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Post-Strike Behavior of Timber Rattlesnakes (Crotalus horridus) During Natural Predation Events


Rulon W. Clark, Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA, 14853-2702.


The complexity of natural environments is an important component of animal behavior, and laboratory environments often cannot reproduce that complexity. Strike-induced chemosensory searching (SICS) is a robust phenomenon among venomous snakes that has been studied extensively in the laboratory. To date, observations of this behavior in the field have been limited largely to anecdotes; the extent to which post-strike behaviors in the laboratory accurately reflect what occurs in nature has not been examined. In this study, I use time-lapse video equipment in the field to record the predatory behavior of timber rattlesnakes (Crotalus horridus). This represents the first quantitative analysis of post-strike predatory behaviors associated with natural feeding events. As in the laboratory, stereotyped post-strike behaviors were only observed after successful strikes, and not after missed strikes. Snakes in the field were observed to proceed through the same basic behavioral stages that have been documented in the laboratory: striking prey, releasing prey immediately after strike, post-strike immobility, location of the chemosensory trail, trail following, and prey swallowing. However, the duration of post-strike immobility, trail location, and prey swallowing was substantially longer in field than in laboratory studies. Additionally, post-strike immobility was significantly longer when snakes struck large prey (prey over 100 g) than when they struck small prey. Overall, these results indicate that the behavioral challenges associated with SICS may be more robust than laboratory studies have indicated.