A Preliminary Report on the Social Organisation of Cheirogaleus medius (Cheirogaleidae; Primates) in North-West Madagascar

Abstract

Key WordsLemuriformes · Madagascar · Nocturnal prosimians · Cheirogaleus medius ·Dwarf lemur · Radio-tracking · Social organisation · Solitary speciesIntroductionBoth currently recognised species of the genus Cheirogaleus, C. majorand C.medius, are notable for seasonal storage of fat (especially in the tail) and for extendedtorpor phases during the austral winter, i.e. the dry season [1, 2]. The fat-tailed dwarflemur, C. medius, has been reported to hibernate for 6–8 months and such a longperiod would inevitably have a major influence on social organisation [2]. Firstly, theanimals have only a few months to reproduce and rear offspring. Secondly, the ani-mals have to ensure sufficient fat storage to survive during the following dry season.To date, knowledge of the ecology and behaviour of C. mediushas been based onoccasional field observations [1–3], a few longer-term studies [4], investigations incaptivity [for citations see 2, 5, 6] and zoo reports [7], but social organisation has sofar been poorly documented [2, 8].Inferences concerning the social organisation of nocturnal prosimians can bemade from range overlap between individuals, associations within ranges (at particu-lar sleeping sites) and patterns of dispersal of individuals from their natal areas [9].For C. medius , Hladik et al. [4] determined individual ranges with a maximal diameterof 200 m and a population density of 300–400 animals/km