Ontogeny of Anti-Predator Behavioral Habituation in Cottonmouths (Agkistrodon piscivorus)

Predation can be an important factor in shaping the behavior and ecology of species (Tuttle & Ryan 1981). Over evolutionary time, behavior is shaped to maximize net benefits as predicted by optimality models (Smith 1978). Because the cost of defense may affect fitness (Ueta 1999; Van Buskirk 2000; Raberg & Stjernman 2003), we might expect individuals to make behavioral decisions based on contextdependent costs and benefits when confronted by a predator (Endler 1986). Accordingly, factors such as the risks represented by a predator, as well as prior experience of the individual with the predator could influence an individual’s final decision. One way in which individuals can adjust their behavior is through habituation, a mechanism by which organisms display a stimulus-specific response decrement resulting from exposure to the responseeliciting stimulus (Wyers et al. 1973). Long-term habituation (as opposed to short-term habituation) occurs over multiple training sessions and is typically measured over days or weeks (Owen & Perrill 2000), demonstrating capacity for memory in experimental subjects. Intuitively, we might expect individuals with the ability to adjust their defensive behavior as a result of discrimination between highand lowrisk threats to be at a selective advantage. For instance, if prior experience with a potential predator suggests that the risk of being preyed upon is Correspondence Xavier Glaudas, Department of Biological Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway Las Vegas, NV 89154, USA. E-mail: [email protected]