Some animals matter so much to their ecosystems that losing them is like removing the keystone from an arch—the entire ...

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 ...

The story of Yellowstone National Park and its wolves is a lesson in the consequences of humans meddling with the world's natural order. Wolves that live in temperate grasslands, specifically gray ...