A Noninvasive Technique for Blocking Vomeronasal Chemoreception in Rattlesnakes

Abstract

To examine the effects of vomeronasal deprivation on strike-induced chemosensory searching (SICS) in rattlesnakes we used a newly developed technique to anesthetize the vomeronasal organs. We compared rate of tongue flicking after striking prey in avomic rattlesnakes to vomic controls. Avomic rattlesnakes exhibited significantly fewer tongue flicks after striking prey than did vomic controls. However, avomic subjects still exhibited a significantly higher rate of tongue flicking (RTF) than did subjects that were presented with prey but not allowed to strike indicating that the increase in RTF seen in avomic snakes reflects a component of predatory behavior that is released by the strike and not dependent upon further vomeronasal activation. A second experiment was conducted to examine the role of the vomeronasal system (VNS) in location of envenomed prey. Disruption of the VNS chemoreception significantly reduced the number of poststrike tongue flicks, significantly increased the latency to locate the prey item and significantly increased the latency to commence swallowing the prey item, indicating that normal expression of these behaviors is dependent upon a functioning vomeronasal system.