Meeting Abstract

53.2  Thursday, Jan. 6  Kinematics of tongue-flicking in garter snakes (Thamnophis sirtalis) RYERSON, W.G.*; SCHWENK, K.; Univ. of Connecticut; Univ. of Connecticut william.ryerson@uconn.edu

The forked tongue of snakes is used to gather environmental chemicals (odorants) and to deliver them to the vomeronasal organs in the roof of the mouth. Snakes use two methods to sample odor particles, often in combination: oscillatory tongue-flicking (TF) in the air and substrate-touching with the tongue tips. We used high-speed imaging to visualize TF of adult snakes in dorsal, lateral and anterior views. While variable within and among individuals, the general pattern of movement is consistent. As the tongue leaves the mouth, protrusion pauses while the tines spread and move dorsally above the head. Once the tines reach their apex, the tongue protrudes further as the tines swing ventrally below the head. Protrusion pauses again as the tines are again elevated and the process is repeated. The angle/distance between the tines varies depending on tongue position and direction of movement. Tines are furthest apart above the head, move closer together as the tongue swings down, separating again at the bottom of the arc. During the downstroke, the tines appear to maintain a 90 degree angle relative to the direction of movement. This pattern of movement has important implications for the fluid dynamics of air flow around the tongue and the mechanics of chemical sampling in snakes.