11 Ferocious Facts About Wolverines

When you hear the world wolverine, chances are the first thing that pops into your mind is the super-buff, clawed comic book character. This depiction isn't far off from the actual animal, a weasel that also has some pretty sharp claws. Once hunted nearly to extinction for their fur, wolverines have rebounded and are currently a species of least concern. Still, that doesn't mean they're easy to find: These animals are elusive, and much about them remains mysterious—but here are a few things we do know.

1. THEY'RE MADE FOR COLD WEATHER.

Wolverines can be found in boreal forests and tundras in North America, Europe, and Asia, where temperatures are cool even in the summer, so it's no surprise that these animals have evolved to deal with frigid weather. They have big paws that that spread to twice their size when they hit the ground, distributing their weight to help them travel through snow (they can run up to 30 mph!), and thick, oily fur that resists frost—a fact that has made them a target for fur traders.

2. THE ANIMAL'S SCIENTIFIC NAME MEANS "THE GLUTTON"—AND IT'S A PRETTY APT DESCRIPTOR.

At four feet tall and weighing up to 22 pounds (females) and 40 pounds (males), these fierce creatures are the largest members of the weasel family. Still, they're small compared to some of the animals they compete with for food—but a wolverine has no problem standing up to wolves or a bear when a meal is on the line.

Gulo gulo are opportunistic eaters that hunt live prey—including small animals like hares and rodents as well as larger animals, like caribou, that are weak or ill—but will also scavenge from any carcass they can get their claws on. (They also eat vegetables and berries.) Frozen meat isn't a deterrent: An upper molar that sits sideways at 90 degrees lets them rip into ice-covered carcasses. Their teeth are so sharp and strong that they can even eat bones. Once they've got food, they often bury it to save it for later; mere hours after a meal, they'll go on the hunt again.  

3. THEY'RE BURROWERS.

Wolverines use their non-retractable claws not just to bury food but also to build dens; females dig as deep as 15 feet into snow to create burrows for their young. But the claws aren't just good for digging: They also allow the animals to climb trees (though, as the video above shows, they're not exactly adept at it).

4. WOLVERINES ARE PRETTY STINKY.

One Native American tribe calls wolverines "skunk bear." The stench comes from special anal glands that allow the animals to emit an offensive odor that protects their food and marks their territory (they'll also use it when threatened, raising their tails like skunks). The fragrant odor has traces of methylbutanoic acid (think smelly cheese), methyldecanoic acid, and phenylacetic acid, and has a composition similar to that of smaller members of the weasel family, pine and beech martens.

5. THEY'RE NOT THE STRONGEST MAMMAL POUND-FOR-POUND.

Though folklore would have you believe that wolverines are the strongest animals in the kingdom, science has proved this to be largely untrue. Yes, these animals can be aggressive, but they only have a moderately strong bite: According to findings published in a 2007 research paper, the animal's bite force at the canines is 224 Newtons. Compare that to the highest number, 1646.7 Newtons, which belongs to the polar bear. Grizzlies, tigers, and lions aren’t far behind. 

The researchers also calculated bite force quotient (BFQ) to compare the bite force of animals with differing body sizes. According to the scientists, “Species with BFQs around 100 may be regarded as having near 'average' bite force for their body size.” Wolverines come in at around 105—in other words, pretty average. The palm civet (161.1) and the Sun bear (160.5) both rank higher, as do several other weasels. The animal in the paper with the highest BFQ is Mustela nivalis, or least weasel, at 164. Outdoing them all is the Tasmanian Devil, which has a BFQ of 181.

6. THEY HAVE GREAT NOSES.

Wolverines can smell prey even when buried under 20 feet of snow, and have even been known to find and kill animals that are in hibernation.

7. THEY CAN TRAVEL INCREDIBLE DISTANCES.

When looking for food, wolverines can cover as many as 15 miles in a single day. In the United States, these mostly solitary creatures wander a territory of 47 square miles, and in Scandinavia, they roam territories that stretch over more than 270 miles. But that's nothing compared to the distance one wolverine covered in 2009: Scientists figured out that the animal, which was spotted in Colorado, had trekked over 500 miles from its home in Wyoming. 

8. THEY'RE POLYAMOROUS.

In the wild, wolverines have a life span of seven to 12 years. When they reach sexual maturity, around age two, one male will mate with several females he allows to live in his territory in the spring and summer months. Implantation of the fertilized eggs is delayed until the fall/winter, after which gestation lasts from four to seven weeks. Females typically give birth to an average of three kits, which are under five inches long, weigh just a few ounces, and are covered in snow-white fur. By the time the kits are six weeks old, they're exhibiting darker fur; each animal will develop unique coloration patterns on its face, neck, and chest. Kits stick with their moms for at least a year, and sometimes longer, and dad often returns to help out.

9. THEY'RE QUITE SMART.

These animals use low traffic human roads when traveling through their territory and can sneak bait out of traps set by scientists who want to collar them for study.

10. OTHER ANIMALS ARE SOMETIMES MISTAKEN FOR WOLVERINES.

According to the Colorado Parks & Wildlife [PDF], badgers, marmots, bear cubs, and porcupines all look like wolverines from a distance.

11. SCIENTISTS ARE WORKING HARD TO FIND OUT MORE ABOUT THESE ELUSIVE ANIMALS.

Groups like the Citizen Wildlife Monitoring Project have spotted wolverines with remote cameras mounted in the Washington state wilderness, and the University of Alberta has developed The Wolverine Project, which is focused on trapping wolverines and attaching GPS-tracking collars to their bodies in order to study their movement. The project has led to some pretty awesome—and occasionally crazy—experiences: The scientists recount that when they went out to find F7, a female whose GPS collar was "providing very few and weak signals," they had trouble locating her den when "suddenly, the deep, distinctive growl of a wolverine filled the air":

"Unable to determine from which direction the growl was coming from, biologists continued to search the area. Soon after, they found what they believe were tracks, which led them to the log stack in the photo—very likely her den. Satisfied, they concluded the trek. However, upon reviewing the GPS telemetry data they discovered something a little unsettling: F7 had been circling, stalking them the entire time."

All images courtesy of iStock.