Hapalemur griseusbamboo lemur

Geographic Range

Hapalemur griseus is the endemic to Madagascar. It is the most widespread of all bamboo lemurs. Each of the 4 subspecies occupies a slightly different zone with Hapalemur griseus griseus being the most widely distributed subspecies. Hapalemur griseus griseus is found throughout the eastern rainforest zone except for the far southern portion. Hapalemur griseus alaotrensis is only found around Lac Alaotra, living in reedbeds and floating reed islands. Hapalemur griseus occidentalis is found in small rainforest region in northwestern Madagascar. Hapalemur griseus meridionalis is only found near the Fort Dauphin area of extreme southeast Madagascar. ("Gray Gentle Lemur (Hapalemur griseus)", 2007; Grassi, 2001)

Habitat

Hapalemur griseus is endemic to Madagascar. Average air temperature of this area is 21°C, but varies from 4°C to 30°C. The environment is typically very humid. It is commonly found in areas containing bamboo, marshlands, lowlands, and forests and primarily inhabits primary and secondary forests. Four different sub-species of Hapalemur griseus have been documented (H. g. griseus, H. g. alaotrensis, H. g. occidentalis, and H. g. meridonalis), all of which occupy slightly unique habitats at different elevations throughout the species' geographic range. The overall range for the species occur from sea level to 2050 meters. ("Gray Gentle Lemur (Hapalemur griseus)", 2007)

  • Range elevation
    0 to 2050 m
    0.00 to 6725.72 ft

Physical Description

Hapalemur griseus is a small to medium-sized lemur, with an average length of 66 cm and an average weight of 0.935 kg. Males tend to be slightly larger than females. In general, H. griseus has grey fur; however, four different subspecies have been documented, all of which exhibit subtle variations in physical appearance. It has a non-prehensile tail, its forearms are shorter than its hindlimbs, it has sweat glands on its forearms and near its armpits, and it has a dental formula of 2:1:3:3. Hapalemur griseus griseus is mostly gray with olive tones, a dark gray tail and lighter gray fur along the venter. It has large ears, which are mostly hidden in the fur, and its tail is longer than the head and body combined. Hapalemur griseus alaotrensis is darker than H. g. griseus, is slightly larger, and its large ears are also relatively hidden by its fur. Its tail is generally the same length as the head and body combined. Hapalemur griseus occidentalis is lighter than that of Hapalemur griseus griseus and its large ears are relatively less hidden. Its tail is longer than its head and body combined. Hapalemur griseus meridionalis is dark gray or beige. Its ears extend out noticeably from its fur, but to a lesser extent than that of Hapalemur griseus occidentalis and its tail is equal to or slightly longer than the head and body combined. ("Gray Gentle Lemur (Hapalemur griseus)", 2007; "The IUCN Red List of Threatened Species", 2010)

  • Sexual Dimorphism
  • male larger
  • Average mass
    0.935 kg
    2.06 lb
  • Average mass
    1347.5 g
    47.49 oz
    AnAge
  • Average length
    66 cm
    25.98 in

Reproduction

Hapalemur griseus primarily lives in groups. Studies have shown that 42% of groups have one adult male and one adult female. Around 27% of groups have multiple adults of each gender, 19% have two adult females and 1 adult male, and 12% have two adult males and one adult female. Most groups have more reproducing males than females. Although most breeding relationships are monogamous, they can also be polygynous. Polygynous groups tend to have more offspring. Many groups also include sub-adults. Mating season runs from June to July, with births occurring in October and November. Females have on average one baby per year and they usually once annually. Intragroup females are often related; however, males tend to be unrelated. Mating occurs almost exclusively within group. One study found that only 8.5% of births had extra-group paternity. The sub-species H. g. alaotrensis has a longer breeding season than other sub-species of H. griseus. ("Gray Gentle Lemur (Hapalemur griseus)", 2007)

H. griseus comes into estrus once a year. It typically gives birth to only one offspring, and rarely has twins. Breeding season occurs during the dry season (i.e., summer or fall) and birthing typically occurs during the rainy season, during which time bamboo, their primary forge, is abundant. Gestation lasts roughly 140 days and most young are completely weaned by 20 weeks of age. Most females are reproductively mature by 2 years old, and most males are reproductively mature by 3 years old. ("Gray Gentle Lemur (Hapalemur griseus)", 2007; "Ranamafana National Park", 2001; Grassi, 2001; "The IUCN Red List of Threatened Species", 2010)

  • Breeding interval
    Hapalemur griseus breeds once yearly.
  • Breeding season
    Breeding season in Hapalemur griseus occurs during the dry season, from June-August.
  • Average number of offspring
    1
  • Average number of offspring
    1.2
    AnAge
  • Average gestation period
    140 days
  • Average gestation period
    140 days
    AnAge
  • Average weaning age
    20 weeks
  • Average age at sexual or reproductive maturity (female)
    2 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    880 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    3 years

Average birth weight for Hapalemur griseus is 45.2 g. The mother carries the infant in her mouth for about two weeks until young are strong enough to hold on. Infants then cling to the mother until they are a little larger. Sometimes the father or a sibling carries the infant, but most often it is the mother’s responsibility. Young are carried for approximately 3 months; however, once young become a little bigger, they remain in a tree while the mother searches for food. Once the infant is about three weeks old they are able to jump around, hop, and walk. Young can eat bamboo by 6 weeks of age, but still depend on their mother to provide them with food. Females reach reproductive maturity by 2 years of age, and males reach reproductive maturity by 3 years of age. ("Gray Gentle Lemur (Hapalemur griseus)", 2007)

Lifespan/Longevity

There is no information available regarding the lifespan of Hapalemur griseus in the wild. In captivity, records indicate a maximum age of 23 years. The primary cause of death in the wild is predation. ("Gray Gentle Lemur (Hapalemur griseus)", 2007)

Behavior

Average group size for Hapalemur griseus is around 4 individuals. Groups are territorial and males defend their group's territory from potential rivals. Territorial behavior includes scent marking, chasing, vocalizations, displays, and staring. Confrontations are typically not violent and only 25% of these become aggressive. Intergroup disputes usually arise because of an overlap in territories. Although males are primarily responsible for group protection, females are dominant within the group. Once females reach sub-adulthood, they either disperse or remain with their natal group. Males disperse upon reaching adulthood, which occurs around three years of age. Hapalemur griseus also exhibits latrine behavior and takes turns defecating in a single, centralized location. It frequently clings to trees and when moving between trees, it leaps from trunk to trunk. Movement is quadrupedal once individuals descend to the ground. ("Gray Gentle Lemur (Hapalemur griseus)", 2007)

  • Range territory size
    0.06 to 0.15 km^2
  • Average territory size
    0.1 km^2

Home Range

Home range size is highly variable in Hapalemur griseus and depends on what region of Madagascar the individual or group resides in. In some parks, home range has been found to be between 0.06 km^2 and 0.1 km^2. In other parks, home range has been found to be around 0.15 km^2. In general, home range size is relatively small for H. griseus when compared to other bamboo lemures. Hapalemur griseus only ventures out of its home range during times of scarcity.

Communication and Perception

Hapalemur griseus has scent glands that assist in olfactory communication with group members and rivals. Many forms of communication occur on or with papyrus plants, including substrate marking. When substrate marking, individuals scratch papyrus leaves with their teeth and either rub the piece of papyrus on its scent glands or urinate on it. Hapalemur griseus also performs scent marking with its tail by rubbing the forearm scent glands along the length of the tail while watching staring at a rival. Other forms of communication include running around a patch of vegetation in circles to identify ones location, by confronting individuals, by chasing away individuals, and by staring. Tactile communication is largely restricted to social grooming. Vocal communication of H. griseus is accomplished through a variety of grunts, clicks, screeches, trembles, teeth grinding, and purrs. Infants often purr when licked by their mother and perform a high-pitched distress call when separated from its mother. When reunited with their young, mothers create a grunt-like sound. Hapalemur griseus also performs mating calls, low-intensity alarm calls, high-intensity alarm calls, intimidation calls, and calls that are used to identify the location of conspecifics. ("Gray Gentle Lemur (Hapalemur griseus)", 2007)

Food Habits

The primary forage of Hapalemur griseus is bamboo. There are over 40 species of bamboo, but the main species consumed by H. griseus is giant bamboo. Although bamboo is considered toxic due to high concentrations of cyanide found throughout the plant, bamboo lemurs do not experience cyanide poinsoning. The mechanism of how this is accomplished is still unknown. A typical diet for this species is 72% bamboo, 16% grasses, 5% fruits, 4% leaves (usually from various lianas), and 3% from other sources. Hapalemur griseus eats the bases and the inner walls of young bamboo shoots. It feeds through one side of its mouth and chews the bamboo on the other side. Around 70% of its time is spent feeding on bamboo. Food preferences are contingent on time of year and resource availability. Females tend to eat more than the males because of the physiological stress induced by gestation and lactation. ("Gray Gentle Lemur (Hapalemur griseus)", 2007)

  • Plant Foods
  • leaves
  • wood, bark, or stems
  • fruit

Predation

Known predators include Malagasy tree boas as well as other boas, ring-tailed mongooses, humans, fossas, owls, and Madagascar serpent eagles. Other potential predators include other raptors, lemurs, dogs, and cats. Visual monitoring and vocal communication are the primary means of evading predation by H. griseus. In addition, their arboreal nature likely reduces risk of predation as well. ("Gray Gentle Lemur (Hapalemur griseus)", 2007; "Ranamafana National Park", 2001)

Ecosystem Roles

Other than their role as prey for a number of Malagasy predators, little is known of the potential impact of Hapalemur griseus on their local environment. Major predators of H. griseus include Malagasy tree boas as well as other boas, ring-tailed mongooses, humans, fossas, owls, and Madagascar serpent eagles. There is no information available regarding parasites of this species. ("Gray Gentle Lemur (Hapalemur griseus)", 2007; "Ranamafana National Park", 2001)

Economic Importance for Humans: Positive

Hapalemur griseus is hunted by humans throughout their geographic range and is also collected for the local pet trade. ("The IUCN Red List of Threatened Species", 2010)

Economic Importance for Humans: Negative

There are no known adverse effects of Hapalemur griseus on humans. Questions have been raised about the potential transmission of zoonotic diseases from lemurs to humans and domestic animals.

Conservation Status

Hapalemur griseus is classified as vulnerable on the IUCN's Red List of Threatened Species. Although it is currently recognized as common, populations are decreasing due to hunting and the pet trade. In addition, habitat loss due the clearing of bamboo stands and slash-and-burn agriculture have had a negative impact on the range and abundance of this species. CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) lists H. griseus under Appendix I and it occurs in a number of national parks and habitat reserves. ("The IUCN Red List of Threatened Species", 2010)

Contributors

John Hibbs (author), Augsburg College, Kevin Potts (editor), Augsburg College, John Berini (editor), Animal Diversity Web Staff.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

polygynous

having more than one female as a mate at one time

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

References

2007. "Gray Gentle Lemur (Hapalemur griseus)" (On-line). Accessed April 15, 2011 at http://www.theprimata.com/hapalemur_griseus.html.

2001. "Ranamafana National Park" (On-line). Hapalemur griseus griseus. Accessed April 18, 2011 at http://icte.bio.sunysb.edu/rano.biodiv/Mammals/Hapalemur-griseus/index.html.

2010. "The IUCN Red List of Threatened Species" (On-line). Hapalemur griseus. Accessed April 18, 2011 at http://www.iucnredlist.org/apps/redlist/details/9673/0.

Grassi, C. 2001. The Behavioral Ecology of Hapalemur griseus griseus: The Influences of Microhabitat and Population Density on this Small-bodied Prosimian Folivore. University of Texas. Accessed April 21, 2011 at http://icte.bio.sunysb.edu/pdf_files/GrassiDissertation.pdf.

Gron, K. 2010. "Primate Info Net" (On-line). Hapalemur. Accessed April 19, 2011 at http://pin.primate.wisc.edu/factsheets/entry/bamboo_lemur/taxon.

Nievergelt, C., T. Mutschler, A. Feistner, D. Woodruff. 2002.

Social System of the Alaotran Gentle Lemur (Hapalemur griseus alaotrensis): Genetic Characterization of Group Composition and Mating System
.
American Journal of Primatology
, 57: 157-176. Accessed April 19, 2011 at http://polymorphism.scripps.edu/Reprints/AJP-CN-2002.pdf.

Ralainasolo, ., . Waeber, . Ratsimbazafy, . Durbin, R. Lewis. 2006.

The Alaotra gentle lemur: Population estimation and subsequent implications
. MADAGASCAR CONSERVATION & DEVELOPMENT, 1/1: 9-10. Accessed April 19, 2011 at http://www.ajol.info/index.php/mcd/article/viewFile/44044/27559.