Wolverine

The wolverine's questionable reputation as an insatiable glutton (reflected in its Latin genus name Gulo, meaning "glutton") may be in part due to a false etymology. The less common name for the animal in Norwegian, fjellfross, meaning "mountain cat", is thought to have worked its way into German as Vielfraß, However, in France, the wolverine's name is glouton (glutton). Purported gluttony is reflected neither in the English name wolverine nor in the names used in North Germanic languages. The English word wolverine (alteration of the earlier form, wolvering, of uncertain origin) probably implies "a little wolf". The name in Proto-Norse, erafaz and Old Norse, jarfr, lives on in the regular Icelandic name jarfi, regular Norwegian name jerv, regular Swedish name järv and regular Danish name jærv. ==Taxonomy and evolutionary history==

Classification of Germany at the Natural History Museum, Berlin , Italy Genetic evidence suggests that the wolverine is most closely related to the tayra and martens, all of which shared a Eurasian ancestor. There are two subspecies: the Old World form, Gulo gulo gulo, and the New World form, G. g. luscus. Some authors had described as many as four additional North American subspecies, including ones limited to Vancouver Island (G. g. vancouverensis) and the Kenai Peninsula in Alaska (G. g. katschemakensis). However, the most accepted taxonomy recognizes either the two continental subspecies or G. gulo as a single Holarctic taxon. Evolution Recently compiled genetic evidence suggests most of North America's wolverines are descended from a single source, likely originating from Beringia during the last glaciation and rapidly expanding thereafter, though considerable uncertainty to this conclusion is due to the difficulty of collecting samples in the extremely depleted southern extent of the range. ==Physical characteristics==

Anatomically, the wolverine is an elongated animal that is low to the ground. With strong limbs, broad and rounded head, small eyes and short rounded ears, it most closely resembles a large fisher. Though its legs are short, its large, five-toed paws with crampon-like claws and plantigrade posture enable it to climb up and over steep cliffs, trees and snow-covered peaks with relative ease. Exceptionally large males of as much as are referenced in Soviet literature, though such weights are deemed in Mammals of the Soviet Union to be improbable. The males are often 10–15% larger than the females in linear measurements and can be 30–40% greater in weight. According to some sources, Eurasian wolverines are claimed to be larger and heavier than those in North America, with weights of up to . However, this may refer more specifically to areas such as Siberia, as data from Fennoscandian wolverines shows they are typically around the same size as their American counterparts. It is the largest of terrestrial mustelids; only the marine-dwelling sea otter, the giant otter of the Amazon basin and the semi-aquatic African clawless otter are larger—while the European badger may reach a similar body mass, especially in autumn. Wolverines have thick, dark, oily fur which is highly hydrophobic, making it resistant to frost. This has led to its traditional popularity among hunters and trappers as a lining in jackets and parkas in Arctic conditions. A light-silvery facial mask is distinct in some individuals, and a pale buff stripe runs laterally from the shoulders along the side and crossing the rump just above a bushy tail. Some individuals display prominent white hair patches on their throats or chests. Wolverines, like other mustelids, possess a special upper molar in the back of the mouth that is rotated 90 degrees, towards the inside of the mouth. This special characteristic allows wolverines to tear off meat from prey or carrion that has been frozen solid. Wolverine have the highest compressive strength per trabecular bone volumetric fraction (A 10mm high × 5mm diameter cilinder) at the mandibular condyle among all carnivore mammals at 940.8 Newtons, followed by the cheetah at 784.4 Newtons, the Malagasy civet at 714.4 Newtons, the honey badger at 710.8 Newtons and the kinkajou at 693.2 Newtons. ==Distribution==

Wolverines live primarily in isolated arctic, boreal, and alpine regions of northern Canada, Alaska, Siberia, and Fennoscandia; they are also native to European Russia, the Baltic countries, the Russian Far East, northeast China and Mongolia. Wolverine remains have been found in Ukraine, but they were extirpated and it is unclear whether the wolverines would have formed sustainable populations. Unique records of encounters with wolverines have been noted in Latvia, the most recent one being in late July 2022 (although it can be disputed because of the unclear footage); the population was widespread in the 16th and 17th centuries, but it is no longer native to the area. Most New World wolverines live in Canada and Alaska. areas of the southwestern United States (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 in New York and Pennsylvania. In the Sierra Nevada, wolverines were sighted near Winnemucca Lake in spring 1995 and at Toe Jam Lake north of the Yosemite border in 1996; and later photographed by baited cameras, including in 2008 and 2009, near Lake Tahoe. According to a 2014 U.S. Fish and Wildlife Service publication, "wolverines are found in the North Cascades in Washington and the Northern Rocky Mountains in Idaho, Montana, Oregon (Wallowa Range), and Wyoming. Individual wolverines have also moved into historic range in the Sierra Nevada Mountains of California and the Southern Rocky Mountains of Colorado, but have not established breeding populations in these areas". In 2022, Colorado Parks and Wildlife considered plans to reintroduce the wolverine to the state. Wolverines are also found in Utah but are very rarely seen, with only six confirmed sightings since the first confirmed sighting in 1979. Three of these six confirmed Utah sightings have been caught on video. A wolverine, a male, was finally captured and tagged in Utah in 2022 before being released back into the wild to better understand the animal's range. In August 2020, the National Park Service reported that wolverines had been sighted at Mount Rainier, Washington, for the first time in more than a century. The sighting was of a reproductive female and her two offspring. In 2004, the first confirmed sighting of a wolverine in Michigan since the early 19th century took place when a Michigan Department of Natural Resources wildlife biologist photographed a wolverine in Ubly, Michigan. The specimen was found dead at the Minden City State Game Area in Sanilac County, Michigan, in 2010.{{Cite web|last=Mattson|first=Kyle|date=18 January 2016 ==Behavior and ecology==

of Helsinki Diet and hunting Wolverines are primarily scavengers. Most of their food is carrion, especially in winter and early spring. They may find carrion themselves, feed on it after the predator (often, a wolf pack) has finished, or simply take it from another predator. Wolverines are known to follow wolf and lynx trails to scavenge the remains of their kills. Whether eating live prey or carrion, the wolverine's feeding style appears voracious, leading to the nickname of "glutton" (also the basis of the scientific name). However, this feeding style is believed to be an adaptation to food scarcity, especially in winter. The wolverine is also a powerful and versatile predator. Its prey mainly consists of small to medium-sized mammals, but wolverines have been recorded killing prey many times larger than themselves, such as adult deer. Prey species include 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. This may be because competing predator populations in Eurasia are less dense, making it more practical for the wolverine to hunt for itself than to wait for another animal to make a kill and then try to snatch it. They often feed on carrion left by wolves, so changes in wolf populations may affect the population of wolverines. Wolverines often cache their food during times of plenty. This is of particular importance to lactating females in the winter and early spring, a time when food is scarce. Reproduction Wolverines are induced ovulators. Successful males will form lifetime relationships with two or three females, which they will visit occasionally, while other males are left without a mate. Wolves are thought to be the wolverine's most important natural predator, with the arrival of wolves to a wolverine's territory presumably leading the latter to abandon the area. Armed with powerful jaws, sharp claws, and a thick hide, wolverines, like most mustelids, are remarkably strong for their size. They may defend against larger or more numerous predators such as wolves or bears. By far, their most serious predator is the grey wolf, with an extensive record of wolverine fatalities attributed to wolves in both North America and Eurasia. It has been reported that packs of grey wolves occasionally kill wolverines, either to defend their kills or to protect dens containing their own pups. In North America, another (less frequent) predator is the cougar. At least one account reported a wolverine's apparent attempt to steal a kill from a black bear, although the bear won what was ultimately a fatal contest for the wolverine. There are a few accounts of brown bears killing and consuming wolverines as well and, although also reported at times to be chased off prey, in some areas such as Denali National Park, wolverines seemed to try to actively avoid encounters with grizzly bears as they have been reported in areas where wolves start hunting them. Urine scent marking Wolverines have been observed to use urine as a scent-marking behavior. Headspace analysis of the volatiles emanating from urine samples identified 19 potential semiochemicals. The major classes of identified chemicals are the ketones: 2-heptanone, 4-heptanone and 4-nonanone and the monoterpenes: alpha-pinene, beta-pinene, limonene, linalool and geraniol. In other mammals, the excretion of these terpenes is unusual. The conifer needles that are found in wolverine scat are likely the source of these monoterpenes. ==Threats and conservation==

The world's total wolverine population is not known. The animal exhibits a low population density and requires a very large home range. The wolverine is listed by the IUCN as Least Concern because of its "wide distribution, remaining large populations, and the unlikelihood that it is in decline at a rate fast enough to trigger even Near Threatened". This requirement for large territories brings wolverines into conflict with human development, and hunting and trapping further reduce their numbers, causing them to disappear from large parts of their former range; attempts to have them declared an endangered species have met with little success. In November 2023, the United States Fish and Wildlife Service announced that it was adding the wolverine in the United States Lower 48 states to the threatened list. The Wildlife Conservation Society reported in June 2009 that a wolverine researchers had been tracking for almost three months had crossed into northern Colorado. Society officials had tagged the young male wolverine in Wyoming near Grand Teton National Park, and it had traveled southward for about . It was the first wolverine seen in Colorado since 1919, and its appearance was also confirmed by the Colorado Division of Wildlife. In May 2016 the same wolverine was killed by a cattle ranch-hand in North Dakota, ending a greater-than- trip by this lone male wolverine, dubbed M-56. This was the first verified sighting of a wolverine in North Dakota in 150 years. In February 2014, a wolverine was seen in Utah, the first confirmed sighting in that state in 30 years. In 2024, Colorado's state government passed a bill authorizing the reintroduction of wolverines into the state. As of February 2026, Colorado Parks and Wildlife plans to release 15 wolverines annually over the course of three years. This will be the first attempt to reintroduce wolverines to a region where they have been extirpated. In captivity Around a hundred wolverines are held in zoos across North America and Europe, and they have been bred in captivity, but only with difficulty and high infant mortality. ==Human interactions==

, when wolverines were still found in southern France Many North American cities, sports teams, and organizations use the wolverine as a mascot. For example, the US state of Michigan is, by tradition, known as "the Wolverine State", and the University of Michigan takes the animal as its mascot. There have also been professional baseball and football clubs called the "Wolverines". The association is well and long established: for example, many Detroiters volunteered to fight during the American Civil War and George Armstrong Custer, who led the Michigan Brigade, called them the "Wolverines". The origins of this association are obscure; it may derive from a busy trade in wolverine furs in Sault Ste. Marie in the 18th century or may recall a disparagement intended to compare early settlers in Michigan with the vicious mammal. Wolverines are, however, extremely rare in Michigan. A sighting in February 2004 near Ubly was the first confirmed sighting in Michigan in 200 years. The animal was found dead in 2010. The Marvel Comics superhero James "Logan" Howlett was given the nickname "Wolverine" while cage fighting because of his skill, short stature, keen animal senses, ferocity, and most notably, claws that retract from both sets of knuckles. The wolverine is prevalent in stories and oral history from various Algonquian tribes and figures prominently in the mythology of the Innu people of eastern Quebec and Labrador. The wolverine is known as Kuekuatsheu, a conniving trickster who created the world. The story of the formation of the Innu world begins long ago when Kuekuatsheu built a big boat similar to Noah's Ark and put all the various animal species in it. There was a great deal of rain, and the land was flooded. Kuekuatsheu told a mink to dive into the water to retrieve some mud and rocks which he mixed together to create an island, which is the world that is presently inhabited along with all the animals. Many tales of Kuekuatsheu are often humorous and irreverent and include crude references to bodily functions. Some Northeastern tribes, such as the Miꞌkmaq and Passamaquoddy, refer to the wolverine as Lox, who usually appears in tales as a trickster and thief (although generally more dangerous than its Innu counterpart) and is often depicted as a companion to the wolf. Similarly, the Dené, a group of the Athabaskan-speaking natives of northwestern Canada, have many stories of the wolverine as a trickster and cultural transformer much like the coyote in the Navajo tradition or raven in Northwest Coast traditions. ==References==