This year marks the 20th anniversary of the wolf’s return to Yellowstone National Park.

Wolves once roamed the United States before decades of unregulated slaughter wiped them out. It wasn’t until they were missing that people began to recognize the crucial role wolves play in maintaining the health of the natural world.

The gray wolf was one of the first to be protected by the Endangered Species Act. Its re-introduction in the northern Rockies restored a balance in the ecosystem.

Join the pack: http://earthjustice.org/howl