The Effects of Prey Species and Prey Elevation on Caudal Luring in Neonate Pigmy Rattlesnakes (Sistrurus miliarius)
Farrell, Terence M.
Korotasz, Alexis M.
Department of Biology
DeLand, FL USA
Lind, Craig M.
Department of Natural Science and Mathematics
Galloway, NJ USA
The caudal motions involved in prey luring vary both among and within snake species and we have little understanding of this variation. We performed experiments with naïve neonates to investigate plasticity in luring behavior. In 2015 and 2016 we captured 20-22 gravid female pigmy rattlesnakes and held them in field enclosures until parturition. We placed neonates into experimental arenas after their first ecdysis and let them acclimate for 24-48 hours. In 2015 we exposed 60 neonates to either a live lizard (Anolis carolinensis) or live frog (Hyla squirella) tethered to a perch 20 cm above the arena substrate. We recorded the foraging behavior of each snake for 15 minutes and analyzed the videos for caudal luring, luring latency, luring persistence, and luring amplitude (the arc over which the tail was moved). Luring occurred in 39% of frog trials and 38% of lizard trials. There were no significant effects of prey species on luring amplitude or persistence. In 2016 we examined whether caudal luring was dependent on the perch elevation of green tree frogs (Hyla cinerea). We presented 55 neonates with a frog tethered at either a high (20 cm above the substrate) or low (0 cm) elevation perch. Each snake was exposed to both elevation treatments in random order with 24 hours between trials. We found that the proportion of snakes luring was not significantly related to prey elevation, nor was there a significant effect of prey elevation on any measure of luring motion. Our results indicate that variation in both luring frequency and motion was not dependent on prey elevation or prey species. Sistrurus miliarius may display less phenotypic plasticity in luring behaviors than that observed in other well-studied species of snakes.