Disentangling Anthropogenic Stimuli: Visual and Acoustic Components Differentially Impact Captive Pied Tamarin Behaviour

Anthropogenic activity is increasingly disturbing wildlife, leading to negative impacts on species welfare and conservation. Despite this, very few studies have investigated how the different components of anthropogenic activity (including visual, acoustic, or other components differentially affect animals. Such studies are important to better understand what animals may perceive as aversive in order to improve, not only captive management and welfare, but also improve wild management. This study aimed to disentangle the impacts of the visual and acoustic components of two different anthropogenic stimuli (zoo visitors and construction activity) on the critically endangered pied tamarin (Saguinus bicolor). We exposed 12 pair-housed pied tamarins at Jersey Zoo to either no stimuli (baseline), individual components (visual or acoustic stimuli only), or combinations of components (54 trials in total). We found that pied tamarins varied in their responses to the two different stimuli and to their different components, especially when presented in isolation. Visitor visual and visitor acoustic components presented in isolation led to increased vigilance. The combined presentation of visitor components weakened responses, indicating that simultaneous exposure to visual and auditory cues may provide more perceptual context to the primates. In contrast, construction noise caused a significant decrease in environmental engagement (indicated by decreased foraging and increased retreat behaviour). These findings emphasize the importance of understanding how animals respond to different sensory components of stimuli to improve captive management practices, enhance welfare, and ultimately help the conservation of endangered species.