Black lemurs live in groups of between 2-15 individuals, with adult males and females in equal numbers, together with their dependant offspring (5). The activities and movements of the group are dictated by the dominant female, and group relationships are maintained by grunts, contact calls and grooming. Home ranges extend for five to six hectares and there is considerable overlap with the ranges of neighbouring groups (2).
This species, like other lemurs, exhibits an activity pattern that is virtually unique amongst primates and rarely encountered amongst other arboreal mammals. They have activity bursts which may occur during the day and the night, though most activity occurs in the early morning and late afternoon (5). This activity pattern is called cathemeral, meaning ‘all hours’, contrasting with the usual distinction between nocturnal and diurnal (9). Foraging is concentrated in the middle and upper parts of the canopy, where this lemur feeds on fruit, flowers, leaves, fungi and occasionally invertebrates like millipedes. This primate plays an extremely important role is seed dispersal through the forests because it has such a high amount of fruit in its diet (6). In the dry season nectar becomes an important part of its diet as well (2). During the day it forages in the understory of the canopy where it is more protected from predatory birds such as hawks, and at night is able to feed in the upper levels (2).
The breeding season is seasonal and births occur after a gestation period of 12 - 129 days. One offspring is usual, though twins are fairly common. The young cling to their mother’s belly for three weeks and will only move to suckle. After three weeks the young are heavier and ride on the mother’s back, and at 5 - 6 months of age they are fully weaned (5).