Cooperation occurs amongst individuals embedded in a social environment. Consequently, cooperative interactions involve a variety of persistent social influences such as the dynamics of partner ...choice and reward division. To test for the effects of such dynamics, we conducted cooperation experiments in a captive population of Japanese macaques (Macaca fuscata, N = 164) using a modified version of the loose-string paradigm in an open-experiment design. We show that in addition to becoming more proficient cooperators over the course of the experiments, some of the macaques showed sensitivity to the presence of potential partners and adjusted their behavior accordingly. Furthermore, following an unequal reward division, individuals receiving a lesser reward were more likely to display aggressive and stress-related behaviors. Our experiments demonstrate that Japanese macaques have some understanding of the contingencies involved in cooperation as well as a sensitivity to the subsequent reward division suggestive of an aversion to inequity.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The self‐initiated split of a social group, known as fission, is a challenge faced by many group‐living animals. The study of group fission and the social restructuring process in real time provides ...insights into the mechanism of this biologically important process. Previous studies on fission in Japanese macaques (Macaca fuscata) assigned individuals to newly reorganized groups mainly using behavioral observations and group attendance records based on periods before or after fission itself. Here, we present a novel framework for group classification during the process of fission that uses quantifiable behavioral variables and statistical analyses. The framework was tested on a group fission process at Affenberg Landskron (Austria), a park that housed around 160 semi‐free‐ranging Japanese macaques. The behavioral data were collected for 26 days during fission. We analyzed three behavioral developments recurrent in fissions in Japanese macaques, that is, independence of behavior, participation in group movements, and separation of nomadic ranges. These analyses were combined to assign individuals to different groups. Our study resulted in one main group (N = 33), one subgroup (N = 36) and 56 individuals whose group membership was still undefined. The demographic characteristics of these newly formed groups were comparable with those of fissioned groups in wild populations. Furthermore, we found that these newly forming groups showed early social dynamics of fission five months before group level movements, that is: grouping based on spatial proximity and spatial withdrawal of the subgroup to the periphery. These results underline the validity of our novel framework to study social dynamics in Japanese macaques during the process of fission. It represents an important addition to existing methods, and we recommend testing its scope in other primate societies.
Graphical overview of a novel methodological framework for group classification during fission in Japanese macaques (Macaca fuscata).
Research Highlights
We studied semi‐free‐ranging Japanese macaques during group fission
Our applied methodology uses multiple behavioral variables for group classification
Our framework represents an important addition to existing methods used to study fission
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