Researchers at the University of Strasbourg, France studying the behavior of penguins have found that robots tend to be more useful for studying the animals than humans.

The team, led by Yvon Le Maho, used a remote-controlled rover disguised as a king penguin chick to study the stress levels of emperor penguins, according to Discovery News. The study involved 34 breeding king penguins fitted with external heart rate monitors.

The penguins' heart rate and behavior showed that the birds were less stressful when approached by the rover than they would be if they were approached by a human, four times less stressful to be exact.

The four-wheeled rover needs to get within 60 centimeters (23.6 inches) in order to read a penguin's heart rate, CNET reported.  While the birds initially squawked and pecked at the rover, alarmed by its presence, the machine was able to get close enough to get good readings. The birds' heart rates recovered quickly once the rover stopped moving.

The team had to go through five different disguises to make sure the machine wouldn't scare the birds. The rover was able to fit in well enough for chicks to huddle against it as they would with each other, as well as for adults to sing to it.

The rover was also tested with a colony of elephant seals, which appeared indifferent to the robot when it approached them, Discovery News reported. The robot got close to their heads and tails, which are often tagged for Radio Frequency Identification (RFID).

"This is notable, as elephant seals generally react strongly when humans approach their tails," the authors wrote.

The team believes they can eventually modify the rover to record radio, as well as use cameras and different sensors to gather environmental information, CNET reported. The findings give them a chance to collect different information from studying penguins up close, such as how the birds deal with the effects of climate change.

The study was published in the journal Nature Methods.