Meeting Abstract
91.9 Wednesday, Jan. 7 Physiological and Behavioral Adaptations of the Ribbonsnake (Thamnophis sauritus) to Cold Climates AMIEL, J.J.*; WASSERSUG, R.J.; Dalhousie University, Halifax, Nova Scotia, Canada js448419@dal.ca
Temperate region snakes that encounter climatic extremes may have behavioral and physiological adaptations that allow them to thermoregulate well below their preferred body temperature. To explore this possibility we used infrared cameras to collect thermal data from ribbon snakes (Thamnophis sauritus) in Nova Scotia, where the species is at the northern limit of its range. At our field site T. sauritus have been found to be active at air temperatures below 10oC in the early spring, before all the snow has melted, and in the late fall, after the first snow fall of the season. Two experiments were performed. In the first we tested whether snakes at low ambient temperatures can restrict warm blood to their tails in order to conserve heat for vital organs. In the second experiment we examined whether snakes can perfuse warm blood throughout their bodies by exposing only their heads to direct light while keeping their bodies concealed. When the ambient air temperature is well below the snakes’ preferred active temperature they display significant temperature differentials between their bodies and tails. They warm their bodies but their tails remain cold. Snakes also appear to be able to create a thermal gradient along their bodies by exposing just their heads to direct light, and distributing warm blood from their heads to their unexposed bodies. We suggest that behaviors, such as this head-basking coupled with anatomical shunts and preferential perfusion of warm blood, allow these snakes to function at low environmental temperatures. These thermoregulatory processes challenge the widely held belief that reptiles, such as snakes, must be thermal conformers at low ambient temperatures.
