Wolverine Mom and Kits Spotted in Washington

wolverine

Story at-a-glance -

  • Wolverines, one of the rarest and most elusive animals in North America, may be expanding their range and making a comeback in Washington state, particularly south of Interstate 90
  • A female wolverine was not only spotted south of I-90, but it was revealed that she’s lactating, which suggests she’s also reproducing
  • It was the first breeding female to be discovered in the area in decades; then, a short time later, two kits were detected in the same area; it’s the first time wolverine kits have been photographed in the area south of I-90

By Dr. Karen Shaw Becker

Wolverines, one of the rarest and most elusive animals in North America, may be expanding their range and making a comeback in Washington state, particularly south of Interstate 90. Members of the weasel family, wolverines are tough, resourceful animals that may travel up to 15 miles a day.

Blackfeet Indians called wolverines "skunk bears,"1 perhaps because they resemble a cross between the two, and although they once lived throughout the U.S. Northwest and even into the Midwest and Northeast, there are only an estimated 250 to 300 wolverines living in the U.S. today — and "far fewer are successfully contributing to the gene pool in any given year," according to Defenders of Wildlife.2

This makes recent news from the Cascades Carnivore Project, which monitors rare carnivore species living in the Cascades Mountains, all the more exciting.

A female wolverine was not only spotted south of I-90, but it was revealed that she's lactating, which suggests she's also reproducing. It's the first breeding female to be discovered in the area in decades. Then, a short time later, two kits were detected in the same area. Jocelyn Akins, Ph.D., a wildlife biologist and conservation director of the Cascades Carnivore Project, told the Seattle Times, "This is showing that wolverines are able to expand into more of this historic distribution that has been unoccupied since the 1930s."3

Only 25 Wolverines Are Believed to Live in Washington

It's difficult to track wolverines, who live in remote areas and tend to avoid humans, but only about two dozen are thought to live in Washington. The animals suffered from over-trapping and being targeted as pests in the early 1900s, and much of their population moved to Canada.

A camera mounted outside a wolverine den where the female wolverine was first spotted just recently photographed two kits in the area, which suggests the growing family is doing well.

It's the first time wolverine kits have been photographed in the area south of I-90.4 The finding represents the culmination of a decade-long study that began in 2006. While wolverines had been spotted in the area occasionally, no one knew whether they were passing through or more permanent residents. The discovery of a den in the William O. Douglas Wilderness area was the evidence researchers needed to show that these carnivores had expanded their range south.

Other interesting facts were also uncovered, like the expansive ranges of some of the wolverines, which could cover nearly 2,000 miles. A male wolverine was also tracked moving along with a younger male, thought to be his son, revealing "a degree of social tolerance in wolverines between a father and his male offspring that had not been described previously."5 (It's long been suggested that wolverines are solitary except while mating, but this may not always be the case.)

Are Wolverines Endangered?

Although their numbers are low, wolverines are only considered to be a candidate species to be added to Washington's threatened or endangered list. While the U.S. Fish and Wildlife Service proposed a rule to list wolverines as threatened under the Endangered Species Act in 2013, this was withdrawn in 2014 due to lack of data about how wolverines were responding to threats like habitat loss and fragmentation.6

The U.S. Forest Service considers wolverines a "sensitive" species, while The International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species lists them as a species of "least concern." While wolverines have a wide distribution and remaining areas of large populations, their populations are thought to be declining, although not at a rate fast enough to threaten the species. According to IUCN:7

"Although there is an overall continued decline due to human persecution and land-use change, the global decline of this species is not at a rate sufficient to qualify for categorization even as Near Threatened as of 2015. However, in the mid-2000s the European Mammal Assessment determined that the European populations of Wolverine were in steep decline and would warrant a category of Vulnerable …

Wolverine still faces some threats such as over-exploitation through hunting and trapping, predator-poisoning programs, and habitat resource extraction that caused the contraction of its historical range. More data on population trends, especially in northern Asia, might result in this species being reassessed as Near Threatened or even Vulnerable in the near future."

Indeed, the researchers of the 2016 report also stated, "The conservation of wolverines in Washington will depend on reliable knowledge of their distribution, population status and habitat relations," and they're planning to continue monitoring them in the future.

Wolverines thrive in winter habitats, placing their dens under deep snow packs and even using deep snow as a sort of refrigerator to keep meat fresh. While wolverines do hunt on occasion (including large mammals like caribou), they're effective scavengers and even eat some plants and berries.

Habitat fragmentation is one concern facing wolverines in Washington, in particular, but the installation of wildlife passages over and under I-90 in the Cascades is expected to help. According to Patty Garvey-Darda, wildlife biologist with the U.S. Forest Service on the Cle Elum Ranger District of the Okanogan National Forest, the wildlife passages will assure that viable populations of wildlife will stay in the area, and it's expected to be especially helpful for wolverines.8

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