A tad bit of learning: Place and response learning in green frog (Rana clamitans) tadpoles

Spatial navigation is considered essential for survival and therefore likely to have been selected for across vertebrates; however, similarities and differences in the mechanisms underlying these abilities across species remain unclear. The current experiment was designed to investigate strategies underlying spatial navigation in green frog (Rana clamitans) tadpoles. Tadpoles were trained to navigate a maze either by using external cues to navigate (place learners), or by remembering the specific egocentric actions that led to escape from the maze (response learners). There were no significant differences in acquisition following place or response learning, which suggests some flexibility in their spatial navigation strategies. However, only ten tadpoles reached the learning criterion before metamorphosis, which was fewer than that predicted by chance alone. Of these, six were place learners and four were response learners. Three place learners appeared to retain this information in the short term - pointing to the intriguing possibility that green frog tadpoles may retain this information for a period of several weeks or longer. Future studies should set a stricter learning criterion and focus on how memory is retained following metamorphosis.