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Personality of rhesus monkeys has influence on happiness and welfare

29.04.2021: We know from studies on humans that individual differences in who you are, your very personality, are related to your happiness and well-being. But what about animals? If we can understand how differences in animal personality are related to their happiness and welfare, then maybe we can use this to improve both. With this goal in mind, an international research team led by Vetmeduni devised performed a study, recently published in Applied Animal Behaviour Science, looking at rhesus monkeys (Macaca mulatta) and found that their happiness and welfare are directly linked to their personality. The research also demonstrates that the people that know and care for animals can rate their happiness and welfare, making it possible to use their expertise and knowledge as a cost-effective and valid way to track animal welfare.

The study tested the extent to which an animal’s welfare is related to individual differences in personality using 44 rhesus monkeys living at the California National Primate Research Center. The researchers used a 16-item welfare questionnaire, a 4-item subjective well-being questionnaire, and a 54-item personality questionnaire, the last of which was used to define each macaque’s standing on six personality domains that had been identified in a previous study: confidence, openness, dominance, friendliness, activity, and anxiety.

Measures of behaviour were obtained using focal-animal sampling, an observational method in behavioural research that records the actions and interactions of one particular animal (the focal animal). “We found evidence of agreement for all the welfare items, all but one item from the subjective well-being questionnaire and all but four items from the personality questionnaire,” says first author Lauren M. Robinson from the Konrad Lorenz Institute of Ethology at Vetmeduni.

Animal welfare: observer ratings a valid method

Using principal-component analysis, a multivariate statistical technique used to structure, simplify, and illustrate large datasets, the researchers found that the results on welfare and subjective well-being could be loaded together onto a single component. Macaques that scored higher in this dimension experienced less aggression, engaged in fewer displacement activities such as scratching and were rated higher in confidence, openness, dominance and friendliness.

Affordable and relatively simple methodology

“The results of our study are consistent with reports on chimpanzees and brown capuchin monkeys and provide further evidence that observer ratings are based on objectively observable behavioural states, suggesting them to be a psychometrically valid method for assessing primate welfare,” Robinson points out. This finding is significant because observer ratings are a relatively simple and inexpensive assessment method. Observer ratings have been used to assess animal welfare for only a few years, which makes the validation of this method an important confirmation of its usefulness. The more we know about how differences in animal personality relate to well-being and welfare, the better we can work to individualize their care and hopefully further improve their quality of life.

The article “Happiness, welfare, and personality in rhesus macaques (Macaca mulatta)” by Lauren M. Robinson, Natalie K. Waran, Ian Handel and Matthew C. Leach was published in Applied Animal Behaviour Science.