Date of Graduation

Spring 2016


Master of Science in Biology



Committee Chair

Brian Greene


Predator detection and assessment of predation risk have important survival consequences for animals. However, responses to predatory threats can vary with different stimuli. Chemical cues are important for predator recognition but visual cues may elicit defensive responses. Cottonmouths (Agkistrodon piscivorus) exhibit an array of antipredatory behaviors that have been thoroughly characterized in response to human aggressors, but their responses to cues from other predators are poorly known. I conducted three experiments to evaluate cottonmouth responses to visual and chemical stimuli from predators and non-predators. Snakes exposed to predator chemical cues exhibited elevated tongue-flick rates compared to controls but did not perform any antipredatory behaviors. Snakes exposed to mobile silhouettes of predators and non-predators performed significantly more defensive displays in response to red-tailed hawk models than controls. However, snakes exposed to visual models of terrestrial predators and non-predators exhibited elevated responses to taxidermed mink and muskrat compared to an inanimate object of similar size and color. My results are consistent with risk-sensitivity predictions in that cottonmouths can use chemical cues to recognize predators and use visual cues to distinguish predatory bird silhouettes from those of non-predatory birds. However, snakes generalized their antipredator responses to stationary mammals based on visual cues alone.


threat-sensitivity, chemical detection, visual detection, anti-predator response, behavior, snake, cottonmouth, Agkistrodon piscivorus

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© Kristen Lee Kohlhepp

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