Variations in vocal patterns of Senegal and South African lesser bushbabies and their implications for taxonomic relationships.

Vocalizations of Senegal and South African lesser bushbabies were compared with respect to their acoustic properties analysed from spectrograms and oscillograms. Homologous calls could be identified within comparable functional categories. Considerable similarities were revealed in most of the noisy vocalizations associated with aggressive, defensive or anxiety and alarm behaviour. Striking divergences were detected, however, in almost all of the tonal or harmonic call types given in association with contact or contact-seeking, defensive or alarm behaviour. The results provide strong support for the separation of the two forms into distinct species, Galago senegalensis and Galago moholi.