Wolverines in the lower-48 states are the latest species under consideration for protection under the Endangered Species Act. Wolverines need deep snow to birth and rear their young. As snowpack continues melting earlier each year, we need to take aggressive action to reduce the carbon pollution driving climate change, and to consider climate impacts in wolverine conservation efforts.
Once heavily persecuted and likely eliminated from the lower-48 states, the wolverine returned on its own over the past 50 years, but now climate change puts it at risk. U.S. Fish and Wildlife has proposed (February 2013) that wolverine populations in the lower-48 states be added to the threatened species list under the Endangered Species Act.
Wolverines have a wide variety of nicknames. They are known throughout the lower 48 as glutton, woods devil, Indian devil and ommeethatsees (a Cree Indian word), carcajou, quickhatch, nasty cat and skunk bear.
It is the largest land-living specis in the weasel family, or Mustelids. Other Mustelids in the U.S. include the least weasel, long-tailed weasel, short-tailed weasel (ermine), fisher, badger, pine marten, river otter, sea otter (yep, the sea otter), mink and black-footed ferret.
Other imperiled Mustelids in the U.S. include the black-footed ferret (endangered) and the sea otter (threatened).
Size: The wolverine usually weighs between 17 and 40 pounds, stands up to 1.5 feet tall, and is generally 33 to 44 inches long (including tail). The male is larger than females.
Diet: They are ferocious predators that prey mostly on mammals such as rabbits and rodents. They are also scavengers, eating the carrion (carcasses) of large animals, such as caribou, deer and elk, which died of other causes, to help them through the winter when other food is scarce.
Typical Lifespan: Wolverines may reach anywhere from five to 13 years.
The wolverine ranges widely, up to 15 miles a day, and needs lots of habitat. Home ranges can vary from 100 to 600 square miles.
In the lower-48 they live primarily at high altitudes with alpine vegetation but can venture to lower elevations. It is estimated that 25-300 live in the lower-48 states.
Populations are currently known in the North Cascades Range in Washington, Northern Rockies of Montana, Idaho, Wyoming, and a small portion of Oregon (Wallowa Range). Historically was in the Sierra Nevada mountains of California and the southern Rocky Mountains in Colorado, Wyoming, and New Mexico.
The wolverine also resides in Alaska, Canada and Russia, where it is not imperiled.
In 2008 and 2009 one wolverine was recorded on motion-detector cameras in the northern Sierra Nevada mountains. It is not believed to be a resident population, possibly having come from somewhere in the Rocky Mountains. Wildlife biologists were awed and excited by the sighting of a lone wolverine in California in 2008 and 2009, but nonetheless the risks posed by climate change indicate that the future is challenging for wolverines in the lower-48 states.
Life History and Reproduction
Wolverines usually produce one or two ‘kits’ who are born from mid-February through March.
Male usually has several mates (polygamous), with several smaller female territories within its larger territory. Female raises the young without any male assistance.
Females make their birthing dens in deep snow, usually requiring five or more feet of snow for protection of young from cold and predators, hence dens are usually high up at 7,000 feet or more in altitude. They need these dens usually until May, thus, snow into late spring is important.
The wolverine, like most Mustelids (not quite all), has scent glands with a strong odor they use for marking territory and sexual signaling.
Threats to Wolverines
Although the wolverine has very specific habitat needs, was never a common species and was widely persecuted, the primary reason now for a threatened listing is climate change. It is estimated that, due to climate change:
- Within 30 years about 30 percent of wolverine habitat in the lower-48 states will be gone.
- Within about 70 years, an estimated 60 percent of their habitat will be lost in the lower-48 states.
- With snowpack melting earlier, scientists project wolverine habitat will shrink significantly by the end of the century.
Wildlife Promise & National Wildlife Magazine
Climate Change Takes a Bite out of Wolverines’ Habitat
Ready to Fight the Stealth Attack on Wildlife? Wolverines
Cantankerous Carnivore: On the Trail of a Wolverine
Sources: U.S. Fish and Wildlife Service, Wolverine Foundation