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Polar bear 'cannibalism' pictured

24 comments, 308 views, posted 1:22 pm 09/12/2011 in Nature by tricpe
tricpe has 10260 posts, 4186 threads, 560 points, location: In a pair of Speedo
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Polar bear 'cannibalism' pictured
By Jonathan Amos Science correspondent, BBC News, San Francisco

It is an image that is sure to shock many people. An adult polar bear is seen dragging the body of a cub that it has just killed across the Arctic sea ice.
Polar bears normally hunt seals but if these are not available, the big predators will seek out other sources of food - even their own kind. The picture was taken by environmental photojournalist Jenny Ross in Olgastretet, a stretch of water in the Svalbard archipelago. "This type of intraspecific predation has always occurred to some extent," she told BBC News. "However, there are increasing numbers of observations of it occurring, particularly on land where polar bears are trapped ashore, completely food-deprived for extended periods of time due to the loss of sea ice as a result of climate change." The journalist was relating the story behind her pictures here at the 2011 American Geophysical Union (AGU) Fall Meeting, the largest annual gathering of Earth scientists. A paper describing the kill event in July 2010 has just been published in the journal Arctic. It is co-authored with Dr Ian Stirling, a polar bear biologist from Environment Canada. Ross had approached the adult in a boat. She could see through her telephoto lens that the animal had a meal, but it was only when she got up close that she realised it was a juvenile bear. The kill method used by the adult was exactly the same as polar bears use on seals - sharp bites to the head. "As soon as the adult male became aware that a boat was approaching him, he basically stood to attention - he straddled the young bear's body, asserting control over it and conveying 'this is my food'," the journalist recalled. "He then picked up the bear in his jaws and, just using the power of his jaws and his neck, transported it from one floe to another. And eventually, when he was a considerable distance away, he stopped and fed on the carcass." Ross said there was another bear in the area and she speculated that it might have been the mother of the dead juvenile. Olgastretet is a passage of water that divides the two main islands of Svalbard. Traditionally, it has been an area that has stayed ice-covered throughout the year.

But the recent dramatic retreat of Arctic sea ice in summer months has seen open water appear in the area for extended periods. And without their customary platform on which to hunt seals, bears have gone looking for alternative sources of food, says Ross. "On land, they're looking for human garbage and human foods; they're starting to prey on seabirds and their eggs. "None of those alternative foods can support them, but they are seeking them out. "Predating another bear is a way to get food; it's probably a relatively easy way for a big adult male. And it seems that because of the circumstances of the loss of sea ice - that kind of behaviour may be becoming more common."

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Extra Points Given by:

HeadOfPins (3), ctxmark (3)

Comments

1
1:36 pm 09/12/2011

HeadOfPins

They need to survive, more and more so as the ice caps shrink. They will eat whatever they can get their massive paws on...polar bear, human, seal, chicken wings....they arent fussy.

I hear they are not preferable to butternut squash however.

4
2:30 pm 09/12/2011

griffin

Quote by tricpe:
as a result of climate change


I just knew they were going to throw that shit in there.

1
2:32 pm 09/12/2011

z0phi3l

It was about Polar Bears, it HAD to be about that shit, otherwise no one cares about them

1
3:17 pm 09/12/2011

Edorph

Quote by griffin:
I just knew they were going to throw that shit in there.


Quote by z0phi3l:
It was about Polar Bears, it HAD to be about that shit, otherwise no one cares about them


I love this knee-jerk reaction to anything mentioning "climate change", wherever it's found :-) I'd be sincerely interested in hearing why you don't find climate change relevant to this article. Are the polar bears' climate not changing?

4
3:21 pm 09/12/2011

Edorph

I don't think male polar bears eating, or at least killing, cubs is that unusual btw. Although in many cases I think it's just as much to make the female ready to breed again as it is for food.

2
3:25 pm 09/12/2011

griffin

Quote by Edorph:
Are the polar bears' climate not changing?


No.
Is that simple enough?

And I notice that polar bears + anything = CLIMATE CHANGE WE'RE ALL GOING TO DIE

I don't believe in man-made climate change, I believe in science. You may believe what you wish.

1
3:32 pm 09/12/2011

Edorph

You seem to be making the assumption that he means global warming or even man-made climate change. The arctic ice levels have been low for quite a few years now, some have even proposed to lay communication cables in the Northwest Passage. You may assume what you wish, of course.

1
3:38 pm 09/12/2011

backroom

I assume climate change is real. (better safe than sorry)
But by the time we have enough scientific evidence to outweigh millions of years of geologic change and convince griffin we will all be dead.

2
3:39 pm 09/12/2011

backroom

Quote by z0phi3l:
it HAD to be about that shit, otherwise no one cares about them


Yeah...
That's the only reason.

1
3:45 pm 09/12/2011

griffin

Quote by Edorph:
You seem to be making the assumption that he means global warming or even man-made climate change.


Yep, and I think that's a safe assumption to make. You think he was talking about something else?

1
3:49 pm 09/12/2011

Edorph

Yes, I think he's talking about the reduced thickness of the arctic sea ice over the last decades.

Code:
http://upload.wikimedia.org/wikipedia/commons/6/64/Decrease_of_old_Arctic_Sea_ice_1982-2007.gif


(apologies for not linking, Teoti seems intent on displaying the 6MB gif )

I'm not sure whether we're just discussing semantics, or if you don't agree with the ice thickness records.

1
4:26 pm 09/12/2011

griffin

I don't think variation in ice thickness is an indication of climate change. And he IS talking about climate change.

"Observations of cannibalism by polar bears (Ursus maritimus) on summer and autumn sea ice at Svalbard, Norway / Stirling, I. Ross, J.E.

As the climate continues to warm in the Arctic and the sea ice melts earlier in the summer..."

1
4:37 pm 09/12/2011

Edorph

You'll have to clarify a few things for me. Surely if the variation curve's descent spans decades, you would consider it a climate change for the region in question? Or do you not believe that there has been a reduction during the period? (Or that there has been a reduction, but it's not because of increased temperatures).

1
4:46 pm 09/12/2011

backroom

If I may interject... I believe I can sum up griffin's beliefs.
There has been a reduction.
That reduction is because of increased temperatures.
The increased temps are not due to the influence of man.

1
4:50 pm 09/12/2011

griffin

I think I have been clear enough. Let me try again: the current theory of man made global warming is bullshit. Is this clear enough for you? I'm not sure I can make this any more fundamental. Variations in ice thickness and temperature are within normal variations, imo.

If there is indeed any natural climate change taking place, it is far beyond our capacity to change or alter it.

UK Met Office: World temperature back down to 1997 level
Antarctic ice formed at CO2 levels much higher than today's

1
4:56 pm 09/12/2011

Edorph

You have been clear enough indeed on all of that except the vague term "variation". How long does a variation curve's trends have to span before you consider them climate change during that trend's period?
Would you say that the 10k years since the last ice age have been a climate change? Or is this also within "normal variations" (because in the big picture, it is)?

1
5:03 pm 09/12/2011

backroom

Quote by griffin:
If there is indeed any natural climate change taking place, it is far beyond our capacity to change or alter it.


I can not agree more.
However, if there is any man-made climate change it is entirely within our power.

And that is the dispute.

2
5:26 pm 09/12/2011

Edorph

Actually, the dispute in this thread is of a more semantic nature, I think. The definition of climate change is arguably entirely appropriate for what's happening in the arctic (retreating sea ice over multiple decades). Griffin - correct me if I'm wrong - argues that the term must mean global warming (or something of similar magnitude), even introducing man-made climate changes. He claims that the arctic situation qualifies only as "normal variations", but seems unwilling to provide the specifics of such variations.

The photographer or researcher in question may be the biggest GW fraudster there is, but the statements made here (and in the linked ucalgary story) are entirely reasonable. That's why I find the immediate "aaaah, he said climate change, it must be shit" outcry silly.

A disagreement with someone you consider reasonable is usually a path worth exploring. I think I'll file this as hair splitting, but interesting nonetheless.

1
5:35 pm 09/12/2011

backroom

Quote by Edorph:
qualifies only as "normal variations",


That is the argument used for any of these discussions.
Scientists taking measurements from samples of... whatever, from... where ever... he accepts.
Scientists making realtime observations and measurements he rejects.

It is not a matter of believing science as much as what science you believe.

Quote by Edorph:
I think I'll file this as hair splitting, but interesting nonetheless.


Best way to go about it.
As I say... By the time either side is proven right or wrong we we all be long gone.

1
5:37 pm 09/12/2011

griffin

I cannot remember the last time I saw any article about polar bears that did not hinge upon global climate change (of the man made variety) as the cause of whatever problem the polar bears were encountering.
Polar bears + danger to their survival = global warming is trying to kill the polar bears.

These articles are usually accompanied by a picture of this kind:

Global warming makes polar bears cling to ice, weren't you aware of this?

In any case, as soon as I saw the title of this post, I strongly suspected that it would follow the consistent pattern I have described. It did.

2
5:41 pm 09/12/2011

Flee

Quote by Edorph:
He claims that the arctic situation qualifies only as "normal variations", but seems unwilling to provide the specifics of such variations.


Technically, there have been points in earths history where the oceans were frozen up to a mile deep over 90% of the planet. The ice ages we read about in school are just mildly cold compared these events.

There have also been times when there was no polar ice. Granted, this was a LOOOOONG time ago, but it has existed.

The whole point to evolution and natural selection is when your environment changes, you adapt, or die. Is the polar bear the next panda? maybe...

2
3:50 pm 10/12/2011

Quaektem

Quote by Edorph:
I don't think male polar bears eating, or at least killing, cubs is that unusual btw. Although in many cases I think it's just as much to make the female ready to breed again as it is for food.



Bingo. Polar bear population is actually increasing because of the increased availability of food... due to an increase in water temps in the North. In the meantime the Antarctic ice cap is growing.

I never doubted the climate changes, in fact it's a natural even that has occurred for millennia. The Earth isn't a delicate balance waiting to be tilted into a global catastrophe. Life has survived several mass extinctions and impacts from major meteors... do you really thing driving a SUV is really going to cause the entire place to spontaneously combust?

Remember, all the CO2 locked away in fossil fuels once existed in the atmosphere during a time of rampant growth (which then became the fossil fuels). If we succeeded in releasing all of it back why would that do anything but encourage that level of life?

2
3:52 pm 10/12/2011

Quaektem

Quote by Flee:
The whole point to evolution and natural selection is when your environment changes, you adapt, or die. Is the polar bear the next panda? maybe...



Or perhaps they begin to cross breed with their brown cousins to the south and become a whole new species we need to protect (though a tan Coke can may go over even worse than the white one).

1
4:17 pm 10/12/2011

Flee

Realistically, as Edorph noted, I don't think this is unusual. When a male lion takes over a pride, he will kill the cubs of the old male. Brutal? Sure. But when he does that, the female start their cycles again so he can start on spreading his DNA.

Meerkats... If the head female is pregnant at the same time a lesser female is, the lesser female will attempt to kill the head females offspring because as the head female, her offspring would come first, and the lesser mother wants her offspring to have the best chance of survival.

This shit happens over and over. They dont usually get eaten, but many get killed.

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