Because polar bears go North for the winter to hunt for seals, instead of hibernating like most bears, they are forced to have their young on ice. But since global warming has been getting increasingly worse, there is less ice. Usually, polar bears have their young on ice pieces that float out to sea. A study done by U.S.G.S's scientists showed that from 1985 to 1994, 62% of the dens were floating out to sea. But from 1998 to 2004, only 37% were floating out to sea. That's almost reduced by half! Over the past 30 years, the amount of ice in the Arctic had decreased by 27%. Scientists at U.S.G.S. say that they are scared for the poplation of polar bears because they are worried that more and more mother polar bears will have their young are shaky ice and so if they fall through the ice then they would freeze do death causing the population to decrease.
By: Amber and Gennivie
http://www.sciencenewsforkids.com/articles/20070725/Note3.asp
