2014 · 0h 5m · Documentary
Genres: Documentary
When wolves were reintroduced to Yellowstone National Park in the United States after being absent nearly 70 years, the most remarkable "trophic cascade" occurred. What is a trophic cascade and how exactly do wolves change rivers? George Monbiot explains.
Director: George Monbiot
Writers: George Monbiot
Music by: Chris Zabriskie