The case for investigating the cognitive map in nonavian reptiles

Although not without controversy, the cognitive map in mammals and birds (avian reptiles) is generally accepted as plausible. The evidence for similar cognitive abilities is not generally accepted in other vertebrates and invertebrates. A plethora of recent work in nonavian reptiles, however, suggests that these taxa may indeed possess advanced cognitive processing and so may, in principle, be capable of using a cognitive map. To consider the possibility that a nonavian reptile might use a cognitive map, we reexamined the movement of the semiaquatic turtle (Chrysemys picta) in our highly accessible system where turtles follow highly conserved, precise and predictable migratory routes. We determined the movement rate and tortuosity of freely migrating turtles before, during and after a pharmacological manipulation that disrupted their ability to retrieve and create spatial memories. We found that turtles moved linearly on traditional routes prior to treatment. After pharmacological treatment, turtle move-ments became highly tortuous as they moved in some cases hundreds of metres away from their migratory routes. Once turtles recovered their spatial cognitive abilities, they returned directly to their migratory paths using linear movements suggestive of deliberate and purposeful navigation. Although other processes could potentially explain observed turtle movement patterns, we were able to exclude them by new or previous data, or strong inference. What remains is a robust behavioural observation that is consistent with the use of a cognitive map by turtles in our system. As such, we urge researchers to continue to be open to the possibility of cognitive maps in nonmodel taxa, such as nonavian reptiles, to continue to expand our understanding of the evolution of cognition. (c) 2023 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.