Four days before Christmas in 2008, a blur of brown fur scrambled along the snowy Continental Divide in Wyoming. The terrain and the conditions were brutal, food scarce. The bait a biologist placed in a wooden trap proved irresistible.
As soon as the creature crawled in, a signal alerted researchers miles away. They rode a snowmobile deep into the mountains, near Togwotee Pass, at an elevation of 9,380 feet. The temperature was 10 degrees.
Once there, the researchers confirmed the catch, summoned a veterinarian and sedated the animal with a dart. The vet made an incision in its abdomen and implanted an electronic transmitter.
Over time, that transmitter would help tell the story of a singularly tenacious representative of one of the West's most elusive animals: the wolverine. Yet it also would demonstrate the limits of technology in solving the mysteries of the wild.
While biologists and bureaucrats debated whether to protect wolverines under federal law, arguing over climate change and its effect on a species believed to number fewer than 300 in the contiguous United States, the animal captured near Togwotee Pass would blaze an audacious and ultimately untraceable trail. Along the way, it made a cameo appearance in a court case that may help shape the fate of its species.
"If you had to put your finger on the one most interesting wolverine during our whole study," said Bob Inman, the wildlife biologist who led the research project, "that was it."
He is known as M56, or Male 56, the label given to him by Inman, who was working on behalf of the Wildlife Conservation Society at the time. At 32 pounds, M56 was one of the heavier males captured. He was believed to be about 18 months old.
For a time he stayed in the snow-covered reaches where wolverines make their dens. But by winter's end, he was on the move, "dispersing," as experts call the springtime sojourns some males make to look for a mate.
It is one of nature's most challenging dating games. Many wolverines, the largest members of the weasel family, travel hundreds of miles to find a partner. M56 may have traveled thousands.
He scaled 10,000-foot peaks in a few hours, but also endured arid lowlands. He cut across Wyoming's Red Desert, then turned south into the Medicine Bow National Forest. On Memorial Day weekend 2009, he crossed Interstate 80 and by June entered Colorado, the first confirmed wolverine there in 90 years.
Colorado news outlets loved his story. State biologists took over responsibility for tracking him, making flights to locate his signal. Photographers stumbled upon him. Schoolchildren studied him.
His presence provided momentum for an ongoing push to reintroduce wolverines in Colorado. All the while, the effort to list wolverines as a protected species continued.
The battle began in the 1990s. For years the Fish and Wildlife Service declined to protect the animal, but after lawsuits and court rulings, it decided in 2013 that wolverines indeed warranted protection under the Endangered Species Act. The decision was based on projections that, in decades to come, climate change would substantially shrink the high-elevation spring snow cover essential for wolverines to den.
That finding represented a new way of thinking about climate change and endangered species. It also set off a wave of challenges, particularly from Western states, which tried to cast doubt on the science. They were led by Montana, which still allowed trapping of wolverines.
Inman too questioned the science. Of seven wolverine experts consulted, he was one of two who cast doubts. Critics said he was too close to Montana officials. Later, their criticism increased when he was hired as the state's carnivore-furbearer coordinator.
Inman said in an interview that that he did not oppose listing the wolverine, but that listings often lead to litigation that spoils support for voluntary conservation programs.
"It's the carrot and the stick, and sometimes the carrot works better," he said.
In August 2014, the service reversed itself again, withdrawing its decision to list wolverines. Once again, outrage and lawsuits followed.
Nearly two years would pass before a federal judge threw out that decision, labeling it "arbitrary and capricious." The judge, Dale Christensen of U.S. District Court in Montana, said the agency appeared to be bowing to pressure from Western states.
"No greater level of certainty is needed to see the writing on the wall for this snow-dependent species standing squarely in the path of global climate change," Christenson wrote on April 4, noting the two-decade debate.
He said the Endangered Species Act compelled the service "to take action at the earliest possible, defensible point in time to protect against the loss of biodiversity within our reach as a nation. For the wolverine, that time is now."
In justifying its 2014 decision to not list the wolverine, one Wildlife Service official cited M56's arrival in Colorado, as well as a lone wolverine discovered in California's Sierra Nevada, as evidence they were expanding in numbers and range. Christensen did not view the sightings as proof wolverines were not threatened by climate change.
What neither the service nor the judge noted was that the last confirmed sighting of M56 had been in October 2012. After that, his signal went silent and sightings ceased.
Then, on a rainy Sunday morning three weeks after Christensen issued his ruling, Jared Hatter, a ranch hand in North Dakota, jumped in his truck and rushed to a pasture. Something was stirring up his father-in-law's cattle.
The family owns about 200 head of black Angus cattle, and each year they sell about 150 calves for $600 to $1,000 a head. Hatter, 29, is married and has a 1-year-old son.
"Them cows raise our kid, pay our pickup payments, pay our maintenance," he said.
The cows, protecting their calves, had surrounded a furry intruder. They broke their circle when Hatter pulled up. The intruder tried to flee. Hatter aimed his .223-caliber rifle and fired a single shot into the back of its head.
That evening, he and his wife, Jena, scoured the internet to identify the creature. They learned of efforts to track wolverines and the push for federal protection.
Hatter called the state the next morning to report the shooting. Biologists came out the same day, taking measurements and counting teeth.
"He was sopping wet," Hatter said. "It had rained for three days straight."
Stephanie Tucker, North Dakota's furbearer biologist, conducted a necropsy and was surprised at how healthy the animal was, given its apparent age, perhaps 10. No parasites, organs intact. She found a transmitter sewn inside the abdomen. She called Inman.
"Honestly, I didn't even think about M56 in Colorado," Inman said. "But when I looked up the number, bam, there it is, M56."
Hatter would face no charges; it is legal in North Dakota to shoot a furbearing animal perceived to be threatening livestock.
But he did face a backlash. He had posted five pictures on Facebook with a caption: "Killed this here critter out tormenting the cows yesterday."
Before he made his account private, he received what he said were 4,000 friend requests, few of which were actually friendly.
"You killed so-and-so wolverine," he said, summarizing some of the messages. "We'll come kill you."
Hatter has no regrets.
"I'm going to kill a predator preying on my cow herd," he said. "I could have done it a lot worse and nobody would have found out about it, and M56 would have been laying in a creek somewhere, just a carcass and the vultures eating him. But I reported it."
Biologists are not sure M56 would have hurt any cattle - there were no reports of him doing so in Colorado - but Hatter's point about his fate is not lost on them.
Had he not reported the kill, no one would have known that M56 could demonstrate enough restlessness and resourcefulness to travel not only from Wyoming to Colorado but all the way to North Dakota, where no wolverine had been confirmed since statehood in 1889.
"It's an unfortunate situation," Inman said, "but you learn what you can from it after the fact."
The Fish and Wildlife Service has filed notice that it may appeal Christensen's ruling but declined to comment on its next move.
Matthew Bishop, an attorney for the Western Environmental Law Center, who argued in favor of protecting wolverines before Christensen, said climate change presents uncertainties that have complicated the way the agency views many listing questions. The wolverine decision could set a precedent.
"I think they're very concerned about opening up the climate change floodgates," Bishop said. "But we don't have to know precisely why or how climate change is going to adversely affect wolverines. It's enough to know they're going to lose a significant amount of habitat."
So what was M56 doing in North Dakota, 700 miles from the Colorado Rockies?
The best guess is that he was making another springtime dispersal, like the one he made years ago. That first trip made him famous. This one made him a museum piece. North Dakota plans to have M56 stuffed and put on display in Bismarck.
Explore further: Judge: Climate change imperils wolverines and feds must act (Update)