26 January 2011

Wolverines: Dangerous or Endangered?

Picture a weasel -- and most of us can do that, for we have met that little demon of destruction, that small atom of insensate courage, that symbol of slaughter, sleeplessness, and tireless ,incredible activity -- picture that scrap of demoniac fury, multiply that mite some fifty times, and you have the likeness of a Wolverine.
-Ernest Thompson Seton, "Lives of Game Animals.”

The fiercest creature on earth. Demon of the North. A dangerous killer. Indian Devil. Given the wolverine’s astonishing array of sinister nicknames, it is difficult to imagine what would possess a person to acquire a wolverine and keep it as a house pet. However, in his book Demon of the North, a German animal dealer in the 50’s, Peter Krott, recounts his domestication of and affection for these elusive predators. The wolverine plays prominently in Native American mythology as an oftentimes malevolent trickster figure. In Passamaquoddy mythology, “Master Lox” or “the Indian Devil” is a wolverine.  In the popular imagination, the wolverine has come to be representative of the brutal, wild landscapes which it inhabits.  With a bear-like appearance (albeit much smaller), teeth which can crush bones and tear through frozen flesh, and the ability to outrun a snowshoe hare (see video footage here), it’s not entirely surprising that the wolverine has developed a reputation as a ferocious predator.  

Physical Characteristics
The largest member of the Mustelidae (weasel) family, the wolverine is stocky and bear-like in appearance. It has small eyes, rounded ears, short legs, and large, 5-toed feet which act as snowshoes in the snowy habitat in which the wolverine spends much of its time. Adult wolverines generally range in length from 25-35 inches and weigh 20-50 pounds. They display sexual dimorphism, with males often weighing up to 140% the weight of the females. Their fur is a dark, glossy brown, and was prized by the Inuit and fur traders alike for its frost-resistance.

The wolverine’s Latin name, Gulo Gulo, translates to glutton, denoting a voracious appetite and over-consumption but this is an inaccurate depiction of the wolverine’s eating habits. The wolverine is a scavenger and will eat anything from plants, berries, or eggs to caribou. It eats carrion (often the leftovers of other predators) but is also capable of bringing down animals several times its size when necessary. According to Daniel Mathews, in Rocky Mountain Natural History, “Biologists in the Selkirks found a 300-pound caribou brought down by a 25-pound wolverine, which must be close to the extreme size ratio a lone mammal predator can tackle.” What they don’t eat they will often spray with musk and store in a cache for later (the behavior from which the nickname “skunk bear” derives.)

Range and Habitat
Wolverines are capable of traveling prodigious distances. A lone wolverine will travel up to 30 miles in a single day in search of food. A male’s home range may be as large as 400 square miles. They live in remote, vast wilderness areas in boreal forests and tundra in Northern latitudes. The wolverine has been extirpated from much of its former habitat by the encroachment of human development.

Protection Status
The wolverine is not listed as endangered or threatened, though many wolverine advocates have been working tirelessly to achieve protection for wolverines. The potential impact of global warming on critical wolverine habitats is of particular concern. Wolverines rely on the carrion of ungulates which have fallen prey to avalanches and other winter-specific deaths, and as we continue to see milder winters, food could become more and more scarce for these scavengers.  Female wolverines are reliant upon the winter snowpack for their dens and as this snow disappears, it will become increasingly difficult for them to find suitable sites for their dens.  Additionally, a decrease in winter snow cover will fragment already vulnerable wolverine populations even further. A lack of connectivity between different populations increases the likelihood of inbreeding, and the subsequent plummeting of genetic variation and the species’ long-term survivability.

Last December, the U.S. Fish and Wildlife Service acknowledged that wolverines are endangered; however, it refrained from listing them, citing a backlog of petitions for endangered status for different species and a lack of funding as reasons for this decision. Steve Guertin, regional F.W.S. director, said, “Listing the wolverine as a designated population at this time is precluded by the need to address other listings of higher priority, it is proposed for listing when funding and workload priorities allow.” In the meantime, a study done by the Rocky Mountain Research Center and the University of Washington Climate Impacts group predicts that the wolverine’s habitat will decrease 63% by 2099.  This incredibly resilient creature might not be tough enough to survive a changing climate.

1 comment:

  1. Heard Doug Chadwick talk on campus on Wednesday, March 30. An engaging storyteller with a message of conservation and a slide show with numerous great photos of this elusive species that is a mystery to many of us who occupy the same part of the earth that it does.