Ben Achtenberg was able to snap a rare photograph of a fisher cat in Bussey Brook Meadow in the Arnold Arboretum on Halloween.
Fishers are solitary hunters and not commonly seen. They primarily prey on snowshoe hares and porcupines, according to wikipedia. They also eat insects, nuts, berries, and mushrooms.
Scientists have found evidence of birds, small mammals and even deer, which would indicate they're also scavengers and will eat carrion. While not common, fishers have also been known to kill wild turkeys.
Fishers, although larger, are closely related to martens. Male fishers are larger than females, with males being about 35 to 47 inches in total length and weighing between 8 to 13 lbs, and females measuring 30 to 37 inches, and weighing about 4 to 6 lbs. Although the largest male ever reported was 20 lbs.