Brazenly, the down-covered baby penguin lookalike rolls in on four wheels for a huddle with real-life chicks, right under the noses of adult birds which seem to pay it no heed.

The infiltration is for a good cause: the cute and fluffy robot is a remote-controlled spy designed by scientists wishing to monitor the skittish penguins without causing them stress.

An international team tested the rover, with and without the fake chick addition, on king penguins on Possession Island in the Indian Ocean, and on Emperor penguins in Antarctica.

They reported in the journal Nature Methods on Sunday that both versions caused much less alarm, measured by penguin heart rate and behaviour, than a human presence -- and the lookalike could get much closer.

The rover was fitted with an antenna to read the signals from electronic ID tags fitted to some of the birds for population research.

The tags cannot be read beyond a distance of 60 centimetres (24 inches).

"When the rover was camouflaged with a penguin model, all adult and chick emperor penguins allowed it to approach close enough for an electronic identification," they wrote.

"Chicks and adults were even heard vocalising at the camouflaged rover, and it was able to infiltrate a creche without disturbance."

A picture of the penguin-bot shows a ball of fluff complete with flippers, sharp beak and face painted in the distinct black-and-white colouring of Emperor penguin chicks perched on top of a small frame with four wheels.

In another image, the little robot is in a tight huddle of baby penguins supervised by groups of adults.

The rover, still being refined, is meant to shed more light on the breeding patterns and behaviour of penguins, good indicators of the health of marine resources in the Southern Ocean.

In the past, scientists had attached transponders to the penguins' wings.

These could send signals over much longer distances, but researchers soon discovered they hamstrung the penguins in swimming, impairing breeding and hunting.

Nowadays, a tiny chip that weighs less than a gramme (0.03 ounces) is inserted under the skin.

But it has a much shorter range and has thus far necessitated scientists entering penguin colonies to obtain the data they want.

The new rover may lead to "more ethical research that also avoids the scientific bias caused by disturbing the animals in their natural habitat," said study co-author Yvon Le Maho of France's University of Strasbourg.