For eons, female members of the Porcupine caribou herd have made the journey from their winter feeding grounds to their summer calving grounds—which happen to lie on vast reserves of oil. They once roamed borderless wilderness; now they trek from Canada, where they’re protected, to the United States, where they are not.

In April 2003, wildlife biologist Karsten Heuer and filmmaker Leanne Allison set out with the Porcupine caribou herd. Walking along with the animals over four mountain ranges, through hundreds of passes, and across dozens of rivers—a thousand-mile journey altogether, from the Yukon Territory to the Arctic National Wildlife Refuge and then back again—they reached a new understanding of what is at stake in the debate over drilling for oil.

More than a tale of grand adventure or an activist tract, however, Being Caribou is a “gripping, cinematic tale” (Los Angeles Times) with the “bite of a political tract” (Washington Post) about the power of wilderness and how it returns us to the roots of human instinct. On the caribou’s trail Heuer and Allison learn what is possible when two people immerse themselves in the uniquely wild experience of migration, discovering in the process a different way of being.