Polar bear's epic nine day swim

[louise]

Wow

"This bear swam continuously for 232 hours and 687 km and through waters that were 2-6 degrees C," says research zoologist George M. Durner.

"We are in awe that an animal that spends most of its time on the surface of sea ice could swim constantly for so long in water so cold. It is truly an amazing feat."

Although bears have been observed in open water in the past, this is the first time one's entire journey has been followed.

By fitting a GPS collar to a female bear, researchers were able to accurately plot its movements for two months as it sought out hunting grounds.

The scientists were able to determine when the bear was in the water by the collar data and a temperature logger implanted beneath the bear's skin.

news.bbc.co.uk/earth/hi/earth_news/newsid_9369000/9369317.stm

Ignoring any 'climate change' aspects of this story, it was still an amazing feat.

[rsmith7]

Yes, it's amazing how far these animals can swim. It's probably why their population is healthy and increasing.
No-one in their right mind would argue otherwise....would they?

www.nwf.org/Global-Warming/Effects-on-Wildlife-and-Habitat/Polar-Bears.aspx

Oh well - what's one "lie" amongst thousands.

[nickrr]

Jan 25, 2011 21:01:55 GMT 1 rsmith7 said:

It's probably why their population is healthy and increasing

And your evidence for this is ....

[carnyx]

Try this one;


www.21stcenturysciencetech.com/Articles%202007/GW_polarbears.pd

[louise]

From www.skepticalscience.com/polar-bears-global-warming.htm

According to a 2009 report by the IUCN Polar Bear Specialist Group, of the 19 recognised subpopulations of polar bears, 8 are in decline, 1 is increasing, 3 are stable and 7 don’t have enough data to draw any conclusions.

Both habitat degradation and over-harvesting are responsible for the decline in some subpopulations. To understand why the IUCN and US Endangered Species Act consider polar bears to be at risk, it is important to look at how rising temperatures are likely to affect their habitat in the future. Polar bears are highly specialised mammals which rely heavily on sea ice for food and other aspects of their life cycle. Satellite data show that Arctic sea ice has been decreasing for the past 30 years, and projections show that this trend will continue as temperatures carry on rising. The changes in sea ice affect polar bears in several ways:

•The early retreat of summer sea ice means that bears have less time to hunt and therefore less time to build up fat reserves.
•The fragmentation and reduction in sea ice has several impacts. It forces the bears to swim longer distances, using up some of their fat reserves. It also reduces the number of seals, which are the bears’ main source of food, and impedes travelling and den making. And it also forces the bears to spend more time on land, with increased interactions with humans potentially leading to higher mortality.
To get an idea of the potential impacts of future climate change on polar bears, we can look at subpopulations found at the bears’ southern range, where habitat changes have been most noticeable so far. A good example is the western Hudson Bay subpopulation, which is one of the best studied. Here, ice floe break-up is taking place earlier than 30 years ago, effectively reducing the feeding period by about three weeks. As a result, the average weight of female polar bears has dropped by about 21% between 1980 and 2004, and the population declined by 22% between 1987 and 2004. In Alaska, there is evidence of increased cub mortality caused by a decline in sea ice.

In conclusion, the reason polar bears have been classed as threatened comes from the impacts of future climate change on the bears’ habitat. Current analysis of subpopulations where data is sufficient clearly shows that those subpopulations are mainly in decline. Further habitat degradation will increase the threats to polar bears.

and you can read the actual IUCN report at pbsg.npolar.no/en/index.html

[rsmith7]

Some propaganda from a lobby group - oh dear.
Just like greenpeace telling us cod were an endangered species.
How gullible are you?

[louise]

I feel quite sorry for people who are so cynical that they refuse to believe that anybody else could ever be acting for altrusitic reasons.

Is it because they themselves couldn't concieve of ever acting altruistically themselves?

[rsmith7]

You couldn't be more wrong.
I work un-paid as a fishermen's representative - for the last 13 years.
I've become active politically (un-paid) to try and stem the flow of highly damaging tripe from the left/green movement.
You still haven't stated your motivation for your green activism.

[carnyx]

Louise,

I see that you have read stuff about the shrinking of the ice coverage of the Arctic, and the bad effect on the polar bears. Seeing as they swim at least as well as their prey, who are also mammals, what would the problem? Is the seal population declining? ..

And also, polar bears mate with brown bears .. and so are not a separate species but merely white brown bears in fact. ( had it crossed your mind that there migh be some colour discrimination going on here? ) .Anyway, if al ice disappeared tomorrow, and then came back in a thousand years, we woud see bears recolonising the ice, and in a few generations we would see polar bears again.

Now this shows us that bears are very adaptable to environmental change, and wil cope IF the arctic ice melts away.

But how do you explain this? Is there really anything wrong with artic ice?

www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Extent.png

[eamonnshute]

Jan 26, 2011 15:16:05 GMT 1 carnyx said:

Is there really anything wrong with artic ice?

Yes, there is. The volume is decreasing much faster than the area, because the ice is rapidly getting thinner.The maximum volume of ice last winter was not much more than the minimum volume in summer 1980. I expect to see dramatic changes in the extent in the next few years.

upload.wikimedia.org/wikipedia/commons/5/51/Plot_arctic_sea_ice_volume.svg

(link corrected)

[jonjel]

And also, polar bears mate with brown bears .. and so are not a separate species but merely white brown bears in fact.

I don't wish to fall out with you Carnyx, but that simply is not true. One bear was shot a few years ago which appeared to be a hybrid between a grizzly and a polar bear.

Brown bears are a lot smaller than polar bears, grizzlies a bit closer in size.

You also mentioned that polar bears are good swimmers, so why worry about them feeding. Well they hunt on firm ground that is why, they can't chase and catch prey at sea.

[carnyx]

Ah, thanks for that .. grizzlies then.

My point was that the white bears are a subset of the 'grizzly' population .. and if the polar population is subsumed back into the main population the genetic propensity for albino 'sports' is not lost, and so populations of the polar variety will likely re-emerge when the climate is favourable.

And as their main prey, seals, come ashore anyway .. so they too will come up on the shore ( as opposed to the ice) and will not be lost as a foodsource for land-bound bears.

All this is to show that the ice-bear population is very adaptable and will not be 'lost'.

@eamonn,

Are you saying that it is the thickness of the ice rather than the coverage that matters? The graph I gave the link to, was for ice greater that 6 inches, and as you see there is little change over the years. Are you saying that 15 cm of ice will not sustain the weight of a polar bear?

(BTW were you aware that your link was to the output of a Mathematical Model, and not on a plot of measurements?)

[eamonnshute]

Jan 26, 2011 17:15:13 GMT 1 carnyx said:

@eamonn,

Are you saying that it is the thickness of the ice rather than the coverage that matters? The graph I gave the link to, was for ice greater that 6 inches, and as you see there is little change over the years. Are you saying that 15 cm of ice will not sustain the weight of a polar bear?

My point is that if the ice continues to decline as in the past then there will be no ice at all in summer a very few years from now, which is not apparent from graphs of area. And in a few decades there could be no ice even in winter.

[louise]

There are graphs (from observation - not models) and pictures taken from space of both arctic and arctic ice extent over the last decade or so here wattsupwiththat.com/reference-pages/sea-ice-page/

Here are a couple that show very recent vs average but there are lots more at the link.

[carnyx]

Thanks, Louise.

They all show no case for alarm, except perhaps alarming increase in the amount of Antartic ice.

(BTW perhaps we could encourage polar bears to emigrate there?)