Maternal care styles in primates: considering a New World species

When aiming understand the human behavior, comparisons with nonhuman primates are especially relevant to identify homoplasies (similar characteristics that evolve independently in different species). In this paper, we present a two-year longitudinal study on the maternal behavior of capuchin monkeys (Sapajus spp.) under naturalistic conditions. Our results revel distinct maternal care styles within a continuum ranging from permissiveness (laissez-faire) to protectiveness. The observed development of mothers and infants bond suggests that the dependence period of capuchin monkeys infants involves, in addition to physical maturation processes, the establishment and development of psychological processes associated with the attachment system. It is possible that the variability of maternal styles – resulting from the combination of mothers’ and infants’ characteristics, as well as socioecological contexts, along with the extension of the attachment bond – are responsible for paving the way for different developmental trajectories. This may be one of the mechanisms underlying interindividual differences arise in adult populations, as seen in humans.Quando buscamos entender o comportamento humano, comparações com primatas não humanos são especialmente relevantes para identificar homoplasias (características semelhantes que evoluem independentemente em diferentes espécies). Neste artigo, apresentamos um estudo longitudinal de dois anos sobre o comportamento materno de macacos-prego (Sapajus spp.) em condições naturalísticas. Nossos resultados permitiram identificar estilos de cuidado distintos dentro de um contínuo de permissividade a proteção. O desenvolvimento observado do vínculo entre mães e filhotes sugere que o período de dependência de filhotes de macaco-prego envolve, além de processos de maturação física, o estabelecimento e desenvolvimento de processos psicológicos associados ao sistema de apego. É possível que a variabilidade de estilos maternos resultante da combinação de características de mães, filhotes e contextos socioecológicos, aliada ao prolongamento do vínculo de apego, pavimente caminhos para diferentes trajetórias de desenvolvimento. Como em humanos, esse pode ser um dos mecanismos pelos quais surgem e se consolidam as diferenças interindividuais nas populações adultas.Lorsque nous cherchons à comprendre le comportement humain, les comparaisons avec les primates non humains sont particulièrement pertinentes pour identifier les homoplasies (caractéristiques similaires qui évoluent indépendamment dans différentes espèces). Dans cet article, nous présentons les résultats d’une étude longitudinale de deux ans sur le comportement maternel du Sapajou capucin (Sapajus spp.) dans des conditions naturelles. Nos résultats nous ont permis d’identifier différents styles de soins maternels dans un continuum de permissivité à la protection. Nous avons observé que le modèle de lien d’attachement entre la mère et la progéniture suggère que la période de dépendance des bébés singes implique, en plus des processus de maturation physique, l’établissement et le développement de processus psychologiques associés au système d’attachement. Il est possible que la variabilité des styles maternels résultant de la combinaison des caractéristiques de la mère, de la progéniture et du contexte socioécologique, ainsi que l’extension du lien d’attachement, ouvrent la voie à différentes trajectoires de développement. Comme les humains, il peut être un des mécanismes par lequel les différences interindividuelles apparaissent et se consolident au sein des populations adultes.Cuando buscamos entender el comportamiento humano, comparaciones con primates no humanos son especialmente relevantes para identificar homoplasias (características similares que evolucionan independientemente en diferentes especies). En este artículo, presentamos los resultados de un estudio longitudinal de dos años sobre el comportamiento materno de monos capuchinos (Sapajus spp.) en condiciones naturales. Los resultados permitieron identificar estilos de cuidado materno distintos dentro de un continuo de permisividad a la protección. Se observó que el patrón de desarrollo del vínculo de apego entre madre y cría sugiere que el período de dependencia de la cría de monos capuchinos involucra, además de procesos de maduración física, el establecimiento y desarrollo de procesos psicológicos asociados al sistema de apego. Es posible que la variabilidad de estilos maternos resultante de la combinación de características de madres, crías y contextos socioecológicos, aliada a la prolongación del vínculo de apego, establezca caminos para diferentes trayectorias de desarrollo. Tal como en humanos, este puede ser uno de los mecanismos por los que surgen y se consolidan las diferencias interindividuales en las poblaciones adultas

Female emancipation in a male dominant, sexually dimorphic primate under natural conditions

In most group-living animals, a dominance hierarchy reduces the costs of competition for limited resources. Dominance ranks may reflect prior attributes, such as body size, related to fighting ability or reflect the history of self-reinforcing effects of winning and losing a conflict (the winner-loser effect), or both. As to prior attributes, in sexually dimorphic species, where males are larger than females, males are assumed to be dominant over females. As to the winner-loser effect, the computational model DomWorld has shown that despite the female’s lower initial fighting ability, females achieve some degree of dominance of females over males. In the model, this degree of female dominance increases with the proportion of males in a group. This increase was supposed to emerge from the higher fraction of fights of males among themselves. These correlations were confirmed in despotic macaques, vervet monkeys, and in humans. Here, we first investigate this hypothesis in DomWorld and next in long-term data of 9,300 observation hours on six wild groups of robust capuchin monkeys (Sapajus libidinosus; S. nigritus, and S. xanthosternos) in three Brazilian sites. We test whether both the proportion of males and degree of female dominance over males are indeed associated with a higher relative frequency of aggression among males and a higher relative frequency of aggression of females to males. We confirm these correlations in DomWorld. Next, we confirm in empirical data of capuchin monkeys that with the proportion of males in the group there is indeed an increase in female dominance over males, and in the relative frequency of both male-male aggression and aggression of females to males and that the female dominance index is significantly positively associated with male male aggression. Our results reveal that adult sex ratio influences the power relation between the sexes beyond predictions from socioecological models.</p

Stone tool use in wild bearded capuchin monkeys (Cebus libidinosus). Is it a strategy to overcome food scarcity? Anim

Keywords: bearded capuchin Cebus libidinosus fallback food necessity hypothesis nut cracking opportunity hypothesis tool use To determine whether tool use varied in relation to food availability in bearded capuchin monkeys, we recorded anvil and stone hammer use in two sympatric wild groups, one of which was provisioned daily, and assessed climatic variables and availability of fruits, invertebrates and palm nuts. Capuchins used tools to crack open encased fruits, mostly palm nuts, throughout the year. Significant differences between wet and dry seasons were found in rainfall, abundance of invertebrates and palm nuts, but not in fruit abundance. Catulè nuts were more abundant in the dry season. We tested the predictions of the necessity hypothesis (according to which tool use is maintained by sustenance needs during resource scarcity) and of the opportunity hypothesis (according to which tool use is maintained by repeated exposure to appropriate ecological conditions, such as preferred food resources necessitating the use of tools). Our findings support only the opportunity hypothesis. The rate of tool use was not affected by provisioning, and the monthly rate of tool use was not correlated with the availability of fruits and invertebrates. Conversely, all capuchins cracked food items other than palm nuts (e.g. cashew nuts) when available, and adult males cracked nuts more in the dry season when catulè nuts (the most common and exploited nut) are especially abundant. Hence, in our field site capuchins use tools opportunistically.

Stone tool use in wild bearded capuchin monkeys, Cebus libidinosus. Is it a strategy to overcome food scarcity?

To determine whether tool use varied in relation to food availability in bearded capuchin monkeys, we recorded anvil and stone hammer use in two sympatric wild groups, one of which was provisioned daily, and assessed climatic variables and availability of fruits, invertebrates and palm nuts. Capuchins used tools to crack open encased fruits, mostly palm nuts, throughout the year. Significant differences between wet and dry seasons were found in rainfall, abundance of invertebrates and palm nuts, but not in fruit abundance. Catule nuts were more abundant in the dry season. We tested the predictions of the necessity hypothesis (according to which tool use is maintained by sustenance needs during resource scarcity) and of the opportunity hypothesis (according to which tool use is maintained by repeated exposure to appropriate ecological conditions, such as preferred food resources necessitating the use of tools). Our findings support only the opportunity hypothesis. The rate of tool use was not affected by provisioning, and the monthly rate of tool use was not correlated with the availability of fruits and invertebrates. Conversely, all capuchins cracked food items other than palm nuts (e.g. cashew nuts) when available, and adult males cracked nuts more in the dry season when catule nuts (the most common and exploited nut) are especially abundant. Hence, in our field site capuchins use tools opportunistically. (C) 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.University La Sapienza of RomeUniversity La Sapienza of RomeEU [029088]EUFAPESPFAPESP [06/515789, 06/51577-2]CNPqCNPqISTCCNRISTC-CNREthoikos srlEthoikos sr

Flexible and conservative features of social systems in tufted capuchin monkeys: comparing the socioecology of Sapajus libidinosus and Sapajus nigritus

Socioecological models assume that primates adapt their social behavior to ecological conditions, and predict that food availability and distribution, predation risk and risk of infanticide by males affect patterns of social organization, social structure and mating system of primates. However, adaptability and variation of social behavior may be constrained by conservative adaptations and by phylogenetic inertia. The comparative study of closely related species can help to identify the relative contribution of ecological and of genetic determinants to primate social systems. We compared ecological features and social behavior of two species of the genus Sapajus, S. nigritus in Carlos Botelho State Park, an area of Atlantic Forest in Sao Paulo state, and S. libidinosus in Fazenda Boa Vista, a semi-arid habitat in Piaui state, Brazil. S. libidinosus perceived higher predation risk and fed on clumped, high quality, and usurpable resources (fruits) all year round, whereas S. nigritus perceived lower predation risk and relied on evenly distributed, low-quality food sources (leaves) during periods of fruit shortage. As predicted by socioecology models, S. libidinosus females were philopatric and established linear and stable dominance hierarchies, coalitions, and grooming relationships. S. nigritus females competed less often, and could transfer between groups, which might explain the lack of coalitions and grooming bonds among them. Both populations presented similar group size and composition and the same polygynous mating system. The species differed from each other in accordance with differences in the characteristics of their main food sources, as predicted by socioecological models, suggesting that phylogenetic inertia does not constrain social relationships established among female Sapajus. The similarity in mating systems indicates that this element of the social system is not affected by ecological variables and thus, is a more conservative behavioral feature of the genus Sapajus. Am. J. Primatol. 74:315331, 2012. (c) 2011 Wiley Periodicals, Inc.FAPESPFAPESP [06/51577-2, 06/56059-0, 08/55684-3]CNPq [420038/2005-1]CNPqNational Geographic SocietyNational Geographic SocietyLeakey FoundationLeakey FoundationIBAMAIBAMACNPqCNP