The black lemur was the first of two subspecies (Eulemur macaco macaco and Eulemur macaco flavifrons) to be described and named, so blue-eyed lemurs were originally regarded as a subspecies of the black lemur. Scientists and conservationists have since separated the blue-eyed black lemur into its own species, Eulemur flavifrons. A medium sized lemur (adults can weigh 5 lbs [2.4kg]), blue-eyed lemurs have long tails which are often carried high in the air as the animals move. These lemurs generally move in a horizontal position and will walk or run quadrupedally through the trees and on the ground, except when leaping from tree to tree. This species is one of the most distinctively sexually dichromatic (different coloration in males and females) of all the lemurs. Males are completely black, while females vary from reddish-brown to gray. Although black lemur males are the same intense black as blue-eyed males, females of both species are different shades of brown. Blue-eyed lemurs are the only primate besides humans with blue eyes. The Blue-Eyed lemur lives in fairly large groups which may contain more than one breeding animal of each sex.
Blue-eyed Lemurs eat ripe fruit, leaves, flowers and occasionally insects. Since the ecology and behavior of the blue-eyed lemur has not been studied in the wild, the feeding information reported here has been obtained from observations of wild populations of black lemurs, but should hold true for the blue-eyed subspecies as well. Groups of black lemurs studied in the wild have been seen to eat primarily fruit during the rainy season when it is readily abundant. During the dry season when fruit becomes scarce, black lemurs turn to leaves, flowers, nectar and seeds. Hence depending on the season, the animals might be described as either frugivores or folivores. In the wild, black lemurs have been observed feeding on animal matter in the form of millipedes. In poor or disturbed habitats black lemurs might be found on the ground, foraging through the leaf litter for fallen fruit or fungi. They have even been seen feeding on soil. Captive black lemurs have been seen catching and eating a variety of birds including cardinals, brown thrashers and eastern peewees.
Blue-eyed lemurs, like all diurnal lemurs, are seasonal breeders. In Madagascar, the breeding season ranges from April to June. In northern hemisphere locations, such as the DLC, most breeding occurs in November and December with births in March and April. During breeding season, both males and females experience physiological changes. By the time the females are approaching estrous, the testicle size of the males has become notably larger, and the males are becoming more aggressive towards and less tolerant of their fellow males.
In the wild, female blue-eyed lemurs give birth to one or two offspring in the fall, after a gestation period of approximately 126 days. It is possible for two females in the same group to become pregnant during the same breeding season. After successfully giving birth, mothers might immediately become very aggressive to other members of their group, threatening them and lunging at them if they come too close. After a few days or a week of guarding the infants, Juveniles are typically granted first access to the newborns, followed by the father, and later the other adult females in the group.
Although dichromatic as adults, both male and female blue-eyed lemurs are born with the same orange-brown coloration. Males turn black as they age over the first 4-8 weeks. Infants cling to their mothers’ bellies for the first 3 weeks, shifting position only to nurse. At three to four weeks of age, the young lemurs will begin to make short explorations of a foot or two away from their mother, quickly scurrying back to the safety of her belly at the first sign of danger. Infants begin to explore solid food at 4-6 weeks of age, sampling bits of whatever their mothers or other nearby group members are eating. Nursing continues, but with a steady decline in importance in the infant’s diet, until the infant is weaned at 5 – 6 months of age.
Blue-eyed lemurs have not been studied extensively in the wild, so little is known about their behavior outside of captivity. Most of the following information was recorded for black lemurs, but it is assumed that it will also be correct for blue-eyed lemurs. They are reported to live in social groups of between 7 and 10 individuals, although group sizes of between 2 and 15 have been observed. Group sex ratio is often biased in favor of males. Females are dominant to males, which gives them preferential access to food and the choice of whom to mate with. This female dominance is fairly typical of prosimians.
Numerous attempts to introduce blue-eyed lemurs into mixed species groups of lemurs in multi-acre forested enclosures at the DLC have ended in failure due to the relatively aggressive nature of this lemur. In fact there have been several instances of black lemurs at the DLC committing infanticide against other species of lemurs in these forested enclosures. Such behavior has not been demonstrated by any other lemur species in these habitats.
Like most prosimians, blue-eyed lemurs use olfaction as a primary method of communication. The most common method of scent marking for both males and females, is done by way of rubbing the anogenital region, rich in glandular skin, over a suitable substrate. In addition males have two scent marking techniques not seen in the females. The first is palm/wrist marking where the male will rub his palm and wrist vigorously back and forth on a branch or other surface for a few seconds or even a few minutes. The other scent marking technique unique to the males is head rubbing, where the head is lowered and then the surface to be marked is rubbed with one or two head swipes.
Habitat & Conservation
Blue-eyed lemurs are found south of the Sambirano region in northwest Madagascar. Pure populations are found south of the Andranomalaza River near Moromandia and east to the Sandrakota River near Befotaka. Researchers have recently discovered a hybrid zone in the far northern part of its range, where Eulemur macaco macaco might breed with Eulemur macaco flavifrons. This region is considered a transition area between the rain forests of the east coast and the dry deciduous forests of the west coast.
Blue-eyed lemurs are not found in any protected areas in Madagascar, and they are severely threatened by hunting, trapping and forest destruction (especially from slash and burn agriculture) across their entire range. It is thought that there are probably less than one thousand individuals of this species left in the wild. Blue-eyed lemurs are consistently placed in the top ten of the most endangered varieties of lemurs. A reserve in the Befotaka region has been proposed by a collaboration of European Institutions, but so far it has not been legally created. The International Union for the Conservation of Nature recently elevated the status of E. flavifrons from Endangered to Critically Endangered and add them to the Top 25 Most Endangered Primates list.
Efforts to breed this subspecies in captivity began in the mid 1990s with the importation of four wild caught animals to the Duke Lemur Center. There is an SSP in place for this lemur and all North American institutions holding this species are working together cooperatively to maintain genetic diversity. The DLC houses North America’s only 2 breeding females with long term plans to increase the population of this rare lemur. A total of 10 males and 3 females live at Duke.