Hapalemur alaotrensis (Rumpler, 1975)

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Lemuridae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 90-141 : 126-127

4.

Lac Alaotra Bamboo Lemur

Hapalemur alaotrensis

French: Lemur de I'Alaotra / German: Alaotra-Bambuslemur / Spanish: Lémur del bambu del Lago Alaotra

Other common names: Alaotran Bamboo Lemur, Bandro, Lac / Lake Alaotra Gentle Lemur

Taxonomy. Hapalemur griseus alaotrensis Rumpler, 1975 ,

Madagascar, Lake Alaotra.

This species is monotypic.

Distribution. EC Madagascar, confined to two subpopulations on the shores of Lake Alaotra, a small one on the NW part of the lake around the Belempona Peninsula and a larger one in the adjoining marshlands along the lake’s SW shores.

Descriptive notes. Head-body ¢.40 cm, tail c.40 cm; weight 1.2-1.3 kg. The Lac Alaotra Bamboo Lemur is much larger than all other species of Hapalemur except for the Golden Bamboo Lemur ( H. aureus ), with a notably round head and dense woolly pelage. The dorsal coat is gray-brown, with the face and underside a lighter gray. The crown and nape are chestnut-brown. Ears are relatively short and hidden in the fur.

Habitat. Reed beds and papyrus marshes up to elevations of 750 m.

Food and Feeding. The Lac Alaotra Bamboo Lemuris entirely folivorous, eating leaves and stems of only eleven plant varieties. More than 95% ofits diet is restricted to just four species: buds and pithy stems of papyrus ( Cyperus madagascariensis, Cyperaceae ), tender shoots and leaves of reeds ( Phragmites communis, Poaceae ), and two species of grass ( Echinochloa crus-galli and Leersia hexandra, both Poaceae ). Geophagy (eating soil) has been reported in captivity.

Breeding. The mating system of the Lac Alaotra Bamboo Lemur can be either monogamous or polygynous, and reproductive females may be related. Only a single male in the group breeds, and extragroup paternity is uncommon. In the wild, the birth season lasts for six months from September to February. Although twins can be common (making up at least one-third of all births), usually only single young are born after gestation of 135-140days. In captivity, newborns have their eyes open and weigh c.63 g. By 6-8 days, infants can cling to their mother and move independently. By two weeks, they move skillfully by themselves, and by three weeks, they are no longer parked by the mother and will not remain stationary. Solid foods are first eaten between five and six weeks, and captive young are weaned at 20-24 weeks. Infants receive a significant amount of grooming for the first six months of their lives. In general, twins grow more slowly, are carried less, and weaned later than single offspring. In the wild, females reproduce for the first time as early as two years old, while males begin to breed when they are at least three years old.

Activity patterns. The Lac Alaotra Bamboo Lemur is cathemeral and arboreal. Although variable, during daylight, they are most active in the early morning and late afternoon. Bouts of nocturnal activity last 30 minutes or more. The typical mode of locomotion is vertical clinging and leaping, as with the other members of the genus. There are reports of the Lac Alaotra Bamboo Lemur , even mothers with infants, swimming in a dog-like fashion.

Movements, Home range and Social organization. The Lac Alaotra Bamboo Lemur lives in one-male family groups of up to nine, but usually with 3-4 members. Groups generally remain stable, living in small, stable, non-overlapping, and actively defended home ranges of 1-8 ha (average of c.2 ha). Intergroup interactions occur near home range borders and involve adults of both sexes, although males play a more active role than females in border defense. After detecting another group, the resident group moves toward the home range boundary. Intergroup interactions are characterized by visual monitoring, substrate marking (on papyrus), tail scent marking, marking of group members, locomotive and confrontation displays, chasing, and vocalizations. Both sexes disperse from their natal groups, with indirect evidence that females disperse as subadults and males as adults. In the wild, females are dominant to males; they lead group progressions more than males, are more aggressive, and groom more often.

Status and Conservation. CITES Appendix I. Classified as Critically Endangered on The IUCN Red List. The entire distribution of the Lac Alaotra Bamboo Lemur appears to be less than 9000 ha. Conversion of marsh habitat to rice fields has been its most significant historical threat, to the point wherelittle suitable land remains on which local farmers might cultivate rice. Hunting for food and capture for use as pets have also reduced numbers. Various methods of hunting and trapping are used; direct pursuit by dogs is the most common, but individuals are also captured with harpoons, snares, and sticks (the latter to knock them out or into the water). Local people will still occasionally set fire to dry papyrus to drive lemurs out into the open, where they can then be chased down and clubbed to death immediately or captured alive, only to be sold later for their meat or perhaps to tourists as pets. Individuals are frequently kept as pets by local people, but they seldom survive for long. Commercial drainage projects also represent a potential threat. Regular burning to increase cattle pasture, facilitate local fishing, and develop new rice fields in dry years reduces suitable lemur habitat. These activities also promote invasion by exotic plant species that choke the remaining marshes. The most recent available population estimate for the Lac Alaotra Bamboo Lemur (2006) is 3500-5500 individuals, representing a decline of ¢.30% in just over a decade. A population that formerly occurred ¢.60 km to the north of the current distribution has not been observed since the 1950s and may be extinct. Because of the efforts of the Durrell Wildlife Conservation Trust, a 42,478ha protected area was established in 2007, covering Lake Alaotra and surrounding marsh with various zones of usage. This includes both a strict conservation area of8000 ha and an adjacent 5200ha core zone of marsh where controlled activities (e.g. fishing) are permitted. Public awareness campaigns continue to focus on the benefits of habitat conservation to the one-half million or more people that live by the lake. These benefits include erosion control, biologicalfiltering of agricultural pollutants, and flood prevention. Lake Alaotra is a 722,500ha Ramsar wetland site, designated in 2003.

Bibliography. Beattie & Feistner (1998), Feistner & Rakotoarinosy (1993), Jolly et al. (1984), Mittermeier et al. (2010), Mutschler (1999, 2002), Mutschler & Feistner (1995), Mutschler & Tan (2003), Mutschler, Nievergelt & Feistner (1995, 2000), Mutschler, Randrianarisoa & Feistner (2001), Nievergelt, Mutschler & Feistner (1998a, 1998b), Nievergelt, Mutschler, Feistner & Woodruff (2002), Nievergelt, Pastorini & Woodruff (2002), Petter & Peyrieras (1970a, 1975), Rabarivola et al. (2007), Ralainasolo (2004), Ralainasolo et al. (2006), Razafindramahatra (2004), Rumpler (1975), Steyn & Feistner (1994), Tan (2000, 2006), Taylor & Feistner (1996), Vuillaume-Randriamanantena et al. (1985), Waeber & Hemelrijk (2003), Wright (1990).

Figures

0. Greater Bamboo Lemur (Prolemur simus), 1. Gray Bamboo Lemur (Hapalemur griseus), 2. Southern Bamboo Lemur (Hapalemur meridionalis), 3. Northern Bamboo Lemur (Hapalemur occidentalis), 4. Lac Alaotra Bamboo Lemur (Hapalemur alaotrensis), 5. Golden Bamboo Lemur (Hapalemur aureus)

Distribution. EC Madagascar, confined to two subpopulations on the shores of Lake Alaotra, a small one on the NW part of the lake around the Belempona Peninsula and a larger one in the adjoining marshlands along the lake’s SW shores.