Animal of the day: Polar Bears Dec. 31, 06

polar-bear1.jpg

Physical Characteristics
The polar bear is the largest terrestrial carnivore. Adult males can measure more than nine feet in length and weigh between 770 and 1,430 pounds. The bear’s body and neck are elongated, and the head is narrow and long with small, rounded ears.The polar bear’s coat, covering it completely except for the nose and foot pads, is superbly adapted to Arctic environments. Along with a thick layer of body fat, the water-repellent coat insulates the bear from cold air and water. It also serves as camouflage; in fact, polar bears can sometimes pass as snow drifts. The fur is 95 percent efficient in converting ultra-violet sun rays into usable heat. Its transparent hairs have a hollow inner core which scatters ultra-violet light by some unknown mechanism, converting it into heat when it reaches the bear’s black skin. Surprisingly, the fur has no white pigment; it is the reflection of the sun that causes the fur to appear white.

Habitat and Distribution
Polar bear populations can be found in northern Canada, Greenland, Norway and Russia, and there have been reports that polar bear tracks have been found as far north as the North Pole. The five million square-mile range of the polar bear circles the Arctic and contains stretches of open water where its primary prey – seals – are easily caught.

Polar bears live on the annual Arctic sea ice that provides a platform from which they can hunt. But when the edge of the ice retreats to the north during summer, bears must follow the ice floes or become stranded on land where they must stay until the sea ice forms again in the fall.

Diet
Polar bears hunt ringed and bearded seals on the sea ice, between late April and mid-July, by breaking into seal dens in the sea ice. The dens are not visible from above, but seeing is less important than smelling to a polar bear – with their keen sense of smell, polar bears can detect the breathing holes of seals in their dens beneath the snow and ice. Plentiful access to food in this period is critical, particularly for pregnant females. As the southern edge of the arctic ice cap melts in summer, polar bears are stranded on land and spend their summers fasting, living off body fat stored from hunting in the spring and winter.

As a result of global warming, sea ice in the Arctic is melting earlier and forming later each year. Ongoing research funded by WWF is finding that polar bears are left with less time on the ice to hunt for food and build up their fat stores, and increased time on land where they must fast. As their ice habitat shrinks, skinnier and hungrier polar bears face a grave challenge to their survival.

Polar bears also prey upon harp seals, as well as young walruses and beluga whales, narwhal, fish, and seabirds and their eggs.

Reproduction
Polar bears breed in late March, April and May. The males actively seek out females by following their tracks on sea ice. They remain with the female for a short time, then leave in search of another female.

During November and December, the female digs a maternity den in a drift of snow, maintaining and enlarging the chamber as the drifts cover her, snowing her in. Soon she gives birth to twins, which cuddle in their mother’s thick fur. She ceases to feed throughout the winter and instead lives off her stored fat. Her milk, high in fat content, enables the cubs to keep warm and grow rapidly before leaving the dark den in March or April.

Short trips are made to and from the den for several days as the cubs acclimate to the outside temperatures. Then the family leaves and makes its way to the sea ice where the mother feeds and protects her cubs. The family returns to the den the next winter and remains together during the following spring and summer. After two years together, the family disperses.

Status
With about 22,000 polar bears living in the wild, the species is not currently endangered, but its future is far from certain. In 1973, Canada, the United States, Denmark, Norway and the former U.S.S.R. signed the International Agreement on the Conservation of Polar Bears and their Habitat. This agreement restricts the hunting of polar bears and directs each nation to protect their habitats, but it does not protect the bears against the biggest man-made threat to their survival: global warming. If current warming trends continue unabated, scientists believe that polar bears may disappear within 100 years. WWF funds field research by the world’s foremost experts on polar bears to find out how global warming will affect the long-term condition polar bears. To learn more about the topic, read the WWF report Vanishing Kingdom: The Melting Realm of the Polar Bear (PDF, 885k). (WWF’s report, Polar Bears at Risk (PDF, 373k), provides a more detailed analysis.)

Visit the WWF Polar Bear Tracker to track the movements of two polar bears, Samantha and Marianne, in the Barents Sea area above Svalbard, Norway and learn more about how warming and changes in sea ice affect the lives of polar bears over time.

Read more about World Wildlife Fund’s work to stop global warming and help save polar bears.

http://worldwildlife.org/polarbears/ecology.cfm

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31 Responses so far »

  1. 1

    Alexis said,

    I love polar bears so much! They are my second favorite animal besides squirls. Its to bad there is only a little over 20,000 left. I hope there species will grow soon. It might not. I hope someday to move to Northern Alaska where they will be.

  2. 2

    Alexis said,

    These are some interesting facts on this website about polar bears. I knew quite a lot about them (not trying to brag or anything). There fur is actually clear but the sun makes them look more more white. Cubs are actually more white than the yellow-ish color adult bears.

  3. 3

    Davo said,

    I love polar bears,but in the long run is to watch out for the global warming, that is going to be the end of them such a beautifull aminals.

  4. 4

    yo,peeps. I love polar bears do you? write back.

  5. 5

    How U Doin. I’m fine i live in Nadia Arabia.
    polar bears are so cool.

  6. 8

    Yovita said,

    Yes, polar bears are such an amazing creature that our God created. I hope we, and all people in the wide world can stop the Global Warming. It is true the heat of the day has killed many polar bears.
    So please reduced the uses of Freon and CO2 before it’s too late

  7. 9

    Carina said,

    yes I agree I don’t know what I would do id polar bears went extinct. they are magnifnt animals. I wish that global warming could just stop.

  8. 10

    annie said,

    SAVE THE POLAR BEARS PPL……..we are losing one of the greatest animals in the world!!!!!

  9. 11

    sophie said,

    I LOVE POLAR BEARS!!!!!!!!!!!!

  10. 12

    emily said,

    i feel so bad for the polar bears

  11. 13

    abhay said,

    well it is too sad that we cant do anything to save them,the loveliest creature ever after panda

  12. 14

    abhay said,

    i just cant believe that the level of global warming has gone so up that we are unable anything about that.
    we are than just like hunters who hunt for their own benefit.

    AREN’T WE????????????

  13. 15

    carrie dudley said,

    Great site – where did you get this beautiful picture?

  14. 16

    taylor jones said,

    poler bares are kool ot me

  15. 17

    cfghgjg15 said,

    Me likey polar bears

  16. 18

    Jaeger said,

    I am 6 years old and I love polar bears because they are so beautiful and soft looking, even though I know they are very dangerous.

  17. 19

    Jaeger said,

    Do you know that polar bears have two layers of fur? Some baby polar bears need to sleep with special heated beds to keep them warm. There is a great book about Knut, the polar bear in Germany.

  18. 20

    Jaeger said,

    polar bears have sharp claws so they can give seals an extra special hug

  19. 21

    Kaiser said,

    My name is Kaiser and I love polar bears because they remind me of snow days!

  20. 22

    Homer said,

    I love polar bears because they remind me of doughnuts

  21. 23

    Jaeger said,

    Polar bears are my favorite animals in the whole wide world! They help their cubs and keep them warm. I love polar bears!!

  22. 24

    ginger o said,

    Keep On protect the POLAR BEARS.Thank you WWF……..

  23. 25

    harpsz said,

    ii love polar bears wooh lets save them !

  24. 26

    greenpeace eco friendly activist said,

    MUst protect polar bears,

    such adorable cudley creatures, canot let em go extinct like dinosaurs and the might T-REX did, reduce c02 greenhouse gas emission now< GOVERNMENTS
    must ACT NOW< get electric plug in, energy efficent solar cars on da road, get green jobs make ure homes and daily living greener,like GERMANY does.
    global warming is man made cause,save em for future generations,stop the pollutions

  25. 27

    maja said,

    i love animals and i am michael jackson’s sister 🙂

  26. 28

    Angelina said,

    I love bears and polar bears thıs’s a amazing website the knowledges are perfect

  27. 29

    emily said,

    i love polar bears and am doing a report on them soon so i know a little about them POLAR BEARS ARE AWESOME!!!!!

  28. 30

    emma said,

    well i love them tooo ! they recon that they will be gone in less than 11 yrs ! they have found that there is a new species where it is half grizzly and half polar

  29. 31

    Lainer said,

    Hey


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