标签：黄石公园 相关文章
This mother bear's experience gives her family a good chance of survival until spring arrives. They will return again and again as the thaw releases more fish. On the warmer plains and valleys that surround the plateau, grazers are on the move. They
自然百科2012年
Clues to why the herds are drawn to the Yellowstone plateau lie in its deep and unique history. This plateau is the created bowl of a huge sleeping volcano. And melting rock below the surface still pushes the land up to the cold of high altitude. But
自然百科2012年
As 6 months of snow and ice begins to melt, Yellowstone starts to come back to life. Cascading snowmelt swells the streams and rivers. It's a hazard that the migrating herds must cross. Young are barely up to the task. The Yellowstone river has incre
自然百科2012年
As the migrating herds arrive in the plateaus river valleys, the spring is here. This is why they have made the journey after the famine of winter. Food is everywhere. Birds have flown in from as far away as the Arctic and subtropics. Canada geese jo
自然百科2012年
Hot water scorches and drowns the roots of trees encroaching on the valleys. It can keep the forests in check and the rich pastures / open. Those pastures now produce the new grass needed to make rich milk and feed a bison baby boom. The few calves b
自然百科2012年
As soon as she feels it is safe, she settles to suckle and reassure them. Bison can shrug off this sudden change in the weather; they are after all built to survive the Yellowstone winter. But this tiny hummingbird is more vulnerable. Flowers damaged
自然百科2012年
The living is easy. But it won't last long. At this altitude, the air is so dry that rain evaporates before it even hits the ground. The water that flows off the plateau is no longer being replaced. Already there is drought in forests beyond the mead
自然百科2012年
This female grew up on the lake, so she knows where to take the cubs for a very special trip. Yellowstone cutthroat trout are massing in the mouth of the stream that feeds the lake. They are preparing for their annual spawning. But the trout must wai
自然百科2012年
She chews its tail first, to make sure the fish can't get away. While the pups are still demanding milk, the mother otter will often keep the whole fish for herself. Her pups are happy enough with caviar. As the flow becomes slow enough for the trout
自然百科2012年
They are vast smoke plumes. Yellowstone is burning. Throughout the summer, the dry lodgepole pines have become like a tinderbox, and lightening has struck the match. The worst wild fires will burn for weeks. In 1988, a third of Yellowstone burnt in a
自然百科2012年
Bison lose the last of their winter coats. In the heat, tempers fray. To escape soaring ground temperatures, cowbirds choose a bison's back as a cool place to feed and catch the breeze. Biting insects now become a draining nuisance. A grizzly bear es
自然百科2012年
Bison calves are more independent of their mothers. The adults' focus is now set on a ruthless competition to mate. A male bids to enter a herd with females in season. He uses dust to accentuate all his size and power. Another male already establishe
自然百科2012年
But just as the first of Yellowstone's new generation are preparing to leave, its last visitors are arriving. Night after night, army cutworm moths have been escaping the heat of a distant prairie. They have been flying in on favorable winds, hiding
自然百科2012年
As she approaches to see him off again, she realizes she has been injured. A damaged jaw would be a disaster for her and her family. Clearly in pain, she leads the anxious cubs to high ground away from the male. She nurses to calm and / reassure them
自然百科2012年
In just a few weeks, this lake will be frozen, and the beavers wont be able to cut and move trees, but they will be able to swim right under the ice to feed from this underwater larder. Moose also eat twigs and branches and often try to take advantag
自然百科2012年
And for every dam, there is a new habitat for new life, and a richer, more diverse Yellowstone. But just as Yellowstone reveals the complexity of life, it also exposes its fragility. On its lofty ridges, there are signs that all is not well with the
自然百科2012年
his is a tree that needs a cold winter. Its now November and the elk have found their feeding grounds just in time, the snows of winter at their heels. Here they join other herds who come to this place every year, where the snow would be less deep an
自然百科2012年
But now, the final act of the season is about to take place. From out of apparently nowhere come the bighorn sheep, the toughest of all Yellowstones animals. They can stay here all winter on slopes and crags that the biting wind keeps clear of snow.
自然百科2012年
As the snow returns to Yellowstone, it seems like the clock is turning back. All traces of the human world are covered up. A reminder that when the heart of this great wilderness was made a national park nearly 140 years ago, it was one of the most r
自然百科2012年
Imagine a pile of TNT about the size of Rhode Island and reaching eight miles into the sky, to about the height of the highest cirrus clouds, 想像一下，有一堆TNT，面积相当于英国的一个郡，伸向13公里高的天空，达到了最高
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