Snarling, the low-slung but stocky animal stood its ground in front of the Jeep. From my vantage point, walking along that Wyoming road about 20 feet from the confrontation, the wolverine looked uncomfortably large. Its long teeth looked capable of chewing right through the Jeep's tire, in fact. I hung back, unable to take my eyes off of the creature as it gave a final growl, then reluctantly turned and shambled off into the underbrush.
The northern woods of Europe, Asia, and North America are home to a fearless predator and scavenger called Gulo gulo, the wolverine. Wolverines are the largest member of the order Mustelidae (weasels). Females are generally 20-25 pounds, while males can be twice as heavy. Wolverines are active year-round, regardless of the weather, so require plenty of food to maintain themselves.
For their size, wolverines are incredibly strong. While they probably can't disable a Jeep, they can kill such large prey as caribou, deer, moose, bighorn sheep, and elk. Wolverines travel at speeds as fast as 30 miles per hour when running down game, and have broad, cushioned feet which act as snowshoes in deep powder. The paws are tipped with enormous, sharp claws. They've also been known to pounce on large prey from trees, much as cougars or jaguars do. Wolverines aren't particularly picky eaters, however, and will take smaller animals such as rabbits, beavers, porcupines, marmots, and squirrels as well. Nonetheless, because of their bulk and caloric requirements, wolverines cannot survive on an exclusive diet of small game. They are found only in areas where large ungulates like moose or caribou are available.
Wolverines are expert scavengers as well as hunters, frequently eating carrion from winterkills and other animals' prey. A scavenging wolverine can appear almost suicidally aggressive; they have been known to drive cougars, wolf packs, and even bears away from their kills. The teeth, jaws, and neck muscles are so powerful that a wolverine can crush a moose's femur to get the marrow, or tear chunks of meat from a frozen carcass. Once it has brought down game or found another hunter's kill, the wolverine will stash the meat in a cache, sprinkling it with rancid-smelling musk to discourage other scavengers.
Opportunists to the core, wolverines won't pass up other kinds of food, either. They have been known to eat eggs, roots, berries, and even ants.
In order to reproduce female wolverines require a steady supply of large mammals. Roots and berries won't suffice. In the northern part of their range, reproduction depends upon the availability of caribou; further south, deer and elk supply the protein necessary to fuel a mother wolverine and her cubs.
Wolverines are beautiful (if somewhat intimidating) animals. They play an important role in the boreal ecosystem, cleaning up after other predators, and finishing off weather-weakened large grazers. Sadly, their numbers are low, and thought to be decreasing. If we want our children to have a chance to see a wolverine, as I did when I was 12 years old, we have to conserve the great northern forests.