There are two subspecies of Black Lemur:
Consistent with its common name, the Blue-eyed Black Lemur E. m. flavifrons has blue eyes, the only primate other than humans which has blue eyes. The nominate subspecies E. m. macaco has brown or orange eyes, and ear tufts.
Both subspecies live in northwest Madagascar. E. m. macaco occurs in moist forests in the Sambirano region of Madagascar and on nearby islands. E. m. flavifrons is restricted to the Sahamalaza Pennisula and adjacent forests. There are reports of the two subspecies hybridizing where their ranges overlap in Manongarivo Special Reserve.
The Black Lemur is between 90 and 110 centimetes in length, of which 51-65 centimeters are tail. Weight typically ranges between 1.8 and 2.0 kilograms.
The Black Lemur displays sexual dimorphism in coloration. Males have black or dark chocolate fur, while females' fur is of a lighter brown color, generally medium brown, chestnut brown or even orange-brown. Males of E. m. macaco have large black ear tufts, while females of E. m. macaco have large white ear tufts.
The only other Eulemur species that occur within the range of the Black Lemur are the Common Brown Lemur, E. fulvus, which overlaps with E. m. macacao at the extreme southern and eastern edge of its range, anr the Red-bellied Lemur, E. rubriventer, on the Tsaratanana Massif. E. fulvus and E. rubriventer have different coloration and do not show the extreme sexual dimorphism of E. m. macaco, making confusion between the Black Lemur and the species unlikely.
The Black Lemur primarily eats fruit, which makes up an estimated 78% of is diet. The ripeness of this fruit is vital to the lemur's diet. Other foods eaten include flowers, leaves, fungi, some invertebrates and, especially during the dry season, nectar.
The Black Lemur lives in both primary and secondary forest. It is active both during the day and at night. It forages in both the upper and middle canopy, especially at night, and during the day it also forages in the understory. In degraded habitats, it also forages on the ground and may even eat soil.
The Black Lemur lives in groups of 2 to 15 members, including approximately equal numbers of males and females. Average group size is about 10 members, although the average may be smaller for E. m. flavifrons. Females are dominant over males, although intragroup fighting is rare.
Mating usually takes place in April and May. During mating season, antagonism between males increases, and males sometimes roam between groups. After a gestation of about 125 days, a single infant is usually born between late August and early October. Females typically give birth for the first time at 2 years of age.