Earlier this week, scientist Anna Wilkinson won an IgNobel prize for her research on contagious yawning (really, the lack thereof) in red-footed tortoises. In case you're not familiar with them, the IgNobel Prizes are given for research that "first makes you laugh, then makes you think." Read Scicurious's coverage of the awards here. Since I've covered Wilkinson's research twice on this blog in the past, I thought I'd repost them in honor of her award. There are not many research groups devoted to studying cognition in reptiles, after all. Here's the first of two posts, originally posted June 28, 2010.

Most people who study cognition focus on mammals or birds. But I hope I've convinced you that other animals are important to investigate as well. One research group at the University of Vienna likes cold-blooded critters. Turtles and lizards and such. They argue:


The ability to learn from the actions of another conspecific (a member of the same species) is adaptive. Animals who live in social groups, such as mammals, birds, fishes, and insects, can learn how to solve certain problems by watching other group members solving those problems. Nobody, according to these authors, has studied this form of social learning in reptiles. But the evolutionary origins of this trait - the ability to learn by observation - are unclear. Given the right circumstances, could the red-footed tortoise (Geochelone carbonaria) show evidence of this form of social learning?

The red-footed tortoises of the Cold Blooded Cognition Lab. Their feet don't seem particularly red to me.



The red-footed tortoise is a solitary species that is found in the tropical forests of Central and South America. They do not live in permanent groups (unlike a particular group of sewer-dwelling, pizza-eating ninjas), and there is no parental care. So: you're a tortoise and you typically spend your time alone. One day, you're walking around and you find another tortoise. You do a headbob display and figure out if the other tortoise is of the opposite sex. If so, its game on. Eggs are laid and whatnot. If not, the two tortoises ignore each other and move on.

In this experiment, eight tortoises were housed together for two months, allowing plenty of exposure to other conspecifics (members of the same species). Even though they were living together, they never saw anyone do the experimental task except under strict conditions. For the experiment, they were separated into two age- and sex-matched groups.

The goal of the game was to get a piece of food, but there was a transparent V-shaped fence separating the turtle from the food. One group (the "non-observers") had to try to figure out how to get the food on their own. The second group (the "observers") watched a trained individual walk around the fence to retrieve the food before attempting it themselves.


Why should this task be hard? Tortoises probably don't have very good advance planning skills. And in order to reach the food in this task, first the tortoises must increase the distance between itself and the food before turning the corner, when it can then begin to reduce the distance between itself and the food. Without any real ability to plan for the future, increasing the distance between you and your goal probably doesn't make any real sense. Why would you fly from Los Angeles to Las Vegas with a layover in Atlanta? It only makes sense if that is the only way to get to Vegas.


Results, non-observer group.

"But where are the bars?" you ask. I asked the same thing. I wondered if there had been some sort of error in the paper. No error. The data is all there. None of the tortoises succeeded. They all eagerly approached the fence, through which they could visually see the reward, but none of them EVER navigated the detour. Some of them tried to force their way through the barrier. Most just gave up and went to sleep.

Then, Wilhelmina was painstakingly trained to navigate around the right-hand side of the fence to get the food. It took over 150 trials for Wilhelmina to attain reliable performance. (I pity the poor graduate student that had to train her.)

Then, the observer group had its turn. Each of the observer tortoises was placed into a cage and watched Wilhelmina successfully get her reward. Then, Wilhelmina was removed, the reward bowl was re-filled, and the bark that covered the ground was replaced (to make sure that the observers couldn't simply track her scent). Then the observer was released and allowed to retrieve the food.

Results, observer group.


This study demonstrates that red-footed tortoises, which do not live in social groups in the wild, are able to use social information to solve a problem. The fact that sometimes the observer turtles went around the fence on the left side suggests that they were not relying on some other environmental cue not seen by the experimenters - they had more generally learned a problem-solving strategy for that specific problem by watching Wilhelmina. Quinn actually went left on his very first successful attempt, and both Moses and Aldous used both ways around.




Lab tortoise images from Wilkinson lab website. Top red-footed tortoise image used under Creative Commons license via OpenCage.info.