A novel methodological approach for group classification during fission of a semi-free-ranging group of Japanese macaques (Macaca fuscata)

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

Verhalten männlicher Japanmakaken (Macaca fuscata) in Konfliktsituationen und in Abhängigkeit vom MAOA-Genotyp

Japanmakaken (Macaca fuscata) leben in Gruppen mit einer strikten Dominanzhierarchie, welche ein hohes Aggressionspotenzial mit sich bringt. Im Rahmen meiner Masterarbeit untersuchte ich das Sozial- und Konfliktverhalten von 29 Männchen einer semi-frei gehaltenen Gruppe (am Affenberg Landskron, Österreich) in Bezug auf ihren sozialen Rang. Wie angenommen, spielt der soziale Status der Tiere eine große Rolle. Hochrangige Männchen griffen vermehrt in Konflikte von Gruppenmitgliedern ein und waren häufiger als Männchen niederen Ranges an sozialen Interaktionen beteiligt. Zusätzlich zum Einfluss des Ranges wurde der genetische Hintergrund der Fokustiere als möglicher Einflussfaktor auf das Sozial- und Konfliktverhalten miteinbezogen, insbesondere verschiedenen Längenvariationen (VNTRs) des MAOA-Allels, welches bei menschlichen und nicht-menschlichen Primaten in Zusammenhang mit aggressivem Verhalten zu stehen scheint. Bei der von mir untersuchten Beobachtungsgruppe konnten vier VNTRs (7.8, 6.8. 5.8 und 3.8) identifiziert werden. Die Träger der niederaktiven 7.8 Variante gingen aufkommenden Konflikten signifikant häufiger aus dem Weg im Vergleich zu den Trägern der anderen Varianten. Zusätzlich zeigte sich ein Einfluss auf das Sozialverhalten. Die Träger der niederaktiven Enzymvariante hielten sich weniger in Körperkontakt mit anderen Individuen auf und erhielten weniger soziale Fellpflege im Vergleich zu den Trägern der hochaktiven Varianten. Zudem befanden sie sich generell seltener in der Nähe von anderen Gruppenmitgliedern, möglicherweise aufgrund der reduzierten Stressresilienz. Diese Ergebnisse deuten darauf hin, dass nicht nur der individuelle Dominanzrang, sondern auch die genetisch bedingte Fähigkeit der Stressregulation das Sozial- und Konfliktverhalten männlicher Japanmakaken beeinflusst.Japanese macaques (Macaca fuscata) live in groups with a strict dominance hierarchy that bears a high potential of aggression. In my study I investigated the social and conflict behaviour of 29 males of a semi-free ranging troop (at the Affenberg Landskron, Austria) in relation to their social rank. As expected, the individual dominance rank strongly influences the social and conflict behaviour of the macaques. High ranking males intervene more frequently in witnessed conflict scenes and are more often participants in social interactions compared to males of lower ranks. In addition to dominance status I investigated if the genetic background of these individuals influences their social behaviour. Therefore I used data on the distribution of the X-chromosomal MAOA allele among my study group. The MAOA gene received considerable attention for its relation to aggressive behaviour in human and non-human primates. Four alleles with variable number of tandem repeats (VNTRs) were found within my male study group (7.8, 6.8, 5.8 and 3.8 repeats). My data suggest that carriers of the 7.8 repeat variant show higher conflict-avoidance rates compared to carriers of lower repeat length. Furthermore, carriers of the 7.8 repeat variant are groomed for significantly shorter time and spend less time in close contact to conspecifics than individuals with lower repeat lengths. Overall, carriers of the higher repeat variant are less frequently in proximity to other group members, perhaps due to the increased probability to get involved in conflicts and due to decreased stress resilience. In conclusion these data suggest that not only dominance rank but also alleles coding for stress resilience influence conflict and social behaviour in male Japanese macaques.Julia Herzele, BScAbweichender Titel laut Übersetzung des Verfassers/der VerfasserinZusammenfassungen in Deutsch und EnglischKarl-Franzens-Universität Graz, Masterarbeit, 2017(VLID)211699

Exploring the Cognitive Capacities of Japanese Macaques in a Cooperation Game

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

Exploring the Cognitive Capacities of Japanese Macaques in a Cooperation Game

Cooperation occurs amongst individuals embedded in a social environment. Conse-quently, 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 demon-strate 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

Exploring the Cognitive Capacities of Japanese Macaques in a Cooperation Game

Cooperation occurs amongst individuals embedded in a social environment. Conse-quently, 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 demon-strate 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