Meeting Abstract

S5-3   10:00 - 10:30  In the water, on the water, out of the water: context-dependent tongue-flicking mechanics in watersnakes. Ryerson, WG*; Schwenk, K; Saint Anselm College, Manchester, NH; University of Connecticut, Storrs, CT wryerson@anselm.edu http://ryersonalab.wordpress.com

When considering animals moving between environments, the focus is primarily on the mechanics of the movement in an evolutionary context. However, there are many taxa that move through these environments on a daily basis. Transitioning between environments affects more than the classic examples of locomotion and feeding. As an individual transitions between environments, the changes they experience will also include how they perceive their new environment. We used the northern watersnake (Nerodia sipedon) to examine how tongue-flicking mechanics change in response to individuals moving through different environments. Oscillatory tongue-flicking in snakes is known to deliver chemical cues to the vomeronasal system, and has been used for many years as a behavioral metric in snake sensory ecology. We measured the kinematics of tongue-flicking in watersnakes in three different habitats: terrestrially, aquatic, and at the surface of the water. On land, tongue-flicks average 7 oscillations per tongue-flick bout, while under water the average bout averages only 3 oscillations. Velocity, distance of protrusion, and area covered are all higher on land than in water. The individual tines, which are rigid and rotate during a tongue-flicking bout on land, are more flexible in water, likely due to the high viscosity and density of water. In a separate set of mesocosm experiments, we observed several individuals employing a modified tongue-flick. These individuals would not employ full oscillatory tongue-flicks, but used what we are calling “surface taps”. The tines remain pointed downward throughout the entire bout, tapping the surface of the water. We only observed this behavior in adult watersnakes, and hypothesize that this behavior is to optimize of detection of prey (frogs) and potential mates.