Nocturnal Primate Communication: Ecology, Evolution and Conservation.

Auditory, visual and olfactory cues play varying roles in non-human primate communication, and these systems have been intensively studied over the last several decades. The use of vocalisations as a primary mode of communication has been the focus of much research, especially in attempts to understand the origins of human language, with a major focus on anthropoid primates and diurnal lemurs. Over the last decade, technological advances have allowed researchers to begin to conduct in-depth investigations into the communication systems exhibited by the nocturnal and cathemeral prosimian primates, including tarsiers, lemurs and lorises. Understanding how nocturnal prosimians use visual, olfactory and auditory cues is vital for reconstructing the origins of primate communication systems. In this special issue, we highlight some of the more exciting advances in the communication strategies of the prosimians. Contributions come from work conducted in Kenya, Tanzania, Senegal, Rwanda, Madagascar and the Indonesian islands of Java and Sulawesi. Topics will include: the description of novel ultrasonic vocalisations, including frequency and function of these newly discovered calls; the possible use of vocalisations to navigate and assemble at sleep sites; the importance of species-specific contact vocalisations for the identification of new species; the use of urinary and glandular signals to communicate and the methods developed to understand this complex communication in the field; the use of vocalisations for niche separation among nocturnal primates from mainland Africa and Madagascar; and whether or not we can use new technologies to discern whether prosimians use vocalisations for individual identification of group members. We discuss the importance of new field methods including novel equipment and techniques, the use of vocalisation to influence conservation practices and the importance of comparing across prosimian taxa to reconstruct the communication systems of our early primate ancestors.