When lizard eggs are incubated at higher temperatures, smarter lizards are hatched from them, says a report in the journal, Biology Letters.

While researchers already know that warm incubation temperatures lead to larger, more athletic reptile hatchlings, researchers at the University of Sydney wanted to see if temperatures also influenced a hatchling's learning ability.

They incubated nine scincid lizard eggs in cooler temperatures (up to 23.5 degrees) and 12 in warmer temperatures (up to 29.5 degrees), the same temperatures they are exposed to in the wild.

Once hatched, the lizards were placed in enclosures which contained two potential hiding places, one of which had the entry blocked by a see-through barrier.

Researchers did not change the position of the hiding places during the experiment, allowing the lizards to learn the location of the unblocked hide-out.

Each hatchling was then placed underneath a small plastic cover between the two hiding spaces and, when the cover was removed, a researcher ''scared'' the lizard into action by lightly touching its tail with a paintbrush.

Lizards that were able to find the open hiding place within 30 seconds were considered to have made a successful escape.

''Overall, hot-incubated lizards achieved higher learning scores than did cold-incubated lizards, and the number of errors they made decreased more from the first to the second half of the trials,'' the report found.

''Hence, factors such as maternal nest-site selection and climate change affect not only the size, shape and athletic abilities of hatchling reptiles, but also their ability to learn novel tasks.''

It was likely being a faster learner could increase the lizard's chance of survival and reproduction because it could better respond to environmental threats, said Joshua Amiel, who wrote the report.

However, there was likely to be a temperature threshold.

''If temperatures get too warm, the lizards may not develop inside the egg at all,'' he said. ''It may be that there is a window of opportunity for lizards over the next few years, when the temperatures are ideal for them to become smarter.''