by Douglas H. Chadwick
Back in the Ice Ages, the ancestors of wolverines competed for prey and carcasses with saber-toothed cats, dire wolves, mega-bears and giant northern hyenas. Natural selection in this crowd did not favor the slow, shy or even slightly polite. Which helps explain why the 25- to 45-pound wolverines we know today singlehandedly bring down grown caribou and an occasional moose, and will fight a grizzly over the spoils.
But when I say these might be the toughest animals in the world, I’m also including the way wolverines relentlessly roam vast territories here along the top of the Rockies, taking on cliffs, icefalls and summits through some of the nastiest weather modern winters can throw at a mammal. Climbers and extreme skiers come back from such expeditions and tell riveting tales of survival. Wolverines just growl and keep going 24/7. Fierce and strong beyond all proportion to their modest size, they have nevertheless finally met a force they may not be able to overcome: climate change.
I volunteered on a study radio-tracking this species along the continental divide in Montana’s Glacier National Park, where winter starts in October and lingers into June. During the cold months, we would trap wolverines in stout log boxes and tag them with radios. Once the sedative we used wore off and we lifted the box’s lid to free them, some would sprint directly away. But others, like M1, a big gnarly guy with anger-management issues, would bound a few dozen feet and stop, as if they’d remembered the trap still held food and why the hell shouldn’t they go back to take it with them. M1 would circle us as if trying to make up his mind, and scentmark as he went, staking his claim. Once, he didn’t leap from the opened box at all but just perched on its lip glaring around at the two-leggeds, maybe figuring his chances of shredding what he saw as the competition.