These lizards may be able to learn from each other

PRINCETON, N.J. — Learning can be a quick shortcut for figuring out how to do something on your own. The ability to learn from watching another individual — called social learning — is something that hasn’t been documented in many species outside of primates and birds. But now a lizard can be added to the list of critters that can learn from one another. Young eastern water skinks were able to learn by watching older lizards, Martin Whiting of Macquarie University in Sydney reported August 10 at the Animal Behavior Society meeting at Princeton University.

The eastern water skink, which reaches a length of about 30 centimeters, can be found near streams and waterways in eastern Australia. The lizards live up to eight years, and while they don’t live in groups, they often see each other in the wild. That could provide an opportunity for learning from each other.

Whiting and his colleagues worked with 18 mature (older than 5 years) and 18 young (1.5 to 2 years) male skinks in the lab. The lizards were placed in bins with a barrier in the middle that was either opaque or transparent.

In the first of two experiments, the skinks were given a yellow-lidded container with a mealworm inside. They had to learn to open the lid to get the food. In that task, skinks that could see a demonstrator through a transparent barrier were no better at opening the lid than those who had to figure it out on their own.

But in the second experiment, there were signs that some of the lizards learned from each other. In that task, two containers were given to a lizard. A blue-lidded container had a mealworm; the other, with a white lid, had a mealworm but it was hidden and inaccessible (both had to have a mealworm so that the skinks wouldn’t choose based on smell). For the test to be successful, a skink had to choose the blue-lidded container first (the video shows a failed test).

When young lizards, though not old, had a demonstrator, they took fewer trials to figure out that the container with the blue lid contained a mealworm. By watching another lizard perform the task, the young skinks were able to learn more quickly which container had the meal.

“Young lizards may be more likely to pay attention to social information than adults,” Whiting said.

Plus, older lizards in the wild are territorial; they’re more likely to kick an older skink out of its territory than a young one. So social dominance may play a role in how the lizards are interacting with each other and when they might learn from one another.

Whiting and his colleagues also reported their findings in the July Biology Letters.