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A triple bacon cheeseburger seems like a heart attack on a plate.
三层奶酪咸肉汉堡感觉吃完很容易让人突发心脏病。
So how can polar bears thrive on their version, seal blubber?
那么,北极熊是如何处理这些高热量食物的呢?
Turns out they've stocked up on genes that let them clear fats from their blood.
结果显示它们储存在遗传基因里的信息使得它们能够清除血脂。
That's according to a study in the journal Cell.
这是根据《细胞》杂志上的一篇研究得出的结论。
Polar bears are well adapted to life on the sea ice.
北极熊非常适应在浮冰上的生活。
Up to half their body weight's fat, which gives them extra insulation and buoyancy, and provides them with a ready source of energy.
几乎占它们身重一半的脂肪足以使它们保暖并且维持体力，提供给它们一种易转化的能量。
But how can an animal so fat also be so fit?
但一种动物怎么能又胖又健康？
Researchers compared the genomes of polar bears with those of brown bears, and found that polar bears have accumulated genetic changes that boost their heart health and fat metabolism.
研究人员们通过比较北极熊和棕熊的基因，发现北极熊的基因组中积累了不少有利于心脏健康和脂肪代谢的遗传突变。
One gene in particular, called ApoB, helps move cholesterol out of the blood—where it causes problems in humans—and into cells.
特别是编码为载脂蛋白B的基因有助于清除血液中对人类有害的胆固醇转变成细胞代谢。
These genomic changes happened quickly, evolutionarily speaking.
这些遗传变化从进化的角度来讲发生的十分快。
Polar bears and brown bears diverged from a common ancestor less than half a million years ago.
北极熊和棕熊都来自于同一个祖先，它们是在大约50万年前左右开始向不同分支进化。
But if that seems super speedy, the ability to digest lactose didn't spread through human populations until we domesticated cows, just 10,000 years ago.
但是如果这种变化看上去十分快速的话，消化乳糖的酶逐渐进化到人类各个种群中也还是发生在大概1万年前我们可以驯化乳牛之后。
A moooving testament to the power of natural selection.
这是自然选择力量的证明。
