Eulemur

Diversity

The genus Eulemur , also known as brown lemurs, contains 8 known extant species: red-bellied lemurs ( Eulemur rubriventer ), mongoose lemurs ( Eulemur mongoz ), crowned lemurs ( Eulemur coronatus ), gray-headed lemurs ( Eulemur cinereiceps ), brown lemurs ( Eulemur fulvus ), black lemurs ( Eulemur macaco ), red-fronted lemurs ( Eulemur rufus ), red-collared lemurs ( Eulemur collaris ). There are 7 known subspecies in total, spread between several species in the genus Eulemur . Eulemur species are one of several genera in the "true lemur" family, Lemuridae . Lemurs are considered a part of the suborder Strepsirrhini , within the order Primates .

Geographic Range

Lemurs (family Lemuridae ) are endemic to Madagascar and are the only primate group present on the island. Two species in the genus Eulemur , mongoose lemurs ( Eulemur mongoz ) and common brown lemurs ( E. fulvus ), are also found in the Comoro Islands, although they were most likely introduced by humans. Evidence suggests that ancestral primates of the suborder Strepsirrhini ranged across what is currently North America, Europe, Asia, and Africa. However, competition with other primates drove many species to extinction. Other extant members of the suborder Strepsirrhini are found in parts of Asia and Africa, but lemurs are only native to Madagascar.

• Biogeographic Regions
• oceanic islands oceanic islands
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

Brown lemur species are found throughout Madagascar. Although they primarily live in rainforests and dry deciduous forests, they are also present in montane areas and wetlands. Two species in the genus Eulemur also live on islands between Madagascar and mainland Africa. Mongoose lemurs ( Eulemur mongoz ) are found on Mwali and Nzwani, in the Comoros archipelago, and common brown lemurs ( Eulemur fulvus ) are found in the Mayotte archipelago. It is suspected that lemurs were introduced to these islands by humans.

• Habitat Regions
• tropical tropical

• Terrestrial Biomes
• forest forest
• rainforest rainforest
• scrub forest scrub forest
• mountains mountains

Systematic and Taxonomic History

There have been many debates regarding the number of species that belong in the "true lemur" family, Lemuridae , as opposed to other families in the superfamily Lemuroidea .The true lemur family comprises five extant genera: bamboo lemurs and gentle lemurs ( Hapalemur ), greater bamboo lemurs ( Prolemur ), ring-tailed lemurs ( Lemur ), ruffed lemurs and variegated lemurs ( Varecia ), and brown lemurs ( Eulemur ). There is ongoing debate regarding the organization of species within the genus Eulemur and the family Lemuridae .

Physical Description

Brown lemurs may have gray, black, brown, or reddish coloration, often with a mix of several shades or different colors. Brown lemurs generally have elongated snouts, curved nostrils, large eyes, and tufts of fur on their ears. Several species have lighter coloration and/or longer fur on their cheeks and chins. Brown lemurs have long digits, long hind legs, wooly fur, and bushy tails that are often longer than the length of their bodies. Most species are between 2 and 3 kg in body mass and exhibit little noticeable sexual dimorphism, although males generally have more scent glands.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Many brown lemur species are monogamous, though some species exhibit both polygynous and polygynandrous reproductive behavior. Brown lemurs do not exhibit sexual dimorphism, and it is suspected that males do not compete for mates by physical confrontation. Rather, sperm competition is important in polygynous and polygynandrous species. Males generally have more developed scent glands compared to females, which suggests the pheromones they release play a role in sexual selection.

• Mating System
• monogamous monogamous
• polygynous polygynous
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Most brown lemur species have short mating periods - usually around 3 weeks per year. Females only enter estrus for a few days annually. Furthermore, brown lemurs often avoid mating when food supplies are limited. As a result, brown lemur population growth rates are generally slow.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • external external
• viviparous viviparous

Brown lemurs have an average gestation period of 54 to 135 days, depending on the species. Most species give birth to 1 or 2 offspring at a time. Newborn brown lemurs are altricial and highly dependent on their mothers for several years. Females carry their young on their chests for the first few days, until the young are strong enough to cling to the backs of their mothers. Females nurse their young for around two years, at which point the young have developed molars and transition to solid foods. The time at which juvenile brown lemurs are fully weaned usually coincides with times of the year when food is most plentiful. While females demonstrate extended parental care, males exhibit little parental care beyond the act of mating.

• Parental Investment
• precocial precocial
• female parental care female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female
• extended period of juvenile learning

Lifespan/Longevity

The average lifespan of wild brown lemurs is 25 to 35 years. Some species have been reported to live up to 40 years in captivity. In the wild, the highest rates of mortality are in newborns and juveniles, although adults are still at risk of predation and illness.

Behavior

Although some brown lemur species live in pairs, most species live in groups with up to 15 individuals, both males and females. Typically, females have dominant roles in the group social structure. Within their groups, brown lemurs are highly social, exhibiting behaviors such as social foraging, food sharing, and allogrooming. Often, individuals higher in the social hierarchy get groomed first. Brown lemurs also fight and exhibit other aggressive behaviors, both within groups and between groups. Some species have been observed mourning the loss of young, and many studies have noted brown lemurs exhibiting various emotional states. Some species have also been observed purposely eating millipedes to combat gastrointestinal parasites. Most brown lemurs are primarily arboreal, spending most of their time in the trees foraging for plant material and insects. However, some species spend more time on the ground compared to others. Depending on the species, brown lemurs may be diurnal, nocturnal, or crepuscular.

• Key Behaviors
• arboreal arboreal
• scansorial
• terricolous
• motile motile
• sedentary sedentary
• territorial territorial
• social social
• colonial colonial
• dominance hierarchies dominance hierarchies

Communication and Perception

Brown lemurs have large ears and eyes, which help them detect predators. They rely heavily on visual and chemical stimuli while foraging. They have binocular vision, trichromatic vision, and a well-developed sense of smell. These adaptations help them navigate in the trees and detect fruit and insect prey. Brown lemurs communicate with each other using visual, acoustic, chemical, and physical cues. They produce a range of species-specific vocalizations to communicate with members of their group or other groups. For instance, mothers often make purring sounds to their young, and most species use grunting noises as a form of friendly communication or to communicate during breeding periods. Furthermore, most brown lemurs use high-pitched screams to warn others of danger or to communicate territorial boundaries, and they make meowing sounds to call other group members to a central location. Brown lemurs also use chemical signals to mark territory and communicate with potential mates. Both sexes have scent glands that they use to mark objects in their environment. Brown lemurs communicate aggression visually using specific body language and eye contact. They also exhibit physical communication, often grooming other group members to strengthen social bonds.

• Communication Channels
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Most brown lemur species feed primarily on nuts and fruits, although they also eat other plant material, such as leaves, flowers, and nectar. When these food sources are scarce, brown lemurs will also eat insects or small animals, such as birds, reptiles, and their eggs. During periods of low food availability, brown lemurs can reduce their metabolic rates to conserve energy. When food is plentiful, they may eat so much that they double in body mass. Food competition is common within and between brown lemur social groups. Individuals typically hunt for their own food, but dominant females have some control over the eating habits of other group members. When there are limited food sources, all individuals in a group tend to eat less.

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates
  • eats eggs
  • insectivore insectivore
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore
  • granivore granivore
  • nectarivore nectarivore
• omnivore omnivore

Predation

The primary natural predators of brown lemur species are fossas ( Cryptoprocta ferox ) and birds of prey, such as Madagascar serpent eagles ( Eutriorchis astur ) and Madagascar harrier-hawks ( Polyboroides radiatus ). Madagascar harrier-hawks are active at night and often prey on young lemurs. Human ( Homo sapiens ) hunting practices are also a large predation threat to brown lemurs.

Brown lemurs often live in social groups, which provide them some protection from predation. They produce alarm calls to warn conspecifics of threats, or to recruit other group members to a central location. Brown lemurs also exhibit mobbing behaviors, working together to deter predators. Lemurs have also been reported to use tools, such as sticks and rocks, to fight off predators.

Ecosystem Roles

Brown lemur species serve as prey for mammalian carnivores and birds of prey. They also serve as herbivores and predators of insects and small animals. Because much of their diet consists of fruits and nuts, brown lemurs act as seed dispersers for many plant species. Brown lemurs have large home ranges, so they are capable of dispersing seeds long distances, and some seeds live longer and germinate faster after passing through lemur digestive systems. Some brown lemur species are partly nectarivorous, and thus play a role in plant pollination. Because of their roles as plant pollinators and seed dispersers, brown lemurs have mutualistic relationships with many plant species. They also have a mutualistic relationship with their intestinal flora, which helps them further process plant material after ingestion. Brown lemurs serve as hosts for ectoparasites, such as ticks and mites, and endoparasites, including several groups of parasitic worms.

• Ecosystem Impact
• disperses seeds
• pollinates

Economic Importance for Humans: Positive

Brown lemurs are pollinators and seed dispersers, and thus play a vital role in maintaining the health of forests. Forest ecosystems provide local and global human communities with sources of food, medicine, ecotourism, and many other benefits. Brown lemurs also play a role in controlling insect pests, which benefits human agricultural practices and public health. Research on lemur behavior and health may also have important implications for human behavior and medicine, as lemurs are primates and share some similarities with humans and other primates. Brown lemurs are part of the illegal pet trade market, and benefit Malagasy economies as a source of ecotourism. Because lemurs are charismatic, some tourists come to Madagascar specifically to see them in the wild.

• Positive Impacts
• pet trade pet trade
• ecotourism ecotourism
• research and education
• produces fertilizer
• pollinates crops
• controls pest population

Economic Importance for Humans: Negative

There are conservation measures in place to protect brown lemurs that reduce the potential profits of logging companies. Brown lemurs can also bite or scratch humans if they are kept as pets or approached too closely in the wild. This can lead to infection or the transmission of disease through saliva. Because humans and lemurs are primates, the risk for disease transmission is relatively high.

• Negative Impacts
• injures humans
  • bites or stings
  • carries human disease

Conservation Status

Brown lemurs, along with other genera in the family Lemuridae , are at high risk of extinction. Because they have a limited geographic distribution, habitat loss on the island of Madagascar has a large negative impact on their population sizes. Deforestation due to logging and agricultural practices are becoming more prevalent in Madagascar. They are also threatened by unsustainable hunting practices, and some local communities will kill brown lemurs because they believe some species to be bad spirits. Additionally, some tourists will hunt brown lemurs for sport. Although the Madagascar government currently has laws against lemur hunting, these laws are rarely enforced. Habitat loss and poaching are particularly harmful to brown lemurs because they have slow population growth rates. Brown lemur females only enter estrus for a few days out of the year, and will forego reproduction when habitat conditions are poor, as is the case in developed areas. Furthermore, brown lemurs give birth to a maximum of two offspring at a time and juveniles are highly dependent on their mothers for several years after birth. There are several organizations promoting lemur conservation, such as the "Save Lemur Campaign" in Madagascar and the "Lemur Conservation Foundation" in the United States. These organizations promote captive breeding programs, conservation education, and lobbying against habitat destruction and poaching.

Additional Links

Encyclopedia of Life

Contributors

Vivian Strout (author), Colorado State University, Galen Burrell (editor), Special Projects.

References

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