Making use of Capuchins’ behavioral propensities to obtain hair samples for DNA analyses

Genotyping wild and captive capuchins has become a priority and hair bulbs have high quality DNA. Here, we describe a method to non-invasively collect fresh-plucked strands of hair that exploits capuchins’ manual dexterity and propensity to grasp and extract food. The apparatus consists of a transparent tube baited with food. Its extraction requires the monkey to place its forearm in contact with double-sided tape applied on the inner surface of the tube entrance. The “tube” method, successfully implemented with captive (N=23) and wild (N=21) capuchins, allowed us to obtain hair bulbs from most individuals and usable genomic DNA was extracted even from a single bulb

Contextualised behavioural measurements of personality differences obtained in behavioural tests and social observations in adult capuchin monkeys (Cebus apella)

We applied a new framework for behavioural research on personality differences in 26 adult tufted capuchin monkeys. Using the Behavioural Repertoire x Environmental Situations Approach, we generated systematically 20 non-lexical emic personality constructs that have high ecological validity for this species. For construct operationalisation, we obtained 146 contextualised behavioural measures repeatedly in 15 experimental situations and 2 group situations using computerised and video-assisted methods. A complete repetition after a 2–3-week break within a 60-day period yielded significant test–retest reliability from individual-oriented and variable-oriented viewpoints at different levels of aggregation. In accordance with well-established findings on cross-situational consistency, internal consistency was only moderate. This new and important finding highlights fundamental differences between behavioural approaches and judgment-based approaches to personality differences

Lack of prosociality in great apes, capuchin monkeys and spider monkeys : convergent evidence from two different food distribution tasks

This work was conducted while the first author held a Humboldt Research Fellowship for Postdoctoral Researchers (Humboldt ID no. 1138999).Prosociality can be defined as any behaviour performed to alleviate the needs of others or to improve their welfare. Prosociality has probably played an essential role in the evolution of cooperative behaviour and several studies have already investigated it in primates to understand the evolutionary origins of human prosociality. Two main tasks have been used to test prosociality in a food context. In the Platforms task, subjects can prosocially provide food to a partner by selecting a prosocial platform over a selfish one. In the Tokens task, subjects can prosocially provide food to a partner by selecting a prosocial token over a selfish one. As these tasks have provided mixed results, we used both tasks to test prosociality in great apes, capuchin monkeys and spider monkeys. Our results provided no compelling evidence of prosociality in a food context in any of the species tested. Additionally, our study revealed serious limitations of the Tokens task as it has been previously used. These results highlight the importance of controlling for confounding variables and of using multiple tasks to address inconsistencies present in the literature.PostprintPeer reviewe

Neonatal Imitation in Rhesus Macaques

The emergence of social behaviors early in life is likely crucial for the development of mother–infant relationships. Some of these behaviors, such as the capacity of neonates to imitate adult facial movements, were previously thought to be limited to humans and perhaps the ape lineage. Here we report the behavioral responses of infant rhesus macaques (Macaca mulatta) to the following human facial and hand gestures: lip smacking, tongue protrusion, mouth opening, hand opening, and opening and closing of eyes (control condition). In the third day of life, infant macaques imitate lip smacking and tongue protrusion. On the first day of life, the model's mouth openings elicited a similar matched behavior (lip smacking) in the infants. These imitative responses are present at an early stage of development, but they are apparently confined to a narrow temporal window. Because lip smacking is a core gesture in face-to-face interactions in macaques, neonatal imitation may serve to tune infants' affiliative responses to the social world. Our findings provide a quantitative description of neonatal imitation in a nonhuman primate species and suggest that these imitative capacities, contrary to what was previously thought, are not unique to the ape and human lineage. We suggest that their evolutionary origins may be traced to affiliative gestures with communicative functions

Artifact and Artifact Categorization: Comparing Humans and Capuchin Monkeys

International audienceWe aim to show that far-related primates like humans and the capuchin monkeys show interesting correspondences in terms of artifact characterization and categorization. We investigate this issue by using a philosophically-inspired definition of physical artifact which, developed for human artifacts, turns out to be applicable for cross-species comparison. In this approach an artifact is created when an entity is intentionally selected and some capacities attributed to it (often characterizing a purpose). Behavioral studies suggest that this notion of artifact is not specific to the human kind. On the basis of the results of a series of field observations and experiments on wild capuchin monkeys that routinely use stone hammers and anvils, we show that the notions of intentional selection and attributed capacity appear to be at play in capuchins as well. The study also suggests that functional criteria and contextualization play a fundamental role in terms of artifact recognition and categorization in nonhuman primates

Exploration and learning in capuchin monkeys (Sapajus spp.): the role of action-outcome contingencies

Animals have a strong propensity to explore the environment. Spontaneous exploration has a great biological significance since it allows animals to discover and learn the relation between specific behaviours and their consequences. The role of the contingency between action and outcome for learning has been mainly investigated in instrumental learning settings and much less in free exploration contexts. We tested 16 capuchin monkeys (Sapajus spp.) with a mechatronic platform that allowed complex modules to be manipulated and to produce different outcomes. Experimental subjects could manipulate the modules and discover the contingencies between their own specific actions and the outcomes produced (i.e., the opening and lighting of a box). By contrast, Control subjects could operate on the modules, but the outcomes experienced were those performed by their paired Experimental subjects (\u27\u27yoked-control\u27\u27 paradigm). In the exploration phase, in which no food reward was present, Experimental subjects spent more time on the board and manipulated the modules more than Yoked subjects. Experimental subjects outperformed Yoked subjects in the following test phase, where success required recalling the effective action so to open the box, now baited with food. These findings demonstrate that the opportunity to experience action-outcome contingencies in the absence of extrinsic rewards promotes capuchins\u27 exploration and facilitates learning processes. Thus, this intrinsically motivated learning represents a powerful mechanism allowing the acquisition of skills and cognitive competence that the individual can later exploit for adaptive purposes