Many large mammals are found on or near the refuge. Moose ("Alces laces") and black bear ("Ursus americanus") are becoming more common in southern Maine as their populations continue to grow. They have been sighted on all refuge divisions except Moody. A bobcat ("Lynx rufus") was reported as sporadically using the Upper and Lower Wells divisions in 1991 and 1992. Fishers ("Martes pennanti") are increasingly sighted on the refuge; a vehicle killed a fisher near refuge headquarters in 1998, and several sightings around the headquarters have occurred since then. Gray fox ("Urocyon cinereoargenteus") and short-tailed weasel ("Mustela erminea") most likely use several refuge divisions. Porcupines ("Erethizon dorsatum") and woodchucks ("Marmota monax") are found throughout the refuge, where they occur in varied habitats.