This species has been studied in western Madagascar in the deciduous forests of Antserananomby and Tongobato (Sussman, 1974, 1975, 1977), in the Kirindy Forest (Donati et al., 1999; Ostner and Kappeler, 1999), and in eastern Madagascar in Ranomafana National Park (Meyers, 1988; Overdorff, 1991; Johnson and Overdorff, 1999). These publications pre-date the recent recognition of E. rufifrons and E. rufus as separate species, and therefore refer to this species as E. fulvus rufus. The results of these and other studies demonstrate a very adaptable behavioral ecology. In the west, population density is reported to be very high and home ranges small, while in the east, population densities tend to be lower and home ranges as large as 100 ha. Group size is more consistent geographically, varying from 4–17 (with an average of nine) in the west and from 6–18 (with an average of eight) in the east. Dominance hierarchies are unknown in any populations, and rates of aggression appear very low. The diet of some western populations is less diverse and much more folivorous than that of eastern populations, and includes a high proportion of leaves, pods, stems, flowers, bark, and sap of the kily tree (Tamarindus indica). At Kirindy, E. rufifrons includes substantial amounts of fruit in its diet, and is the sole seed disperser for a large number of tree species with large seeds (Ganzhorn et al., 1999). The diet of eastern populations is dominated by fruit (Overdorff, 1993, 1996a, 1996b). Along with E. rubriventer, E. rufifrons feeds on flowers and nectar more often during in the warmer, wetter months of the year (Overdorff, 1992). Although largely diurnal, western populations of this lemur increase their nocturnal activity during the dry season (Donati et al., 1999; Rasmussen, 1999; Kappeler and Erkert, 2003). Eastern populations are entirely cathemeral and active across a 24-hour period throughout the year (Overdorff and Rasmussen, 1995). Reproduction is seasonal. In western populations, one male typically monopolizes the females of the group, while in the east several males may participate in reproductive pairings (Overdorff, 1998; Ostner and Kappeler, 1999). In the west, mating takes place in June, births occur in September and October, and the young are weaned by January (Sussman, 1977).