How Wolves Changed An Entire Ecosystem! Amazing!

This amazing phenomenon is called “trophic cascade.”  It is an ecological process that starts from the top of the food chain and reaches the base.
It changed the entire ecosystem – even the rivers.  “When we try to pick out anything by itself, we find it hitched to everything else in the Universe.”
John Muir (1838-1914).  Narrated by George Monbiot.  Music by Chris Zabriskie.