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This study primarily was funded by the Swiss National Science Foundation through grant nos. (31003A_166458 and 310030_185324) awarded to K.Z. How do non-human primates learn to use their alarm calls? Social learning is a promising candidate, but its role in the acquisition of meaning and call usage has not been studied systematically, neither during ontogeny nor in adulthood. To investigate the role of social learning in alarm call comprehension and use, we exposed groups of wild vervet monkeys to two unfamiliar animal models in the presence or absence of conspecific alarm calls. To assess the learning outcome of these experiences, we then presented the models for a second time to the same monkeys, but now without additional alarm call information. In subjects previously exposed in conjunction with alarm calls, we found heightened predator inspection compared to control subjects exposed without alarm calls, indicating one-trial social learning of ‘meaning’. Moreover, some juveniles (but not adults) produced the same alarm calls they heard during the initial exposure whereas the authenticity of the models had an additional effect. Our experiment provides preliminary evidence that, in non-human primates, call meaning can be acquired by one-trail social learning but that subject age and core knowledge about predators additionally moderate the acquisition of novel call-referent associations. Publisher PDF

Figures and Tables;Individual Assesement , Horse model ;Same trial as Video S1 with different camera showing model exposure;Individual Assesement , Caterpillar model ;Group exposure, Alarm treatment with the Horse Model

The study was funded by an ERC grant (prilang 283871) to KZ and funding from the University of Neuchatel. Chimpanzee inter-group encounters are typically aggressive in nature, as individuals have evolved the predisposition to jointly defend their home range against neighbouring groups. In the current study, we present data on the behavioural strategies of chimpanzees (Pan troglodytes) during the integration of one male and two female into a well-established group at Basel Zoo, Switzerland. We found that, shortly after integration, social relationships were generally of better quality in dyads of individuals from the same group than dyads of individuals from different origins. More interestingly, immigrants targeted males as preferred interaction partners, contrary to what is seen in inter-group encounters in the wild. In addition, immigrants also targeted the resident juveniles for play interactions, significantly more so than residents did. The alpha male’s policing of his resident group members further facilitated immigrants’ integration, including the integration of another male. In contrast, both resident and immigrant females had better relationships with members from their own group than with members from other groups. Overall, these diverse behavioural strategies led to the successful long-term integration of the immigrant individuals, a demonstration of the social flexibility of this species orthogonal to their evolved xenophobic propensities. Publisher PDF

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It is generally accepted that comparative studies on animal communication can provide insights into the coevolution of social life, vocal communication, cognitive capacities and notably the emergence of some human language features. Recent studies suggested that non-human primates possess combinatorial abilities that may allow a diversification of vocal repertoires or a richer communication in spite of limited articulatory capacities. However, the functions of combined calls and the information that receivers can extract remain poorly understood. This thesis investigated call combination systems in two species of guenons: Campbell’s monkey (Cercopithecus Campbelli) and Diana monkey (Cercopithecus Diana). Firstly, I studied the combinatorial structure and relevance to receivers of combined calls in of both species using playback experiments. Results confirmed the presence of a suffixation mechanism reducing the emergency of danger signaled by calls of male Campbell’s monkeys. Also, they showed that combined calls of females Diana monkeys convey linearly information via their two units, which signal respectively caller’s emotional state and identity. Secondly, focusing on the context associated with the emission of simple and combined female Campbell’s monkey calls, results revealed flexible use of combination reflecting the immediate need to remain cryptic (i.e. simple calls) or to signal caller’s identity (i.e. combined calls). Finally, I compared females’ communication systems of both species to identify their similarities and differences. As predicted by their close phylogenetic relatedness, their repertoires are mostly based on homologous structures. However, the females differ strongly in their use of those structures. In particular, the great number of calls combined by Diana monkeys increases considerably their vocal repertoire compared to Campbell’s monkeys. Given that the combinations are non-random, meaningful to receivers and used flexibly with the context, I propose a parallel with a rudimentary form of semantic morphosyntax and discuss more generally the possible existence of similar capacities in other non-human animals., Il est classiquement admis que les études comparatives sur la communication des animaux peuvent permettre de mieux comprendre la coévolution de la vie sociale, de la communication vocale et des capacités cognitives, notamment l’émergence de certaines propriétés du langage humain. De récentes études ont suggéré la présence de capacités combinatoires chez les primates non humains, capacités qui permettraient à ces animaux de diversifier leurs répertoires ou d’enrichir les messages transmis par leurs vocalisations en dépit de capacités articulatoires limitées. Toutefois, les fonctions des cris combinés et les informations qui en sont extraites par les receveurs restent méconnues. Cette thèse porte sur les capacités de combinaison vocale de cercopithèques forestiers sauvages : la mone de Campbell (Cercopithecus Campbelli) et le singe Diane (Cercopithecus Diana). Premièrement, à l’aide d’expériences de repasse acoustiques, j’ai étudié la nature combinatoire de cris combinés et les informations qui en sont extraites par les receveurs chez ces deux espèces. Les résultats ont confirmé chez les mâles mone de Campbell la présence d’un mécanisme de suffixation diminuant l’urgence du danger signalé par un cri d’alarme ainsi que, chez les femelles singe Diane, la présence de cris complexes combinant linéairement les messages des deux unités qui les composent, signalant respectivement l’émotion et l’identité de l’émetteur. Deuxièmement, une étude observationnelle du contexte d’émission de cris simples et combinés par des femelles mones de Campbell sauvages a révélé une utilisation flexible de la combinaison en fonction du besoin immédiat de rester discret (i.e. cris simples) ou de signaler son identité (i.e. cris combinés). Finalement, j’ai comparé les systèmes de communication des femelles de ces deux espèces pour identifier leurs points communs et leurs différences. Leurs répertoires sont basés principalement sur des structures acoustiques homologues, comme prédit par leur proximité phylogénétique. Cependant, les femelles de ces deux espèces diffèrent fortement dans leur utilisation de ces structures. Par exemple, le grand nombre de cris combinés chez les singes Diane semble permettre un accroissement considérable de leur répertoire vocal par rapport aux mones de Campbell. Etant donné l’organisation non-aléatoire de ces combinaisons vocales qui font sens pour les receveurs et de leur utilisation flexible en fonction du contexte, je propose un parallèle avec une forme simple de morphosyntaxe sémantique et discute aussi plus généralement de la possibilité de trouver des capacités similaires chez d’autres espèces animales.