张俊佳的回答：

Polar bears are the world largest land carnivore, also known as polar bear. By zoological classification is mammalia, Bear Branch. Male polar bear in length about 240-260cm, weight is generally 400-800 kg. The shape of female polar bears than about half of male small, body length 190-210cm, weighs about 200-300 kg. Time to sleep before the arrival of the winter, due to the massive accumulation of fat, their body weight up to 800 kg. Vision and hearing of polar bears and humans a considerable, but their extremely sensitive sense of smell is seven times the dogs, speed of up to 60 km, is 1.5 times the world 100 meters champion 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

黄清的回答：

Polar bears are the world largest land carnivore, also known as polar bear. By zoological classification is mammalia, Bear Branch. Male polar bear in length about 240-260cm, weight is generally 400-800 kg. The shape of female polar bears than about half of male small, body length 190-210cm, weighs about 200-300 kg. Time to sleep before the arrival of the winter, due to the massive accumulation of fat, their body weight up to 800 kg. Vision and hearing of polar bears and humans a considerable, but their extremely sensitive sense of smell is seven times the dogs, speed of up to 60 km, is 1.5 times the world 100 meters champion 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

褚亚琦的回答：

on under ......

李白．的回答：

北极熊又称白熊，是在北极里生长的熊，它是陆上最庞大的肉食动物。在它生存的空间里，它是食物链最顶层。它拥有极厚的脂肪及毛发来保暖，其白色的外表在雪白的雪地上是良好的保护色，而且它可以在陆上及海上捕捉食物，因此它能在北极这种极严酷的气候里生存. polar bears, is also called arctic bear in the arctic grows, it is the largest predator on land. in its existent space, it is the topmost food chain. it has thick fat and hair to stay warm, its white appearance on white snow is good protective coloration, and it can on land and sea, so it can catch food in the arctic this extremely harsh climate survive.

王桂权的回答：

Polar bears are bears 北极熊是熊 最简单的了