as signs that a warming climate could be melting pack ice, may be taking their toll on the bears. And concern is growing about pollutants, such as mercury and other toxic chemicals, that are making their way into the once pristine Arctic food chain. As a result, scientists are keeping an increasingly close eye on the up to 40,000 bears that live in Canada, Russia, Alaska, Greenland, and Norway. “If a polar bear population is healthy, then one can probably safely assume that the rest of the components of that food chain are doing well,” explains a spokesman for the Canadian Wildlife Service, which has sponsored extensive monitoring studies. “However, if problems develop with polar bear populations, it may indicate problems elsewhere in the ecosystem.”

The goal, scientists involved in such studies say, is to make sure that the Arctic’s great white bear continues to roam across the top of the world.

  • M&M

    i like this this

  • andreea balasescu

    vreau in romana

  • hanna

    I love these!

  • Mike Mills

    Who are the scientists mentioned in your story? Where are the links which may back up your speculation? Your additional resources does not list them.

  • Alyssa

    i think polar bears are WONDERFUL!!!

  • bre

    polar bears are going endagerd and we have to save them!!!! :)

  • april

    i love polar bears . i think these are very clear and they never give people harm .nevertheless i love them forever.

  • Elizabeth

    Polar bears must not be thretened by the human(polar bears are awsome).

  • kathesia

    polar bears are wonderful

  • anish

    Polar bear is beautiful, where i get more good pics of white bear?

  • Maritza

    i love these animals they’re so adorable!:)

  • raycalcia yazzie

    i like bears like this one when i was a little girl i use to like little bears and i had a buch of teddy bears of them i called it bears the bear and i never changed it so i could fouse on the name of the bear.

  • kaitlyn james

    the polar bears areso cute and thay make you want to hold them and i love them so much!!!!!!!!!!

  • vishesh agarwal

    I am 5 years old ,love wild animals,try to resque..
    statues of all most all wild animals are in my collection,but,a beatifulpolar bear.Ilike Polar Bear

  • taylah & grace

    they are cute.

  • seth

    I love them.

  • rodica

    do the polar bear have to stay in the snow.why. are they cold or not.

  • REESE

    I think polerbears are awsome

  • Taylorr

    i love polar bears, i dont want then to go extinct. care about our earth, and STOP global warming

  • lola

    what do white bears do usally?

  • Daphne

    I love these!Cool!There should be more pics!! agreeing with Taylorr.

  • Sammantha

    Ohh!This is so cool!

  • Simon Dayl

    This is so cool!Infct..it is the coolest!Stop global waeming!People should know more about this.THE ICE IS MELTING!At least take the bears from Arctic to..any other country!At the ZOO!

  • Spanky

    YEAH!!!!!! SAVE THE POLAR BEARS!!!!!!

  • Mariya

    I like all kind of animals and even I have started liking snakes but only if I don’t meet them personally. If I watch them on pictures is OK I can accept that these kinds of reptails should exist to scare the people. Whatever, I didn’t know some things about the Polar Bear and I didn’t know that they travel on icebergs to reach some destinations. And what upsets me the most is that becasue of the warming of the weather these creatures could lose their ability to travel and not this is the worst part but the thing that this is one of the ways for their survival. It’s really sad when I watch a baby polar bear( really sweet to me) next to his mother and imagine that this sweet baby could die and it would never reach the size of his mother. I just mean not because of the size but becuse the opportunity to live as long as his mother.

  • hichem

    wonderful animals , should be protected !!

  • shiva

    I like polar bears.

  • Jezz

    OMG soo wonderfully fat! illyyy!!!

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  • cinnamon stick

    AWESOME.. i love this!!!:):):)

  • Jon

    I thought you would this interesting. Back in the 60’s I was on an Coast Guard Ice Breaker doing oceanographic survey work up about Point Barrow. Anyway we had to set hydrophone on the ice and retrieve them by hand. This would require a party of two going out on the ice and into the pressure ridges lay cable and the instruments. I never thought to much about it as we had a gunner mate on the ship to watch out for us with M1 Carbines. Well I was just a kid and one day I got to go with the civilian scientist to gather up the survey equipment and we were rounding one of the pressure ridges and I was a little bit nervous because we could not see the ship. I asked the civilian scientist what would happen if we ran into a polar bear? He just replied and reached into pocket and said he had some fire crackers and would just light them to scare away the bear. I kind of remember that statement as it seemed kind of redicuous at the time a fire cracker and my life in his hands. Jon

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  • Emily Lee

    I hope polar bear won’t die.

  • Catrina Acal

    Espero y deseo que el año que viene también pueda ser madre, que con 35 años ya va siendo hora.

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  • theresa

    these gave me a reprot to do. i think they are so cute

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