North America’s scrappiest critter weighs in at 30 pounds, fights bears, and gives birth in an avalanche chute

BOZEMAN, MT (December 1, 2011) – Born during February in snow-caves at 9,000 feet on the north slope of craggy peaks in the Rocky Mountains, Yellowstone’s wolverines are tough.

This week in the Journal of Wildlife Management, scientists with the Wildlife Conservation Society and their state and federal partners published the first in a series of papers that will help fill in the blanks regarding the biology of this mysterious and awe-inspiring species.

Eight years of capturing and radio-tracking the elusive wolverine revealed that adults live year-round in the high mountains, near the alpine tree-line, and inhabit some of the west’s most remote and rugged terrain. Amazingly, the home range of an individual male can cover 500 square miles. “Not only do they use an area even larger than a grizzly bear does,” said Kurt Alt, a coauthor with Montana Department of Fish, Wildlife and Parks, “they cover their territory on a fairly regular basis to scent mark it and defend it from other wolverines.”

The wolverine’s capability for movement is stunning. Their large feet allow them to float on top of deep snow, and they were documented making winter traverses from one side of the massive Teton Range in Wyoming to the other in just a few hours. “They are the winter endurance athletes of the animal world.” said Steve Cain of the National Park Service. “We were impressed by their constant movements across large areas of snow-covered and incredibly rugged terrain.”

But covering this terrain comes with its risks, as two of the radio-collared wolverines were killed in avalanches.

Another wolverine travelled over 500 miles from near Grand Teton National Park in northwest Wyoming to Rocky Mountain National Park in Colorado. This was the first documented wolverine in Colorado in almost a century. Other young wolverines regularly moved 100 miles or more searching for their own territory.

While bears are hibernating and most ungulates and their predators have moved to low elevation wintering ranges, the wolverine patrols a vast, frozen territory, looking for scraps of meat that they cache under boulders and snow. “We learned that wolverines are adapted to eke out a living in very harsh conditions,” said Robert Inman, conservationist for the Wildlife Conservation Society. “As a result, they naturally exist in low numbers and reproduce slowly.”

The wolverine’s reputation as a fierce competitor was also affirmed during the study. One individual challenged a bear probably 10 times his size over an elk carcass.

The study notes that wolverines roam widely across multiple jurisdictions and are influenced by a complexity of land ownerships and management authorities. Conservation of wolverines, say the scientists, will require coordinated multi-state management across the western U.S. and implementation of practices facilitating survival, reproduction, and gene flow at the locations where it is most important from the perspective of a western U.S. population.

Other journal articles based on the field study are forthcoming and will focus on foods and behaviors critical to wolverine populations along with a synthesis of information that can be used to prioritize conservation actions for maintaining the species in the lower 48.

Authors of the paper include Robert Inman, Kristine Inman, Anthony McCue and Mark Packila and of the Wildlife Conservation Society; Gary White of Colorado State University; Jens Persson of the Swedish University of Agricultural Science; Bryan Aber, Jay Frederick and Mark Orme of the United States Forest Service; Kurt Alt of Montana Fish Wildlife and Parks, Steve Cain of the National Park Service; Bob Oakleaf of the Wyoming Game and Fish Department, and Shawn Sartorius of the United States Fish and Wildlife Service.

To view the abstract for the paper appearing in the Journal of Wildlife Management, please go here:

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