Do lizards have a theory of mind?

We often wonder what lurks in the hearts of beasts, but how far “down” the phylogenic (evolutionary) tree does a “theory of mind” go? It’s easy to understand that another human has a theory of mind, and perhaps also dogs and cats and other smart animals, but do ants and frogs and lizards understand that others have desires and intentions different from their own?

There is now claimed to be the first published scientific evidence that reptiles can learn through imitation; that is, they not only mimic what they see but also understand the intention behind the action. This is different from emulation, which is mimicking what is seen without understanding intention.

Some herpetologists took a few lizards out of their natural environment and subjected them to a learning test that did not emulate natural behavior, yet the reptiles consistently got it right. A food item (mealworm) was placed under a wire trapdoor that could be slid aside by either the lizard’s snout or a forelimb to reach the snack. A “demonstrator” lizard was taught to slide the trapdoor aside with its snout, and test lizards then watched the demonstrator perform the deed. All the test lizards quickly learned to slide the trapdoor aside with their snouts whereas control lizards (that were not instructed) all failed to open the trapdoor by any means.

The scientists also pointed out that the snout was used by all the test lizards but none of the controls. The latter used only their forelimbs to try to move the trapdoor, suggesting that the snout-swing motion is not part of their “spontaneous behavior.” In other words, these lizards used social information in order to learn a new trick. Is this not evidence of a theory of mind in lizards?

This is the original reference:

Anna Kis, Ludwig Huber, Anna Wilkinson. Social learning by imitation in a reptile (Pogona vitticeps). Animal Cognition, 2014; DOI: 10.1007/s10071-014-0803-7.