Colorado’s only wolverine photographed on Guanella Pass

Posted by Paige Singer - May 23, 2012 - Blog - No Comments

M56, Colorado's only known wolverine, traveled 500 miles from NW Wyoming to Colorado in 2009. Photographer Cameron Miller recently spotted M56 near Mt. Bierstadt.
© Cameron Miller

In late April, one lucky Coloradan, Cameron Miller, caught a glimpse of something very rare in Colorado. M56, Colorado’s only known wolverine, was spotted on Guanella Pass.  Not only did Cameron see M56, he was also able to capture him in some amazing photographs. Read more about his story on the Forum or check out his website, Cameron Miller Photography.

In the spring of 2009, Colorado welcomed the arrival of M56 who traveled 500 miles from northwest Wyoming. He is thought to be Colorado’s first wolverine in over 90 years and, three years later, he is still calling Colorado’s high country home.




Wolverines are pretty amazing creatures that many of us would love to see in the wild. Here are wolverines by the numbers:

17-22 lbs., 26-40 lbs. – Weight of adult female and adult male wolverines, respectively.  The wolverine is the largest land dwelling member of the mustelid family.

7-12 years – Average lifespan of wolverines in the wild.

2-3 – Average number of kits produced by a female wolverine.

3.5-5.11 oz. – Weight of wolverine kits at birth.

300 – Rough estimate of the number of wolverines in the lower 48 states.

December 14, 2010 – Date wolverines became a candidate for protection under the Endangered Species Act.

Early 1900’s – Time when wolverines are thought to have been extirpated from Colorado.

1 – Number of wolverines currently known to be in Colorado.

5 – Number of wolverines that can be legally trapped in Montana each year.

0 – Documented instances of wolverines taking down live ungulates in the lower 48 states.

104.6 N, 104.2 N – Bite force quotient for wolverine’s canine teeth and carnassial teeth, respectively. The bite force quotient is a numerical value used to represent the bite force of an animal while taking the animal’s size into account – useful for comparing bite force across species.  A wolverine’s bite force quotient is lower than that of a gray wolf, and higher than that of a grizzly bear.

20th – Rank of the wolverine’s bite force quotient when compared to 37 members of the mustelid family.

25 -1079 square miles – Area required to support 1 wolverine in the lower 48 states (based on estimates of home range or activity area for one wolverine).

20% – Percent of total suitable wolverine habitat in the lower 48 states found in Colorado.

95% and 86% – Percentage of summer and winter (respectively) wolverine telemetry locations that occurred in locations with persistent spring snow cover.

562 – Number of known reproductive dens in Fennoscandia and North America. All 562 reproductive dens occurred at sites with persistent spring snow cover during the wolverine’s reproductive denning period.

15 feet – Distance below the snow that female wolverines have been known to build their dens.

20 feet – Distance below the snow that wolverines can detect a carcass.

120 miles – Distance a radio-collared male wolverine at Glacier National Park traveled in one week moving around within his close to 200 square mile territory.

500 miles – Distance a young radio-marked male wolverine traveled from Togwotee Pass, Wyoming (near Grand Teton National Park) south into Colorado in May of 2009.

1500 vertical feet, 20 minutes – A radio-collared male wolverine at Glacier National Park climbed 1500 vertical feet in 20 minutes over Iceberg Notch at Glacier National Park…in WINTER.

5,000 vertical feet, 90 minutes – A radio-collared male wolverine (M1) climbed 5,000 vertical feet in 90 minutes to summit Mt. Cleveland, the tallest peak in Glacier National Park…in WINTER.

Appetite whetted?  Here are some additional resources:

PBS NATURE Documentary Wolverine: Chasing the Phantom

Colorado Parks and Wildlife

Northern Rockies Conservation Cooperative

Wildlife Conservation Society

The Wolverine Foundation

The Wolverine Way by Doug Chadwick

Blog by Megan Mueller and Paige Singer