The social system of the Masoala fork-marked lemur has been described as pre-gregarious. Some adults live as monogamous couples, sharing the same nest hole by day but moving about independently for at least part of the night (the male often follows a few metres behind the female), but a few live as solitary bachelors or have ranges overlapping more than one female. The average size of a female territory is with a male territory averaging . The lemurs sometimes gather at the places where the territories overlap; there is no aggression on these occasions, but much vocalisation for a period of ten or twenty minutes. The animal moves on all fours, running rapidly along branches, climbing and jumping, mostly at a few metres above the ground, but descending to the forest floor on occasion.