Juvenile Collared Lizards Adjust Tail Display Frequency in Response to Variable Predatory Threat

Antipredator behavioral tactics have evolved in phylogenetically diverse animal clades and often involve prey initiating conspicuous display patterns when encountering potential predators. Using detailed behavioral observations in the field, we report the first description of conspicuous tail displays in juvenile collared lizards ( Crotaphytus collaris ), a species that does not have tail autotomy. When approached in the field, lizards gave four stereotypical displays involving the tail, suggesting that these might function as antipredator signals. To test this hypothesis, we compared the frequency of tail displays given by juveniles during approach experiments relative to control trials involving observation from afar. We then further manipulated the intensity (low threat, high threat) with which we threatened lizards by varying our angle of approach relative to the body‐axis orientation of lizards resting on a perch sloping away from the observer. Our results show that juveniles consistently performed all four types of tail displays in response to our approaches, but subjects never displayed during non‐threat control trials. Moreover, lizards were more likely to remain emergent and give tail displays when we approached them head‐on with their bodies sloping away (low threat), but were more likely to take refuge when approached from the side and behind (high threat). The positive relationship between the frequency of display and risk level suggests that tail displays function to signal that juvenile lizards have detected potential predators, which may deter further pursuit. Together, our results provide the first account of visual displays involving the tail in collared lizards and suggest that these displays function to signal potential predators.