Socialidad, redes sociales y estrategias de gestión de conflictos en primates hominoideos

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Psicología, leída el 28-09-2021Sociality is a widespread behavioural strategy that has been selected for in many animal species, including humans and other hominoid primates. Although sociality is a widespread phenomenon, the specific mechanisms and processes that may give rise to and maintain the structuring and cohesion of social groups remain poorly understood. The primate order, that includes humans, is made of reputedly social species. However, although they tend to live in social groups, the characteristics of their grouping units can be very variable both within and across species. This means that the very same outcome (group life) may arise through a variety of processes that may be activated by different mechanisms. In several studies in which this issue has been addressed, researchers have found that regardless of a group’s size, individuals tend to cultivate relationships with just a few of their members, those that belong to the same network. This implies that social time is really a serious constraint on the chances that individuals have of maintaining membership in large networks. It appears that individuals have a quota for social time and that the way they deal with this constraint can greatly vary from one individual to another and can also vary as a function of environmental factors...La conducta social (socialidad) y la vida en grupos es una estrategia de comportamiento que ha sido seleccionada en muchas especies animales, incluyendo la humana y otros primates hominoideos. Aunque la socialidad es un fenómeno muy extendido, los mecanismos y procesos específicos que generan y mantienen tanto la estructura como la cohesión de los grupos siguen siendo poco conocidos. El orden de los primates está formado por especies que son esencialmente sociales, sin embargo, pese a que tienden a vivir en grupos, estas agrupaciones pueden variar mucho no solo entre especies, sino también dentro de la misma especie. Esto significa que el mismo producto (la vida en grupo) puede surgir a través diversos procesos que se activan mediante diferentes mecanismos. En varios estudios en los que se ha abordado esta cuestión, se observó que independientemente del tamaño de un grupo, los individuos tienden a cultivar relaciones con un número reducido de individuos, aquellos que pertenecen a su misma red. Parece, por tanto, que los individuos tienen una cuota de tiempo social y que la manera de afrontar esta limitación puede variar mucho de un individuo a otro, así como también puede variar en función de factores ambientales...Fac. de PsicologíaTRUEunpu

Raising the level : orangutans solve the floating peanut task without visual feedback

This study was supported by project grants from the Regional Government of Madrid and the Universidad Complutense de Madrid (CCG07-UCM/SAL-2578; UCM-BSCH GR58/08) awarded to F. Colmenares.Chimpanzees and orangutans are able to generate innovative behaviors to solve complicated physical problems. For example, when presented with an out-of-reach peanut at the bottom of a vertical tube (Floating Peanut Task-FPT), some of them spontaneously spit water into the tube until the peanut floats to the top. Yet, it is unclear whether this innovative solution results from repeating those actions that bring the peanut incrementally closer to the top or from anticipating the solution before acting. In the current study, we addressed this question by presenting three naïve orangutans with an opaque version of the FPT that prevented them from obtaining visual information about the effect of their actions on the position of the peanut. One of the subjects solved the opaque FPT in the very first trial: he collected water from the faucet and poured it into the opaque tube repeatedly until the hitherto non-visible peanut reached the top. This provides evidence for the first time that orangutans can potentially solve the FPT without relying on sensorimotor learning, but to some extent by mentally representing the problem.Publisher PDFPeer reviewe

L'effet du statut social sur la flexibilité alimentaire des singes magots (Macaca sylvanus)

Parmi les animaux, les primates se caractérisent par leur flexibilité comportementale, connue comme la capacité à s'adapter à de nouvelles conditions ou à des conditions très variables à travers de nouveaux comportements. Cette caractéristique définit particulièrement le comportement du macaque de Barbarie. Traditionnellement, la plupart des études réalisées chez cette espèce ont eu comme objectif principal l'étude de la variabilité de son régime alimentaire dans leur aire de répartition naturelle. Peu de ces travaux ont approfondi notre compréhension sur le rôle que le statut des individus joue sur la flexibilité de son régime alimentaire. Dans cette étude, nous avons analysé les interactions sociales ainsi que le comportement alimentaire d'un groupe multi-mâles/multi-femelles de Macaca sylvanus (9 mâles adultes, 5 femelles adultes, 1 femelle subadulte, 4 mâles subadultes et 3 jeunes) hébergé au parc de La vallée des Singes (Romagne, France). Afin d'obtenir des données sur la structure sociale et le régime alimentaire du groupe, nous avons étudié les animaux au cours d'une période comprise entre les mois d'août et d'octobre 2006. Les résultats montrent une plus faible utilisation des ressources alimentaires chez les individus ayant un statut social plus élevé et plus particulièrement chez les mâles adultes. Les informations obtenues pourraient être utiles à la gestion de groupes de primates hébergés dans des enclos naturels où il est possible pour les animaux d'utiliser différentes sources d’aliments. Ce travail a été financé partiellement par El Ministerio Español de Economía y Competitividad (PS12011-29016-C02-02) et Le Programme Eurodyssée (Région de Poitou-Charentes et Comunidad Valenciana)

Raising the level:orangutans solve the floating peanut task without visual feedback

Chimpanzees and orangutans are able to generate innovative behaviors to solve complicated physical problems. For example, when presented with an out-of-reach peanut at the bottom of a vertical tube (Floating Peanut Task-FPT), some of them spontaneously spit water into the tube until the peanut floats to the top. Yet, it is unclear whether this innovative solution results from repeating those actions that bring the peanut incrementally closer to the top or from anticipating the solution before acting. In the current study, we addressed this question by presenting three naïve orangutans with an opaque version of the FPT that prevented them from obtaining visual information about the effect of their actions on the position of the peanut. One of the subjects solved the opaque FPT in the very first trial: he collected water from the faucet and poured it into the opaque tube repeatedly until the hitherto non-visible peanut reached the top. This provides evidence for the first time that orangutans can potentially solve the FPT without relying on sensorimotor learning, but to some extent by mentally representing the problem

Paramètres socio-spatiaux, réseaux sociaux et budget d'activité chez un groupe de mâles chimpanzés : stabilité dans le temps et effet de la réduction spatiale

Within chimpanzee communities, males are well known for forming strong social bonds with one another. These bonds are most evident in the non-random patterns of associations, affiliations and proximity exhibited by males. In captivity, crowding conditions, demographic changes and other factors such as individuals’ maturity can modify social relationships, the type of interactions and also the way individuals manage conflicts. We believe that the combined study of grouping patterns, social networks, and activity budgets can provide a deeper understanding of the processes that drive behavioral changes under different conditions. With this in mind, we studied a group of male chimpanzees housed at La Vallée des Singes in France under two housing conditions, indoors (spatial crowding condition) and outdoors; and at two different time-points, in 2007 and 2009. In this period, the two most significant demographic changes were that most individuals reached maturity and that a chimpanzee died. We studied their grouping patterns (i.e. sociality, closeness and gregariousness), their social network and their activity budgets to examine how different changes of diverse nature affected their social structure and their interactions. Compared to outdoors, in the indoor condition, individuals stayed closer and were more sociable and gregarious. They also affiliated and aggressed more often indoor than outdoors. Their social network also varied, being the diameter smaller and the density higher indoors than outdoors. After analyzing the stability across time no differences were found in sociality, closeness and gregariousness but we observed an increase in self-directed behaviors from 2007 to 2009. Their social network varied, decreasing its diameter and increasing its density from 2007 to 2009. Our data would be in agreement with a coping model for conflict management since the chimpanzees altered their behavior by increasing affiliative behaviors and reducing proximity distances under spatial crowding conditions. Across time, changes in maturity and the death of a member did not affect proximity patterns in this colony. The mentioned increase of self-directed behaviors is usually interpreted as an index of stress; however, our data, as agonism and other measures remained stable from 2007 to 2009, should be interpreted with caution. Together with grouping patterns and activity budgets, the analysis of social networks allowed a better understanding of the variation in the social structure of this group. Partly funded by project grant SFRH/BD/69069/2010 to NAV and PSI2011-29016-C02-01 to FC

Types de dominance agressive dans une colonie constituée exclusivement de males chimpanzés : intensité, fréquence, durée et direction de l'agression

Living in groups entails several fitness benefits but also leads to conflicts of interest. The strategies that different species have evolved to manage these conflicts are diverse and in some species aggressive exchanges of various kinds are commonplace. In some species, aggressions are important contributing elements to the organization of their social systems, providing a social order that may serve to avoid future agonistic encounters. Male chimpanzees are known for being gregarious, for exchanging complex social interactions and for forming dominance relationships where aggressions of different intensities can be frequent. Aggressions are costly interactions as they are energetically demanding but also because they encompass social consequences and risks. In this study we aimed to investigate the relationship between aggressive dominance styles and the intensity, the frequency, the duration and the direction of the aggressive interactions in a group of ten young male chimpanzees (“Pan troglodytes verus”) housed at la Vallée des Singes in France. First, we investigated whether aggressive interactions were costly behaviors; for this, we classified aggressions into three intensity levels, low, middle and high; we expected to find that if they were energetically demanding, then a negative relation between intensity and duration of aggressive interactions should be obtained. Second, we investigated whether the rank order of individuals varied depending on whether we assessed occurrence of aggression or duration of aggressive episodes for each one of the three levels and for the pooled category. Next, we correlated the two rank orders thus obtained. Finally, we studied whether aggressive dominance rank orders were consistent across the various aggression-based measures. As expected, we found that low intensity aggressions lasted longer than did medium and high aggressive exchanges. With both measures, occurrence and duration, we found similar aggressive patterns for the three levels of aggressions and for the totality of aggressive behaviors. Finally, we found some minor but interesting differences in the aggression-based dominance rankings when we compared individual measures, dyadic measures, the h’ de Vries dominance index and the David’s Score method. Our results suggest that due to the consistency of several measures, aggressive interactions are valuable to study aggression dominance in this species and that these interactions are selectively used. We also believe that although probing into the aggressive dominance relationships of male chimpanzees can provide a more nuanced view of their social relationships, a fuller understanding of this species’ group structure and dominance hierarchies should also incorporate other agonistic behavioral interactions (e.g., submission) and affiliative measures. Partly funded by project grant SFRH/BD/69069/2010 to NAV and PSI2011-29016-C02-01 to FC