Species Profile
Environmental Conservation Online System

North American wolverine (Gulo gulo luscus)

Kingdom: Animalia
Class: Mammalia
Order: Carnivora
Family: Mustelidae

Listing Status:    and  

General Information

The wolverine is the largest terrestrial member of the family Mustelidae, with adult males weighing 12 to 18 kilograms (kg) (26 to 40 pounds (lb)) and adult females weighing 8 to 12 kg (17 to 26 lb) (Banci 1994). It resembles a small bear with a bushy tail. It has a round, broad head; short, rounded ears; and small eyes. There are five toes on each foot, with curved and semiretractile claws used for digging and climbing (Banci 1994).

Population detail

The FWS is currently monitoring the following populations of the North American wolverine 

Map of Species occurrence

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Map Image Map of Species occurrence Map of Species occurrence

This map represents our best available information about where a species is currently known to or or is believed to occur; however, it should NOT be used as an official species list for Section 7 Consultation purposes. To obtain an official species list for this purpose, please visit the Information, Planning, and Conservation (IPaC) System (click here: http://ecos.fws.gov/ipac)

  • Population location: 
    Listing status:  Proposed Threatened
  • Population location: Nonessential Experimental Population of the North American Wolverine in Colorado, Wyoming, and New Mexico
    Listing status:  Proposed Experimental Population, Non-Essential
Current Listing Status Summary
Status Date Listed Lead Region Where Listed
Mountain-Prairie Region (Region 6)
Mountain-Prairie Region (Region 6) NEXP

» Candidate Information

Former Candidate Status

Listing Priority: 
Magnitude: 
Immediacy: 
Taxonomy: 
Species Assessment: 
Candidate Notice of Review Documents (Showing 5 of 6: view all)
Date Citation Page Title
11/21/2012 77 FR 69993 70060 Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions
10/26/2011 76 FR 66370 66439 Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions
11/15/1994 59 FR 58982 59028 ETWP; Animal Candidate Review for Listing as Endangered or Threatened Species.
11/21/1991 56 FR 58804 58836 ETWP; Animal Candidate Review for Listing as Endangered or Threatened Species; 56 FR 58804 58836
01/06/1989 54 FR 554 579 ETWP; Animal Notice of Review; 54 FR 554 579

» Federal Register Documents

Most Recent Federal Register Documents (Showing 5 of 16: view all)
Date Citation Page Title
02/05/2014 79 FR 6874 6875 6-Month Extension of Final Determination for the Proposed Listing of the Distinct Population Segment of the North American Wolverine Occurring in the Contiguous United States as a Threatened Species
10/31/2013 78 FR 65248 65249 Threatened Status for the Distinct Population Segment of the North American Wolverine in the Contiguous United States
02/04/2013 78 FR 7863 7890 Threatened Status for the Distinct Population Segment of the North American Wolverine Occurring in the Contiguous United States; Proposed Rules
02/04/2013 78 FR 7890 7905 Establishment of a Nonessential Experimental Population of the North American Wolverine in Colorado, Wyoming, and New Mexico: Proposed rule.
11/21/2012 77 FR 69993 70060 Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions

» Recovery

Recovery Plan Information Search

No recovery information is available for the North American wolverine.

» Critical Habitat

No critical habitat rules have been published for the North American wolverine.

» Conservation Plans

Habitat Conservation Plans (HCP) (learn more) (Showing 2 of 2)
HCP Plan Summaries
Cedar River Watershed HCP
West Fork Timber HCP (formerly Murray Pacific)

» Petitions

Most Recent Petition Findings (Showing 5 of 6: view all)
Date Citation Page Title Finding
11/21/2012 77 FR 69993 70060 Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions
  • Notice 12 month petition finding, Warranted but precluded
  • Notice CNOR
  • 10/26/2011 76 FR 66370 66439 Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions
  • Notice 12 month petition finding, Warranted but precluded
  • Notice CNOR
  • 12/14/2010 75 FR 78030 78061 12-Month Finding on a Petition To List the North American Wolverine as Endangered or Threatened; Proposed Rule
  • Notice 12 month petition finding, Warranted but precluded
  • 03/11/2008 73 FR 12929 12941 12-Month Finding on a Petition To List the North American Wolverine as Endangered or Threatened
  • Notice 12 month petition finding, Not warranted
  • 10/21/2003 68 FR 60112 60115 90-day Finding for a Petition To List as Endangered or Threatened Wolverine in the Contiguous United States
  • Notice 90-day Petition Finding, Not substantial
  • » Life History

    Habitat Requirements

    Wolverines do not appear to specialize on specific vegetation or geological habitat aspects, but instead select areas that are cold and receive enough winter precipitation to reliably maintain deep persistent snow late into the warm season (Copeland et al. 2010, entire). The requirement of cold, snowy conditions means that, in the southern portion of the speciesí range where ambient temperatures are warmest, wolverine distribution is restricted to high elevations, while at more northerly latitudes, wolverines are present at lower elevations and even at sea level in the far north (Copeland et al. 2010, Figure 1). Deep, persistent, and reliable spring snow cover (April 15 to May 14) is the best overall predictor of wolverine occurrence in the contiguous United States (Aubry et al. 2007, pp. 2152-2156; Copeland et al. 2010, entire).

    Food Habits

    Wolverines are opportunistic feeders, consuming a variety of foods depending on availability. They primarily scavenge carrion, but also prey on small animals and birds and eat fruits, berries, and insects (Hornocker and Hash 1981; Wilson 1982; Hash 1987; Banci 1994). Wolverines have an excellent sense of smell, enabling them to find food beneath deep snow (Hornocker and Hash 1981).

    Movement / Home Range

    Wolverines have large spatial requirements; the availability and distribution of food is likely the primary factor in determining wolverine movements and home range (Hornocker and Hash 1981; Banci 1994). Wolverines can travel long distances over rough terrain and deep snow, with adult males generally covering greater distances than females (Hornocker and Hash 1981; Banci 1994). Home ranges of wolverines are generally extremely large, but vary greatly depending on availability of food, gender, age, and differences in habitat. Home ranges of adult wolverines range from less than 100 square kilometers (km2) to over 900 km2 (38.5 square miles (mi2) to 348 mi2) (Banci 1994). Home range sizes are large relative to the body size of wolverines, and may indicate that wolverines occupy a relatively unproductive niche in which they must forage over large areas to consume the amount of calories needed to meet their life-history requirements (Inman et al. 2007a, p. 11).

    Reproductive Strategy

    Breeding generally occurs from late spring to early fall. Females undergo delayed implantation until the following winter to spring, when active gestation lasts from 30 to 40 days (Rausch and Pearson 1972). Litters are born between February and April, containing one to five kits, with two to three kits being the most common number (Hash 1987). Female wolverines use natal (birthing) dens that are excavated in snow. Persistent, stable snow greater than 1.5 meters (m) (5 feet (ft)) deep appears to be a requirement for natal denning, because it provides security for offspring and buffers cold winter temperatures (Pulliainen 1968, p. 342; Copeland 1996, pp. 92-97; Magoun and Copeland 1998, pp. 1317-1318; Banci 1994, pp. 109-110; Inman et al. 2007c, pp. 71-72; Copeland et al. 2010, pp. 240-242). Female wolverines go to great lengths to find secure den sites, suggesting that predation is a concern (Banci 1994, p. 107). Natal dens consist of tunnels that contain well-used runways and bed sites and may naturally incorporate shrubs, rocks, and downed logs as part of their structure (Magoun and Copeland 1998, pp. 1315-1316; Inman et al. 2007c, pp. 71-72). Occupation of natal dens is variable, ranging from approximately 9 to 65 days (Magoun and Copeland 1998, pp. 1316-1317).

    Other

    The primary threat to the North American wolverine is from habitat and range loss due to climate warming. Wolverines inhabit habitats with near-arctic conditions wherever they occur. In the contiguous United States, wolverine habitat is restricted to high-elevation areas in the West. Wolverines are dependent on deep persistent snow cover for successful denning, and they concentrate their year-round activities in areas that maintain deep snow into spring and cool temperatures throughout summer. Wolverines in the contiguous United States exist as small and semi-isolated subpopulations in a larger metapopulation that requires regular dispersal of wolverines between habitat patches to maintain itself. These dispersers achieve both genetic enrichment and demographic support of recipient populations. Climate changes are predicted to reduce wolverine habitat and range by 23 percent over the next 30 years and 63 percent over the next 75 years, rendering remaining wolverine habitat significantly smaller and more fragmented. By 2045, maintenance of the contiguous U.S. wolverine population in the currently occupied area will likely require human intervention to facilitate genetic exchange and possibly also facilitate metapopulation dynamics by moving individuals between habitat patches that are no longer accessed regularly by dispersers. Other threats are minor in comparison to the driving primary threat of climate change; however, they could become significant when working in concert with climate change if they further suppress an already stressed population. These secondary threats include harvest, i.e., trapping ; inadequate regulatory mechanisms to protect against human recreational disturbance, infrastructure developments, and transportation corridors; and demographic stochasticity and loss of genetic diversity due to small effective population sizes.

    » Other Resources

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    Last updated: July 28, 2014