Two vertical black lines run above the inner corners of their eyes. In winter, long hairs grow between the toe pads on their feet, similar to the snowshoe hare . Thick fur helps keep their feet warm and helps them travel long distances on snow. Pine martens have long, bushy tails, one-third the length of their body. Fishers live in similar habitat, have similar tracks and are darker in color than pine martens.
Stone martens are non-native species and are also about the size of the male pine marten.
They are pale gray to brown with a white throat patch. They'll pursue prey, red squirrels or chipmunks, up a tree and may climb trees to escape danger. Martens move across the ground in a zig-zag fashion, then take a series of jumps. They're solitary but curious animals. Pine martens live in mature, dense conifer forests in northern Wisconsin.