Mongoose lemurs are the smallest species of the genus Eulemur , which includes five species. Head and body length averages 35 cm long and their tail length averages 48 cm long. The pelage is woolly and the tails are bushy and gray.
Males have a gray body with red fur on the side of the body and the face.
Males have white beards when they are born that turn red as they grow older. Females are darker gray than males and they have white fur on the sides of their bodies and face. They taste whatever the older members of the group are eating, which includes pollen, fruit, and leaves. Mongoose lemurs have very small upper incisors and upper canines and their premolars become vertically smaller posteriorly. The molars are hypocone, but the trigonids and talonids become less distinct toward the posterior.