What Is the Smartest Reptile? What Lab Studies Actually Show
No study we found ranks reptile species on one set of tasks, and reptiles have no IQ. The best-documented results are small: four of four red-footed tortoises solved a detour task after watching another tortoise, and none of four that did not watch solved it.
What you need to know
- We found no study that ranks reptile species on one set of tasks, so there is no verified "smartest reptile". Reptiles have no IQ: no standardised IQ test exists for them.
- Wilkinson and colleagues (Biology Letters, 2010) tested 8 red-footed tortoises on a detour task: all 4 that watched another tortoise solved it, none of the 4 that did not watch did. The sample is tiny, so treat it as a first demonstration.
- A 2012 study trained 4 red-footed tortoises on an eight-arm radial maze, and its authors say tortoise spatial navigation may be more like that of mammals and birds than previously thought.
- A 2011 paper on a tropical lizard reports problem-solving with several strategies and rapid learning, in animals "commonly believed to have limited cognitive abilities".
No one can name a single smartest reptile, because we found no study that ranks reptile species on one set of tasks. Reptiles also have no IQ, since no standardised IQ test exists for them. What exists is a handful of small lab studies, and the best known is on the red-footed tortoise: in 2010, four of four tortoises that watched another tortoise solved a detour task, and none of four that did not watch solved it.
Below: what that study did, what other reptile studies show about lizards and tortoises, why "reptile intelligence" cannot be turned into a ranking, and how to read animal intelligence claims.
What is the smartest reptile?
There is no verified answer about the smartest reptiles, because "smartest" needs a common yardstick and reptile researchers have not built one. Studies use different species, different tasks and very few animals, so the results cannot be set side by side.
Two groups are the best studied: tortoises and some lizards. Birds, which descend from reptiles in the evolutionary sense, are usually left out of lists of reptile intelligence, so we leave them out too. Our wider smartest animals ranking explains why even for mammals the lists depend on the task chosen.
Are tortoises smart? What the detour study found
Are tortoises smart? They can learn by watching, at least in one lab test. In 2010 Anna Wilkinson, Karin Kuenstner, Julia Mueller and Ludwig Huber published "Social learning in a non-social reptile (Geochelone carbonaria)" in Biology Letters (volume 6, issue 5, pages 614-616). The authors write that the red-footed tortoise "can learn from the actions of a conspecific in a detour task; non-observer animals (without a conspecific demonstrator) failed".
In the detour task, food sits behind a V-shaped fence. To reach it, the tortoise must first walk away from the food, go around the fence and come back. According to a reprint of the paper in a University of Vienna thesis chapter, eight tortoises took part: four watched another tortoise do the detour, and four did not. Each had two minutes per trial.
- Animals tested: 8 red-footed tortoises, split 4 and 4
- Non-observers: none of the 4 reached the food in any of their 12 trials
- Observers: all 4 completed the task at least twice, and 2 did it on the first trial
- Statistic: observers did significantly better than non-observers (Fisher exact test, p < 0.05)
Four of four tortoises that watched solved the task. None of four that did not watch did.
What does the small sample mean for reptile intelligence?
It means the result is a first demonstration, not an estimate of how common the skill is. With four animals per group, one unusual tortoise could shift the outcome, and the study cannot say how well another species would do. The authors call it the first evidence that a non-social species can use social cues to solve a task it cannot solve alone.
It is also one task. A tortoise that solves a fence detour after watching is showing social learning, which is a different skill from the problem solving a lizard shows in a puzzle box. Scores on different tasks cannot be added up to a single number, which is why we do not give one.
Is there a smartest lizard? What other reptile studies show
There is no smartest lizard on record, but two papers show reptiles doing more than the old picture allows. Leal and Powell (Biology Letters, 2011, volume 8, issue 1, pages 28-30) studied a tropical lizard and reported that it solved a new motor task with several strategies and showed reversal learning and rapid associative learning. They add that this was unexpected "because lizards are commonly believed to have limited cognitive abilities and highly stereotyped behaviour".
Back to tortoises: Mueller-Paul and colleagues (Journal of Comparative Psychology, 2012, volume 126, issue 3, pages 305-317) trained four red-footed tortoises to run an eight-arm radial maze. Their abstract says the findings suggest that tortoise spatial navigation "may be more similar to that observed in mammals and birds than previously thought". Four animals again.
Do reptiles have an IQ?
No. An IQ is a position inside a norm group of people on a standardised test, and no such test or norm group exists for reptiles. We found no peer-reviewed statement on this point, so this is our own statement, based on how IQ scores are built. Our guide to how IQ tests work sets out what a score needs.
So compare tasks, not scores. A memory task, a detour task and a maze test different things. For the same reason, our look at the smartest animal in the ocean and the smartest dog breeds both end up describing tasks, and our page on dog IQ shows the limits of any animal "IQ" number.
How should you read claims about animal intelligence?
- Look for the number of animals: results from 4 animals are a pilot, not a ranking
- Look for the task: say what the animal did, not only that it was "smart"
- Be wary of a single "IQ" for any animal: there is no norm group
- Check the species: a result for one tortoise species is not a result for all reptiles
You can test one skill the detour task leans on, short-term memory, in our memory game. It scores memory, not IQ. For a measure with a norm group, start with the IQ test and read the result with the IQ percentile calculator.
Where would your own score land?
To see how your own reasoning compares with other people, take the IQ Metrics test and get a percentile with your report.
Find your IQ score now! →Common questions
What is the smartest reptile?
No one can say. We found no study that ranks reptile species on one set of tasks. The best-documented results are small studies of red-footed tortoises and a tropical lizard.
Are tortoises smart?
In one lab test they learned by watching. Wilkinson and colleagues (Biology Letters, 2010) found that all 4 red-footed tortoises that watched another tortoise solved a detour task, while none of the 4 that did not watch did. The sample was only 8 animals.
Is there a smartest lizard?
None is on record. Leal and Powell (Biology Letters, 2011) report that a tropical lizard solved a new problem with several strategies and learned quickly, which challenges the view that lizards have limited cognitive abilities.
Do reptiles have an IQ?
No. No standardised IQ test or norm group exists for reptiles, so any "reptile IQ" number is invented. Studies compare what animals do on a task, such as a detour or a maze.
Sources for this story
- Wilkinson, Kuenstner, Mueller and Huber, Social learning in a non-social reptile (Geochelone carbonaria), Biology Letters 6(5):614-616 (2010), doi 10.1098/rsbl.2010.0092 — The Royal Society
- Trial numbers from the reprinted chapter "Social learning in a non-social reptile", doctoral thesis of Julia Mueller-Paul, University of Vienna — University of Vienna
- Mueller-Paul, Wilkinson, Hall and Huber, Radial-arm-maze behavior of the red-footed tortoise (Geochelone carbonaria), Journal of Comparative Psychology 126(3):305-317 (2012), doi 10.1037/a0026881 — American Psychological Association
- Leal and Powell, Behavioural flexibility and problem-solving in a tropical lizard, Biology Letters 8(1):28-30 (2011), doi 10.1098/rsbl.2011.0480 — The Royal Society
Corrections: spotted an error? Email corrections@iqmetrics.org and we will update this story and note the change here.
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