Kleptoparasitism and the Possibility of Chemical Crypsis in Rattlesnakes
Teshera, Mark S. msteshera@miners.utep.edu
Department of Biological Sciences
The University of Texas at El Paso
El Paso, Texas, USA
Clark, Rulon W.
Department of Biology
San Diego State University
San Diego, California, USA
Greenbaum, Eli
Department of Biological Sciences
The University of Texas at El Paso
El Paso, Texas, USA
While some aspects of rattlesnake and rodent predator-prey dynamics have been well documented, others are in need of further investigation. Although there is a large body of work documenting the ability of rattlesnakes to detect and follow chemical cues from envenomated prey, one area of research that has not been investigated is the possibility that rattlesnakes might use this heightened chemosensory ability to “steal” prey envenomated by others (kleptoparasitism). We used an experimental setup to examine the propensity of rattlesnakes to locate mice envenomated by either conspecifics or heterospecifics. We hypothesized that rattlesnakes would respond more strongly to conspecific-envenomated prey over heterospecific-envenomated prey of a closely related species, which would in turn be preferred over heterospecific-envenomated prey of a non-closely related species, followed lastly by non-envenomated prey. In a separate experimental study, we investigated the possibility that rattlesnakes, like puff adders, might be chemically cryptic in order to facilitate their ambush foraging strategy. We hypothesized that, if rattlesnakes show enhanced chemical crypsis, rodents would display fewer alarm behaviors to rattlesnake scent than to scent from an active foraging snake species. We examined rodent responses to two rattlesnake species and three active foraging snake species. Preliminary results from these experiments suggest 1) no difference in preference for rodent carcasses envenomated by different types of venoms, and 2) rattlesnakes do not appear to be more chemically cryptic than active foraging snakes. We believe these studies will constitute important contributions to our detailed understanding of the foraging ecology of these important predators.