Tortoises were able to select specific colored balls nine years after they were trained to bite it.
Aldabra (Geochelone gigantea) and Galapagos (Chelonoidis sp.) tortoises are trainable in certain respects and have long memories, according to new research from Okinawa Institute of Science and Technology and the Hebrew University and Tiergarten Schönbrunn, Maxingstrasse.
Researchers Tamar Gutnick, Anton Weissenbacher and Michael Kuba initially believed that the tortoises retained good memory because of the long distances that they traveled on the Galapagos and Aldabra islands. They figured that the tortoises had to remember the paths that they traveled. So, the researchers conducted training exercises with both species of tortoises living in zoos, teaching them to bite on the same colored ball that was attached to a stick.
When they bit the correct colored ball, they received a reward, but when the wrong ball was bit, they did not.
More than three months after the initial exposure to the colored balls, the tortoises were then presented with the same balls and sticks. The tortoises remembered the training and picked the correct ball. Nine years later, the researchers went back to see the tortoises at the zoos and exposed them to the balls, and each of the tortoises picked the correct ball without having to remind them in any way.
The researchers also noted that the tortoises seemed to learn faster in groups, suggesting that the tortoises learned from their fellow chelonians.
An astract of the paper "The underestimated giants: operant conditioning, visual discrimination and long-term memory in giant tortoises," can be read on the Animal Congition/Springer website.