In a preliminary experiment, garter snakes were trained to follow earthwormextract trails in a multiple-choice maze and were subjected to either sham surgery (n = 4) or complete bilateral vomeronasal nerve transection (n = 4). Snakes with sham surgery trailed and ate at preoperative levels, whereas snakes lacking a functional vomeronasal system developed a feeding deficit and trailed at chance levels. In a second experiment, 16 snakes were preoperatively tested for their abilities to follow a battery of trails including a range of trail concentrations and two trail manipulations. After baseline testing, the snakes were subjected to sham surgery (n = 2), olfactory nerve transection (n = 7), or vomeronasal nerve transection (four partial; three complete). Snakes with vomeronasal nerve lesions demonstrated trailing and feeding deficits commensurate with the extent of nerve damage. In contrast, snakes with olfactory nerve cuts and sham surgery continued to follow all trails at preoperative levels and maintained high tongue-flick rates when following the stronger extract trails. Four of the snakes (two with sham lesions, one with olfactory nerve lesion, and one with a partial vomeronasal nerve lesion) were subsequently tested with the vomeronasal ducts sutured closed. These snakes were unable to follow any of the extract trails at better than chance levels, but in contrast to snakes with vomeronasal nerve cuts, most of these snakes continued to attack and ingest earthworm bits. These results suggest that garter snakes are heavily dependent on their vomeronasal system for following chemical prey trails.Garter snake feeding is guided by the The prey attack appears to be elicited by chemical senses (Burghardt, 1970). Garter vomeronasal stimulation, since snakes snakes readily follow odor trails to locate without a functioning vomeronasal system potential prey (Kubie & Halpern, 1975, do not exhibit the behavior (Burghardt & 1978), and once in the vicinity of the prey, Hess, 1968;Burghardt & Pruitt, 1975; Wilde, they attack objects coated with appropriate 1938). It is not clear, however, which sense chemicals (Burghardt, 1966;Wilde, 1938). modalities garter snakes use when following prey-odor trails. In addition to garter snakes, a variety of snakes can use odor trails This research was part of a doctoral dissertation f lorflf notpntial nrpv Vinprs and rohi submitted by John L. Kubie to the State University of ?° . locate Potential prey. V ipers and CO1U-New York Downstate Medical Center. The research bn d snakes follow prey trails in an Open was supported by National Institutes of Health Grant arena, and when doing so, they are described NS11713. We wish to thank Sarah Winans and Ruu-as exhibiting rapid tongue flicks and keeping Tong Wang for their thoughtful advice, Vincent Tuonv their headg low to the groun( } (Baumann, for teaching us the duct-suture technique, Alice -,c.r,n n UIK i \\i *^] • v v n -ian-t Vagvolgyi for data collection and historical processing, 1927 > ^ehlback, Watkms, & Kroll, 1971, Jack Illari and ...
