The Wolverine Way

The list of adaptations that make winter a wolverine’s ally is impressive. Yet until scientists started to focus on climate change, no one gave much thought to how Ice Age-built creatures with a supercozy fur coat, smoldering metabolism and food cached in nature’s refrigerators are supposed to handle swimsuit weather in our ever-toastier Age of Industrial Exhaust. In February, pregnant females go into snow dens and prepare to give birth. Fewer than two dozen dens have ever been discovered in the Lower 48, about half of them during the Glacier study. They were all at high altitudes and dug eight to 10 feet down into the snowpack. White as polar bears when born, baby wolverines weigh only a few ounces. They need all that snow overhead for insulation, especially when mom, their furry furnace, is away hunting. They also need to be too far under the surface for passing predators to find. The kits won’t venture out until sometime in May. Wolverine biologist Jeff Copeland and ecologist Kevin McKelvey created a continental map showing where snow lasts through the first half of that month. Then they charted the range of Gulo gulo. The two patterns were nearly identical. When Copeland took a closer look at the species’ exact whereabouts, he discovered that the animals rarely occurred where the average maximum daily temperature in August exceeds 70 degrees F (22° C). As it turns out, wolverines’ ties to a deep, persistent snowpack and places where summers don’t get too hot are what ecologists call obligate. Like the better-known polar bear, they simply can’t get by without chilly conditions. Only about 300 remain in the Lower 48 today. The very least we two-leggeds can do is safeguard habitat corridors – especially north/south-running ones – to keep the surviving groups connected and give wolverines a better chance of adjusting to changing conditions. While we get dead serious about turning down the planet’s thermostat for all our sakes.