Meeting Abstract
P2.12 Jan. 5 Behavioral Responses Of Lizards To A Snake Predator: What To Do When Far From Safety ZANI, P.A.*; JONES, T.D.; NEUHAUS, R.A.; MILGROM, J.E.; Hamilton College, Central College; Central College; Central College; Hamilton College pzani@hamilton.edu
Side-blotched lizards (Uta stansburiana) use sagebrush-desert habitat above cliffs and often flee over and down the nearest cliff when disturbed. We conducted field experiments to test the responses of lizards to potential predation by a common local snake, the yellow-bellied racer (Coluber constrictor). Our goal was to determine if lizards use cliffs as a refuge from snakes, which cannot climb the sheer rock face. During the 2006 breeding season in eastern Oregon (May�June), we located 104 undisturbed lizards above a cliff (cliff distance = 11.1 � 0.7 m [avg. � S.E.M.]; min.�max. = 1.4�47.4 m) and approached them from a random direction with a rubber snake model. We found no differences in responses between the sexes (P�s > 0.11) and so pooled data for males and females. When the snake model approached to within 0.23 � 0.04 m (0.01�1.95 m), lizards fled 2.36 � 0.28 m (0.1�19.4 m), at a rate of 1.52 � 0.07 m/s (0.14�3.67 m/s), and significantly toward the nearest cliff (V test for circular uniformity: u = 6.58; P < 0.001). Furthermore, lizards fled more directly toward the cliff the farther from the cliff they were found, up to ~15 m (angular-linear correlation: r = 0.53; P = 0.03). However, beyond ~15 m lizards were less likely to flee toward the cliff and more likely to flee in circles (F1, 37 = 41.7; P < 0.001), relying on greater flight distances (F1, 69 = 6.7; P = 0.01) and appearing to use crypsis to escape detection (pers. obs.). This distance (15 m) is very close to the minimum individual endurance capacity for this lizard population based on concurrent treadmill trials. Thus, lizards apparently use a cliff as a refuge when it is close, but rely on other methods to escape when the cliff is farther away, possibly minimizing the risk of exhaustion.
