06/20/2026
In June 1991, researchers in Alberta's Kananaskis Country fitted a five-year-old female gray wolf with the first satellite tracking collar ever placed on a wolf. It was raining, so they named her Pluie. French for rain. Then they let her go and watched the signal leave the province.
Over the next two years, Pluie covered 40,000 square miles. That is ten times the size of Yellowstone National Park. Fifteen times Banff. She crossed two Canadian provinces, three American states, more than thirty political jurisdictions, an international border, private ranches, First Nations territories, and the boundaries of multiple national parks and wilderness areas. She did it on foot, without a map, without a permit, and without any awareness that the invisible lines she was crossing changed her legal status from protected to huntable and back again with every step.
Her route reads like someone dragging a finger across the spine of the continent. From Kananaskis she moved east, then turned south into Montana. She passed the western edge of Glacier National Park and continued into the Idaho panhandle. She crossed into Washington state, turned east again, recrossed Idaho, moved back into Montana, and eventually returned north to the Canadian Rockies near Banff. A single loop through the largest remaining intact mountain ecosystem in the temperate world, completed by one animal whose collar was transmitting to satellites that had to be specially redirected to track her because her range exceeded what anyone had planned for.
Jodi Hilty, Y2Y's chief scientist and president, described what happened when the research team lost Pluie's signal after she left Alberta. The scientists in Banff had to call down to Texas and ask them to train more satellites on her. Nobody had expected a wolf to move that far that fast across that many jurisdictions. The tracking infrastructure was not built for an animal that treated the Rocky Mountains from Yellowstone to the Yukon as a single neighborhood.
What Pluie's collar data showed was not that she was exceptional. It was that she was normal. Wolves, grizzlies, lynx, cougars, golden eagles, and bull trout all travel distances of a thousand miles or more through the same mountain corridors. Indigenous peoples across the region had known this for millennia. The satellite collar proved it to the institutions that needed proof before they would act.
In 1993, a Canadian conservationist named Harvey Locke looked at Pluie's tracking data and proposed something that most people in the room thought was impossible. A connected system of protected wildlands stretching from Yellowstone National Park in Wyoming to the Yukon Territory in northern Canada. 3,400 kilometers of mountain corridor, managed not park by park or province by province but as a single interconnected landscape scaled to the animals that use it. He called it Yellowstone to Yukon. Y2Y.
The idea was motivated by two facts that Pluie's collar had made undeniable. First, no single park or protected area, no matter how large, contains enough habitat to sustain a viable population of wide-ranging carnivores. Banff is enormous. Yellowstone is enormous. Pluie used an area fifteen times the size of Banff in two years. A park that covers one-fifteenth of one wolf's range is not protecting the wolf. It is protecting a fraction of the wolf's Tuesday.
Second, the gaps between parks are where the animals die. Pluie crossed thirty jurisdictions. In some she was fully protected under the Canadian Species at Risk Act or the U.S. Endangered Species Act. In others she was a legal target for hunting. The legal status of the same wolf changed depending on which side of a line she was standing on, and she crossed those lines constantly because wolves do not read signs.
In December 1995, Pluie was shot and killed in a legal hunt south of Kootenay National Park in British Columbia. She was nine years old. Her collar was recovered. The bullets that killed her are still lodged in it. Y2Y displays the collar at conservation events. The holes in the plastic casing where the rounds entered are visible from across the room.
Thirty years after Pluie was collared, the Y2Y region has seen an eighty percent increase in protected areas. More than 204 wildlife crossings connect key landscapes across the corridor. The gap between the two largest Rocky Mountain grizzly populations in Montana and Canada has been reduced from 240 kilometers to just under fifty. Pluie did not live to see any of it. She showed one thing with her collar and the people who read the data spent three decades trying to build a landscape that would let the next wolf survive the same journey.
A wolf named for rain walked across two countries, three states, two provinces, and thirty jurisdictions in two years. She was shot legally in the gap between two parks. Her collar still has the bullets in it. Everything Y2Y has built since 1993 exists because one wolf proved that the mountains were one place and the maps were wrong.
Source: Yellowstone to Yukon Conservation Initiative / Parks Canada / National Park Service, Glacier / The Narwhal / Rocky Mountain Outlook.
