114.
Lorenz Von Liburnau’s Woolly Lemur
(Avahi occidentalis)
EN
Overview
Western woolly lemurs are medium sized lemurs that, like all indriids, are characterized by long powerful hind limbs adapted to their specialized mode of locomotion: vertical clinging and leaping. The dense and woolly coat is pale grey on the underparts and throat and medium-grey on the upper parts, with tinges of sandy brown on the back and tail. They live in small family groups formed of monogamous parents and their offspring. Almost exclusively nocturnal, the western woolly lemur becomes active around dusk. The family unit largely stays together while foraging.
Urgent Conservation Actions
Populations occurring outside of reserves need to be identified and protected. This species is known to occur in only two protected areas, although it has also been reported in a third. Research should be carried out to verify these reports.
Distribution
Madagascar.
Media from ARKive
ARKive image - Western woolly lemur with infant
ARKive image - Western woolly lemurs with infant
ARKive image - Western woolly lemur with young
ARKive image - Western woolly lemur with young in tree
ARKive image - Young western woolly lemur with adult
ARKive image - Western woolly lemur in tree
ARKive image - Western woolly lemur in tree
Evolutionary Distinctiveness
Order: Primates
Family: Indridae
Lemurs belong to the suborder Strepsirhini, which also includes bushbabies, pottos and lorises. These groups are the most basal living primates. Ancestral prosimians, possibly resembling today’s mouse lemurs, are thought to have colonised Madagascar from mainland Africa 50-60 million years ago. In the absence of competition from other non-primate mammals, these species diversified to fill a wide range of unusual ecological niches. There are five distinct families of lemurs: Lemuridae, Indriidae, Megaladapidae, Cheirogaleidae and Daubentoniidae. The Indriidae comprises six species in three genera: Avahi (woolly lemurs), Propithicus (sifakas), and Indri. There are three recognised species laniger, Avahi unicolor and Avahi occidentalis.
Description
Size: 
Head-body length: 25 – 28.5 cm
Tail length: 31 – 36.5 cm
Weight: Males: ~800 g (average)
Males tend to be slightly larger than females and the skulls of males are slightly wider than females, but for the most part this species is not sexually dimorphic. The lower incisors have been modified to form a tooth comb which is used in grooming. Western woolly lemurs are medium sized lemurs that, like all indriids,are characterized by long powerful hind limbs adapted to their specialized mode of locomotion: vertical clinging and leaping. The dense and woolly coat is pale grey on the underparts and throat and medium-grey on the upper parts, with tinges of sandy brown on the back and tail. The face is rounded and pale with a dark muzzle. Although similar in overall appearance to its eastern relative, the eastern woolly lemur (Avahi laniger), the western woolly lemur is smaller in size and much paler.
Ecology
This is a primarily folivorous nocturnal species. Feeding occurs most in the two hours after dusk and the two hours before dawn at the top and the periphery of trees. The Western woolly lemur spends a large part of its time resting due to the low nutritional quality of their food. Their diet is highly specialized and includes tree species that are relatively rare. They live in distinct family groups, which consist of a monogamous breeding pair and their offspring. A single offspring is usually born between September and October after a gestation period of 120 to 150 days, and juveniles may remain with their natal group until up to two years of age. Family units occupy overlapping home ranges of two hectares and territories are defended and demarcated via calls.
Habitat
It is found in dry deciduous forests, including secondary forest. It is predominantly arboreal.
Distribution
This species is endemic to the island of Madagascar. The core distribution is to the north and east of the Betsiboka River as far as Bay of Narindra, and in Ankarafantsika National Park. It is considered that the isolated population much farther north in the Ankarana region also represents this species, but that in between A. unicolor inhabits both the Ampasindava Peninsula and the Sambirano region, including the Manongarivo Special Reserve. They have also been recorded from Mariarano Classified Forest. The population in Bemaraha, traditionally classed as Avahi occidentalis, has recently been reclassified as a distinct species, Avahi cleesei.
Population Estimate
Unknown.
Population Trend
Decreasing.
Status
Classified as Endangered (EN B1ab(iii)) on the 2010 IUCN Red List of Threatened Species.
Threats
15 species of lemur have become extinct since sea-faring humans arrived on Madagascar’s shores around 2,000 years ago, and humanity is still wreaking ecological destruction on the island. Habitat destruction through forest felling and burning poses the principle threat to the biodiversity on Madagascar, including the western woolly lemur. Small-scale but widespread clearing of forests is conducted for firewood, cattle grazing, charcoal production, and construction materials. In the dry season people often set brush fires to clear pasture for cattle but the fires frequently burn out of control and threaten protected areas. Hunting also occurs in some regions. These factors, coupled with the species’ restricted range, give cause for concern.
Conservation Underway
This species is listed on Appendix I of CITES. It is known to occur in the Ankarafantsika National Park, and in Mariarano Classified Forest.
Conservation Proposed
It has so far been impossible to keep western woolly monkeys in captivity, probably because of their highly selective folivorous diet. It appears, therefore, that conservation of forests in situ where this species occurs is the best viable option of protecting the western woolly lemur. To achieve this further research on population numbers and distribution is required. Consideration should be given to improving the protected areas status of Mariarano Classified Forest, which is already very well protected by the local people.
References
Andrainarivo, C., Andriaholinirina, V.N., Feistner, A., Felix, T., Ganzhorn, J., Garbutt, N., Golden, C., Konstant, B., Louis Jr., E., Meyers, D., Mittermeier, R.A., Perieras, A., Princee, F., Rabarivola, J.C., Rakotosamimanana, B., Rasamimanana, H., Ratsimbazafy, J., Raveloarinoro, G., Razafimanantsoa, A., Rumpler, Y., Schwitzer, C., Thalmann, U., Wilmé, L. & Wright, P. 2008. Avahi occidentalis. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. <www.iucnredlist.org>. Downloaded on 15 November 2010.

Garbutt, N. 2007. Mammals of Madagascar: A Complete Guide. A & C Black Publishers Ltd.

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