Happiness, welfare, and personality in rhesus macaques (Macaca mulatta)

Towards an Integrated Concept of Personality in Human and Nonhuman Animals

Every individual has an idiosyncratic way of feeling, thinking and behaving, which is relatively stable across time and situations. Usually known as Personality, today this phenomenon is recognized in many species, including arthropods, fish, avian or mammals. From an evolutionary perspective, research has shown that personality differences are manifest in distinctive forms of dealing with selective pressures, with consequences for fitness. Despite these facts, the study of personality in animals other than humans is relatively new. Only two decades ago, consistent behavioral individual differences were considered 'noise' around an optimal strategy for behavioral ecologists. Also, psychologists were not interested in animal personality as a consequence of the fear of anthropomorphization and the erroneous belief that humans are unique in nature. Fortunately, this misconception seems already overcome but there are still conceptual issues preventing a unified concept of personality. Throughout this review, we first explore the etymological origins of personality and other terminological issues. We further revise the historical course of the study of personality in humans and other animals, from the perspectives of Psychology and Behavioral Ecology, on the basis of the most used approach, the trait theory. We present the study of nonhuman primates as a paradigmatic example in between both frameworks. Finally, we discuss about the necessity of a unified science of personality.

Differing animal welfare conceptions and what they mean for the future of zoos and aquariums, insights from an animal welfare audit

Animal welfare is a growing public concern that has the potential to undermine the social license of zoos and aquariums. The lack of consensus on how animal welfare is defined across such a diverse sector combined with and a widespread belief that commercial priorities such as entertaining visitors conflicts with animal welfare, hinders efforts to effectively address this fundamental issue for the sector. Data derived from an audit of habitats across a major North American wildlife attraction revealed that holistic animal welfare assessments undertaken by animal carers embracing three principal constructs of animal welfare, correlated strongly with visitor perceptions of animal happiness. Visitor assessments of animal happiness also correlated with animal carer assessments of social, behavioural and locomotor opportunities and inversely with the prevalence of stereotypic behaviours, supporting the proposition that folk conceptions of animal welfare are more accurate than may have previously been considered to be the case. However, the holistic animal welfare assessment inversely correlated with assessments of a habitat's capacity to safeguard welfare as determined by the facility's veterinary staff, supporting the proposition that tensions exist between physical and psychological components of captive animal welfare provisioning. This further underlines the importance of clarity on how animal welfare is conceived when developing institutional animal welfare strategies. Finally, the data also showed that both holistic animal welfare assessments and visitor perceptions of animal happiness strongly correlated with the level of enjoyment experienced by visitors, challenging the belief that animal welfare competes with the commercial priorities of zoos and aquariums. The audit supports the case that maintaining high animal welfare is a commercial imperative as well as a moral obligation for zoos and aquariums and underlines the necessity to utilize conceptions of animal welfare that acknowledge the centrality of the affective states of animals in maintaining those standards.

Using a behaviour random permutation model to identify displacement grooming in ungulates

Behaviour affects an individual’s life in all aspects, e.g., enhancing fitness, leveraging predation risk, and reducing competition with conspecifics. However, the sequential distribution of behaviours received less attention and is unclear what the function of displacement behaviour is. Displacement activities can be found in vertebrate species but there is no formal method to determine whether a behaviour is expressed as a displaced or normal activity. Analysing the sequential distributions of behaviours in a natural setting may allow researchers to identify unexpected distributions as a possible signature of displacement activities. In this study, we used a behaviour random permutation model to detect the presence of a displacement activity in the Tibetan antelope Pantholops hodgsonii and the Tibetan gazelle Procapra picticaudata. The results showed that grooming in both ungulates tended to be accompanied with vigilance, and the frequency of grooming after vigilance was significantly higher than before vigilance. A significant positive correlation between the scan rate and grooming rate in the two ungulates was obtained. We suggest that grooming could sometimes be expressed as a displacement activity in ungulates. In addition to providing a general method for further research on displacement activities in a variety of animal species, this study sheds light on the importance of a spectral analysis of sequential distribution of animal behaviours. Behaviour random permutation models can be used to explore the relevance between any two behaviours in a specific sequence, especially to identify a myriad of unexpected behaviours relative to their normal context of occurrence.

The relationship between personality, season, and wounding receipt in zoo-housed Japanese macaques (Macaca fuscata): A multi-institutional study

It is important to those managing Japanese macaques (Macaca fuscata) in captive settings to understand predictors of wounding. While studies have demonstrated that season (breeding or nonbreeding) and sex predict rates of wounding received by zoo-housed Japanese macaques, we investigated whether individual differences in personality ratings also might explain some of the observed interindividual variance in wounding. Such patterns were previously observed in rhesus macaques (M. mulatta), such that individuals rated higher on Anxiety and Confidence received greater wounding. Here, we collected wounding data over 24 months on 48 Japanese macaques from eight AZA-accredited zoos. Each macaque was also rated by keepers using a 26-item personality questionnaire. Principle components analysis of these ratings revealed four personality components: Openness, Friendliness, Dominance, and Anxiety/Reactivity. The model with the best fit revealed an interaction effect between season (breeding vs. nonbreeding) and the personality component Friendliness, such that individuals rated higher on Friendliness incurred fewer wounds in the nonbreeding season. The second-best model revealed both a main effect of the season as well as an interaction effect between season and Openness, such that macaques rated higher in Openness received more wounds in the nonbreeding season than those rated lower in Openness. Thus, as with rhesus macaques, personality mediated wounding receipt rate in Japanese macaques, although different personality components explained interindividual variance in wounding for these two species. These differences likely reflect species differences in behavior and personality structure, as well as the influence of differing management practices, highlighting the importance of species-specific approaches for captive primate care and welfare. This study provides further support for understanding primate personality to create individualized strategies for their care.