Avahis in Madagascar: Meeting the Nocturnal Woolly Lemurs

The 4 most famous avahi species

Eastern woolly lemur (Avahi laniger)

The eastern woolly lemur is the best-known species and the easiest to spot during a Madagascar lemur safari. Found in the rainforests of the east coast—from the Masoala Peninsula in the north down to Tolagnaro in the south—this lemur is recognised by its dense grey-brown fur with reddish tones on its back. Its belly is generally lighter, ranging from pale grey to creamy white.

This species inhabits both primary and secondary forests, adapting relatively well to disturbed habitats; this explains why it is often seen in highly accessible protected areas like Andasibe-Mantadia and Ranomafana. Weighing between 800 grams and 1.3 kilograms, the eastern avahi is slightly larger than its western cousins. Its diet consists mainly of leaves from plants in the Rubiaceae and Fabaceae families. Despite its relative adaptability, the species is classified as Vulnerable (VU) by the IUCN due to ongoing deforestation.

Western woolly lemur (Avahi occidentalis)

Living in the dry deciduous forests of western Madagascar, the western woolly lemur shows remarkable adaptation to an environment very different from that of its eastern cousin. Its range stretches from the Ankarafantsika region in the north down to the Morondava region in the south, in dry forests that drop their leaves during the dry season.

Its fur is generally lighter than that of the eastern species, featuring silver-grey to light-brown tones—an adaptation that aids thermoregulation in this drier environment with sharper temperature shifts. Smaller than its eastern relative, it weighs between 700 and 900 grams. The western avahi has developed a remarkable tolerance to seasonal food availability, adjusting its diet based on which leaves are accessible during the dry season.

This species faces critical threats, as Madagascar’s western dry forests are under intense deforestation pressure for agriculture and cattle grazing. Its IUCN status is Endangered (EN).

Bemaraha woolly lemur (Avahi cleesei)

Formally described in 2005, the Bemaraha woolly lemur is named after British actor John Cleese, the famous Monty Python star, in recognition of his longstanding commitment to the conservation of lemurs and Malagasy wildlife. This honorary naming also aimed to draw media attention to the critical situation of this newly discovered species.

Strictly endemic to the Tsingy de Bemaraha region in north-western Madagascar, Cleese’s avahi is one of the rarest and most geographically restricted species in the genus. It is distinguished by its small size, generally weighing between 600 and 800 grams, and its particularly dense reddish-brown fur with coppery reflections on its head and back. Its ears are relatively small, and its face is rounder than those of other species.

This species lives exclusively in the dry limestone forests of Bemaraha, set against a spectacular landscape of karst formations. Because of its extremely limited distribution and ongoing habitat degradation, it is classified as Endangered (EN). Sightings of the Bemaraha woolly lemur remain exceptionally rare, even for specialised researchers and experienced guides.

Betsileo woolly lemur (Avahi betsileo)

The Betsileo woolly lemur, named after the Betsileo ethnic group that inhabits Madagascar’s southern central highlands, was formally described as a distinct species in the early 2000s. This species is endemic to a relatively restricted area in the humid mountain forests of south-central Madagascar, particularly in the Fianarantsoa region, which includes Ranomafana National Park and surrounding forests.

Medium-sized for the genus, the Betsileo woolly lemur weighs between 700 grams and 1 kilogram. Its fur features a distinctive chocolate-brown back with grey undertones, while its belly is light grey to white. A notable trait is the presence of orange or reddish markings on its limbs, which are particularly visible in some individuals.

Adapted to high-altitude forests between 800 and 1,600 metres, the Betsileo woolly lemur tolerates cooler temperatures than most other avahi species. Its mountainous forest habitat is relatively better preserved than lowland forests, but it still remains threatened by fragmentation. This species can be spotted during night walks in Ranomafana, though distinguishing between the various eastern avahi species in the field remains difficult without genetic analysis. Its IUCN status is Endangered (EN).

This recently documented diversification highlights just how much of Madagascar’s biodiversity remains to be explored and understood, even for relatively common animals. The five other species (A. unicolor, A. meridionalis, A. peyrierasi, A. ramanantsoavanai, and A. mooreorum) have even more restricted geographical ranges and are the subject of ongoing studies to better understand their ecology and conservation needs.