Wolverines: Wild Weasels Of The Alpine
A small dark blur upslope materialized into a loping wolverine, coming straight toward us! Afraid this wolverine wanted to share our lunch, we left our backpacks where they lay, and hurried out of its path.High on the west side of Logan Pass in Glacier National Park, bloated marmots grazed and pikas chirped, darting over rocks with mouths full of grass and flowers. My family and I were enjoying lunch, noting our luck in relative seclusion from the crowds often drawn to this popular pass.
Suddenly, startled marmots interrupted our solitude, squealing and shuffling down the steep slope to the tree-line. We strained our eyes to see what could have caused the disturbance.
A small dark blur upslope materialized into a loping wolverine, coming straight toward us! Afraid this wolverine wanted to share our lunch, we left our backpacks where they lay, and hurried out of its path.
Without even a glance, the shaggy golden-retriever-sized member of the weasel family ran right past us into the trees. Clearly, it was after a more exciting lunch than our PB&J.
Captivated by this creature, I was eager to learn more about one of the Treasure State’s most elusive and endangered residents. Wolverines once hunted and scavenged their prey from Maine to California.
Reduced primarily to the North American Rockies, Scandinavia, and Siberia, these tenacious weasels now inhabit a rugged snowy landscape for which they are well suited.
In Montana, wolverines reside mostly within the Crown of the Continent ecosystem, including the Bob Marshall Wilderness and Glacier National Park. This high, wide, and handsome country has become virtually the southern tip of their current range.
Among the craggy peaks and deep valleys of our state, each wolverine maintains a vast territory. Regularly spanning hundreds of square miles, wolverines can cover their entire range in a matter of days!
Food sources in this high country can get fairly slim, so wolverines tend to stay spread out to avoid competing with each other. With only slightly overlapping territories, it’s a wonder these critters don’t get lonely, considering they have a very low population densities, roughly one animal per 100 square miles.
On average, each individual wolverine’s territory would cover Missoula more than four times over! Wolverines hunt for much of their food, but they won’t often pass up an opportunity to enjoy a free meal.
Wolverines regularly scavenge animals they find dead, and have powerful noses that can help them find a carcass from miles away. Mountain goats, deer, elk, caribou, and various rodents make up their main diet.
Interestingly, wolverines store food under the snow to keep it from rotting and being eaten by other scavengers. Like many other Montana predators such as wolves, lynx and bobcats, wolverines are active throughout the winter.
They have wide snowshoe-like paws that help them run on crusted snow. Without this adaptation, these dense muscular animals would punch right through, making it difficult for them to search for food.
Female wolverines can weigh as much as 26 pounds, and males can weigh up to 39, making them the largest land-dwelling weasel. With four snowshoes on the ends of legs built for running, they’d make any winter hike look like an Olympic sprint.
Perhaps the most important issues concerning wolverines today are habitat loss, trapping, and climate change. New highways, ski areas, and housing developments break up habitat, cutting wolverines off from their historic home ranges.
Climate change threatens the patches of snow that last all year, necessary for wolverines to den and cache food in. The U.S. Fish & Wildlife Service considers the wolverine a “species of concern,” and has recommended them for protection under the Endangered Species Act.
Lucky for us, we still have the opportunity to share a landscape with wolverines when there are so many other areas that have lost theirs.
Already, effective management strategies and habitat conservation are “paving the way” for wolverines to expand their territory. In the meantime though I’ll be in high places, listening for more squealing marmots and their shaggy indomitable pursuers.
"Field Notes" is produced by the Montana Natural History Center.