They released 14 wolves to the wild. What happend after that is a mircle.. wait to 3:08 minutes. Crazy!

In 1995, U.S wildlife and fisheries organization amongst with canadian biologists, caught 14 wolves in Canada and moved them to Yellowstone Park in the North-Western United States, where they have become extinct from 1926. Within a few years the number of wolves got bigger, but it was the smallest change occuring in Yellowstone Park.

The impact of the wolves on the park was much larger than anyone could expect. The park's ecosystem completely changed and even rivers have changed. How can it be? Watch this marvelous video and the remarkable way in which nature works.