Eulemur flavifrons

Geographic Distribution and Habitat

Blue-eyed black lemurs are found in the northwestern region of Madagascar. They have one of the smallest geographical ranges, limited to the southern part of the Sambirano region. This area is known for having habitats with rainforest and dry deciduous forest-type trees. So these lemurs have adapted to different types of food sources including forests that have been disturbed by human development such as plantations.


Blue-eyed black lemurs (sometimes called Sclater’s lemurs) are one of the least studied lemur species in the world. They were first described in 1867, but no one published any studies on them until 1985! Between those years, people even doubted the species existed, as no one reported further sightings. They were once classified as a subspecies of the black lemur (Eulemur macaco), but the geographical separation of the two species by the Andramaloza River and in-depth genetic studies have shown them to be a separate and distinct species.

Their common name comes from the males’ dark fur and contrasting light eyes. Their scientific species name “flavifrons“, comes from the yellow brow of the females (“flavus” means yellowish, and “frons” means forehead).

These lemurs have some geographical overlap with the black lemur (Eulemur macaco) and, in these areas, mating between the species results in hybrid young with lighter eyes than the black lemur (that is, light brown eyes).

Blue-eyed black lemur range, IUCN 2023

Size, Weight, and Lifespan

Compared to other lemur species, the blue-eyed black lemur is a medium-sized primate weighing 3.6-4.8 pounds (1.6 – 2.2 kg).  From the head to the base of their tail, they measure about 1.3-1.5 feet (39-45 cm). Their tails are bushy and much longer than their body measuring 1.7-2.1 feet  (51-65 cm)

The blue-eyed black lemur’s life expectancy is unknown. Their lifespan is probably similar to its closest relative, the black lemur, which is about 27 years. In captivity, one blue-eyed lemur lived for over 21 years. 


These lemurs are strikingly beautiful as they curiously peer into the world with their highly contrasting fur and eye color.  As their name suggests, blue-eyed black lemurs have large bluish-gray or bluish-green eyes and are covered in black fur. They have the classic lemur face with a fox-like elongated snout. Their long, bushy tails usually do not touch the ground as they hold their tails upright with an S-shaped curve at the end.

The most notable part of their appearance is the differences between males and females that can be used to tell them apart. This is called sexual dimorphism. Males are all almost entirely black, and females are a burnt-orange color (sexual dichromatism). Males can have brownish fur along their chest and belly, and their hands and feet are black. Males also have a visible crest of hair on their head. Female bodies are covered in reddish-brown fur with a dark stripe along their back, and their bellies are a much lighter cream or gray. Female hands and feet are brown. Male blue-eyed black lemur faces are covered in black fur, while female faces have dark gray fur.  The stark difference in the appearance of the two sexes led early explorers to think that male and female blue-eyed black lemurs were two different species and not different sexes of the same species!

Their lower incisor teeth are separated and act as a “tooth-comb” which helps them groom and remove pesky bugs or dirt from their fur. 


Blue-eyed black lemurs eat a variety of foods such as fruits, leaves, flowers, fungi, and insects. One study showed that the lemur diet was almost equally split between fruits and leaves, which is probably because these are the most abundant and energy-rich food sources.  Throughout the year, they switch their diet seasonally, so they eat more fruits during the fruiting season and switch to more leaves and seeds during drier months. These lemurs prefer to feed in tall trees, but in areas where trees have been cut down for plantations, they descend to the ground and feed on fallen fruits and seeds. 

Behavior and Lifestyle

These lemurs are active during the day and also after sunset. In this unusual “cathemeral” activity pattern, the animals’ peak activity is not strictly determined by time of day. This flexible nature is most likely a reaction to unpredictable food sources that may be available in different seasons or in different parts of the forest throughout the year. 

Blue-eyed black lemurs are arboreal and spend most of their time in trees. They move by vertically clinging onto trees and leaping in a similar vertical position from one tree to another. While they feed on fruits and forage for leaves, they walk on all fours (quadrupedally) on tree branches. 

Female blue-eyed black lemurs are more aggressive than other lemur species, and they are dominant over the males within their troop. Females also show territorial behavior and actively chase out other female intruders. This phenomenon of female aggression and dominance is rare among mammals and is referred to as the Female Challenge (or Masculinization) Hypothesis. 

Fun Facts

Blue-eyed black lemurs are one of the most endangered primates in the world. 

They exhibit sexual dichromatism with males mostly black and females mostly orange-red. 

Females are more dominant than males. 

They have a cathemeral activity pattern where peaks of activity occur in the morning and at twilight. 

Daily Life and Group Dynamics

Blue-eyed black lemurs have a cathemeral or bimodal activity pattern where they are most active early in the morning and again at night (during twilight). They spend the mornings traveling and looking for food. Then, they take a long break in the afternoon, when it is the hottest. They can rest for more than half the day. During these rest periods, young lemurs play, mothers nurse their young, and some adults socialize, groom, or lazily eat. As the day cools into the evening, their activity levels increase and they forage for more food as they travel to their sleeping sites. They prefer to sleep in the safety of large trees with lots of leaves for cover so that they can avoid predators, particularly the fossa. Lemurs huddle together at night for warmth, wrapping their bodies with their fluffy tail. 

They live in multi-male, multi-female groups with a skew towards more males. A troop of 6-10 individuals usually has a maximum of three females. Female dominance among lemurs is common, and in blue-eyed black lemurs, it is even more pronounced with 81% of the dominance interactions involving physical attacks and 99% of the male-female interactions won by the females. 

Within the troop, male-male interaction can become aggressive during breeding seasons. Males sometimes disrupt mating events and aggressively guard females from other male troop members. Females in the troop are usually peaceful and pleasant with each other. However, negative interactions are more frequent during the breeding season when males and females are under hormonal and mating stress.  


Lemur are highly vocal and capable of making high and low-pitched sounds that carry through the forest. When animals live in dense forests, where they cannot always see their family members, yelling is the best tool to call or warn others quickly. Each lemur species probably evolved to have a different set of calls or vocal repertoire so that they can tell them apart when different species live near each other. Humans can pick out many of these vocal differences, but not at the level that lemurs can, and so most studies on lemur vocalization use some form of recording and sound wave analysis technology.

Blue-eyed black lemurs have loud alarm calls emitted in five clusters of repeated sounds. Grunting sounds are used to communicate directly with each other and long grunts are usually done by males. Sometimes hoot or grunt-hoot sounds are made for short-distance communication.

Most lemur species use some form of scent or olfactory marking, using glands that they rub onto branches. These glands have special secretions that can contain information about the lemur’s identity, sex, age, reproductive health, etc. Both males and females use their anogenital glands located near under their tails to rub secretion on trees. In blue-eyed black lemurs, males use glands on their wrists and on the top of their heads as additional scent marks. Researchers do not know the exact purpose of these markings. Some common explanations include territorial boundary markings and landmark or presence marks that can indicate trees they prefer or have traveled to.

Reproduction and Family

These lemurs tend to reproduce seasonally, with young being born just before the wet season (August to October). Females control the mating events and reject undesirable males. Males fight amongst themselves for mating privileges with the females. Larger and more dominant males will usually get to mate with females, while subordinate males have to wait for the next breeding season.

A female can become pregnant when she is as young as three years old and gives birth to one child or sometimes twins. In a family, multiple females can be pregnant at the same time.

One peculiar observation was that the first-borns tended to be males and the second-borns had a higher chance of being females.
Mothers spend all their time with infants, usually resting (66% of their activity), eating (19% of their activity), traveling with their babies clinging to the mother’s chest (12% of their activity), and very little time is spent socializing with other family members or even grooming their babies. Non-mothers (particularly adult males and older sisters) are permitted to babysit and hold babies, especially if the infant is a second child.

All blue-eyed black lemur babies are born covered in black-brown fur. This dark coloring helps the infant hide in their mother’s chest fur and they are rarely seen during their first three weeks. When the infants are between three and four weeks old, they move to their mother’s back where they are carried till they become more independent. Around the same time, the fur on the infant’s tail changes colors, becoming light brown. Their infants’ dark body and lighter-colored tails help them blend into the dark stripe and orange-red fur on their mother’s back. At this stage, young lemur males and females look the same. After they become four weeks old, the tails of female infants continue to lighten and change color to a bright orange color (similar to adult females) while the tails of male infants remain black-brown.

Four-week-old lemurs become more adventurous and move around their mothers’ bodies reaching out for twigs and licking fruits. It is not until they are six weeks old that they start leaving their mother’s body to walk quadrupedally on branches. The young lemurs are still cautious and do not stray too far away from mom. They usually play with other infants or explore their environment learning the skills of how to navigate branches and what foods to eat. By the time infants become 10 weeks old, they are weaned off their mother’s milk and consume solid food.

Infant mortality can be quite high (in one study, as many as 22% of new infants died before the age of 10 weeks). 

Sub-adult males and females leave their natal troop (the one they were born into), but males tend to disperse further away.

Male. Photo: ©Charlie Marshall/iNaturalist/Creative Commons
Ecological Role

Blue-eyed black lemurs are the main primate species that can thrive in the transitional zone between rainforests and dry deciduous forests of northwestern Madagascar. As seasons change, these lemurs can adapt to eating insects and fungi instead of fruits and leaves. This ecological plasticity makes them well-suited to this habitat. As these lemurs travel and feed on fruit, they drop seeds on the forest floor. In this way, they are seed dispersers, and like a farmer spreading out seeds, they help new trees grow in the forest. They also feed on nectar from flowers and help pollinate flowers. 

When lemurs feed on leaves, they thin out large trees, allowing more sunlight to pass through the dense canopy and reach smaller plants. The ecological ties between the lemur and the forest are vital for the survival of both the lemur and the habitat.

In the food chain of Madagascar, lemurs are the main prey for the largest mammalian carnivore in Madagascar, the fossa. The balance between the predator and prey population is vital to maintaining a healthy ecosystem, which starts to fail if lemurs such as the blue-eyed black lemur populations decrease.

Conservation Status and Threats

The International Union for Conservation of Nature lists blue-eyed black lemurs as Critically Endangered (IUCN, 2018), appearing on the IUCN Red List of Threatened Species.

Blue-eyed black lemurs are listed in IUCN’s 2008 Primates in Peril publication: The 25 Most Endangered Primate Species. Between 1990 and 2014, the population of these lemur species decreased by more than 80%. Given the current trend, some scientists think that the largest populations of this species may be extirpated (eliminated from that area) by 2026!

Blue-eyed black lemurs have a limited habitat in which to live. These forests are under pressure to be logged for timber, converted to agricultural land, or mined for ores. Habitat destruction is the biggest threat to lemur survival. Traditional conversion of forests to agricultural land in the area is a harsh process of burning down the forest to clear trees and temporarily increase organic ash and material in the soil. Many animals, including lemurs, die in these fires.

These lemurs are also hunted for bushmeat and trapped as pets, further threatening their survival.

Conservation Efforts

The blue-eyed black lemur is listed in Appendix I of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.

One challenge to the conservation of blue-eyed black lemurs is that they are found only in the transitional forests limited to the northwestern region of Madagascar. The geographical range for this species is one of the smallest of all lemurs. Part of their habitat is nationally protected through the Sahamalaza-Iles Radama National Park, which limits human activity in core habitats.

Organizations like the Association Européenne pour l’Etude et la Conservation des Lémuriens (AEECL), a group of European zoos that have committed to wild lemurs, have started a community-based conservation program to protect local populations of lemurs and improve human quality of life through sustainable management.

There are a few blue-eyed black lemurs in captivity in Europe and North America. However, survival and breeding of the species in captivity is challenging and any programs to maintain genetic health within the species or reintroduce them into the wild will be even more challenging.

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Written by Acima Cherian, May 2024