Wolverine — Chasing the Phantom

Wolverine: Chasing the Phantom

 While legend paints the wolverine as a solitary, blood-thirsty killer, there is another, more complex image of the wolverine that is just beginning to emerge. This episode of NATURE takes viewers into the secretive world of the largest and least known member of the weasel family, revealing it to be one of the most efficient and resourceful carnivores on Earth.

Wolverine: Chasing the Phantom

Introduction

Wolverines are among the most elusive creatures on the planet. They seek out the toughest terrain – the most rugged, remote and fiercely raw – and they’ve always been scarce to begin with. So they’re hard to find. They weigh only about 30 pounds, but they have a ton of attitude and a reputation to match. They eat everything, dead or alive, warm or frozen, and will climb anything, even mountains. It’s impossible for humans to keep up with them. They’re built to travel long distances with minimum effort across deep snow or up the sides of sheer cliffs. They roam an enormous territory of about 500 square miles – a home turf larger than an average grizzly bear’s. And they share it only with their immediate family. It’s “no trespassing” for everybody else.

Few researchers have observed wolverines in the wild, though some have tried, for years on end. Most must settle for capturing their images on remote cameras, tracking them from a distance, and getting to know them from their DNA. Those that study them become completely captivated by them, full of admiration and respect for these totally outrageous and independent creatures. Author and wolverine enthusiast, Doug Chadwick, puts it this way:  

“Like most of the guys on the project, what I really want to do is just be a wolverine. I want to go where I want to go, do what I want to do, bite who I want to bite, and climb what I want to climb.”

Yet there is one man whose experience with wolverines has been completely different. Wildlife filmmaker Steve Kroschel has spent 25 years with wolverines, and has even shared his home with them. Caring for injured and orphaned animals on a sixty-acre refuge in Alaska, he is one of the few men in the world to raise wolverines in captivity. The two orphans he has cared for since their birth have become his lifelong responsibility – and they are a handful! But he remains their committed and devoted advocate, a more than willing substitute parent to these remarkable animals he has come to love.

Species: Gulo gulo

Type: Weasel

Family: Mustelidae

Habitat: Arctic, subarctic, alpine, and boreal zones such as forests, grasslands, tundra, and rocky areas (e.g. inland cliffs, mountain peaks).

Range: Circumpolar: Canada, China, Estonia, Finland, Mongolia, Norway, Russian Federation, Sweden, and the United States.

Population Health: Decreasing, but classified under “Least Concern” according to the IUCN Red List due to its “wide distribution and remaining large populations.”

Estimated Population Size: Due to low density and wide distribution, estimates are extremely difficult. Combining conclusions from various recent studies, the worldwide population likely ranges between 15,000 and 30,000 individuals.

Size: Resembling a small bear, the wolverine is 26 – 36 inches long, excluding its bushy, 5 – 10 inch tail; shoulder height is 14 – 17 inches, and weight is 20 – 66 pounds.

Diet: Deer, sheep, small bears, rodents, hares, and other small burrowing mammals. Large portion of diet also comes from scavenged meat from carcasses of large mammals such as caribou and elk.

Additional Facts:

• The wolverine’s binomial name, Gulo gulo, comes from the Latin word gulo meaning glutton. It’s a fitting name; the wolverine has a voracious appetite and is known to devour even the bones and teeth of the animals it finds or kills. The wolverine can accomplish this feat thanks to its razor sharp teeth and powerful mandibles.

• During the 19th century, wolverine populations nearly disappeared due to hunting and other human activities like deforestation and recreational use of their habitats. But over the last few decades, they have been staging a comeback—many scientists expect large populations living in Canada and the northern United States.

• While the wolverine is the largest species of the land-dwelling weasels, it is much smaller than many of the other mammals within its territory. However, its size belies its strength and remarkable fearlessness—there is at least one reported story of a 30 pound wolverine attempting to steal a kill from a 400 to 500 pound black bear!

• The wolverine’s sense of smell is uncanny—it can detect a carcass lying 20 feet under the snow, allowing it to find the remains of animals killed in avalanches.

• A solitary and nocturnal hunter, the wolverine spends most of the year by itself, roaming its enormous territory, which varies from 65 km in Montana, USA to over 600 km in Scandinavia.

• Wolverines were once thought to be entirely reclusive and anti-social, getting together only for the purpose of mating. However, new findings indicate that after infants are born, they stay with their mother for up to an entire year and the dad returns periodically to help raise the kits. It turns out wolverine dads like to show their offspring the ropes.

• Wolverines have an average life expectancy of 4 to 6 years, but some can reach up to 13. They come to sexual maturity around 2.5 years and mate during the spring and summer months with new litters of 1-2 infants, sometimes as many as 5, being born between February and April.

• Weighing only 30 pounds, the wolverine’s proportionally enormous paws act as snow shoes, allowing it to move quickly over snow covered areas. While this gives wolverines a huge advantage over their competitors, it also makes them highly vulnerable to climate change. Snow, in other words, is crucial for their survival.

• Wovlerine paws not only act as show shoes, but also double as claws, with the tip of each of its twenty toes curved and extremely sharp. Equipped with these hook-like extremities, the wolverine possesses what might be called natural crampons, which allow it to scale an ice fall or a sheer cliff with little difficulty.

• Not only do wolverines use snow to their advantage when hunting, they also build snow dens in which the kits are born and nursed. Because reproduction occurs during spring, this requires that snow cover persists well into February and March. Climate change, however, will likely bring spring temperatures earlier in certain areas, which poses another risk to the wolverine’s survival by further limiting its range.

• When female wolverines build their dens in late February, they dig as deep as 15 feet below the snow to protect their young from predators and the cold.

• Wolverines are perhaps best known for their attitude. They don’t hesitate to fight with wolves and other predators over a meal, and given the right snow conditions are even capable of taking down a moose—a feat wolverine specialist Doug Chadwick likens to “a house cat bringing down a deer.”

• In 2009, a wolverine named M56 was captured near Grand Teton National Park. Scientists tracked M56 using radio equipment and were astonished by its journey—it traveled 550 solitary miles during April and May, over highways, mountain ranges, and across state lines. M56 became the first observed wolverine in Colorado since 1919.

• The wolverine has a great deal of spiritual significance for Native Americans. For some, it functions as a link to the spiritual world and is understood as both a trickster and a hero.

• Wolverines are known for having a very strong odor. They use their pungent smell in order to mark their territory and ensure that no rival wolverines invade their range.

• Because wolverines are both extremely territorial and highly sensitive to disturbance, the increasing popularity of winter backcountry recreation combined with new and more powerful snow machine technologies suggests that wolverine range will continue to diminish to due human activity.

• Wolverines are notoriously difficult to study in the wild, which is why so little has been known about them. Scientists are only just beginning to put together an accurate picture of this marvelous creature by combining a number of research methods such as radio-tracking, remote camera surveys, live traps, and DNA traps.