20 Years Since Wolves Returned to Yellowstone

This month marks the 2oth anniversary of the reintroduction of wolves in Yellowstone. On March 22, 1995, after years of legal battles and logistical preparation, the gates of acclimation pens in Yellowstone National Park were opened and wolves – captured in Canada and transported to the United States – were once again part of the natural environment of northwest Wyoming. The wolves’ return set in motion a natural—and therefore uncontrolled—experiment that is still unfolding, and which offers biologists a rare opportunity to observe predator-prey relations among large mammals. Today, 95 wolves in 11 packs live in Yellowstone, hunting elk, deer, and bison.