Watch the YouTube video - Predators, with Bill Ripple.
Watch the Oregon Field Guide special, Wolves in Oregon?. Bill Ripple and his Yellowstone research are featured at minutes 14.36-17.25.
View the NATURE documentary In the Valley of the Wolves which premiered November, 2007 on PBS.
Watch the Bio Bulletin video entitled "Wolves Help Aspen Trees Grow" from the American Museum of Natural History.