Evidence of lingual-luring by an aquatic snake

We describe and quantify the components of an unusual snake behavior used t o attract fish prey: lingual-luring. Our earlier research on the foraging b ehavior of the Pacific Coast aquatic garter snake (Thamnophis atratus) indi cated that adults are active foragers, feeding primarily on aquatic Pacific giant salamanders (Dicamptodon tenebrosus) in streambed substrates. Juveni le snakes, however, use primarily ambush tactics to capture larval anurans and juvenile salmonids along stream margins, behaviors that include the lin gual-luring described here. We found that lingual-luring differed from typi cal chemosensory tongue-flicking by the position of the snake, contact of t he tongue with the water surface, and the length of time the tongue was ext ended. Luring snakes are in ambush position and extend and hold their tongu es out rigid, with the tongue-tips quivering on the water surface, apparent ly mimicking insects in order to draw young fish within striking range. Thi s behavior is a novel adaptation of the tongue-vomeronasal system by a visu ally-oriented predator.