Facilities housing captive animals are full of staff who, every day, interact with the animals under their care. The expertise and familiarity of staff can be used to monitor animal welfare by means of questionnaires. It was the goal of our study to examine the association between chimpanzee (Pan troglodytes) welfare, happiness, and personality. To these ends we collected two waves of welfare and subjective well-being ratings of 18 chimpanzees housed at the Edinburgh Zoo and one set of ratings of 13 chimpanzees housed at Fundació Mona. Ratings were made on a welfare questionnaire that included 12 items related to stress, psychological stimulation, and behavioural indicators of negative and positive welfare states, and a 4-item subjective well-being questionnaire. In addition, ratings were made on the 54-item Hominoid Personality Questionnaire and an abbreviated version of this scale consisting of 37 antonym pairs. We used generalizability theory to test whether welfare ratings generalized across items, raters, chimpanzees, and time. We then assessed the validity of the welfare and subjective well-being questionnaires by examining their associations with behaviour. Finally, we tested whether the welfare and subjective well-being ratings were associated with personality. Welfare ratings generalized across items, raters, chimpanzees, and time. Principal components analysis and regularized exploratory factor analysis indicated that ten welfare items and all four subjective well-being items formed a single dimension (welfareSWB).LASSO regression found that lower welfareSWB was associated with regurgitation, coprophagy, urophagy, and decreased proximity to nearest neighbour. A linear model that adjusted for age, sex, and facility, indicated that higher Extraversion and lower Neuroticism were related to higher welfareSWB. Welfare ratings were reliable and associated with subjective well-being and personality, demonstrating that staff ratings are a valid and potentially valuable tool for chimpanzee welfare assessment.

We evaluate a sanctuary chimpanzee sample (N = 11) using two adapted human assessment instruments: the Five-Factor Model (FFM) and Eysenck's PsychoticismExtraversion-Neuroticism (PEN) model. The former has been widely used in studies of animal personality, whereas the latter has never been used to assess chimpanzees. We asked familiar keepers and scientists (N = 28) to rate 38 (FFM) and 12 (PEN) personality items. The personality surveys showed reliability in all of the items for both instruments. These were then analyzed in a principal component analysis and a regularized exploratory factor analysis, which revealed four and three components, respectively. The results indicate that both questionnaires show a clear factor structure, with characteristic factors not just for the species, but also for the sample type. However, due to its brevity, the PEN may be more suitable for assessing personality in a sanctuary, where employees do not have much time to devote to the evaluation process. In summary, both models are sensitive enough to evaluate the personality of a group of chimpanzees housed in a sanctuary.

More data are needed for a better understanding of the long‐term influence of wider and combined stressful events in chimpanzee personality development. We evaluated the effects of bushmeat trade outcomes on the personality development in 84 African sanctuary chimpanzees. The chimpanzees presented different backgrounds regarding maternal care, social exposure, and abuse. We evaluated personality traits in chimpanzees using the Cattell 16PF personality questionnaire, the first application of this questionnaire in this species. We found that chimpanzees were rated as higher in anxiety after long social deprivation during infancy and juvenility, and if high human exposure was experienced. Mother‐reared chimpanzees were rated as lower in restraint than hand‐reared chimpanzees. Finally, mother‐reared chimpanzees were rated as less dominant than hand‐reared chimpanzees and rated higher when they had experienced severe mistreatment. Results suggest a wide range of possible stressful events could be potentially shaping rescued chimpanzees’ personality and demonstrating the detrimental outcomes and consequences of the bushmeat and pet trade.

The comparative study of animal personality has received great interest in recent years. Some studies have analyzed personalities in cetaceans (exclusively in dolphins), but none have analyzed the factorial structure of personality of any species in this order. Our objective was to evaluate a sample of captive killer whales (n = 24) adapting one of the most widely used models of personality in humans and nonhuman animals: the five-factor model. A total of 38 personality descriptive adjectives were rated by 55 raters (mainly trainers and curators). Principal components analysis and regularized exploratory factor analysis revealed four statistically significant factors with acceptable standards of interrater reliability and validity, accounting for 49.85% of the variance. The first factor indicated an Extraversion factor, the second one revealed a combined factor of Conscientiousness and Agreeableness, the third one yielded in a Dominance factor, and the fourth one reflected a Careful factor very close to a combination of Conscientiousness and Agreeableness factor. The results were compared with the results obtained for humans and chimpanzees in prior studies. The similarities could be explained as a result of convergent adaptive traits despite a deep evolutionary divergence, adaptation to physically dissimilar environments, and very different neuroanatomical organization.

Personality has been linked to individual variation in interest and performance in cognitive tasks. Nevertheless, this relationship is still poorly understood and has rarely been considered in animal cognition research. Here, we investigated the association between personality and interest, motivation and task performance in 13 sanctuary chimpanzees (Pan troglodytes) housed at Fundació Mona (Spain). Personality was assessed with a 12-item questionnaire based on Eysenck’s Psychoticism-Extraversion-Neuroticism model completed by familiar keepers and researchers. Additionally, personality ratings were compared to behavioral observations conducted over an 11-year period. Experimental tasks consisted in several puzzle boxes that needed to be manipulated in order to obtain a food reward. Dependent variables included participation (as an indicator of interest), success and latency (as measures of performance), and losing contact with the task (as an indicator of motivation). As predicted, we obtained significant correlations between Eysenck’s personality traits and observed behaviors, although some expected associations were absent. We then analyzed data using Generalized Linear Mixed Models, running a model for each dependent variable. In both sexes, lower Extraversion and lower Dominance were linked to a higher probability of success, but this effect was stronger in females. Furthermore, higher Neuropsychoticism predicted higher probability of success in females, but not in males. The probability of losing contact with the task was higher in young chimpanzees, and in those rated lower on Extraversion and higher on Dominance. Additionally, chimpanzees rated higher on Neuropsychoticism were also more likely to stop interacting with the task, but again this was more evident in females. Participation and latency were not linked to any personality trait. Our findings show that the PEN may be a good model to describe chimpanzee personality, and stress the importance of considering personality when interpreting the results of cognitive research in non-human primates.

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Research on felid personality has been conducted in a few species. Further research on new species could be highly informative in regard to the influence that adaptation to different ecological challenges has on felid personality. We evaluated the personality of 58 Iberian lynxes (Lynx pardinus) hosted at 3 different breeding centers for reintroduction. A total of 43 adjectives obtained from previous studies with felids were assessed by 30 raters according to the knowledge on the lynx behavior they acquired by observing a live video feed of the animals, finding acceptable standards of interrater reliability. Principal components analysis and regularized exploratory factor analysis revealed 4 factors. Based on the pattern of factor loadings and on previous labeling in felid personality research, we labeled the factors as Boldness, Dominance, Neuroticism, and Attentiveness. The results were similar to that of the previous studies on felids, although some differences were found, which could be due to the evolutionary distance among species and to methodological differences among studies. Future research on endangered felids could provide insights into the influence of personality on conservation outcomes related to successful breeding and reintroduction.

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