Common marmosets (Callithrix jacchus) weigh up potential risk when faced with conflicting motivations

Abstract

Animals face a myriad of stimuli requiring responses; however, the appropriate behavioural response to one stimulus may be inappropriate to another, conflicting stimulus. In the case of predatory stimuli, the appropriate response may be determined by the perceived degree of potential risk of predation. However, food is often used as a way to measure response to the predatory cue, rather than considered as having an attractant effect. To understand how risk is perceived when a conflicting motivation is present, we exposed captive common marmosets (Callithrix jacchus) to visual and auditory stimuli pertaining to a predator (visual and auditory) and food (visual only), individually and simultaneously. The behaviour measured (distance, latency to retrieve food, vocalisations) was as important in understanding how the marmosets perceived risk as the type and combination of stimuli presented. The presence of food was a strong attractant, with the marmosets demonstrating willingness to approach even though a potential predator was nearby. However, the marmosets responded more cautiously when the visual and auditory predator cues were presented simultaneously with the food.

These results demonstrate that 1) marmosets alter their responses to conflicting stimuli rather than prioritising one over the other, 2) there is a need to measure multiple behavioural responses to stimuli, 3) food can be a strong attractant, which may skew the results of predator avoidance studies, and 4) marmosets perceive the combination of visual and auditory cues of a potential predator to be a greater threat than either alone. This has consequences for conservation programs training captive-bred animals to avoid predators.