The other reason is that mother bears may not be fat enough to produce milk for their babies, so some bears could stop having babies.

另一个原因是熊妈妈可能不够胖，无法为它们的幼崽产奶，所以一些熊可能会停止生育。

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With thick layers of fat and fur, the bears are well prepared for cold climes.

北极熊因为有厚重的脂肪与皮毛而能很好的适应寒冷的气候。

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In the western portion of the bay, the ice begins to melt in late spring. The polar bears then go into hibernation, living off reserves of body fat until the sea freezes again.

在哈德逊湾的西部地区，冰雪在晚春就会开始融化，此时北极熊将进入夏眠，以消耗自身存储的脂肪为生，直到海面再次结冰。

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"Bears just aren't as fat as they used to be, " he said, which makes them less able to live through low-sea-ice years.

CNN: Don't feed the (polar) bears

It's all about the skin, each gleaming, crisp scallop of which bears a slender, super-tender cargo of meat and fat (which shouldn't need the hyped-up hoisin sauce it's often served with).

WSJ: Let Them Eat Fat: In Praise of Fatty Foods