White-Fronted Lemur, Eulemur albifrons
WHITE-FRONTED LEMUR
Eulemur albifrons
Geographic Distribution and Habitat
The white-fronted lemur (Eulemur albifrons), whose aliases include white-fronted brown lemur, white-headed lemur, and white-headed brown lemur, is native to the large island country of Madagascar—the only place in the world where these primates exist in the wild. Located in the Indian Ocean approximately 250 mi (400 km) off the coast of East Africa across the Mozambique Channel, Madagascar (officially known as the Republic of Madagascar), together with India, broke away from Africa 150 million years ago. (Scientists believe that lemur ancestors likely drifted to the island of Madagascar on clumps of floating vegetation.) Madagascar’s isolation and lack of predators have allowed species found nowhere else on earth—including all lemur species—to thrive. Opulent, rare flora flourish in the island’s hot and humid climate.
Found only in the northeastern region of the island, white-fronted lemurs inhabit Madagascar’s remaining tropical rainforests. Here these primates dwell within primary and secondary tropical moist lowland and montane rainforests from sea level to 5,479 feet (1,670 m). Compared to rainforests in other parts of the world, Madagascar’s rainforests are characterized by a large variety of low canopies and small trees.
The species’ geographic distribution, or extent of occurrence (EOO), encompasses only about 10 percent of the island’s total land area of 226,917 square miles (587,712 sq km). Their range stretches about 19,267 square miles (49,901 sq km) from the Bemarivo River near the city of Sambava, south to the commune of Mananara-Nord (aka Mananara Avaratra). Included in the Mananara region is the magnificent rainforest-covered Masoala Peninsula—accessible only by boat and one of Madagascar’s foremost conservation priorities for its high biodiversity of animal and plant life.
The Betampona Nature Reserve within Toamasina Province is home to an isolated population. Another population of white-fronted lemurs lives within the small island reserve of Nosy Mangabe, “introduced” there by conservationists. The reserve is part of the larger Masoala National Park (within the Masoala Peninsula), located in Antongil Bay just over 1 mile (about 2 km) offshore from the seaport town of Maroantsetra in northeastern Madagascar.
Unconfirmed sightings have been reported south of Mananara. But significant hybridization occurs—over a wide area—between white-fronted lemurs and common brown lemurs (Eulemur fulvus); simply put, the two species mate with one another, resulting in a hybrid animal. Further study is needed to determine whether this region is, in fact, part of the white-fronted lemur’s natural geographic distribution. Wildlife researchers have, however, ruled out the species’ presence on the Makira plateau, where these primates were once believed to live.
Before being elevated to distinct species status in 2001, the white-fronted lemur had been considered a subspecies of the common brown lemur (Eulemur fulvus). Four other lemur species received this same “promotion”: the gray-headed lemur (E. cinereiceps), collared brown lemur (E. collaris), red-fronted brown lemur (E. rufus), and Sanford’s brown lemur (E. sanfordi); each enjoys distinct species status today. Not all wildlife biologists are in full agreement, however. Some insist that the white-fronted lemur and red-fronted brown lemur should continue to be considered subspecies (or “child”) to the common brown lemur. Irrespective of this assertion, lemurs belonging to the family Lemuridae—comprised of five genera, including the genus Eulemur—are considered “true lemurs,” with a membership of 21 species. The total number of all lemur species is a subject of scientific debate, with some wildlife biologists putting that number as high as 111, and others asserting that 50 is a more likely total species headcount.
Size, Weight, and Lifespan
Considered medium-sized lemurs, adults have an average weight of 5.1 pounds (2.3 kg), and a body length of 16 inches (40 cm). Males and females are similar in size. A long, nonprehensile tail adds another 20 inches (50 cm) to the white-fronted lemur’s body.
Documented lifespan for the species is between 20 and 25 years in the wild. Captive white-fronted lemurs are reported to live up to 36 years.
Appearance
Like other members belonging to the primitive primate suborder strepsirrhini—who include lorises, pottos, and galagos (aka, “bushbabies”)—lemurs are not monkeys. Rather, these primordial-looking beings are prosimians, characterized by long, pointy, wet snouts; big ears; round, arresting eyes; and, with the exception of the Indri lemur, exceptionally long tails. Other “inherited” strepsirrhine traits include a grooming claw (aka toilet claw), located on the second digit of each foot; a tooth comb (aka dental comb), located on the lower front teeth and accompanied by a serrated sublingual structure that cleans the toothcomb (think of built-in dental floss!); and a bony arched structure known as a postorbital bar, located behind their convex forehead that runs sideways around each eye socket and connects the front of the skull to the cheekbone. Strepsirrhines’ more “evolved cousins” of the suborder haplorhine (tarsiers, monkeys, and apes—including humans) are fitted with a postorbital plate (or closure) a thin wall of bone behind each eye that fully encloses the primates’ eye sockets. The haplorhines also have dry noses.
White-fronted lemurs are no exception to strepsirrhine’s ancestral, otherworldly appearance—they are either weirdly cute or exceptionally peculiar looking, depending on your perspective. Males and females are sexually dichromatic, which means that the two sexes differ in fur coat coloring.
As one of their aliases indicates, a furry white cap covers the heads of males. Dark, scalloped ears peep out. White fur extends to and generously encompasses the cheeks and chin, adding dramatic contrast to the prosimian’s onyx-black muzzle. The throat and chest may also be covered with white fur. Reddish-orange eyes cast a spellbinding gaze. The male’s back is cloaked by a medium-to-dark brown fur coat that darkens and turns to a reddish shade as it reaches the dark, furred tail. Pale gray fur covers the male’s belly.
Females lack a furry white cap. Instead, Nature has given them a dark gray crown and has demurely outlined their dark gray muzzles with reddish-brown fur trim, far less bushy and outlandish than the cheeks of males. Like males, females have spellbinding reddish-orange eyes. Their fur coat is more reddish than that of males, and paler fur covers their underparts. They also have darker feet than males.
Diet
White-fronted lemurs are omnivores, meaning that they eat both plant-based and animal-based foods. While nearly 70 percent of their diet is composed of fruits, mature leaves, flowers, stems, sap, moss, bark, and mushrooms—they also eat insects, spiders, centipedes, and millipedes. And these primates are known to eat soil, a practice known as “geophagia,” which may provide protection against certain toxins in the environment.
Dietary variation is more pronounced in females. During the dry season, when they typically give birth, females eat mostly flowers. They continue with this penchant during lactation (while they are producing milk and nursing their young). When not in a reproductive stage, females join their male counterparts in eating more varied food items, including mature leaves and millipedes.
Researchers studying the dietary proclivities of black lemurs (Eulemur macaco) have found that these millipede-munching cousins of white-fronted lemurs capture the crawly creatures for reasons other than a quick meal. Black lemurs practice capture and release—they don’t actually eat the millipedes. By gently biting into their prey, the creature releases a secretion that the lemur then rubs through its fur, where it acts as a natural insect repellent. But there may be another reason for sampling these invertebrates. Millipede secretion also acts as a narcotic, causing a lemur to salivate profusely and to become somewhat intoxicated—or high. Whether or not white-fronted lemurs engage in the same practice has not been documented.
Behavior and Lifestyle
These arboreal (tree-dwelling) prosimians are usually found in the rainforest treetops, just beneath the canopy. They frequent lower-canopy trees, from 16.4 to 49.2 feet (5–15 m). As cathemeral animals, they are active at varying times throughout the day and night, depending on circumstances in their environment. (Contrast this behavior to exclusively diurnal animals, who are active during daylight; nocturnal animals, who are active during the night; and crepuscular animals, who are active at dawn and dusk.) The level and variety of their activities depend on the season, weather, and food availability.
Moving through the forest understory quadrupedally (using both their hands and feet), white-fronted lemurs maintain a horizontal posture. They are highly athletic and are phenomenal leapers, pushing off with their strong legs and jumping from tree to tree at distances up to six times their body length—that’s 30 feet or more! Their long tail, while unable to grip, becomes a rudder as they fly through the air and helps them to balance as they “stick their landing” on the next tree limb.
For their mid-day nap, these lemurs deliberately choose dense lianas and crown lianas with restricted arboreal access. Their siesta “hideout” conceals them from predators and also shields them from heavy rains and wind. Individuals huddle together, tails intertwined, in what scientists posit is a function of social thermoregulation—a fancy way of saying “body heat.” As with humans, the quality of lemurs’ sleep sites affects their overall fitness and health. Of course, you won’t find any high-end mattress stores in the rainforest. Other sleep sites for white-fronted lemurs include tree holes and constructed nests.
Lemurs have stereoscopic (or “binocular”) vision, meaning their brain is able to register three-dimensional shapes, or depth perception, from visual inputs. Although this vision allows them a wider visual field, they must still turn their heads to look at an object, because their large eyes (even though they point forward, though not as forward-pointing as their haplorhine cousins) have limited movement within each orbit (socket). As such, they rely more on their peripheral vision and less on stereoscopic focus.
Overall, lemurs don’t have strong eyesight. While Mother Nature saw fit to give those fancier and more well-known prosimians, the ring-tailed lemurs (exclusive occupant of the genus Lemur), an adaption known as a tapetum lucidum (a thin, specialized layer of tissue behind the retina that reflects visible light back through the retina, enhancing nighttime vision)—she didn’t get around to giving this attribute to white-fronted lemurs or to their many other cousins.
Fortunately, white-fronted lemurs—like all prosimians (unlike monkeys)—have a strong sense of smell which they rely upon heavily to determine which foods are safe to eat and to distinguish between individuals in their family groups. Their keen hearing alerts them to approaching predators. Predators include large birds of prey, large snakes, fossas (large carnivorous mammals, related to the mongoose with cat-like qualities), and humans. To outwit predators, lemurs are said to conspire with one another by using a technique called “mobbing.” As an example, an entire troop may work together to attack (or mob) a snake.
The word lemur means “ghost” in Latin.
The word prosimian means “before monkeys.”
A group of lemurs is called a “conspiracy.”
Gorilla-sized lemurs once lived on the island of Madagascar. Weighing nearly 353 pounds (160 kg)—based on fossil evidence—these docile giants spent their time in trees, feasting on fruits, nuts, and seeds. Classified by paleontologists as Archaeoindris, these animals vanished 350 BCE (before common era), after humans hunted them to extinction.
These highly social primates live in multimale, multifemale family groups (known as troops). Group size varies between 3 and 11 individuals, with primary forest locations hosting larger populations. Unlike other lemurs in the genus Eulemur, where females are dominant to males, “girl power” does not appear to be the case with white-fronted lemurs.
While foraging, a troop focuses on small areas within a home range of up to 39.5 acres (16 hectares, or 0.06 square mile). These primates prefer to feed on trees with a diameter of less than 8 inches (about 20 cm). Though Nature has fitted them with opposable thumbs and big toes, lemurs do not display tool usage in the wild.
With some lemur species (such as the ring-tailed lemur), females remain with their birth (natal) group, while males leave home between 3 and 5 years old and join a neighboring group. This behavior has not been documented for white-fronted lemurs.
Other animals who share habitat with white-fronted lemurs include the red-ruffed lemur (Varecia rubra), aye-aye (Daubentonia madagascariensis), hedgehog tenrec (Echinops telfairi), striped civet, fanaloka (Fossa fossana), a rare mongoose-like mammal called the falaouc (Eupleres goudotii), fossa (Cryptoprocta ferox), and a plethora of insects.
Lemurs communicate primarily through scent, facilitated by enlarged scent glands and a strong sense of smell. The secretions of these glands convey various messages, such as an individual’s physical condition, the location of a family member, or a territorial boundary. While much more has been written about the scent glands and olfactory communication of the iconic ring-tailed lemur (who has scent glands on the wrists, chest, and anal area), we know that white-fronted lemurs are at least fitted with a scent gland on each of their wrists.
Similarly, much has been written about the “stink fights” that ring-tailed lemurs engage in to establish dominance. To intimidate a foe or rival, males rub their tails against scent glands on their chests and wrists and then wave their tails at each other, releasing a strong, off-putting odor. For dramatic effect, they might do a handstand while thrusting their tails over their heads. Whether white-fronted lemurs give such a performance is unknown. But we know that their long, furry, nonprehensile tail is much more than a rudder that helps them stick their landings when leaping from tree to tree. It’s an indicator of mood—much like that of a cat. A lemur who holds her tail straight up vertically while she walks is thought to express confidence and contentment; a tail that extends out horizontally with hairs on end (known as piloerection) indicates fear or agitation.
While olfactory communication is key for lemur species, vocalizations are also used. These vocalizations vary by species; those in the genus Eulemur, including white-fronted lemurs, emit grunts. They might also emit calls associated with the common brown lemur: an “ohn” call is used to maintain group cohesion; a “cree” is a high-pitched territorial call; and a “crou” is sounded as an alarm call.
Tactile communication, in the form of social grooming, helps to establish social bonds between family members. White-fronted lemurs use their tooth comb for this intimate pastime.
To get an idea of the reproductive society of white-fronted lemurs, we look toward others in the genus Eulemur, who are either monogamous (having only one mate) or polygynous (where males have multiple female mating partners). Researchers posit that white-fronted lemurs practice similar mating habits.
Sexual maturity likely occurs between 1 and 2 years of age. A female gives birth to a single infant after a gestation period of about 120 days. Births occur from mid-October through early December. Mothers are the primary, if not sole, caregivers.
For the first three weeks of life, an infant clings to his mother’s belly, only shifting position to nurse. At the end of three weeks, he begins to ride on his mother’s back as she travels. Shortly thereafter, the young lemur begins taking his first steps. He may begin sampling solid food, but he is not fully weaned till about four months of age. Between 4 and 6 months of age, he is considered independent.
Lemurs are important citizens to their ecosystem, acting as both seed dispersers and pollinators. Thanks to the many fruits they eat, white-fronted lemurs disperse seeds (via their feces) throughout their rainforest habitat and carry pollen on their pointy snouts—both actions help regenerate new forest growth.
White-fronted lemurs are classified as Vulnerable by the International Union for Conservation of Nature (IUCN, May 2018), appearing on the IUCN Red List of Threatened Species. However, some conservationists believe that the species should be assessed as Endangered, citing a population decline of greater than 30 percent over a period of 24 years (three generations).
Habitat loss is the greatest threat to the species’ survival. Pristine tracts of forest are razed through slash-and-burn agricultural practices. Illegal logging, mining for quartz, and, most recently, illegal rosewood harvesting also destroy white-fronted lemur habitat. A staggering 90 percent of Madagascar’s forest cover has already been lost—putting many species at risk.
Hunting is another major threat. Of all lemur species, white-fronted lemurs are the most heavily hunted. Even in so-called “protected” areas, these primates are hunted for their flesh, known as “bushmeat.” The animals are trapped in snares and killed with firearms. Occasionally, they are captured and kept as pets.
The earth’s climate crisis is another specter looming over this species; researchers estimate a further 8 percent reduction in habitat by the year 2080.
And then there’s the pandemic. COVID led to a serious setback in conservation due to the temporary cessation of ecotourism. Prior to the pandemic, lemur-watching was a popular activity with visitors to the island. But without a steady income from Madagascar’s tourism industry, locals turned to the forests for food and fuel—cutting down forestland and hunting lemurs.
A study funded in part by The Leakey Foundation, and published in The Journal of Biogeography in August 2018, found that as many as 1.3 million white-fronted lemurs remained in the wild. While this number, if accurate (and now several years outdated), sounds optimistic, the IUCN reports that the species population number continues to decline—due to bad human behavior. Zoos worldwide account for a captive population, where more than 150 white-fronted lemurs are attractions to visitors.
White-fronted lemurs are 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.
The species is found in three national parks (Mananara-Nord, Marojejy, and Masoala) and in two special reserves (Anjanaharibe-Sud and Nosy Mangabe), with an introduced population in the Betampona Strict Nature Reserve. In theory, these white-fronted lemurs should be safe. But they are not. Laws to protect them are routinely flouted, and hunting is rampant.
One organization dedicated to saving lemurs from extinction is the Lemur Conservation Network (LCN). Founded in 2015 as a project of the IUCN Species Survival Commission Primate Specialist Group, in 2021 LCN became an independent not-for-profit organization registered in the USA. Working with over 60 conservation organizations worldwide, LCN raises awareness through various educational and community programs—including the annual World Lemur Festival.
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Written by Kathleen Downey, February 2023