This is Scientific Americans 60 Second Science. I'm Jason Goldman. Got a minute?

Chameleons have it easy. If they need to hide from a predator, they just change their appearance and disappear against whatever they happen

to be standing on.

Surrounded by leaves, turn green.

Tree trunk?

Brown it is.

But Aegean wall lizards have a different strategy. They live on the Greek islands, and instead of changing their appearance, they find a safer spot. That is, they're really good at picking out just the right background to minimize the chances that they'll be spotted by a hungry grow or raptor.

That's according to a new study in the journal Scientific Reports.

Birds can perceive both visible and ultraviolet light,

so researchers snapped regular and UV photos of lizards basking on rocks

to figure out how the lizards look to birds.

The scientists discovered that the lizards camouflage is precisely tuned to avian eyeballs,

helping them seem to disappear. Lizards with darker backs hang out on darker rocks.

Lighter ones choose lighter rocks.

It's the first time that wild animals have been recorded explicitly choosing the best background to enhance their own camouflage.

Another observation, when lizards aren't under the constant threat of death, they're less picky.

On the island with the lower risk, this kind of background choice to improve their level

of camouflage is much less evident than on the islands with high relation risk.

University of Cambridge zoologist Kate Marshall, lead researcher of the study.

To pick out the right rocks, a G.N. Wall lizards must have an awareness of what color they

are.

But how do they know? Yeah, it's a big puzzle and I'm fascinated by the answer.

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