Species-typical patterns of infant contact, sleeping site use and social cohesion among nocturnal primates in Africa.

This paper provides a checklist and summary of what is currently known of the variation in infant contact, sleeping site preference and aspects of social cohesion in the nocturnal primates of Africa. Genera and species are compared, based on previously unpublished field observations and a review of the literature. There is a clear pattern of similarity between the species within each genus and distinct differences between genera. Species in the same genus tend to be ecologically equivalent and replace each other allopatrically, whereas species in different genera are more likely to be sympatric, with up to 6 species living together. Maximum sympatry within genera is found in Otolemur and Galagoides, where species are ecologically divergent. This may reflect an ancient origin of species within these genera or suggest that further taxonomic revision is required at the generic level. Some data are recorded for the first time for species that have only recently been separated (cryptic species), but some taxa remain very poorly known. It is concluded that field studies are still at an elementary stage and further research with radio tracking is urgently needed in the face of rapidly declining habitats.