The cottonmouth is one of several species of venomous (poisonous) snakes in the United Sates. Although they use their venom primarily to obtain food, it also serves as an important defensive weapon. Dr. Hayes will investigate how cottonmouths use their venom when feeding, in particular whether or not they can control the quantities of venom they inject, and whether or not they inject more venom into larger prey. Perhaps more important, we need to understand how snakes use their venom when striking defensively. Because many human snakebite victims are fortunate to have received "dry" bites, with no apparent injection of venom, it is widely held that snakes attempt to conserve their venom supplies when biting defensively. However, experimental data are lacking. Thus, two experiments will be conducted to examine how cottonmouths use their venom when feeding on prey of different sizes and when striking defensively. From a biological perspective, this study should provide important insights into how the remarkable feeding and defensive adaptation of venomous snakes have evolved. It should also shed light on the biological roles and evolution of snake venom. Defensive bites in particular are of medical significance to humans. At present, physicians simply treat the symptoms of snakebite victims, with no knowledge of how much venom was injected. This research may provide important baseline data and techniques for future studies on how much venom snakes inject when biting humans.
