The blue-eyed black lemur (Eulemur flavifrons), also known as the Sclater's lemur, is a species of true lemur. It can attain a body length of 39–45 cm, a tail length of 51–65 cm- a total length of 90–100 cm, and a weight of 1.8-1.9 kg.^[3] Being a primate, it has strong hands with palms like a human, which have a rubbery texture to give it a firm grip on branches. Its tail is longer than its body and non-prehensile.

Like many of the species in the Eulemur genus, the blue-eyed black lemur is sexually dichromatic. Males are solid black in color, with the hairs sometimes tinged brown at the roots. Females are reddish-brown in color with their underside and outline of their face a lighter tan. They have a dark brown or gray muzzle and the back of their hands and feet are a similar dark color. Both sexes have blue eyes, hence the common name, and are one of the only primates other than humans to consistently have blue eyes. The eyes can range in color from shocking electric blue, a light sky-glue, or a softer gray-blue.

Although the blue-eyed black lemur and the black lemur look similar, they can be differentiated by the blue eyes and lack of prominent ear tufts of this subspecies, while the black lemur has orange-red eyes and long, spiky cheek hairs. In the Manongarivo Special reserve, where the range of the two species overlap, there is report of hybridization between the two species, but the resulting offspring always have orange eyes. Until 2008, the blue-eyed black lemur was considered a subspecies, E. macaco flavifrons, of the black lemur.^[1]

Behavior

This true lemur has not been studied intensively in the wild, but it is known to be fairly social. Group sizes vary dramatically with numbers of 2-15 individuals having been observed, although 7-10 individuals being the most common. Females are dominant as in most lemur species, and there are usually more males than females in each social group. The blue-eyed black lemur is thought to be polygynous. Females give birth to one or two offspring in June or July, after a gestation of 120 to 129 days. The young are weaned after about 5–6 months, and reach maturity at about 2 years of age. It may live between 15–30 years in captivity, with little data recorded on their longevity in the wild. It demonstrates a cathemeral activity pattern, being awake sporadically throughout the day. The occasional nighttime activities are thought to be based on the intensity of the moonlight.

The blue-eyed black lemur communicates with scent-marking, vocalizations, and perhaps some facial expressions. Scent marking is an important means of communication as with most lemur species. Both genders will mark on trees with anogenital glands, while males will also mark using wrist and palm glands by rubbing and twisting them against leaves, twigs or branches. Males also use a scent gland on the top of their head to mark, lowering their head and rubbing in quick sliding motions.^[4] Little is known of its vocalizations, but it has been observed making a variety of grunts, chirps, barks and clicks. The males are known to make a sharp 'scree' when distressed.

The blue-eyed black lemur has also been observed to be a highly aggressive subspecies. There is frequent infighting between troop members, especially during the breeding and birthing seasons. In captivity it has been observed committing infanticide against other species of lemurs, a behavior that is usually uncommon, especially in captivity.

Diet

Detail of face showing blue eyes (male, captive specimen in Edinburgh Zoo)

Fruit, pollen, and nectar make up the bulk of this lemur's diet. During the dry season when food is scarce it may eat leaves, seeds and berries and rarely insects. It may also raid farmlands and eat some of the crops, which may lead to it being shot by farmers.

The blue-eyed black lemur helps propagate many rain forest plants. Since it digests the flesh but not the seeds of the fruits it eats, it spreads the seeds of more than 50 different plant species (deposited in a fresh pile of fertilizer), and some plants may have evolved specifically to be dispersed by this lemur. The blue-eyed black lemur also pollinates many plants while it eats nectar and pollen from the plants' flowers.

Habitat

The blue-eyed black lemur inhabits primary and secondary sub-tropical moist and dry forests in the northwestern tip of Madagascar. Its range extends from the Andranomalaza River in the north, to the Maevarano River in the south. Some areas where it can readily be seen are in the forests south of Maromandia near Antananarivo and Antsiranana. It may also be seen in the remaining forest patches of the Sahamalaza Peninsula, such as the Ankarafa forest. Unfortunately, it is not currently found in any protected forests on the island.

Conservation

Humans have cut down almost all of this subspecies' habitat to clear farm land. As a result, the blue-eyed black lemur is nearly extinct in the wild. The blue-eyed black lemur is listed on Appendix I of CITES, and is critically endangered.^[2] As few as 1,000 individuals are thought to remain in the wild, largely due to slash and burn habitat destruction, as well as a mild threat from hunting problems. Consequently, this species has been named one of "The World's 25 Most Endangered Primates."^[5]

References

This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. Please help to improve this article by introducing more precise citations. (April 2009)

• C. Birkinshaw. Biotropica. 2001. 33(3): 478–486.
• Birkinshaw, et al. Folia Primatology (Basel). 1998. 69(5):252-259.

Sclater's LE. flavifrons has blue eyes, the only primate other than humans which has blue eyes,^[4] while E. macaco has brown or orange eyes, and ear tufts.^[4][5]

Both species live in northwest Madagascar. E. macaco occurs in moist forests in the Sambirano region of Madagascar and on nearby islands.^[4] E. flavifrons is restricted to the Sahamalaza Peninsula and adjacent forests.^[4] There are reports of the two species hybridizing where their ranges overlap in Manongarivo Special Reserve.^[6]

Physical description

The Black Lemur is between 90 and 110 centimeters in length, of which 51-65 centimeters are tail.^[4] Weight typically ranges between 1.8 and 2.0 kilograms.^[4]

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.^[4] 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. macaco at the extreme southern and eastern edge of its range,^[4] and the Red-bellied Lemur, E. rubriventer, on the Tsaratanana Massif.^[6] E. fulvus and E. rubriventer have different coloration and do not show the extreme sexual dimorphism of E. macaco, making confusion between the Black Lemur and the species unlikely.^[4][6]

Diet

The Black Lemur primarily eats fruit,^[7] which makes up an estimated 78% of is diet.^[8] The ripeness of this fruit is vital to the lemur's diet.^[8] Other foods eaten include flowers, leaves, fungi, some invertebrates and, especially during the dry season, nectar.^[4]

Behavior

Male and female Black Lemurs. This image was taken in Madagascar.

The Black Lemur lives in both primary and secondary forest.^[7] It is active both during the day and at night.^[4] It forages in both the upper and middle canopy, especially at night, and during the day it also forages in the understory.^[4] In degraded habitats, it also forages on the ground and may even eat soil.^[4]

The Black Lemur lives in groups of 2 to 15 members, including approximately equal numbers of males and females.^[4] Average group size is about 10 members,^[9] although the average may be smaller for E. m. flavifrons.^[4] Females are dominant over males, although intragroup fighting is rare.^[7]

Groups have home ranges of about 3.5 to 7 hectares.^[9] Ranges overlap considerably, and population density can reach 200 individuals per square kilometer.^[7]

Black lemurs also have a habit of picking up and biting at toxic millipedes. The toxins are usually not fatal to the lemurs and they try to stimulate the millipede to release its toxins in self defence. Once this is achieved the black lemur will rub the millipede around its body to get the toxins on its fur. Its believed that they do this to help repel insects with the millipedes poison. However other researchers have theorized that they may also do this for a source of pleasure. Because when they inhale or swallow too much of the toxins it inhibits their monoamine oxidase system and as a result gives them a high sensation.^{[citation needed]}

Reproduction

Mating usually takes place in April and May.^[4] During mating season, antagonism between males increases, and males sometimes roam between groups.^[7] After a gestation of about 125 days, a single infant is usually born between late August and early October.^[4] Females typically give birth for the first time at 2 years of age.^[7]

References