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)
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)
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)
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)
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)
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)
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)
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.
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)
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)
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)
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)
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.
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)
John Hibbs (author), Augsburg College, Kevin Potts (editor), Augsburg College, John Berini (editor), Animal Diversity Web Staff.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
uses sound to communicate
Referring to an animal that lives in trees; tree-climbing.
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.
uses smells or other chemicals to communicate
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.
parental care is carried out by females
an animal that mainly eats leaves.
A substance that provides both nutrients and energy to a living thing.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
an animal that mainly eats fruit
An animal that eats mainly plants or parts of plants.
animals that live only on an island or set of islands.
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).
marshes are wetland areas often dominated by grasses and reeds.
Having one mate at a time.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
the business of buying and selling animals for people to keep in their homes as pets.
having more than one female as a mate at one time
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.
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
Living on the ground.
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
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sight to communicate
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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.