Learning in freshwater stingrays (Potomotrygon falcneri)
Kerstin Elisabeth Thonhauser 1, Karl Kral 1, Michael Kuba 2
1 Institut für Zoologie, Karl-Franzens-Universität Graz, Austria; 2 Department of Neurobiology, Hebrew University, Jerusalem, Israel
Testing the behavioral abilities of cartilaginous fish is an important step towards understanding the evolutionary origins of cognitive functions in higher vertebrates. In our study we used 7 South American fresh water stingrays (Potomotrygon falcneri) in a social learning and problem-solving task. We used a tube apparatus developed for testing the cognitive abilities of aquatic animals. 3 animals where chosen as demonstrators that initially learnt to handle the tube and extract a food reward. After the demonstrators had reached criterion the 4 observer animals were positioned to watch them perform trials. The observers were then tested on their ability to learn to handle the tube and extract food. Comparison showed significant differences between demonstrator and observer groups. Observers required less trials to reach criterion (p = 0.0023) and shorter trial duration (p = 0.0005). The two groups also showed a significant difference in acquiring the best strategy for food extraction. This study is the first conclusive evidence of imitation learning in fish.