Is There a “Right” Side of Communicating Friendship? Lateralization of Social Interactions in Zoo Barbary macaques (Macaca sylvanus)

Social laterality in non-human primates has started to attract attention in recent years. The positioning of individuals during social interactions could possibly suggest the nature of a relationship and the social ranking of the subjects involved. The subjects of the present study were 12 adult Barbary macaques (Macaca sylvanus) housed in a zoological garden. We carried out fourteen 210-min video-recorded sessions and we used a focal animal sampling method to collect the position of the subjects during different social interactions. Data on the position of each macaque during three types of social interactions were collected (approach, proximity and affiliative contacts). Moreover, we focused on the outcomes of dyadic agonistic encounters to build the hierarchy of the colony. For each social interaction, two conditions were considered: the side preference (being kept on the left or on the right) and the sagittal preference (being kept in front or on the rear). Bouts of preference of different positions were collected for different social interactions (approach, proximity and contacts). No group-level side preferences were found for any social interaction, suggesting that both hemispheres might be complemental and balance each other during intraspecific communication. For the sagittal preference, we found a group-level bias for proximity, with macaques being kept in front rather than on the rear by close conspecifics. This might be due to the need to detect emotions and intentions of conspecifics. Moreover, high-ranking individuals are kept more frontally than on the rear when in proximity with other macaques. More studies are needed to better investigate social laterality, possibly distinguishing more categories of social interaction, and detecting other variables that might influence the positioning preferences.

Decolonizing Primate Conservation Practice: A Case Study from North Morocco

Understanding the historical context of an area enables an incoming conservationist to reflect on their role in communities and to better position themselves both politically and socially within them. Here, we explore how outside agencies and institutions, including a former colonial power, have affected and influenced local communities who share their landscape with Barbary macaques (Macaca sylvanus) in Bouhachem forest, north Morocco. In the context of initiating Barbary macaque conservation activities, we interviewed representatives from local governmental and nongovernmental organizations, city dwellers, and villagers about the historical, political, and social context of the study site. We found that villages around Bouhachem were politically and socially marginalized and discriminated against by the state and urban society. The existence of these divisions and the outside agencies’ simplistic view of villages as homogeneous communities negatively influenced conservation interventions, because people resisted initiatives imposed on them without prior consultation. We found that Bouhachem villagers have been, and still are, excluded from meaningful participation in the conservation of the forest and this finding encouraged us to decolonize our own practice. We engaged meaningfully with members of the surrounding communities and responded to news of erroneous stories about our activities by developing a project working in three villages that included all households. Based on our experiences, we recommend that all conservationists conduct historical and qualitative research to gain a deeper, more nuanced understanding of the communities they work in. This understanding should encourage conservationists to recognize their own social and cultural biases and to decolonize their practice. Attending to our own position may help us to avoid underestimating and alienating people who view conservation actions through a very different but equally valid lens.التخلص من التداعيات الاستعمارية في المحافظة على الرئيسيات :دراسة حالة من شمال المغربخلاصة : إن فهم السياق التاريخي لمنطقة معينة، يمكّن المحافظ البيئي الوافد من التفكير في دوره في المجتمعات، ولانسجامٍ سياسيٍ واجتماعي أفضل داخلها. هنا نكتشف كيف أثرت الوكالات والمؤسسات الخارجية ، بما في ذلك القوة الاستعمارية السابقة، على المجتمعات المحلية التي تتعايش مع قرود المكاك البربري (Macaca sylvanus) في غابة بوهاشم شمال المغرب. في سياق بدء أنشطة الحفاظ على المكاك البربري، أجرينا مقابلات مع ممثلين من المنظمات الحكومية وغير الحكومية المحلية وسكان المدن والقرويين حول السياق التاريخي والسياسي والاجتماعي لموقع الدراسة. وجدنا أن القرى المحيطة بغابة بوهاشم كانت مهمشة و معرضة للتمييز ضدها سياسياً واجتماعياً من قبل الدولة والمجتمع الحضري. و أثر بشكل سلبي وجود هذه الانقسامات والنظرة السطحية للوكالات الخارجية للقرى على أنها مجتمعات متجانسة، على تدخلات الحفظ البيئي، لأن الناس رفضوا أي مبادرة مفروضة عليهم دون استشارة مسبقة. و وجدنا أن القرويين في بوهاشم كانوا ولا يزالون مستبعدين من المشاركة الهادفة في الحفاظ على الغابة، وهذا الاكتشاف شجعنا على التخلص من التداعيات الاستعمارية في ممارستنا. لقد تواصلنا بشكل هادف بأعضاء من المجتمعات المحيطة، واستجبنا لأخبار القصص الخاطئة حول أنشطتنا من خلال تطوير مشروع يعمل في ثلاث قرى شمل جميع الأسر. بناءً على تجاربنا، نوصي جميع دعاة الحفاظ على البيئة بإجراء بحث تاريخي ونوعي لاكتساب فهم أعمق وأكثر دقة للمجتمعات التي يعملون فيها. يجب أن يشجع هذا الفهم دعاة الحفاظ على البيئة على التعرف على التحيزات الاجتماعية والثقافية الخاصة بهم، والتخلص من التداعيات الاستعمارية في ممارساتهم.قد يساعدنا الاهتمام بموقفنا الخاص على تجنب الإبعاد و التقليل من شأن الأشخاص، الذين ينظرون إلى إجراءات الحفاظ على البيئة من منظور مختلف تمامًا لكن عادل .

The Function of Mounts in Free-Ranging Barbary Macaques (Macaca sylvanus)

Generally, nonreproductive sex is thought to act as “social grease,” facilitating peaceful coexistence between subjects that lack close genetic ties. However, specifc nonreproductive sexual behaviors may fulfill different functions. With this study, we aimed to test whether nonreproductive mounts in Barbary macaques are used to 1) assert dominance, 2) reinforce social relationships, and/or 3) solve conflicts. We analyzed nonreproductive mounts (N = 236) and postmount behavior in both aggressive and nonaggressive contexts, in 118 individuals belonging to two semi-free-ranging groups at La Montagne des Singes (France). As predicted by the dominance assertion hypothesis, the probability to be the mounter increased with rank difference, especially in aggressive contexts (increasing from 0.066 to 0.797 in nonaggressive contexts, and from 0.011 to 0.969 in aggressive contexts, when the rank difference was minimal vs. maximal). The strength of the social bond did not significantly predict the proportion of mounts across dyads in nonaggressive contexts, providing no support for the relationship reinforcement hypothesis. Finally, in support of the conflict resolution hypothesis, when individuals engaged in postconflict mounts, 1) the probability of being involved in further aggression decreased from 0.825 to 0.517, while 2) the probability of being involved in grooming interactions with each other increased from 0.119 to 0.606. The strength of the social bond between former opponents had no significant effect on grooming occurrence and agonistic behavior after postconflict mounts. Overall, our findings suggest that nonreproductive mounts in Barbary macaques have different functions that are not affected by the strength of the social bond.

Correction to: Trichuris trichiura isolated from Macaca sylvanus: morphological, biometrical, and molecular study

An amendment to this paper has been published and can be accessed via the original article.

Complete Mitochondrial Genome of Trichuristrichiura from Macaca sylvanus and Papio papio

Trichuriasis is among the most prevalent worldwide parasitism caused by helminths. For many years, Trichuris spp. have been described with a relatively narrow range of both morphological and biometrical features. The use of the complete mitochondrial genome (mitogenome) is an alternative and powerful molecular method for inferring phylogenies. Here, we present an overview of the contributions of mitogenome for Trichuris spp. from human and non-human primates. In addition, we carry out structural and phylogenetic comparative analyses with genomes of Trichuris species available in public datasets. The complete mt genomes of Trichuris trichiura and Trichuris sp. from Macaca sylvanus and T. trichiura from Papio papio are 14,091 bp, 14,047 bp and 14,089 bp in length, respectively. The three mt genomes are circular and consist of 37 genes—13 PCGs (cox1–3, nad1–6, nad4L, atp6, atp8 and cob), 22 transfer RNA genes (tRNAs), and two rRNAs (rrnL and rrnS). The molecular evidence presented here supports the hypothesis that T. trichiura de M. sylvanus (TMF31) and T. trichiura de P. papio (TPM1) were similar but genetically different with respect to Trichuris sp. from macaques (TMM5). The phylogenetic study also supported the evolution of the different Trichuris species. In conclusion, we suggest the existence of two cryptic species parasitizing M. sylvanus.

Nonsensus in the treatment of proximal humerus fractures: uncontrolled, blinded, comparative behavioural analysis between Homo chirurgicus accidentus and Macaca sylvanus

Objective To investigate the inter-rater reliability of Barbary macaques compared with an expert group of surgeons for the choice of treatment and predicted outcome of proximal humerus fractures. Design Uncontrolled, blinded, comparative behavioural analysis. Setting Germany and United States. Participants 10 blinded experts in the field of orthopaedic trauma surgery ( Homo chirurgicus accidentus ), with special focus on upper extremity surgery from Germany and the US, and five Barbary macaques ( Macaca sylvanus ) from a semi-free range enclosure. Main outcome measures The reliability of agreement between raters assessed with Fleiss’ ĸ. Results Barbary macaques seem to have inferior inter-rater reliability in comparison with experts for choice of treatment (non-surgical v surgical), but for the geriatric age group most frequently affected by proximal humeral fractures, they performed similarly to the experts in their choices of treatment and choice of surgical procedure. Agreement about predicted outcome was poor among the macaques and slight among the experts. All experts almost always predicted the outcome incorrectly and tended to underestimate it. While only 4 (4.4%) of 90 experts’ predictions were correct, 13 (28.9%) of 45 macaques’ predictions were correct. Conclusions Consensus on treatment and expected outcomes of proximal humeral fractures is lacking even beyond the human species. Although Barbary macaques tend to predict the clinical outcome more accurately, their reliability to assist surgeons in making a consistent decision is limited. Future high quality research is needed to guide surgeons’ decision making on the optimal treatment of this common injury.

Trichuris trichiura isolated from Macaca sylvanus: morphological, biometrical, and molecular study

Background Recent studies have reported the existence of a Trichuris species complex parasitizing primate. Nevertheless, the genetic and evolutionary relationship between Trichuris spp. parasitizing humans and Non-Human Primates (NHP) is poorly understood. The hypothesised existence of different species of Trichuris in primates opens the possibility to evaluate these primates as reservoir hosts of human trichuriasis and other putative new species of whipworms. Results In this paper, we carried out a morphological, biometrical and molecular study of Trichuris population parasitizing Macaca sylvanus from Spain based on traditional morpho-biometrical methods, PCA analysis and ribosomal (ITS2) and mitochondrial (cox1 and cob) DNA sequencing. Morphological results revealed that Trichuris sp. from M. sylvanus is Trichuris trichiura. Ribosomal datasets revealed that phylogenetic relationships of populations of Trichuris sp. from M. sylvanus were unresolved. The phylogeny inferred on mitochondrial datasets (partitioned and concatenated) revealed similar topologies; Thus, phylogenetic trees supported the existence of clear molecular differentiation between individuals of Trichuris sp. from M. sylvanus appearing in two different subclades. Conclusions Based on morphological parameters, biometrical measurements, and molecular sequence analysis, we conclude that the whipworms isolated from M. sylvanus were T. trichiura. Further, the evolutionary relationship showed that these worms belonged to two genotypes within the T. trichiura lineage. Since T. trichiura is of public health importance, it is important to carry out further studies to improve the understanding of its hosts range, evolution and phylogeography.

Differential ageing trajectories in motivation, inhibitory control and cognitive flexibility in Barbary macaques ( Macaca sylvanus )

Across the lifespan, the performance in problem-solving tasks varies strongly, owing to age-related variation in cognitive abilities as well as the motivation to engage in a task. Non-human primates provide an evolutionary perspective on human cognitive and motivational ageing, as they lack an insight into their own limited lifetime, and ageing trajectories are not affected by customs and societal norms. To test age-related variation in inhibitory control, cognitive flexibility and persistence, we presented Barbary macaques ( Macaca sylvanus ), living at La Forêt des Singes in Rocamadour (France), with three problem-solving tasks. We conducted 297 trials with 143 subjects aged 2–30 years. We found no effect of age on success and latency to succeed in the inhibitory control task. In the cognitive flexibility task, 21 out of 99 monkeys were able to switch their strategy, but there was no evidence for an effect of age. Yet, the persistence in the motivation task as well as the overall likelihood to participate in any of the tasks declined with increasing age. These results suggest that motivation declines earlier than the cognitive abilities assessed in this study, corroborating the notion that non-human primates and humans show similar changes in motivation in old age. This article is part of the theme issue ‘Evolution of the primate ageing process'.