The wolverine ( , ; Gulo gulo), also called the carcajou or quickhatch (from East Cree, kwiihkwahaacheew), is the largest land-dwelling member of the family Mustelidae. It is a muscular carnivore and a solitary animal. The wolverine has a reputation for ferocity and strength out of proportion to its size, with the documented ability to kill prey many times larger than itself.
The wolverine is found primarily in remote reaches of the northern boreal forests and subarctic and alpine tundra of the Northern Hemisphere, with the greatest numbers in Northern Canada, the U.S. state of Alaska, the mainland Nordic countries of Europe, and throughout western Russia and Siberia. Its population has steadily declined since the 19th century owing to trapping, range reduction and habitat fragmentation. The wolverine has become essentially absent from the southern end of its range in both Europe and North America.
Naming 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, which means "glutton" (literally "devours much"). Its name in other West Germanic languages is similar (e.g. ).
The Finnish name is ahma, derived from ahmatti, which is translated as "glutton". Similarly, the Estonian name is ahm, with the equivalent meaning to the Finnish name. In Lithuanian, it is ernis; in Latvian, tinis or āmrija.
The Eastern Slavic росомаха (rosomakha) and the Polish and Czech name rosomák seem to be borrowed from the Finnish rasva-maha (fat belly). Similarly, the Hungarian name is rozsomák or torkosborz which means "gluttonous badger".
In French-speaking parts of Canada, the wolverine is referred to as carcajou, borrowed from the Innu-aimun or Montagnais kuàkuàtsheu. 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
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.
The adult wolverine is about the size of a medium dog, with a body length ranging from ; standing at the shoulder; and a tail length of . Weight is usually in males, and in females . 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.Holbrow, W. C. (1976). The biology, mythology, distribution, and management of the wolverine (Gulo gulo) in western Canada. The University of Manitoba (Masters Thesis).Krott, P. (1959). Demon of the North. A.A. Knopf, New York. 260pp. (Translated from German). 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.Weedle, F. (1968). The wolverine: the problems of a wilderness outcast. Defenders of Wildlife News 43: 156–168.Pulliainen, E. (1968). Breeding biology of the wolverine (Gulo gulo L.) in Finland. In Annales Zoologici Fennici (Vol. 5, No. 4, pp. 338–344). Finnish Zoological and Botanical Publishing Board.Järvenpää, J., & Norberg, H. (2011). Carnivore Nature Guide. European Agricultural Fund for Rural Development.Wiig, Ø. (1989). Craniometric variation in Norwegian wolverines Gulo gulo L. Zoological Journal of the Linnean Society, 95(3), 177–204. 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.
Like many other mustelids, it has potent anal scent glands used for marking territory and sexual signaling. The pungent odor has given rise to the nicknames "skunk bear" and "nasty cat." The anal gland secretion for the samples obtained from six animal's secretion was complex and variable: 123 compounds were detected in total, with the number per animal ranging from 45 to 71 compounds. Only six compounds were common to all extracts: 3-methylbutanoic acid, 2-methylbutanoic acid, phenylacetic acid, alpha-tocopherol, cholesterol, and a compound tentatively identified as 2-methyldecanoic acid. The highly odoriferous thietanes and dithiolanes found in anal gland secretions of some members of the Mustelinae [ferrets, mink, stoats, and weasels (Mustela spp.) and zorillas (Ictonyx spp.)] were not observed. The composition of the wolverine's anal gland secretion is similar to that of two other members of the Mustelinae, the pine and beech marten (Martes spp.)
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.
Wolverines have the highest compressive strength per trabecular bone volumetric fraction (A 10mm high × 5mm diameter cylinder) 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.LIU Xu, MA Ming, XU Fujun, XIONG Jiawu, Zhu Shibing, CUI Shaopeng, JIANG Zhigang, ZHANG Tong, GUO Hong, ERBOLAT Tuoliuhan. A preliminary study of wolverine in Altay, Xinjiang[J]. ACTA THERIOLOGICA SINICA, 2018, 38(5): 519–524.
Wolverine remains have been found in Ukraine, but they were extirpated and it is unclear whether the wolverines would have formed sustainable populations.
The species was present in Scotland until 6,000 BC.
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. However, wolverines were once recorded as also being present in Colorado, 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.Wolverine Sighting on SPI Land near Truckee . yubanet.com. 18 March 2009 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.
Behavior and ecology
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.Wolverine Gulo gulo , eNature.com