(Image: OIST)
They are famous for their slowness and longevity – giant turtles, on the other hand, are not particularly clever. But apparently this is a false impression: the bizarre reptiles learn quickly and have long-term memory, an experimental study shows.
They trot leisurely across the Galapagos and Seychelles: on these remote islands, various types of tortoises have developed that can weigh several hundred kilograms and can reach an age of over 150 years.
“The reputation of these animals as simple and stupid was partly shaped by the discoverers who simply collected and stored them as meat stores,” says Tamar Gutnick from the Okinawa Institute of Science and Technology in Japan. But, as the scientist emphasizes, there were people early on who noticed complex behavior in giant tortoises. Among them Charles Darwin: He noticed that Galapagos turtles travel long distances to get to different places in their habitat where they eat, drink, sleep or bathe in the mud. This wandering behavior already suggested a memory.
No “stupid” reptiles
“In dealing with the animals, we have repeatedly found that they recognize their caregivers,” Gutnick says of her experience with the giant turtles, which began around ten years ago in the Schönbrunn zoo in Vienna. “It was clear to me that they also have very different personalities. With our study, we can now scientifically clarify that these reptiles are not as simple as many assume, ”says the biologist. Together with her colleagues, she experimented with giant tortoises from the Vienna Zoo and Zurich Zoo to find out to what extent the animals are capable of learning and can remember what they have learned.
The researchers succeeded in teaching the test subjects, some of whom were over a hundred years old, to combine an abstract charm with food: the turtles learned that they get a delicious carrot when they bite into a ball of a certain color. The animals were able to choose the right color ball from two alternatives, the tests showed. Three months later, the turtles still mastered the task. But that was not the most impressive proof of their long-term memory: As the researchers report, the turtles were able to choose the right ball even after another test after nine years.
Evidence of social learning
The scientists also found evidence of another interesting aspect of the giant turtles’ ability to learn: They almost said that the animals learned the task with the balls faster when they were trained in groups than when they were alone. This suggests that they could at least partially see the behavior of their peers. “It was a very unexpected result,” says Gutnick. “Because giant turtles are not known as particularly social animals, but the increase in learning speed was unmistakable”. The scientists speculate that this ability has to do with the fact that animals in the wild receive important information when they observe other turtles in certain behaviors.
The study shows how little is known about the cognitive abilities of reptiles, the scientists say. According to them, research potential is now emerging: “Zoos can now enable us to explore this aspect in more detail,” says Gutnick.
Video: Zoovienna zoo Schönbrunn
Source: Okinawa Institute of Science and Technology (OIST) Graduate University, professional article: Animal Cognition, doi: 10.1007 / s10071-019-01326-6