Effect of refuge distance on escape behavior of side-blotched lizards (Uta stansburiana)

Abstract

Side-blotched lizards ( Uta stansburiana Baird and Girard, 1852) use sagebrush desert habitat above cliffs and typically flee over and down the nearest cliff when disturbed. We tested antipredator escape tactics of lizards to a common local snake, the western yellowbelly racer ( Coluber mormon Baird and Girard, 1852). Our goal was to determine if lizards use cliffs as a refuge from snakes, which cannot climb the sheer rock face, and whether distance to refuge affects escape behavior. We located undisturbed lizards above a cliff and approached them from a random direction with a realistic rubber snake model. When the snake model approached, lizards fled nonrandomly toward the nearest cliff refuge, indicating considerable spatial awareness. Lizards fled more directly toward the cliff the farther from the cliff they were found. However, when beyond ~15 m from the cliff the escape behavior of lizards changed to one of flight in circles (nondirectional) without hiding. Performance capacity (endurance) of the lizards is much greater than 15 m, indicating that lizards have the physiological capacity to reach the cliff. We suggest that the costs of potential intraspecific interactions (i.e., escape into unfamiliar or a competitor’s territory) are greater than the immediate risks of predation by snakes.