As Arctic ice melts, polar bear cubs die making long swims
With less fat on them, and less buoyancy, the young bears often can't survive the increased distances to get to stable ice or land. (Getty Images)
July 21st, 2011
12:28 PM ET

As Arctic ice melts, polar bear cubs die making long swims

Editor's Note: The following piece comes from Global Post, which provides excellent coverage of world news – importantmoving and odd.

As the Arctic sea ice habitat retreats, polar bears have to swim longer distances to find stable ice or to reach land, and their cubs are suffering, according to a new study presented Tuesday at the International Bear Association Conference in Ottawa, Canada.

Polar bears, not naturally aquatic animals, hunt, eat and give birth on ice or on land, according to Reuters. Earlier studies have shown that the bears are swimming hundreds of miles to reach solid ice or land, but a new study demonstrates that the longer swims increase cub mortality, compared with cubs that didn't swim such long distances. According to Reuters:

“Climate change is pulling the sea ice out from under polar bears’ feet, forcing some to swim longer distances to find food and habitat,” said Geoff York of World Wildlife Fund, a co-author of the study.

Between 2004 and 2009, a team of researchers led by Anthony Pagano of the U.S. Geological Survey gathered data from 68 GPS collars that had been put on adult female polar bears, and looked at that data along with satellite imagery of sea ice, in order to isolate episodes where bears swam more than 30 miles at one time, according to a synopsis of the research on PRWeb. (The final report is not yet released but the full abstract is provided with the synopsis at PRWeb.) Researchers identified 50 long-distance swimming events, involving 20 polar bears, over the six years. The bears swam distances of as far as 426 miles, and as many as 12.7 days.

Eleven of the polar bears that swam the long distances had young cubs at the time that they were collared; five of those bears lost their cubs during the swims, which translated to a 45 percent morality rate. Only 18 percent of cubs died when they weren't swimming the long distances with their mothers.

A big difference

The long-distance swims took a toll on the cubs partially because young polar bears don't have much fat and thus can't be in the cold water for long periods of time, Time said. Steve Amstrup, a former scientist at the U.S. Geological Survey and chief scientist at the conservation group Polar Bears International, said, according to Reuters:

“Young bears don’t have very much fat and therefore they aren’t very well insulated and cannot cope with being in cold water for very long,” Amstrup said in the same telephone conversation.

Because they are leaner than their parents Amstrup said, “They probably aren’t as buoyant (as adult polar bears) so in rough water they’ll have more difficulty keeping their heads above water.”

Evidence that long-distance swimming takes a toll on polar bears was already presented in a study published earlier this year that tracked a polar bear mother that swam for 232 consecutive hours in search of pack ice, and lost 22 percent of her body mass as a result, while her cub lost its life, Discovery reported. And in 2006, researchers came to the conclusion that an apparent rise in the number of polar bears found drowned could be linked to the bears being forced to swim longer distances.

The Arctic is warming faster than elsewhere because of greenhouse gases accumulating in the atmosphere, and the melting of sea ice in the summer speeds up the warming effect, according to Reuters.

The extent of Arctic sea ice dropped to record low levels in July 2011; sea ice volume is now 47% lower than the levels in 1979, when satellite records began.

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Topics: Animals • Environment

soundoff (21 Responses)
  1. mememine69

    Upon settlement, the polar bear was indigenous to as far south as Minnesota but called the yellow bear because it retained its summer coat longer for obvious reasons but still the same bear.
    Boycott all fear mongering climate blame media.

    July 21, 2011 at 12:59 pm | Reply
  2. j. von hettlingen

    Save all bears from distinction! We humans are partly responsible for the destruction of their habitats.

    July 21, 2011 at 2:29 pm | Reply
    • j. von hettlingen

      Please read: EXTINCTION!

      July 22, 2011 at 5:25 am | Reply
      • Ty Tymkovich

        Ty Tymkovich agrees

        August 27, 2011 at 10:01 pm |
  3. [(S3kShuN8)]

    05-29-1996 -{
    Earth cries out to us in our sleep
    A mournful tear streams down her cheek.
    Who will listen when she speaks?
    Will we get a chance to wonder why
    After she has sadly said goodbye?
    }- 05-29-1996

    July 21, 2011 at 6:42 pm | Reply
  4. fernace

    With a tag like "me me mine" I understand your point of view. Don't feel singled out, many feel as you do! "Me & mine is all that is important in My world , don't believe in or have time for climate change, starving kids on another continent or near extinct animal populations!" The problem with this mindset is that what affects the planet affects all it's inhabitants. The planet we pass on to our kids, grands & greatgrands will be in pitiful shape if no1 cares about it! I care about me & mine too, but I also give a damn about the plight of animals that are affected by our blatant disregard! I'll continue to do my small part in cleaning up our act!!

    July 21, 2011 at 7:09 pm | Reply
    • leeintulsa

      @fernace: perhaps it isn't disregard. Does it not make sense that the world evolves, just like everything else? I've seen footage of a polar bear/grizzly mix. Whadaya know, a new species. Polar bears can go now, we've got some in zoos and surely stories will live on forever.

      You can't save everybody.

      July 21, 2011 at 9:18 pm | Reply
      • j. von hettlingen

        How can you be so heartless? Of course we should keep the polar bears!

        July 22, 2011 at 5:28 am |
  5. fernace

    @ j. von hettlingen, I think you mean "extinction".

    July 21, 2011 at 7:13 pm | Reply
    • j. von hettlingen

      Yes, thanks, I oversaw it!

      July 22, 2011 at 5:25 am | Reply
  6. [(S3kShuN8)]

    I have more which is RESERVED for 2012 ... 🙂

    July 21, 2011 at 8:45 pm | Reply
  7. leeintulsa

    There will always be polar bears, just not as many. It's sad and all.

    Yeah, humans are spreading. Nothing you can do about that.

    Last year didn't we have the same story? Different bear? Different cubs? At what point does it become a snuff film? I guess the human stalkers won't inspire one to turn left instead of right. The wrong way in the scheme of things.

    People should leave em alone and let em live their lives.

    July 21, 2011 at 9:06 pm | Reply
  8. [(S3kShuN8)]

    CO{2} is a Global Atmospheric Problem , requiring a Global Strategic Response
    [HOW2 hit 2 birds with one stone]
    All participating Nations should extract CO{2} from the atmosphere and prepare it for small-scale space transit . . .
    \/\DISSENTERS reference HERE
    \/\/\GLOBAL Public Address VIA [GPS]

    July 21, 2011 at 10:01 pm | Reply
    • leeintulsa

      @s3yadayada: no.

      Wait, what?

      July 21, 2011 at 10:17 pm | Reply
  9. [(S3kShuN8)]


    July 21, 2011 at 10:05 pm | Reply
  10. [(S3kShuN8)]

    dark green forest with only a sliver of the moon visible high above .
    HTref: __Bjoork_Isobel_LYRICS__
    ...soft music playing in the distance...
    tRADE new Quarters for old ; etc.

    tRADE__VIA_NZD{?}_{(Yen)}_etc . . . Will accept Canadian Quarters ? "Not today, Al" . . .{LOL}

    July 21, 2011 at 10:27 pm | Reply
    • leeintulsa

      That's what i thought you said. No.

      July 21, 2011 at 10:30 pm | Reply
  11. WTTF08080

    THE S3KshuN8 File:

    Sorry for the name change , it really only applies to this current address vehicle . ;
    tHE_LAST_S3kShuN8_P0STwas_at_ 07-21-2011 @ 10:27 PM P0ST / PREcursAry STATEMENT ;

    SUBFUNCTION Republic ( Decorative Drivel ) == Democrats + Tea + Republican (CENTRISTIC) + democrat (CENTERist)
    2012 Will be a no-brainer by Election Day , you can QWote me on that . ;

    SUBFUNCTION Republic ( Decorative Drivel ) == Democrats + Tea + Republican (CENTRISTIC) + democrat (CENTERist)
    2012 Will be a no-brainer by Election Day , you can QWote me on that . ;

    July 22, 2011 at 1:06 am | Reply
    • WTTF08080

      TToday's _hidden_ word : Agamemnon

      July 22, 2011 at 1:08 am | Reply
  12. Bob

    July 29, 2011 at 2:32 pm | Reply

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