Zoologger is our weekly column highlighting extraordinary animals and occasionally other organisms from around the world

Species: Podarcis erhardii, a wall lizard Habitat: The rocky scrubland, open sand dunes and high mountaintops of Albania, Macedonia, southern Bulgaria and Greece

Imagine being on holiday in Greece's Cyclades Islands, when you spot a greenish, speckled lizard. How close can you get before it runs away or tries detaching its tail in an effort to distract you? The answer depends which island you're on.

Erhard's wall lizard is found across the Cyclades, a set of islands in the Aegean Sea that became isolated from each other and mainland Europe at the end of the last ice age, more than 11,000 years ago. That stranded the islands' lizards, marooning them alongside different enemies. As a result, the lizards have been walking different evolutionary paths ever since.

Larger islands host a mix of feral cats, stone martens, hawks, snakes and rats, all hungry for a lizard-shaped snack. Smaller islands are less dangerous, inhabited by rats and a snake species or two, if anything. And it seems that those cohabitants have had an evolutionary effect on how edgy the lizard is - lizards on some islands are much more laid-back than elsewhere.

Islands are useful for studying evolution because they are isolated from each other, says Kinsey Brock of the University of Michigan, Ann Arbor. "One can ask interesting questions about evolution in a natural living laboratory that has been running an experiment for you on the order of thousands, maybe even millions of years."

And Brock's question is this: how close can you get to an Aegean wall lizard? To find out, she walked straight towards 913 different individuals, living on 37 islands plus the Greek mainland, at a speed of 1.3 metres per second. The average lizard ran from her when she got within 1.8 metres, but some lizards let her come as close as 10 centimetres. Others fled when she was 8.5 metres away.

She found a link between the distance at which a lizard flees and the island it hailed from. Lizards from smaller islands with fewer types of predator, or that had been disconnected from mainland predators for longer, let her come far closer by about 68 centimetres compared with their more fearful relatives.

Brock says that lizards on smaller, safer islands probably evolved this tameness because time is money. "If you're living in a predator-free environment, it would be evolutionarily disadvantageous to spend your time on the lookout for predators or running away while other lizards are foraging and mating."

Brock and her colleagues also investigated the lizard's tendency to resort to the extreme tactic of detaching its own tail. Called autotomy, this is usually a last-ditch attempt to escape a predator's grasp, or at least distract them with the writhing, wriggling remnant.

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