Suffixation in Non-Human Primates: Meaningful Sound Combinations in Free-Ranging Guenons

International audienceCompared to humans, non-human primates have very little control over their vocal production. Nonetheless, some species produce various call combinations, which may partially offset this lack of flexibility. In previous work, we have described context-dependent call combinations in male alarm calls and female social calls of two sympatric species of African forest guenons, Campbell’s monkeys (Cercopithecus campbelli) and Diana monkeys (C. diana) . In particular, male Campbell’s monkeys give one alarm call type (‘Krak’) to leopards and a suffixed version of the same call (‘Krak-oo’) to unspecific danger. Similarly, female Diana monkeys give four social calls emitted alone or merged into six combinations; in combinations, the initial call conveys information about social context, while the final call conveys information about caller identity. We performed playback experiments using natural and artificially combined calls for both male Campbell’s and female Diana monkey calls, using wild Diana monkeys as subjects in both experiments. Responses indicated that monkeys attended to the way calls were combined regardless of contextual origin. We conclude that non-human primates are able to produce meaningful call combinations in both predatory and social contexts, which generates interesting hypotheses about the nature and evolution of sound combination in the evolution of primate communication. This study was conducted in accordance with the current International Primatological Society Guidelines and has been approved by the University of St Andrews (School of Psychology) ethics committe