Hapalemur griseus

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.

• Biogeographic Regions
• ethiopian ethiopian
  • native native

• Other Geographic Terms
• island endemic island endemic

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.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest

• Wetlands
• marsh marsh

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.

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

• Sexual Dimorphism
• male larger

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 .

• Mating System
• monogamous monogamous
• polygynous polygynous

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.

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

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.

• Parental Investment
• female parental care female parental care
• pre-weaning/fledging
  • provisioning
    • female

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.

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.

• Key Behaviors
• arboreal arboreal
• scansorial
• motile motile
• territorial territorial
• social social

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.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• scent marks scent marks

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

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.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore
  • lignivore

• 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.

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.

Economic Importance for Humans: Positive

Hapalemur griseus is hunted by humans throughout their geographic range and is also collected for the local pet trade.

• Positive Impacts
• pet trade pet trade
• food food

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.

Additional Links

Encyclopedia of Life

Contributors

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

References

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

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

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, F., P. Waeber, J. Ratsimbazafy, J. 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 .

Williams, G. 2001. "Hapalemur griseus griseus" (On-line). Welcome to Ranomafana National Park. Accessed April 18, 2011 at https://web.archive.org/web/20110913140122/http://icte.bio.sunysb.edu/rano.biodiv/Mammals/Hapalemur-griseus/index.html .