Polar bears do not hibernate, the other bears hibernate when it is cold, and you wouldn't see them as they hide away.
Actually they found a polar bear fossil that was 130,000yrs old, which meant it lived in the Eemian period, which was a lot hotter than now,and sea levels were higher.
What global warming? it hasn't warmed for 15yrs.
It's called aestivation if it happens during the Summer, the general term is Torpor. However global warming may last millions of years while torpor can only be maintained for short bouts. Bears don't truly hibernate as their body temperatures only drop slightly.
It's suspected that the mammalian hibernation response developed from a survival adaptation to global warming during the Permian extinction due to the presence of hydrogen sulfide. We do not see many mammals aestivate today but as food becomes more rare and it becomes more dry, perhaps we will. Of course, mammals were much smaller during the Permian extinction so the survival strategies for that period of global warming may not be of much assistance now.
No, watching bears hibernate would probably not be useful to track global warming but watching their ranges would.
I would expect to see a shorter hibernation season.
We already are seeing a similar effect--animals are getting smaller. The internal heat an animal produces goes as its volume, which (approximating bodies as spherically shaped) goes as the radius cubed. The heat loss goes as its surface area that goes as the radius squared. So larger animals do not get rid of heat as easily--that is why animals in cold regions tend to be large. It has already been seen empirically that animal sizes have been shrinking--e.g present day frogs are smaller than frogs several decades ago.
Bears and other hibernating animals tend to hibernate during the cold winter months, as the springtime temperatures start rising the hibernation period ends. The main reason for hibernating is because food is scarce during the harsh winter months.
If the world is warming up then we would expect to see animals going into hibernation later in the year and emerging earlier the following year, thus their hibernation period would be shorter. This is precisely what’s happening right around the world.
In recent years it’s been observed that some populations of the European brown bear have stopped hibernating altogether. Over the years their period of hibernation got shorter and shorter and now they don’t have one.
http://www.independent.co.uk/environment...
Whilst it’s quite unusual to have stopped hibernating altogether, it’s very common to see species hibernating for progressively shorter and shorter periods. Similarly, migration patterns have been affected with migrating animals now delaying their departure by an average of two weeks due to climates being warmer than they used to be.
http://www.pnas.org/content/97/4/1630.sh...
http://yalepress.yale.edu/yupbooks/book....
http://www.cabdirect.org/abstracts/19941...
http://journals.ametsoc.org/doi/pdf/10.1...
The bear won't hibernate, he is sitting in YOUR chair, in grade school, learning how to spell.
When bears stop hibernating you'll know the world has really heated up.
Wow, Y!A has a global warming section. I wonder, do they have a smoking cigarettes section?
No. They haven't seen Al Gore's movie yet.
Ha! Ha! Good old Trevor. (the one who I caught in many many lies and he hasn't apologized yet.)
http://answers.yahoo.com/question/index;...
If you go to the 1990 IPCC report, Page 202 (section 7) the third chart down. It shows that the Earth's temperature rose approximately 0.7 degrees C in 350 years (from 1650 to 1990) Ha! Ha! And we are supposed to believe that the bears can feel that change in temperature? Ha! Ha! Even my wife is not that sensitive. Come on Trev, get real. Trevor is not only a BS (Bad Science for the Y!A censors.) expert he is a proven liar, not just claimed, but proven.
Is that a way to see if earths temperature Is too warm, by watching bears?
