竹径通幽处
北极熊是世界上最大的陆地食肉动物，又名白熊。按动物学分类属哺乳纲，熊科。雄性北极熊身长大约240-260cm，体重一般为400-800公斤。而雌性北极熊体形约比雄性小一半左右，身长约190-210cm，体重约200-300公斤。到了冬季睡眠时刻到来之前，由于脂肪将大量积累，它们的体重可达800公斤。北极熊的视力和听力与人类相当，但它们的嗅觉极为灵敏，是犬类的7倍，时速可达60公里，是世界百米冠军的1.5倍
HaoRen19990828
北极熊（学名：Ursus maritimus意即"海熊"），又称为白熊或冰熊，是熊属的一个种，是北极地区的典型动物，可能是六十多万年前（也有不同的科学家认为是十五、二十、四十、甚至上百万年前），由灰熊演化出来。Polar bear (scientific name: Ursus maritimus means "sea bear"), also known as white bear or ice bear, is a species of the genus Ursus, a typical animal in the Arctic, probably more than 600,000 years ago (and different scientists think It was fifteen, twenty, forty, or even millions of years ago, and it evolved from the grizzly bear.
zoemai0505
the fate of the polar bear goes beyond a single oil and gas project. If the species are declared threatened, FWS will have responsibilities under the Endangered Species Act to protect the bears from their main danger—in this case, climate change. That means the government could be challenged legally for anything that increases carbon dioxide emissions—like a new coal power plant—on the grounds that further climate change would further endanger the polar bear. “It would be the first time that the Bush Administration would recognize that global warming had a significant and specific impact on a living being,” says Eben Burnham Snyder, a spokesperson for Markey. “This could have a wide ranging effect on the energy and environmental policies of this country.”来源：新高考·高二语数外
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