Eastern lesser bamboo lemur (Hapalemur griseus)

One of the smallest of the bamboo lemurs ⁽⁵⁾, the eastern lesser bamboo lemur has a dense, woolly coat that is grey to olive-grey on the upperparts, with chestnut-brown tinges on the head, shoulders, and sometimes the back. The face and underparts are a paler grey, becoming creamy-grey on the belly, and the long tail is generally dark ^{(2) (3) (5)}. Like other bamboo lemurs, the head is rounded, and bears a characteristically short muzzle and small, furred ears ^{(2) (3) (6)}. Relatively long back legs allow bamboo lemurs to leap easily between vertical bamboo stems ^{(3) (5)}. Bamboo lemurs are reported to use a variety of different calls ^{(6) (7)}, including distinct calls in response to different types of predators ⁽⁷⁾.

Also known as

bamboo lemur, eastern grey bamboo lemur, eastern grey gentle lemur, grey bamboo lemur, grey gentle lemur, lesser bamboo lemur.

Synonyms

Hapalemur ranomafanensis.

French

Hapalémur Gris, Petit Hapalémur.

Spanish

Lemur Cariancho.

Size

Head-body length: 24 - 40 cm ^{(2) (3)}

Tail length: 32 - 40 cm ^{(2) (3)}

Weight

0.7 - 1 kg ^{(2) (3)}

As the common name suggests, bamboo lemurs specialise in feeding almost exclusively on bamboo ^{(2) (6) (9)}, and are the only primates known to do so ^{(5) (8)}. Bamboo constitutes at least 75 percent of the diet of the eastern lesser bamboo lemur, with the rest made up of fig leaves, grass stems, other young leaves, small fruits, flowers and fungi ^{(3) (5) (9)}. Each species of bamboo lemur appears to specialise on different parts of the bamboo plant ^{(2) (10)}, with the eastern lesser bamboo lemur preferring the new shoots, leaf bases and stem pith ^{(2) (3) (5) (9)}. However, some bamboos contain toxic cyanide compounds that would poison most other mammals. How bamboo lemurs deal with these toxins is not exactly known, but the eastern lesser bamboo lemur may limit its intake by selecting young growth, which contains lower cyanide levels ^{(8) (9)}. It also appears to have a more flexible diet than other bamboo lemurs, using different bamboo species or different food sources depending on the season ^{(9) (11)}, which may help explain its wider geographic distribution ⁽⁹⁾.

Although often considered cathemeral, with regular bouts of activity both day and night ^{(3) (5)}, others report the eastern lesser bamboo lemur to be mainly diurnal ⁽¹¹⁾. Group size ranges from around two to nine, with each group typically containing an adult male, one or two breeding females, and offspring ^{(3) (5) (8) (9)}. The adults are highly territorial, defending the group’s territory with scent-marking, vocal displays and chases. Breeding occurs between October and January, the female usually giving birth to a single offspring each year, after a gestation period of 137 to 140 days. The infant may be carried in the female’s mouth for the first few weeks, after which it may ride on the female’s back, or be “parked” for short periods while the female is foraging ^{(3) (5) (8)}. The young eastern lesser bamboo lemur is weaned after about four months, and young of both sexes are thought to disperse from the group on reaching maturity ^{(5) (8)}. In captivity, the eastern lesser bamboo lemur may live up to 17 years ⁽⁶⁾.

Endemic to Madagascar, the eastern lesser bamboo lemur is the most widespread of the bamboo lemurs ^{(3) (5)}. It is found throughout much of the forests of eastern Madagascar, although the exact limits of its distribution are unclear, and populations may also exist in western Madagascar ^{(1) (5)}.

The eastern lesser bamboo lemur occurs in tropical moist lowland forest and montane forest, in areas where bamboo and bamboo vines are present, and may inhabit both disturbed and undisturbed forest ^{(1) (3) (5) (8)}.

Classified as Vulnerable (VU) on the IUCN Red List ⁽¹⁾ and listed on Appendix I of CITES ⁽⁴⁾. Subspecies: the eastern lesser bamboo lemur (Hapalemur griseus griseus) is classified as Vulnerable (VU) and Gilbert’s lesser bamboo lemur (Hapalemur griseus gilberti) is classified as Data Deficient (DD) on the IUCN Red List ⁽¹⁾.

The eastern lesser bamboo lemur, like many other lemurs, is threatened by ongoing habitat loss ^{(1) (3) (8)}, although paradoxically the species may actually have benefitted from forest clearance in some areas, as older cleared areas often contain more bamboo than the original forest ^{(3) (6)}. However, the eastern lesser bamboo lemur is also one of the most heavily hunted lemurs, often being kept as a pet, and these combined threats have led to an ongoing population decline ^{(1) (3) (5)}.

As well as strict control on international trade in the species under its listing on Appendix I of the Convention on International Trade in Endangered Species (CITES) ⁽⁴⁾, the eastern lesser bamboo lemur also occurs in a number of protected areas within Madagascar, including Ranomafana National Park, Baie de Baly National Park, Mantadia National Park, and Tsingy de Bemaraha Strict Nature Reserve ^{(1) (5) (8) (12)}. However, there is ongoing debate about the species’ exact distribution and, in particular, further research is needed on the recently described subspecies H. g. gilberti before its distribution and conservation status are fully known ⁽¹⁾.

View information on this species at the UNEP World Conservation Monitoring Centre.

To find out more about the conservation of lemurs and other Madagascan species see:

• Lemur Conservation Foundation:
  http://www.lemurreserve.org/
• Madagascar Fauna Group:
  http://www.savethelemur.org/about-main.htm
• Madagascar Wildlife Conservation:
  http://www.mwc-info.net/en/

Cathemeral

Active intermittently throughout the day and night, rather than exclusively during the day or night.

Diurnal

Active during the day.

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

Gestation

The state of being pregnant; the period from conception to birth.

Montane forest

Forest occurring in the montane zone, a zone of cool upland slopes below the tree line dominated by large evergreen trees.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

Territorial

An animal, a pair of animals or a colony that occupies and defends an area.

Territory

An area occupied and defended by an animal, a pair of animals or a colony.

1. IUCN Red List (March, 2009)
   http://www.iucnredlist.org/
2. Macdonald, D.W. (2006) The Encyclopedia of Mammals. Oxford University Press, Oxford.
3. Garbutt, N. (1999) Mammals of Madagascar. Pica Press, Sussex.
4. CITES (March, 2009)
   http://www.cites.org
5. Mittermeier, R.A., Konstant, W.R., Hawkins, F., Louis, E.E., Langrand, O., Ratsimbazafy, J., Rasoloarison, R., Ganzhorn, J.U., Rajaobelina, S., Tattersall, I. and Meyers, D.M. (2006) Lemurs of Madagascar. Second Edition. Conservation International, Washington, DC.
6. Nowak, R.M. (1991) Walker’s Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
7. Haring, D. and Davis, K. (1998) Management of the grey gentle or eastern lesser bamboo lemur Hapalemur griseus griseus at Duke University Primate Center, Durham. International Zoo Yearbook, 36: 20 - 34.
8. Tan, C.L. (2006) Behavior and ecology of gentle lemurs (genus Hapalemur). In: Gould, L. and Sauther, M.L. (Eds) Lemurs: Ecology and Adaptation. Springer, New York.
9. Tan, C.L. (1999) Group composition, home range size, and diet of three sympatric bamboo lemur species (genus Hapalemur) in Ranomafana National Park, Madagascar. International Journal of Primatology, 20(4): 547 - 566.
10. Fleagle, J.G. (1999) Primate Adaptation and Evolution. Second Edition. Academic Press, New York.
11. Overdorff, D.J., Strait, S.G. and Telo, A. (1997) Seasonal variation in activity and diet in a small-bodied folivorous primate, Hapalemur griseus, in southeastern Madagascar. American Journal of Primatology, 43: 211 - 223.
12. Mittermeier, W., Konstant, R., Nicoll, M.E. and Langrand, O. (1992) Lemurs of Madagascar: An Action Plan for their Conservation. IUCN, Gland, Switzerland.