Wolverine

Common Name:
Wolverine
Scientific Name:
Gulo gulo
Type:
Mammals
Diet:
Carnivore
Average Life Span In The Wild:
Up to 13 years
Size:
Head and body: 26 to 34 inches; tail: 7 to 10 inches
Weight:
Up to 40 pounds
IUCN Red List Status:
Least concern

What is a wolverine?

With brownish-black colorations, long claws and teeth, and a formidable reputation, the wolverine walks around with the swagger of a flattened bear. However, this animal is actually a weasel.

As the largest terrestrial member of the Mustelidae, or weasel, family, wolverines are cousins to animals such as otters, ferrets, and honey badgers.  

Sometimes called the skunk bear, due to the way its anal glands produce a stinky secretion when provoked or frightened, wolverines are generally not a threat to humans. Adding to this nickname is the appearance of a light brown or reddish stripe running down their flanks, as well as the way they sometimes arch their backs.

The wolverine is also sometimes called “the glutton,” which is what Gulo translates into from Latin. This is likely because wolverines live in vast territories where food is scarce. So, when one finds something edible, the wolverine will eat as much as possible, returning to a carcass many times until it’s been picked clean.   

With wide paws, and sharp claws, wolverines traverse deep snow and slippery ice like they’re wearing a combination of snowshoes and mountain-climbing boots, or crampons.

Habitat and diet

Wolverines are native to the Arctic and subarctic regions of North America, Europe, and Asia. They prefer habitats undisturbed by humans, including grasslands, alpine forests, taiga, boreal forests, and tundra.

(How DNA from snow helps scientists track elusive animals.)

Scientists consider wolverines to be opportunistic carnivores, and have found everything from reindeer, moose, and porcupines to walrus, seals, and whales in their natural diets. Much of the wolverine’s diet appears to come from scavenging animals that have already died by other means, but they are also capable hunters, sometimes able to bring down full-grown deer and their relatives.

There are also numerous accounts of wolverines chasing much larger animals away from carcasses, from black bears to wolf packs.

Reproduction

Wolverines are solitary for most of the year, usually coming together only to mate.

After a breeding season that lasts from April to August, females remain pregnant for approximately 215 days. When nearing birth, the mother wolverine digs a deep snow den that may have tunnels 15 feet from the surface. Litters tend to include two to four kits, each of which is born with its eyes closed, no teeth, and a soft coat of blond hair. For the first nine to 10 weeks, kits remain with their mother inside the den.

Sometimes, the male will return periodically to help raise the kits.

Conservation

Historically, wolverines were threatened by the fur-trapping trade as well as by other human activities, such as timber operations and general development. Climate change is also a concern due to the way the species relies on snow to make its natal dens and for taking down large game.

(As wolverines battle to survive, warming poses a new threat.)

Perhaps the single greatest threat to wolverines now comes from the mere presence of humans. Females with kits are easily disturbed, and as people push farther into wild spaces, with logging roads and snowmobiles, the wolverines retreat. With an already low reproductive rate, scientists worry that if we don’t protect female wolverines from human disturbance, they’ll give birth to fewer new wolverines to add to an already dwindling population.

It is for these reasons that the Canadian government listed the wolverine as a species of special concern in 2018. The U.S. government followed suit in 2023 by naming the wolverine populations in the lower 48 states as threatened under the Endangered Species Act—which will mean federal agencies such as the U.S. Forest Service and Bureau of Land Management will have to take the wolverine’s status into consideration when planning timber harvests, fossil fuel extraction, or developments such as new roads.

Editor's note: This story was last updated on December 29, 2023.

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