New research by the Okinawa Institute of Science and Technology (OIST) shows that humans have long underestimated the intelligence and memory of tortoises.
Scientists have proven that tortoises can be trained due to their ability to recall long-term memories. “When first discovered, giant land tortoises were viewed as stupid because explorers could simply collect and store them on ships as a supply of fresh meat,” said Dr Tamar Gutnick, first author of the study and a postdoctoral scholar in the OIST Physics and Biology Unit.
Gutnick highlighted that previous investigations into the intelligence of tortoises are contradictory. While undergoing his studies of the Galapagos Islands, Charles Darwin noted that Galapagos tortoises travelled long distances to food and water sources. Darwin also drew attention to how these tortoises would travel to reach where they slept, suggesting they have long term memories of geographical locations.
“We also observed first hand that tortoises recognised their keepers, so we knew they were capable of learning,” added Gutnick. “This research shows the rest of the world just how smart they are.”
Published in Animal Cognition, this study drew attention to almost a decade of work which started when Gutnick was undergoing his master’s degree and began research on the tortoises at Vienna Zoo.
“When I met the tortoises, I immediately fell in love with them,” said Gutnick. “It was clear to me that they all had very distinct – and often cheeky – personalities.”
Dr Tamar Gutnick and Dr Michael Kuba, who formerly worked at Vienna Zoo, trained Aldabra and Galapagos tortoises from Vienna Zoo and Zürich Zoo. Using positive reinforcement, with rewards like beetroot and dandelions, scientist trained the tortoises to perform three tasks.
The first task involved the tortoises biting a coloured ball on the end of a stick, once the tortoises demonstrated an understanding of this task, researcher them taught them to move up to two meters to bite the ball. The final task involved the scientist assigning a colour to each tortoise. The tortoise would have to chose from two colours and bite the correctly coloured ball.