Duration of strike-induced chemosensory searching in cottonmouths (Agkistrodon piscivorus) and a test of the hypothesis that striking prey creates a specific search image

Abstract

Cottonmouths (Agkistrodon piscivorus) emitted significantly more tongue flicks after striking rodent prey than after seeing, smelling, and (or) detecting thermal cues from rodent prey. This strike-induced chemosensory searching (SICS) persisted for about 70 min. Prey-derived molecules acquired during the strike would not be expected to remain available to the vomeronasal organs for more than 10 min. Hence, the duration of SICS suggests (i) that a central nervous system (CNS) representation of prey is formed as a consequence of the strike and (ii) that this representation or search image has memorylike properties and remains available to guide searching behavior for a longer time than would be expected on the basis of poststrike residuation of chemically induced afference in the vomeronasal system. In experiment II, cottonmouths struck either rodent or fish prey (which were removed immediately after the strike) and 10 min later the snakes were allowed to ingest either a fish or a mouse. When the prey offered for ingestion was the same type as the prey struck, snakes grasped their prey quickly, whereas, in all other conditions, only a few snakes responded quickly and others did so after much longer latencies. It is proposed that CNS representations of fish and mice have some nonoverlapping features and that a disposition to grasp the type of prey that was initially struck endures until these prey-specific features have degraded (presumably through the ordinary process of forgetting).