GERALD, G. W.*; CLAUSSEN, D. L.; Miami University, Oxford, OH; Miami University, Oxford, OH: Thermal influences on the velocity of neonate brown snakes (Storeria dekayi) during three different modes of locomotion

Studies investigating the locomotor performance of neonate animals are scarce. Compared to adults, the enhancement of a neonate�s locomotor performance should be under strong selection resulting from an elevated risk of predation. The absolute and relative locomotor speeds of 19 neonate brown snakes (Storeria dekayi) during swimming and two modes of terrestrial locomotion (lateral undulation and concertina) were assessed at 10, 20, and 30° C. At all 3 temperatures, the fastest velocities were recorded during swimming whereas the slowest were recorded during concertina locomotion. Although velocities for all 3 modes increased with increasing temperature, those recorded during concertina locomotion did so to a lesser extent than did the other two modes. Between 10-20° C, the Q₁₀�s of mean and maximum velocities for both terrestrial forms of locomotion ranged from 2.3-3.0 whereas the Q₁₀�s of swimming velocities were 1.7-1.9. Between 20-30° C, the Q₁₀�s of mean and maximum speeds of all 3 modes of locomotion were 1.1-1.3. Our results indicate that the effect of temperature on velocity in neonate S. dekayi is dependent upon the mode of locomotion being utilized. 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 slow crawlers. However, we found no evidence of negative correlations between aquatic and terrestrial speeds. In contrast, positive correlations were detected between velocities of swimming and lateral undulation suggesting that, at least for neonate brown snakes, adaptations for effective locomotion among different modes do not conflict with each other.