Author:

Abstract:

Zoo enclosure designers should aim to offer behavioural opportunities that allow animals to enhance their quality of life. This can be achieved through a “behavioural engineering approach” in which artificial devices can be used, or through the “naturalistic approach” in which the wild environment is mimicked maximally. We hypothesized that the visitors’ perception of the animals’ happiness or wellbeing is influenced by enclosure design. In an online query, we showed pictures of natural versus unnatural looking enclosures for bonobos and we asked to score happiness on a 7-point scale, following an existing 4 item questionnaire, used to score subjective wellbeing in apes. A linear mixed model was applied with individual score as response value, respondent ID as random effect and enclosure type (natural or unnatural) as fixed effect. Respondents gave a significantly higher happiness score to more natural enclosures (df=1, p<0.0001). In more natural enclosures, they thought the bonobos would experience positive emotions during a longer period (df=1; p<0.0001), they gave a higher score to the degree in which they estimated the animals to be successful at fulfilling their needs (df=1; df=0.0001), and they thought they themselves would be happier if they were the animal during one week in that enclosure (df=1, p<0.0001). For each of the four questions, all nine pairwise comparisons of natural versus unnatural enclosures showed that the differences were significant (df=200, p<0.00001) for happiness score, duration of happiness, and happiness if the respondent would be the animal. Similarly, all pairwise comparisons differed significantly for ‘efficiency to fulfil their needs’, except for the comparison of the pictures of a natural but relatively empty grassy area and an unnatural indoor enclosure with climbing structures (df=200, p<0.351), indicating a rough understanding of great apes’ climbing needs. Overall, people feel that naturalistic looking enclosures make bonobos happier. Whether their behavioural and psychological needs are met more efficiently in naturalistic enclosures needs to be assessed separately.