This kill will feed the entire wolf pack, but soon they will need to hunt again.
这次捕杀能使整个狼群饱餐一时，不过很快它们就又得去捕猎了。
The porcupine herd have only just started this journey towards the summer grazing lands that lie two-and-a-half thousand kilometers north.
格兰特驯鹿的这趟夏季牧场之旅才刚刚起步，而它们的目的地远在北面两千五百公里的地方。
And the wolf pack isn't the most deadly enemy that they will face.
狼群也绝非它们将要面临的最危险的敌人。
On their track to northern Alaska, the weather will be a constant threat to life.
在它们前往阿拉斯加北部的路上，天气将成为对它们生存的长期威胁。
In Greenland, conditions on the tundra are extreme. Only a few species can survive here all year round.
在格陵兰苔原上气候条件极为恶劣，只有极少数物种可以一年四季在此生存。
Around ten thousand musk oxen tough out Greenland's winter with the temperatures drop below minus fifty degree Celsius and winds can reach almost a hundred kilometers an hour.
大约有一万头麝牛顽强地挺过格陵兰的寒冬，这里的气温能降至零下五十摄氏度之下，而风速几乎可达每小时一百公里。
Here, each winter, many of Greenland's reindeer freeze to death. But in the tundra, a carcass will not go to waste.
这里，每年冬天都有大量的格陵兰驯鹿被冻死，但在苔原上，每具尸体都不会被浪费。
In the bleak winter of the tundra, prey is so hard to come by. Even Greenland's most cunning predator resorts to scavenging.
在苔原萧瑟的冬季，猎物是很难获取的，即使是格陵兰最狡猾的掠食者也必须依靠腐食。
A carcass provides a welcome meal.
而一具尸体则提供了一顿美餐。
The arctic fox is perfectly adapted for living in the harsh arctic climate.
北极狐很好地适应了在北极恶劣环境中的生活。
They have the best insulating fur in the animal world, helping them withstand temperatures as low as minus fifty degree Celsius.
它们拥有动物界隔热性能最好的毛皮，这使它们能够抵御低至零下五十摄氏度的低温。
The arctic fox is a solitary animal, but when scavenging in winter, they congregate where any carcass they can find.
北极狐是一种独行动物，但当它们在冬季觅食时，就会聚集在任何能找到的尸体旁。
The arctic fox may resort to scavenging when time is tough, but they are one of the Arctic's most skilled predators.
北极狐在觅食艰难的时候就会转而以腐食维生，但它们也是北极地区本领最高的掠食者之一。
And in the pure white snows of the arctic tundra winter, maintaining their camouflage is essential.
而在白雪皑皑的北极苔原的冬季，保持它们的伪装很重要。
Even in Greenland's hostile conditions, many animals have found way to survive.
即使在格陵兰恶劣的环境中，很多动物仍然能找到求生之路。
Lemmings, one of the most numerous mammals and prey in the tundra.
旅鼠，苔原上数量最多的哺乳动物，也是最普遍的猎物。
Unlike most small mammals, lemmings don't hibernate through the harsh northern winter which can last for nine month of the year.
与大多数小型哺乳动物不同，旅鼠在北方整个严峻的寒冬里都不冬眠，而这里一年里的九个月都是冬季。
Instead they remain active, burrowing and tunneling under the snow, eating grass clipped and stored in advance.
它们反而活动频繁，在积雪下挖掘洞穴和隧道，享用着青草的同时还咬下一些并储存起来。
Above ground, temperatures can drop as low as minus fifty degree Celsius.
在地面上，气温可能降至零下五十摄氏度。
But down here, the temperature rarely falls more than two degrees below zero.
但在这下面，气温很少会低于零下二摄氏度。
Lemmings are found across the tundra, but they're solitary animals by nature, meeting only to mate then going their separate ways.
整个苔原地区都有旅鼠的身影，但它们原本是独居动物，只有在交配时才会聚集，之后又会各行其是。
Lemming populations can soar and disappear in a matter of weeks as entire communities migrate across the tundra in search of food.
在整个旅鼠群为了寻找食物而在苔原上迁徙时，旅鼠数量会在几周时间里急剧变化。
