The three types of weasels that occur in North America all leave similar signs behind when they are present in their habitat. The ranges of the least weasel (Mustela nuvalis), the short-tailed weasel (Mustela erminea) and the long-tailed weasel (Mustela frenata) overlap in several regions of the continent, according to the "National Audubon Society Field Guide to Mammals.” The long-tailed weasel has the widest distribution of any carnivore found in North America, so chances are you have seen signs of this creature, whether you realize it or not.
Your best chance of spotting and identifying weasel tracks is in mud or soft sand near water or after a light snowfall. All weasels possess five toes on their front and hind feet, but in their tracks, typically only four toes show up. The tracks of the three species are similar, with the only differences being in the track's size and the distance they are apart. The smaller least weasel has a shorter distance between strides; the larger long-tailed weasel can sometimes have 20 inches between strides when bounding along. Weasels walk by placing the hind foot where the front foot was, leaving a set of side-by-side tracks as they go. The front foot of the weasel is wider than the back, while the back foot is longer. Weasels rarely travel in a straight line, as they zigzag back and forth in a frantic search for prey, investigating every crevice and cranny as they hunt.
The scat that weasels leave behind is similar between species, with the exception that the smaller types create smaller scat. The color is normally a dark shade of black or brown. The scat is thin, long, usually in segments and tapered at one end. In many instances, weasels scat contains small pieces of bone or the hair of its latest meal. Search for this sign of weasels on logs, stumps or rocky outcroppings, where weasels like to defecate.
Signs in the Snow
During times of deep snow when you are out in the woods, look for holes in the snow where the weasel has jumped and dived beneath it in an attempt to locate prey such as mice and voles. You may notice drag marks away from a hole if these efforts were fruitful, as well as the presence of blood. Weasels do not suck the blood of their victims -- a popular belief before more information about them surfaced -- but they do lick it up. Weasels have a habit of storing away any extra prey they manage to kill. You may stumble upon a cache of dead rodents such as voles under a log.
Smells and Sounds
Weasels feature anal glands capable of leaving an unpleasant and pungent smell behind. It often accompanies their tracks and resembles the smell of another member of the family -- the skunk. However, the weasel smell is not nearly as strong. Weasels make a variety of sounds, including screeches, squeals, purrs and twittering trills in rapid succession. Weasels will resort to hissing when they feel frightened or threatened with danger.