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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The seals provide much of the fat the bears need for warmth.

海豹为北极熊提供了保暖所需的大部分脂肪。

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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