The Wolverine (Gulo gulo) is the largest and fiercest member of the weasel family. The wolverine is native to northern regions of North America, Europe and Asia. This land dwelling mammal is known by many other names including the Skunk Bear, Devil Bear, Carcajou (by the French-Canadians) and Glutten (by Europeans). If the wolverine was the size of a bear, it would be the strongest animal on earth.
Once abundant in numbers, the wolverine is a very rare animal due to over-hunting both for its fur and because it is viewed as a pest by some people.
The wolverine has a heavyset, muscular body which measures 65 – 105 centimetres (26 – 41 inches) in length excluding the tail. It weighs around 9 – 17 kilograms (22 – 36 pounds). The males are as much as 30 percent larger than the females. Wolverines have short, thick legs and long, curved, non-retractile claws. Their head and tail are carried low and their back forms a high arch.
Wolverines have a round, blunt head with a short, pointed snout. They have a short, but very bushy tail measuring 17 – 26 centimetres (7 – 10 inches). The individual hairs on their tails measure up to 20 centimetres (8 inches) in length.
Wolverines have thick, dark brown body fur with long glossy hairs and a lighter coloured stripe running the entire length of each side of their body. Their fur is long and dense and does not retain much water, making it very resistant to frost, which is common in the wolverines cold habitat. Their eyes are set widely apart and their ears project only a short distance above the head fur.
Wolverines feet are equipped with pads, which enable them to travel easily through heavy snow. Wolverines have a highly developed sense of smell and can smell food underneath the snow. They are very swift animals and can move around quickly.
Wolverines have very strong teeth and powerful jaws which allow them to devour every bit of their prey including hind, hooves and bone. Wolverines possess a special upper molar in the back of their mouth that is rotated 90 degrees, or sideways, towards the inside of the mouth. This special characteristic allows wolverines to tear off meat from prey or carrion that has been frozen solid and also to crush bones, which enables the wolverine to extract marrow.
Wolverines have very poor eyesight, however, they have very good hearing and a strong sense of smell. They have been known to give off a very strong, extremely unpleasant odour, giving rise to the nickname ‘skunk bear’.
Wolverines prefer forest habitats and open plains. They frequent remote boreal forests, taiga and tundra biomes.
Wolverines eat bird eggs, berries and any animal they can kill. If live prey is unavailable, they will feed up on carrion (dead animal carcasses). This aggressive scavenger will challenge cougars and wolves for their prey. It has also been known to kill prey as large as moose. Wolverines will also dig into burrows and eat hibernating mammals.
The wolverine is a solitary animal who usually travels alone except for the breeding season. Individual wolverines may travel 15 miles (24 kilometres) in a day in search of food. They are nocturnal animals that do not hibernate.
The wolverine is basically a terrestrial animal, however they are very good at climbing trees and are also powerful swimmers. They have great stamina and can travel great distances without breaking for rest.
Armed with powerful jaws, sharp claws and a thick hide, wolverines may defend kills against larger or more numerous predators. Adult wolverines have no natural predators, though they do come into conflict with (and may be killed by) other large predators over territory and food.
The worlds total wolverine population is unknown. The animal exhibits a low population density and requires a very large home range. The range of a male wolverine can be more than 620 kilometres squared (240 square miles) while encompassing the ranges of several females (with smaller home ranges of roughly 130 – 260 kilometres squared (50 – 100 square miles).
Male wolverines use scent glands to mark their territories, however, they share them with several females and are believed to be polygamous. This requirement for large territories brings wolverines into conflict with human development.
Wolverine mating season is in the summer, however, the actual implantation of the embryo (blastocyst) in the uterus is stayed until early winter, delaying the development of the fetus. Females give birth to a litter of 2 – 4 young in the spring after a gestation period of 30 – 50 days. Kits sometimes live with their mother until they reach their own reproductive age at about 2 years old. Females will often not produce young if food is scarce.
Kits develop very quickly, reaching adult size within their first year. The life span of a wolverine may reach anywhere from 7 to 13 years.
Wolverine Conservation Status
Hunting and trapping further reduce their numbers, causing wolverines to disappear from large parts of their former range.
In the past, wolverines were hunted by trappers in North America for their beautiful coat, which was used as a lining for parkas. However, this is not as common these days, with the wolverine being given protective status in several regions. Wolverines are classified as Vulnerable on the IUCN Red List 2007.