Bringing Back the Wolves

An unintended experiment in Yellowstone National Park, in which an ecosystem is devastated and then remarkably rehabilitated, provides crucial lessons about nature’s intricate balancing act.

In the 1800s, hunters were paid by the American government to eliminate threats to livestock on cattle ranches near Yellowstone National Park. They did such a good job that, by 1926, no gray wolf packs were left in the park. Over the following decades, virtually every other part of the park’s ecosystem was affected by the loss of the wolves — from the animals who were their prey, to the plants that were the food for that prey, to the streams that were sheltered by those plants — and the landscape was in distress. So, starting in 1995, in an attempt to reverse course, the government reintroduced gray wolves to the park. Over time, animal populations stabilized, waterways were restored and a healthy ecosystem was recreated across the land. It’s a striking transformation, and a fascinating tale of life’s complicated interdependencies.