The natural world is a world of balance, a world of yin and yang. There are the herbivores, the carnivores, and the insects and bacteria which recycle everything back into the elements. In this world of balance, all species are needed to maintain a healthy natural state. So, when wolves were reintroduced to Yellowstone park in the 1990s, their coming invoked a huge change - for the better. Watch this video and realize once again how magnificent the natural world is, and how smart.