Weasels include a group of animals in the mustelid family. In New Hampshire, we have six species in this family; however, the Monadnock Region is home to only five species. The American marten is currently known to occur in the White Mountains and further north. Although I have heard of observations south of the White Mountains, to my knowledge there has been no documented proof of their presence further south.
The two largest members of the weasel family include the river otter and fisher. Many people consider river otters as very charismatic and playful. Otter slides observed in the snow have been considered by some researchers as a form of play. However, other researchers believe it is more of a way to save energy as sliding on their bellies uses less energy than bounding through the snow. River otters are the only semi-aquatic species in the weasel family where it spends much of its time in streams, marshes, lakes, and beaver ponds. However, they do travel on land as they move across watersheds to new habitats for food. All other species in the Monadnock Region are basically terrestrial, spending most or all of their time on land.
Similar in size to otters, the fisher is locally known as fisher-cat although there is no relation to cats. This name was given as people considered it responsible for eating cats. While some fishers may have been responsible for this behavior the whole notion is probably exaggerated. Standing live hollow trees or dead trees (snags) are important dens sites for fisher. They will also use old porcupine des, rocky areas, and brush piles.
Minks are the mid-sized species of mustelids. Like the otter, minks are known to slide on their bellies in the snow. They are good tree climbers, as well as swimmers. They hunt both on land and in the water where they love eating fish and amphibians. You may have heard of mink farms where they raise these animals for their fur.
The other two mustelids include the smallest species: ermine (short-tailed weasel) and long-tailed weasel. These species are what most people think of when someone brings up the term “weasels.” Both species have white coats in the winter, retaining a black-tipped tail. Their white coats are certainly an evolutionary advantage when snow is present. But in the lack of snow they stand out amongst the gray and brown drab of the forest floor.
Mustelids are elusive by nature. Most people tend to see otters more than any of the others, but some of us may get the occasional opportunity to see other members of the weasel family. Tracks in the snow are more often observed than the animals themselves.
All mustelids are carnivorous, feeding mostly on live prey although they may occasionally eat fruit and other plant parts, as well as carrion (dead animals). Being carnivores, they are actively hunting all year long, even in some of the coldest weather during the winter months.
However, weasels do get a bad rap especially from those that raise chickens. I’ve heard many stories of small weasels and mink getting into chicken coops and creating a horror scene. On a few occasions, I have viewed fisher and mink tracks around our chicken coop. Once, I saw a muddy front track of a fisher on our coop as it appeared to have stood up, leaning on the coop as if it was peering through the hardware mesh in hopes of a meal.
As an ecologist, I think of mustelids as important focal species. This is particularly true about otter, fisher, and mink due to their preference of living in areas with little or no human activity. The presence of these predators means that a prey source exists and indicates healthy, intact ecosystems. This predator-prey relationship is very important in maintaining balance in the natural world.
Jeffry Littleton is the principal ecologist for Moosewood Ecological LLC and NativeScapes Landscape Design located in Chesterfield, NH. He assists clients with conservation and land management planning, as well as native landscape design and installation. He is also adjunct faculty at Antioch University New England and board member for the Monadnock Sustainability Network, a 501c3 whose mission is to encourage sustainable living practices and resource conservation in the region.