Lateralization of predatory behavior in two congeneric ambush predators

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Marley Weiss and Stacey L. Weiss, Biology, University of Puget Sound, Tacoma, WA

Background/Question/Methods
Lateralization, the differential cognitive abilities performed by each hemisphere of an individual's brain, is thought to lead to behavioral biases. Such behavioral lateralization may influence both individual and population level fitness, as well as the efficiency of many essential behaviors, including foraging. It is suggested that squamates may rely on lateralization during foraging behavior to increase foraging success. In this study, we observed the ambush foraging behavior of two congeneric lizards, the Striped Plateau Lizard (Sceloporus virgatus) and Western Fence Lizard (Sceloporus occidentalis), to investigate the question: Do lizards using the same predation style exhibit the same trends of lateralization during foraging? To test this, we observed foraging behaviors in two contexts: unaltered captive foraging and within a y-maze. In both settings we obtained population and individual eye biases, as well as direction preference in the y-maze setting.
Results/Conclusions
In S. virgatus feeding and maze trials we found a significant left eye bias at both the population and individual levels supported by a significant right directional bias. Within our maze, the right directional bias, or preference to travel up the right arm, forces the lizard's left eye to be the primary viewing eye which reinforces our finding of a left eye bias. Taken together, our results suggest S. virgatus are lateralized in favor of the left visual field. However, the results from S. occidentalis are less clear. S. occidentalis did not show a significant bias for either the left or right visual field at the either population or individual level. They also showed a left directional bias within the y-maze, making the right eye the primary viewing eye. Such disparities in foraging lateralization in lizards utilizing the same predation style may be due to niche differences including climatic and dietary variation. Personality may also influence the strength of lateralization by making an organism more or less likely to engage in specific behaviors that benefit from lateralization.