Blue‐tailed skinks have predation‐dependent threat discrimination

Abstract

AbstractThe extent to which prey respond to predation risk may depend upon the level of threat it perceives. A prey's perception of a threat can also be influenced by the background levels of predatory threat in the environment. Many animals also rely on visual cues to discriminate threat and assess risk. Eyes, in particular, are known to elicit an aversive response in prey. However, there is a lack of the literature about what salient physical features of a predator's gaze triggers aversion in prey, especially reptilian prey. We capitalized on the putatively aversive effects of eyes to better understand the influence of average background threat on risk perception. We approached blue‐tailed skinks (Emoia impar) with four different treatments: a blank control and three experimental treatments (two circular eyes, two squares, and one big circle) to test whether eye shape or number induced a greater aversive response in prey measured by the time allocated to key activities, as well as by flight initiation distance (FID) in locations of high and low background threat. Skinks discriminated more between treatments at low risk than in high risk situations by varying their behavior in response to treatments only in low‐risk scenarios, but this did not translate into differences in FID. Our results suggest that in high‐risk situations, the cost to discriminate is higher than at low risk. Although we can assume our treatments were not perceived as eyes due to a lack of discrimination toward the two circle treatment, detectability and more specifically diameter of stimuli are the most salient to skinks. While skinks are able to detect subtle differences in visual stimuli, this does not affect their overall fear response. Remarkably, skinks, a species not hunted by humans, have the ability to discriminate subtle features about them, a finding that is seen in other species and requires more study.