As a result of over 2000 hours of observation of two captiveLemur fulvus groups, their social behavior can now be provisionally described and categorized. Characteristic postures forL. fulvus include the normal standing or walking posture, often accompanied by low-pitched contact grunting, and the tightly curled resting posture. Disturbances in the vicinity of the group may lead to gradational changes in individual postures, culminating in the mob display. Greeting behaviors include passing without interaction, the sniff greeting, tactile greetings, and anogenital marking of one lemur by another. Allogrooming, mutual grooming, and reciprocal grooming may follow initial contact.L. fulvus individuals scent-mark spaces and objects, doing so at an increased rate during the mating season. Throughout most of the year little behavior occurs which can accurately be labelled ‘aggressive’. True agonistic behavior has only been observed during certain phases of the annual cycle: birth season, mating season, and the time of sexual maturation of juvenile animals. Sexual behavior is also rarely observed. Maternal behavior is interesting not only in terms of mother-infant interactions but also with regard to changes in mother-other interactions over time. Finally, play behavior can be distinguished from other kinds of behavior with similar behavioral components by looking at itsGestalt. Most play can be classified as either primarily locomotor/manipulative or primarily social.