灰狼
3.Wolves have also thrown the doors to the Yellowstone meat market wide open.
4.Either of two carnivorous mammals of the family Canidae, especially the gray wolf of northern regions, that typically live and hunt in hierarchical packs and prey on livestock and game animals.
5.ALTHOUGH THE JURY is still deliberating the effects of wolves, early evidence strongly suggests that the canids are unwitting restoration biologists.
6.Now, 30 years later, wolf populations in the midwestern United States have recovered enough to end their protected status .
7.More important, the Yellowstone wolves are bringing into focus hazy ideas of how ecosystems work in a way that has never been so meticulously documented.
8.The wolf-effect theory holds that wolves kept elk numbers at a level that prevented them from gobbling up every tree or willow that poked its head aboveground.
9.Just as the actions of the wolf echo through Yellowstone, they will reverberate into the future as they help to increase the understanding of natural systems.
