Thermal Dependencies of Different Modes of Locomotion in Neonate Brown Snakes, Storeria Dekayi

Abstract

Snakes are capable of moving in one of several ways depending on the substrate and medium being traversed. The locomotor velocities of neonate Brown Snakes (Storeria dekayi) during two modes of terrestrial locomotion (lateral undulation and concertina) and swimming were assessed at 10, 20, and 30 C. At all three temperatures, the fastest velocities were recorded during swimming while the slowest were recorded during concertina locomotion. Velocities of all three modes increased significantly with temperature but Q10 values differed greatly among locomotor modes indicating that the influence of temperature on velocity was mode dependent. Body length of neonates had no significant influence on velocities attained via any locomotor mode at any temperature. Neonate snakes displayed similar, but slightly lower, body length–relative velocities of terrestrial undulation and swimming compared to other snake species tested at the same temperatures. Previous studies have suggested that a trade-off exists between adaptations for aquatic and terrestrial locomotion in snakes, thereby suggesting that individuals that are fast swimmers will be slower on land and vice versa. In contrast to this prediction, significant positive correlations were detected between terrestrial and aquatic lateral undulation at 30 C, meaning that individuals that crawled faster via undulation on land were also faster swimmers. Future studies should relate performance via different modes of limbless locomotion to the actual use of these modes in nature.