Meeting Abstract
Environmental temperatures dictate ectotherm body temperatures (Tb) which has consequences regarding behavioral and physiological processes. Crawling speed is very important to the black racer (Coluber constrictor), given that it uses this behavior to chase down prey and outrun potential predators. To measure the effect of temperature on C. constrictor crawling speed, we conducted thermal performance trials on 17 individuals. We manipulated snake Tbs to specific test temperatures (10, 20, 30, 35, 37.5 °C) and then raced each individual down a straight track. We video recorded each trial and measured the forward velocity of each snake using Tracker Video Analysis software. Snakes performed better at 35 °C then they did at lower Tbs. We determined the thermal performance breadth (B80) to be between 29.1 – 37.7 °C. However, during performance trials, we observed differences with regard to snake kinematics. We further analyzed each trial video using the Tracker Video Analysis software to determine the kinematic properties of each snake at each test temperature. These kinematic properties were then compared to the set properties of each mode of snake locomotion as described by Jayne (1985). When Tbs were within the B80 range, snakes were able to use lateral undulation. However, at low Tbs snakes were constrained to using concertina locomotion and at 20 °C snakes appeared to be transitioning between the two types of locomotion. Thus, our thermal performance curve for “locomotion” was actually comparing two very different modes of locomotion, and not necessarily the same behavior. Future research on snake thermal performance curves should account for thermal effects on kinematics and mode of locomotion.
