Leucisitic Fisher: Diamonds in the Rough

Reports and sightings of albino mammalian wildlife tends to be more prevalent now than ever before. With the onset and popularity of web-based photo sharing and social media, it isn’t out of the norm to come across pictures of snow-white or piebald deer, porcupines, bobcats, and raccoons.

A newly released study in the American Midland Naturalist focuses on another common forest dweller - the Fisher (Pekania pennanti), and some interesting discoveries regarding unique color observations. The study focuses on the recent discovery of leucism traits found in a traveling male fisher, captured on a trail camera image from Price County, Wisconsin in 2017. The report states its the first scientifically documented case of leucism in pekania pennanti. Fisher traditionally bear silky fur coats ranging from brown to black.

The fisher was captured on a trail camera trap set by wildlife professionals for monitoring deer populations.

Leucistic fisher captured on 10/10/2017 at 9:18 AM CST within Price County, Wisconsin, U.S.A. (Photo | Lee Ecker)

The fisher is a medium sized member of the weasel family, found throughout the Northeast US, Canada, and northern ranges of the mid-west. It can typically be found hunting in mixed deciduous and boreal forest dominated by conifer, sugar maple, and spruce. Typically the presence of swampy beaver bogs, rocky outcroppings, or (in recent years) suburban neighborhoods, help to enhance odds of a fisher sighting.

(Photo | Northern Outdoors / Stephanie Merrill)

(Photo | Northern Outdoors / Stephanie Merrill)

While albino traits in animals is the absence of pigmentation (including pink noses, and pink/reddish eyes), leucistic animals display an outwardly white color phase (with coloration still present in nose and eyes).

The study, co-authored by Lucas Olson and Max Allen, focuses on these leucistic traits - primarily in fisher and other wild carnivores.

While the discovery of a leucisitic fisher on a Wisconsin trail camera may be the first scientifically documented case, as we discovered, it wasn’t the first “white fisher” to grace the pages of the world wide web!

Michael O’Brien shared a photo of a leucisitic fisher he trapped in 1996 in Minnesota, stating the proceeds from selling the animal’s hide actually paid for an entire college semester in those days.

According to reports from Northland Outdoors, Minnesota trapper Stephanie Merrill caught what was reported as an “albino” fisher in Carlton County in 2015.

(Photo | Michael O’Brien)

In both of these cases, without inspecting the animal first-hand we cannot confirm leucistic versus albino conditions. However, based on the images, the presence of pigment in the eyes and nose of both animals suggests leucistic traits.

Leucism is genetic, and is described as the abnormality of partial loss of pigmentation which causes individuals to appear partially or entirely white. It is sometimes referred to as partial albinism, or ghosting. Leucism has been previously linked with inbreeding, as well as environmental factors such as nuclear pollution, which has been noted to increase mutation rates. Because Leucism and albinism are not favored traits when roaming animals are looking to breed, they tend to be rare within a population - since these genetic anomalies tend to not be passed on.

There’s question as to whether a mustelid with these traits are formidable for long-term survival. The Ermine, another member of the weasel family, comes to mind as a creature who naturally changes color phases from its traditional brown weasel coat we’re all familiar with in the summer, to a pure white predator in most of the northern hemisphere through winter, which aids in blending with snow cover. The ermine’s color traits shouldn’t be confused with the condition of “albinism” or leucisitic characteristics uniquely found in isolated pockets of other animals, however.

Could a normally brown fisher survive with an all white coat during summer seasons on a brown forest backdrop? Furthermore, does the advent of a white coat bolster survival rates among individuals during snow cover, since winter is arguably the harshest time of year for fisher and other mesopredators? As for the fisher in the Olson/Allen study, it appears to be a totally healthy male specimen.

“The function of pelt color for fishers is not known.” the study states. “Therefore, the advantages or disadvantages of being white for this individual are unknown. Some life history traits of fishers may buffer the potential fitness consequences of being white. Fishers communicate mainly through scent marking, rather than through visual cues. During snow cover, white fur color may provide concealment for fishers from predators, such as bobcat and coyote or concealment from prey while hunting, with the contrasting disadvantages without snow cover.” the study eludes.

Either way, images of snow-white fishers are pretty cool nonetheless. We thank those professionals who have focused their time and effort on the subject, as well as the individuals who have publicly shared their unique specimens!


Mere moments after the posting of this article, we were contacted by multiple readers in Wisconsin about several other Fisher trapped in the state displaying leucisitic qualities or traits. Some of which have been mounted as preserved specimens. With such a noticable concentration of leucisitic fisher in the same general area, this begs the question of a cause. Are fisher in this part of the country inbreeding? Nuclear exposure? Are fisher “not that picky” about pelt color when breeding? Other environmental cause? Something tells us this chapter on leucisitic fisher isn’t closing quite yet…