Winter hiking can be a lot of fun. Clean, cool air, low humidity, no bugs, poison ivy or nettles. And nothing can be much more fun than observing animal tracks in a few inches of newly fallen snow.

In our Appalachian region, we can observe a number of weasel family members, known as the Mustelids. This family includes three genera with seven species: the Martes (fisher and American marten), Mustela (long-tailed, short-tailed and least weasel, and mink) and Lontra (river otter).  Until 2005, the skunk was also included in the weasel family.

The long-tailed weasel, at 17" (head to tail tip) is the largest and most common of the three common North American weasels, along with the short-tailed, or ermine at 11", and least weasel at 5 - 7"; the smallest carnivore on the continent. Tracks of the long-tailed weasel are only ¾" wide, 1" long. Although all weasel members normally leave a print with all five toes, frequently the fifth toe will not register in the tracks.  Stride is about 15 - 18" at a leisurely bound, and 3 to 6' when moving fast.  Straddle (width) is 3".  Often piles of discarded bones and fur of recent prey can be diagnostic around the entrance to the weasel’s home. Scat is dark brown and long, thin, twisted and tapered on both ends; 1 to 2" long and 1/8 to ¼" diameter. The scat is often found at prominent locations, marking the home range of a weasel. Additionally, diagonal paired track patterns are diagnostic in all three weasel species. 

Most mustelids have long tapering bodies with short stubby legs, with the exception of the badger and wolverine. The evolution of this body shape has enabled the weasels to be a major predator of rodents by their ability to enter rodent tunnels in search of their next meal and denning site. They dispatch their prey by piercing the base of the skull with their large canines. Their incisors slip between the neck’s vertebrae to sever the spinal column. Primarily solitary animals, they are fierce and aggressive hunters, willing and able to take down prey much larger than themselves. Stories tell of birds of prey being beaten by their intended prey (a buzzard killed by a weasel it attacked, another one in flight with a weasel attached to it’s belly by teeth and feet, and an eagle that, although surviving an encounter with a weasel, was left with only the bleached head and teeth of a long gone weasel permanently affixed to it’s neck.) Most have well-developed paired anal scent glands used for defense and identification. Unlike most mammals, a strong sexual dimorphism exists, with the male often up to 50% larger than the female.

In general, their various colored pelages (pelts) and their insulative capability makes them valuable to the fur trade. It’s also of interest that the females have denser coats than males, and are of more value in the trade.

Of the four species in the Mustela genus, the mink is the only one whose pelage doesn't turn white in its winter molt.  This might be a reflection of its aquatic nature, even in winter, where a white coat would stand out.  The three others, which include the long-tailed, short-tailed and least weasel, all are known for their winter white coats.  The long-tailed and short-tailed weasels molts to an all-white pelage with a black-tipped tail.  The black tip on the tail has evolved as a distraction to aerial predators, who tend to focus their aim on this dark spot rather than the main body.  The least weasel does not have the dark-tipped tail. This appears to be a function of the least weasel's small size, where the decoy isn't far enough from the vulnerable body to afford any protection.

However, the white winter pelage is only an effective camouflage where there is a reliable snow cover. As a result, there is a transitional zone where the winter coat is a mixture of white and brown (piebald). This zone is found from central Pennsylvania through Maryland and into northern West Virginia and Virginia. South of this zone, the winter coats are solid brown.

Weasels, active all winter, and requiring a high caloric input, must take advantage of prey whenever it can take advantage of it. They do this by caching its prey. Thus, the stories of weasels killing all of the chickens in the hen house, driven by a wasteful and uncontrolled instinct to kill is not indicative of what is occurring. What it does not eat today, it will need/eat tomorrow. Caches of over a hundred rats and mice have been recorded. Additionally, the long and narrow body form creates a small stomach, in which only small amounts of intake can occur at any one time. Thus, the body form, extremely efficient at hunting, also creates a body form that is extremely inefficient at eating and staying warm/alive. With such a high surface area to volume ration of these small mammals, they must compensate through hyperactivity and naturally high metabolic rates that burn a lot of calories and produce heat. To achieve this, a long-tailed weasel’s heart beats 400 to 500 times a minute.

The fisher, extirpated in the early 1900’s from eastern US, has been successfully re-introduced into northern PA and WV (Dolly Sods and Spruce Knob), with those populations spreading into western MD and Highland County, VA (in the Laurel Run area of the GW National Forest) and possibly adjacent counties.

The American marten is questionably found as far south as Pennsylvania.  It officially is listed as "undetermined" by the Pennsylvania Biological Survey.

In historical times, two other members of the weasel family resided in this Appalachian region.  Pennsylvania probably represented the southern terminus of the geographic range of the wolverine in the east.  Based on records principally from northcentral Pennsylvania, the wolverine was always rare in the state and disappeared during the mid to late 1800's.  The wolverine is considered officially extirpated in the Commonwealth of Pennsylvania.

While the badger was probably a resident of Pennsylvania during precolonial times, only one record exists prior to 1900.  Since 1946, four records of the badger exist from Beaver, Fayette, Indiana, and Washington Counties.  Whether these are escapees, releases, or a natural expansion of the native Ohio population is not known.  The status of the badger is considered "uncertain" by the Pennsylvania Biological Survey.