Prior to the recent taxonomic splitting of this species, A. laniger was thought to range almost the entire length of Madagascar’s eastern rain forests, from the Tolagnaro (= Fort-Dauphin) region in the extreme south to as far as the Ankarana Massif in the extreme north (Petter et al., 1977; Tattersall, 1982; Fowler et al., 1989; Hawkins et al., 1990). With the description of a number of new species within this large area, it is now thought to range from the Bemarivo River in the north to the Nesivolo/Mangoro in the south (E. E. Louis Jr., pers. obs).
Groups of up to five have been reported, and home ranges of 1–2 ha are aggressively defended (Albignac, 1981b; Razanahoera-Rakotomalala, 1981; Ganzhorn et al., 1985). Longitudinal and genetic data are needed to better understand their social behavior. Research at the Analamazaotra Special Reserve provides estimates of densities reaching 72–100 individuals/km2, and suggests a social organization based on monogamous pairs and their offspring (Ganzhorn, 1988).
Single births take place in August and September (Ganzhorn et al., 1985). Infants initially cling to the mother’s abdomen, but are eventually carried on her back (Ganzhorn 1988; Harcourt, 1988, 1991).