行星地球英文解说词第1集 PLANET EARTH From Pole to PoleA hundred years ago there were one and a half billion people on Earth. Now, over six billion crowd our fragile planet Earth. But even so, there are still places barely touched by humanity. This series will take to the last wildernesses and show you the planet Earth and its wildlife as you have never seen them before. Imagine our world without sun. Male Emperor penguins are facing the nearest that exists on planet Earth Earth - winter in Antarctica. Its continuously dark and temperatures drop to minus seventy degrees centigrade. The penguins stay when all other creatures have fled because each guards a treasure: a single egg rested on the top of its feet and kept warm beneath the downy bulge of its stomach. There is no food and no water for them, and they will not see the sun again for four months. Surely no greater ordeal is faced by any animal. As the sun departs from the Antarctic it lightens the skies in the far north. Its March and light returns to the high Arctic, sweeping away four months of darkness. A polar bear stirs. She has been in her den the whole winter. Her emergence marks the beginning of spring. After months of confinement underground she toboggans down the slope. Perhaps to clean her fur, perhaps for sheer joy. Her cubs gaze out of their bright new world for the very first time. The female calls them, but this steep slope is not the easiest place to take your first steps. But they are hungry and eager to reach their mother, whos delayed feeding them on this special day. Now she lures them with the promise of milk, the only food the cubs have known since they were born deaf and blind beneath the snow some two months ago. Their mother has not eaten for five months and has lost half her body weight. Now she converts the last of her fat reserves into milk for her cubs. The spring sun brings warmth but also a problem for the mother. It starts to melt the sea ice. That is where she hunts for the seal she needs to feed her cubs. And she must get there before the ice breaks up. For now though its still minus thirty degrees and the cubs must have the shelter of the den. Its six days since the bears emerged and spring is advancing rapidly. But even now blizzards can strike without warning. Being so small, the cubs are easily chilled and they will be more comfortable resting in the den. But their mother must keep them out and active. Shes becoming weak from hunger and theres no food on these nursery slopes. The sea ice still holds firm, but it wont last much longer. Day 10, and the mother has led her cubs a mile from the den. Its time to put them to the test. Theyve grown enormously in confidence, but they dont have their mothers sense of urgency. At last it seems that theyre ready for their journey and theyre 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 shes 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 Canadas wild frontier. Here nature stages one of her greatest dramas - Every year three million caribou migrate across the Arctic tundra. The immensity of the herd can only be properly appreciated from the air. Some herds travel over 2,000 miles a year in search of fresh pastures. This is the longest overland migration made by any animal. Theyre constantly on the move. Newborn calves have to be up and running the day they are born. But the vast herds do not travel alone. Wolves. Packs of them, eight to ten strong, shadow the migration. And they are hungry. Its the newly born calves that they are after. Running directly at the herd is a ploy to generate panic. The herd breaks up and now its easier to target an individual. In the chaos a calf is separated from its mother. The calf is young, but it can outrun the wolf if only it manages to keep its footing. At this stage the odds are even - either the caribou will make a mistake or after a mile the wolf will give up. Midsummer on the tundra and the sun does not set. At these latitudes the suns rays are glancing and not enough of their energy reaches the ground to enable trees to grow. Youll need to travel 500 miles south from here before that is possible. These stunted shrubs mark the tree line - the beginning of the boreal forest - the taiga. The needle-shaped leaves of the conifers are virtually inedible so this forest supports very little animal life. Its a silent place where the snow is unmarked by footprints. In the Arctic winter snow forms a continuous blanket across the land. But as spring creeps up from the south the taiga is unveiled. This vast forest circling the globe contains a third of all the trees on Earth and produces so much oxygen it changes the comp