Utilizing Captive-Bred Bearded Dragons to Study Sensory and Cognitive Capacity in Lizards

The goal of our research is to test the sensory and cognitive abilities of bearded dragons (Pogona vitticeps). Bearded dragons are a species of lizard that inhabit desert and shrubland throughout Australia. In our research, we developed a training/reward assay that would allow us to test their ability to learn to identify certain sensory cues, and we used the assay to explore their visual sensory capabilities. We were particularly interested in their capacity to discriminate colors and spatial orientation, and to test for a capacity to perceive orientation of polarized light. Polarized light perception by the eyes has never been demonstrated in a lizard species. Such a capacity would be extremely useful for navigation and water detection in the desert habitat of these lizards.We chose to use captive-bred individuals of this species because they are unafraid of humans and therefore respond readily to novel stimuli in captivity.  The first step of our research was to train the dragons to accept food from us. We then used operant conditioning and two-choice discrimination learning in order to train one of the dragons to choose one colored light (e.g. red) over a different colored light (e.g. blue), and to train the other dragon to choose the opposite color. Currently, we are working on the last step of our research, which is to use the same Y-maze method to explore the capacity of bearded dragons to detect polarized light, a type of novel sensory stimuli.  In conclusion, we believe by developing a training paradigm in order to test the sensory abilities of our bearded dragons, we can add to the knowledge of lizard cognition and sensory discrimination.