Wolverine

The wolverine (/ˈwʊlvəriːn/ WUUL-və-reen, US also /ˌwʊlvəˈriːn/ WUUL-və-REEN;) is the largest land-dwelling member of the family Mustelidae. Known also as the carcajou or quickhatch, this strong and fierce animal is a solitary carnivore that lives far from other animals.

Wolverines are found in cold places, such as the northern boreal forests, subarctic areas, and alpine tundra across the Northern Hemisphere. They are most common in Northern Canada, Alaska, parts of Europe, and western Russia and Siberia.

Even though wolverines are not very big, they are very powerful. They are known for being able to take down animals much larger than themselves. However, their numbers have gone down since the 1800s because of trapping, losing their homes, and habitat fragmentation. Today, wolverines are rarely seen in the southern parts of North America and Europe.

Naming

The wolverine is known by many names around the world. Its Latin name, Gulo, means "glutton," but this might not be true. In Norwegian, it is called fjellfross, meaning "mountain cat," which later became Vielfraß in German, meaning "devours much."

In Finnish, it is called ahma, from ahmatti, meaning "glutton." In Estonian, it is ahm, with a similar meaning. In Lithuanian, it is ernis, and in Latvian, it is tinis or āmrija.

In Eastern Slavic languages, it is called rosomakha, and in Polish and Czech, it is rosomák, borrowed from the Finnish rasva-maha, meaning "fat belly." In Hungary, it is called rozsomák or torkosborz, meaning "gluttonous badger."

In French-speaking Canada, the wolverine is called carcajou, from the Innu-aimun or Montagnais language. In France, it is called glouton, meaning "glutton."

The English name "wolverine" probably means "a little wolf." In North Germanic languages, it has names like jerv in Norwegian, järv in Swedish, and jærv in Danish, all coming from ancient Proto-Norse and Old Norse words.

Taxonomy and evolutionary history

Genetic evidence suggests that the wolverine is most closely related to the tayra and martens. There are two subspecies: the Old World form, Gulo gulo gulo, and the New World form, G. g. luscus. Recently compiled genetic evidence suggests most of North America's wolverines come from one source, likely from Beringia during the last glaciation.

Physical characteristics

The wolverine is a strong, low-to-the-ground animal with a broad head, small eyes, and short ears. It looks a bit like a large fisher, with strong legs and big paws that help it climb steep cliffs, trees, and snowy mountains.

Adult wolverines are about the size of a medium dog. Males are usually bigger than females, weighing between 11 and 18 kg, while females weigh between 8 and 12 kg. They have thick, dark fur that helps keep them warm in cold weather. Some wolverines have a light-colored stripe on their face and a bushy tail. They also have special glands that produce a strong smell to mark their territory.

Distribution

Wolverines live mainly in cold areas such as arctic, boreal, and alpine regions of northern Canada, Alaska, Siberia, and Fennoscandia. They are also found in European Russia, the Baltic countries, the Russian Far East, northeast China, and Mongolia.

Wolverines have been seen in Ukraine, but they are no longer common there. There have been rare sightings in Latvia, with the most recent in July 2022. They used to live in many parts of the United States, including Colorado, the southwest (Arizona and New Mexico), the Midwest (Indiana, Nebraska, North and South Dakota, Ohio, Minnesota, and Wisconsin), New England (Maine, New Hampshire, Vermont, and Massachusetts), and New York and Pennsylvania. In recent years, they have been spotted in the Sierra Nevada, like near Winnemucca Lake in 1995 and Toe Jam Lake in 1996, and later near Lake Tahoe. They live in the North Cascades in Washington and the Northern Rocky Mountains in Idaho, Montana, Oregon (Wallowa Range), and Wyoming. Some have been seen in California and Colorado, but they haven’t stayed there to have families.

Wolverines are also in Utah, but they are rarely seen. In 2022, a male wolverine was caught and tagged in Utah before being let go again. In August 2020, wolverines were seen at Mount Rainier in Washington for the first time in over a hundred years. This was a female with her two babies. In 2004, a wolverine was photographed in Michigan for the first time since the early 1800s.

Behavior and ecology

Wolverines mostly eat food they find, called carrion, especially in winter and early spring. They might find it themselves or take it after another animal, like a wolf, has finished eating. They follow wolves and lynx to find their leftovers. Even though they are called "gluttons," this way of eating helps them survive when food is hard to find.

Wolverines are also strong hunters. They eat small to medium-sized animals but can even take down much larger prey, like deer. They eat porcupines, squirrels, chipmunks, beavers, marmots, moles, gophers, rabbits, voles, mice, rats, shrews, lemmings, caribou, roe deer, white-tailed deer, mule deer, sheep, goats, cattle, bison, moose, and elk. They sometimes eat smaller predators like martens, mink, foxes, Eurasian lynx, weasels, coyotes, and even wolf pups. In Canada, they have been known to hunt Canada lynx. They also eat birds' eggs, birds like geese, roots, seeds, insect larvae, and berries. Wolverines can even threaten golden eagles, attacking their nests and young. In Sweden, wolverines hunt more actively because there are fewer competing predators. They store food when it is plentiful, which is important during scarce times, especially for females with babies.

Wolverines mate in summer, but the embryo doesn't implant until early winter. Females might not have babies if there isn't enough food. After a gestation of 30 to 50 days, females give birth to two or three kits in spring. Kits grow quickly and reach adult size within a year. In the wild, wolverines usually live between 8 and 10 years.

Larger animals like wolves, black bears, brown bears, and cougars can kill adult wolverines, while smaller predators may target young ones. Wolverines are very strong for their size and can defend themselves against larger animals. Grey wolves are their biggest threat, sometimes killing them to protect their food or pups. In some places, wolverines try to avoid grizzly bears.

Wolverines use urine to mark their territory. They leave special scents that help communicate with other wolverines.

Threats and conservation

The total number of wolverines in the world is not known. They need large areas to live and usually stay far away from other wolverines of the same sex. Because they need so much space, they sometimes come close to places where people live and work.

Wolverines also face challenges from activities like hunting and trapping, which have caused their numbers to drop in many areas. Because of this, there have been efforts to protect them. In the United States, wolverines were added to the list of threatened animals in November 2023. Some areas, like Colorado, are planning to bring wolverines back to places where they used to live.

In captivity

Today, about a hundred wolverines live in zoos in North America and Europe. They have been bred in zoos, but it has been difficult, and many baby wolverines do not survive.

Human interactions

Many North American cities, sports teams, and organizations use the wolverine as a symbol. For example, the US state of Michigan is traditionally called "the Wolverine State", and the University of Michigan uses the animal as its symbol. There have also been professional baseball and football clubs called the "Wolverines". This connection goes back a long way. For example, many people from Detroit volunteered to fight during the American Civil War, and George Armstrong Custer, who led the Michigan Brigade, called them the "Wolverines".

The wolverine appears in many stories and traditions from various Algonquian tribes and is important in the mythology of the Innu people of eastern Quebec and Labrador. In these stories, the wolverine is known as Kuekuatsheu, a clever character who helped create the world. The tale begins long ago when Kuekuatsheu built a big boat like Noah's Ark and placed all the animal species inside. After a great flood, Kuekuatsheu sent a mink to dive into the water to bring up mud and rocks, which were used to form the island that became the world we live on today. Many stories about Kuekuatsheu are funny and include playful references to everyday life. Some tribes, such as the Miꞌkmaq and Passamaquoddy, call the wolverine Lox, who appears in tales as a clever and sometimes tricky character, often shown as a companion to the wolf. Similarly, the Dené, a group of Athabaskan-speaking people from northwestern Canada, have many stories about the wolverine as a clever character and helper, much like the coyote in Navajo traditions or raven in Northwest Coast traditions.