Vocal Repertoire Investigation of Eulemur mongoz in Madagascar and Comoros

Implications of human activities for species conservation are dramatically important. Deforestation and hunting are the main menaces in both Comoros and Madagascar. In Comoros, domestication and poaching are also reducing the number of mongoose lemurs in the wild. The study of vocal behaviour can reveal important aspects of how and why individuals within a species communicate in relation to ecological and social factors. We focused on vocal communication in mongoose lemurs (Eulemur mongoz) in Madagascar and Comoros. We sampled wild groups in 3 locations in Madagascar (Mariarano, Bombetoka, Antsilahiza) and at 2 sites in Comoros (Bambao M’tsanga, Anjouan; Tsembéhou, Anjouan), and in captivity in Europe, Madagascar and Comoros. We visually categorized vocalizations by spectrogram investigation and by ear, took note of their behavioural context, and investigated whether mongoose lemur vocalizations can be grouped in discrete categories. We found that mongoose lemurs have 13 call types in their vocal repertoire, distinguishable by qualitative and quantitative acoustical analysis. They were: grunt, grunt hoot, alarm long grunt, long grunt clear call, long grunt, tonal call, chatter, click, snort, scream, crui crui and aerial alarm call. Some utterances were used only in particular behavioural contexts, and by individuals of specific age, whereas others were emitted under a range of situations. This knowledge of the species’ vocal repertoire is valuable for surveying lemurs acoustically in habitats where visual surveys are difficult.