标签：yellowstone 相关文章
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
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
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 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