Armed with powerful jaws, sharp claws, and a thick hide, wolverines may defend kills against larger or more numerous predators. There is at least one published account of a 27-pound wolverine's attempt to steal a kill from a black bear (adult males weigh 400 to 500 pounds). Unfortunately for the mustelid, the bear won what was ultimately a fatal contest. Mating season is in the summer, but the actual implantation of the embryo (blastocyst) in the uterus is stayed until early winter, delaying the development of the fetus. Females will often not produce young if food is scarce. Litters of typically two or three young ("kits") are born in the spring. Kits develop rapidly, reaching adult size within the first year of a lifespan that may reach anywhere from five to (in exceptional individuals) thirteen years.
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. Juveniles are of course more vulnerable; infants (kits) have been known on occasion to be taken by predatory birds such as eagles.
The world's 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 km² (240 sq mi) while encompassing the ranges of several females (with smaller home ranges of roughly 130-260 km² (50-100 sq mi). Adult wolverines try for the most part to keep non-overlapping ranges with adults of the same sex. Radio tracking suggests an animal can range hundreds of miles in only a few months.
|Country||Population||Area||Year||State of Population|
|Norway||150+||Snøhetta plateau and North||1995-97||Decline|
|Finland||115||Karelia and North||1997||Stable|
|Russia - Komi||885||-||1990||-|
|Russia - Archangelsk Oblast||410||Nenetsky Autonomous Area||1990||Limited|
|Russia - Kola Peninsula||160||Hunting Districts||1990||Decline|
|USA - Alaska||unknown||Kobuk Valley National Park, Selawik National Wildlife Refuge||1998||Decline|
|USA - Alaska||3.0 (± 0.4 SE) wolverines/1,000 km2||Turnagain Arm and the Kenai Mountains||2004||-|
|USA - California||Unknown||Tahoe National Forest||2008||Unknown|
|Canada - Yukon||9.7 (± 0.6 SE) wolverines/1,000 km2||Old Crow Flats||2004||-|
|Canada - Ontario||unclear||Red Lake – Sioux Lookout to Fort Severn – Peawanuck||2004||Stable to Expanding|
|Canada - Overall||15000 to 19000||Overall||-||Stable|
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.
The U.S. state of Michigan is, by tradition, known as "The Wolverine State," and the University of Michigan takes the wolverine as its mascot. Many other educational institutions utilized the wolverine as an athletic mascot (e.g., Bronx High School of Science and Utah Valley University). A major league baseball team from the 1880s was also popularly known as the "Detroit 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. In any event, the animal appears no longer to be indigenous to the state (and in fact may never have been). It is, at the very least, an uncommon sight there: for example, when one was observed in February 2004 by hunters and biologists near Ubly, it was the first confirmed sighting of a wolverine in Michigan in about two centuries. It is unknown whether that particular animal was a state native or if it migrated or had been released by humans.
The European Football League (playing American football in Europe) includes the Helsinki Wolverines, founded in 1995. The team plays in the Maple League, the Finnish top level. The wolverine figures prominently in the mythology of the Innu people of eastern Québec and Labrador. In at least one Innu myth, it is the creator of the world.