Over the last three decades, Yellowstone National Park has undergone an ecological cascade. As elk numbers fell, aspen and willow trees thrived. This, in turn, allowed beaver numbers to increase, ...

A grey wolf prowls through Yellowstone National Park near Mammoth Hot Springs in Montana. A group of 66 wolves was reintroduced to Idaho and Yellowstone in the late 1990s. They now total 2,800 ...

In the heart of Wyoming lies Yellowstone National Park, a sprawling ecosystem that has captivated millions of visitors for centuries. However, its delicate balance faced a near collapse before a ...

When the U.S. Fish and Wildlife Service reintroduced 14 gray wolves to Yellowstone National Park in 1995, the animals were, in some ways, stepping into a new world. After humans hunted wolves to ...

In Yellowstone National Park — where gray wolves were reintroduced starting in 1995 — researchers have gone back and forth on whether the restoration of wolves has impacted the ecosystem. The idea is ...

Across North America, mountain lions, bears and gray wolves have made a remarkable comeback over the last 50 years. Once nearly exterminated, these animals have been recovering their populations and ...

Wildlife cameras positioned throughout Yellowstone National Park have captured something researchers didn't expect to see. Adult wolves have been hauling their helpless pups across vast distances ...