Day ten, and the mother has led her cubs a mile from the den. It's time to put them to the test. They've grown enormously in confidence, but they don't have their mother's sense of urgency. At last it seems that they're ready for their journey and they're only just in time, for a few miles from the coast the ice is already splitting. Now the mother can start hunting for the seals they must have, but she's leading her cubs into a dangerous new world. Nearly half of all cubs die in their first year out on the ice. Summer brings 24 hours of sunlight and the thawing shifting landscape. Further south the winter snows have almost cleared from the Arctic tundra. Northern Canada's wild frontier. Here nature stages one of her greatest dramas. Every year 3 million caribou migrate across the Arctic tundra. The immensity of the herd can only be properly appreciated from the air.


第10天，妈妈已经领着孩子们离开洞穴一二公里远了。该是让它们经受考验的时候了。孩子们的自信心大大增强，但还没有妈妈那样的紧迫感。看来它们终于做好了远行的准备，它们必须走，因为离海岸不远处的冰面已经开裂。现在妈妈可以开始捕猎它们赖以生存的海豹了，但同时她也把孩子们带到了一个危险的新世界。差不多有一半的小熊出洞后第一年在冰上死去。 夏天带来了24小时的阳光和融化浮动的冰景。再往南，北极冻土带的冬雪几乎看不到了。这是加拿大北部的荒野，大自然在这里上演它场面最宏大的戏剧之一。每年有300万只迁徙的北美驯鹿从北极冻土带经过。它的壮观场面只有从空中才能尽收眼底。