The influence of guided tours on the welfare of white-handed gibbons and capuchin monkeys at Maia Zoo

Zoo animals are regularly exposed to a plethora of sensorial stimuli beyond their control, which can adversely impact their behaviour and welfare, including unfamiliar faces, excessive noise and intrusive visitor interaction. Zoos have implemented various measures, such as enrichments and regulation of visitor behaviour, to mitigate these effects. However, guided tours have not been used to simultaneously control visitor behaviour and maintain animal welfare. In this study, we investigated how visitors influence the behaviour of two non-human primate species: white-handed gibbons (Hylobates lar) and capuchin monkeys (Sapajus apella), by observing primate behaviour and visitor noise and behaviour under guided and self-guided tour conditions. The main focus was to assess visitor impact on animal welfare and investigate whether guided tours helped regulate visitors’ unwanted noise and behaviour. Observational data on several behaviours were obtained through instantaneous sampling intervals lasting 15-minutes each. Results indicate that in the gibbons’ enclosure, guided tours, compared to self-guided tours, were associated with lower noise levels (mean reduction of 3.0 dB) and reduced self-grooming frequencies. Conversely, capuchin monkeys exhibited similar behavioural responses between tour types, likely influenced by the presence of an infant born during the study. Although results varied, they suggest guided tours might be associated to reduced visitor noise and may provide a familiar presence for the animals, due to the presence of a guide, which could potentially influence welfare outcomes. However, evidence of enhanced welfare remains inconclusive. Furthermore, integrating guided tours as educational and conservation initiatives could effectively engage visitors and ensure zoo animal welfare.