This video of how wolves cange rivers is an eye-opener and a must be seen! It shows how the Yellowstone National Park got back life once the wolves were released again in the park after nearly 70 years of absence. It shows how primordial wolves are for our ecosystem, and you want to understand what happens to a, from deer devasted land and forest, when wolves come back, and with it a natural order! George Monbiot, the creator of this awesome Youtube video, speaks of a ‘trophic cascade’. Fascinating!