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Sous la Direction du Prof. Ronald Noë, un groupe des chercheurs internationaux recherchent le comportement des singes du Parc National de Taï. Trouvez ici les résumés de quelques chercheurs de ce groupe, mis a la disposition de la Direction du Parc.

Friedericke Range : système sociale des mangabés

Paul Buzzard : Compétition intraspecifique entre trois espèces des singes.

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Friederike Range from the Department of Psychology at the University of Pennsylvania in the USA, studies the social system and social cognition of sooty mangabeys in the Tai National Park.

The cognitive capacities of non-human primates pose an intriguing problem for evolutionary theory. The large primate brain (compared to body size) is energetically costly to develop and thus its possession is expected to bring about a considerable fitness advantage. Several hypotheses have been proposed to explain why the large neo-cortex in the primate brain evolved. One approach suggests that the brain evolved to process information of ecological relevance, for example searching for resources in the home range ('mental map') or recognizing and locating specific food items in the environment (Clutton-Brock, 1980). An alternative hypothesis suggests that the primate brain evolved as an adaptation to cope with social complexity such as kinship networks, friendships, dominance hierarchies and formation of alliances (see Dunbar, 1998 for a concise review). Knowing that complex social structures exist in most non-human primate species, questions arise about the proximate cognitive mechanisms driving behavior, and more specifically the nature of the underlying mental representations. The complex behavior we observe could be the result of relatively simple stimulus response rules or associative contingencies where animals have knowledge about others based on prior observations. Alternatively, primates could have a "declarative representation" of the world meaning that they can recognize relations among other group members and understand concepts like dominance, kinship and reciprocity. The latter hypothesis implies a more abstract knowledge that would allow for greater flexibility in behavior depending upon changes in the social and ecological environment and the ability to make statements and causal inferences. Some experimental and field studies show that primates engage in a number of complex interactions that demonstrate an understanding of third-party relationships implying at least some kind of knowledge about dominance and kinship relationships. However, the question is if monkeys really have an abstract, conceptually knowledge of relationships or if an individuals knows each of the third parties involved as individuals and remembers something of their past interactions with each other.
This study on sooty mangabeys in the Tai National Park focuses on the social brain hypothesis. Sooty mangabeys, a terrestrial and highly social forest species, live in large groups up to 120 individuals with 25-30 adult females and 10-15 adult males. Females establish linear and stable dominance hierarchies, form close and well-differentiated relationships with each other, and do not emigrate from their natal group, while males exhibit an unstable social structure where some males join the group only for a few days every month. Using observation and playback experiments on sooty mangabeys, specific aspects of social knowledge within a group of sooty mangabeys and between neighboring sooty mangabeys groups are tested. The following questions are posed:
What knowledge of social relationships do sooty mangabeys posses and how do they use it? Do sooty mangabeys understand dominance relationships and can they make transitive inferences? What do mangabeys know about third-party relationships in relation to subgroup membership? Are sooty mangabeys able to distinguish between vocalizations of familiar individuals and strangers? How and when do they use vocal communication? Retour

Range, F. & Noë, R, in press, Familiarity and dominance relations among female sooty mangabeys in the Taï National Park. American Journal of Primatology.

Paul Buzzard
PhD. candidate, Dept. of Anthropology, Columbia University
New York Consortium in Evolutionary Primatology (NYCEP)

Interspecific competition among Diana monkeys (Cercopithecus diana ), Campbell's guenon (C. campbelli), and the lesser spot-nosed guenon (C. petaurista)
Ecological relationships among similarly adapted species are often characterized by competition, but there has been debate as to the significance of competition versus other factors in structuring interspecific relationships. At times, other factors such as predation, habitat disturbance, and species differences in habitat and diet preference play a larger role than interspecific competition. This study investigates the role interspecific competition plays in the relationship among C. diana, C. campbelli, and C. petuaurista through observation of two groups of each species in the Tai forest. To assess competition, aggression and cheek-pouch use are measured as interference competition. Niche divergence (in terms of food item and strata use), rates of travel, and group dispersions are compared when the species are together in mixed-species associations or alone. Home range sizes in relation to the area shared with the competing species will also be compared. Intraspecific and interspecific niche differences will indicate the potential for competition. Unlike previous studies, this study will consider several aspects of competition in multiple habituated groups. In addition, I will collaborate with another researcher, Winnie Eckhardt, who is studying the eology of the other guenon in Tai forest, C. nictitans. Comparisons will then be possible with other guenon communities across Africa with closely related species. Retour