For decades, humans have built rovers to visit places we can't easily reach, including the moon and Mars. Now scientists have built a rover to explore another challenging target: colonies of adorable penguins.
A team led by scientists from the University of Strasbourg in France has built a rover that looks like a fluffy penguin chick, allowing it to sneak around Antarctic colonies and get close to individual birds without ruffling too many feathers along the way.
The findings, described this week in the journal Nature Methods, show that when studying animals in the wild, it's often better for humans to stay out of the way and let robots do the work.
"They made a major advance in being able to remotely identify and monitor penguins in the colony," said Paul Ponganis, a research physiologist at the Scripps Institution of Oceanography at UC San Diego, who wasn't involved in the study. "It's a really clever idea."
When humans try to collect the data carried by their animal subjects, their very presence can alter it. Animals' heart rates go up, their stress level rises and they react in alarm. Those reactions can have negative consequences for the animals as well as the scientists who study them.
Unfortunately, human researchers usually have to get close enough — often within 2 feet — to pick up the radio signal from data-collecting devices placed beneath the animals' skin. If they want the data, they have to disturb the creatures wearing the devices.
A possible solution: Send in a wheeled robot to do the work.
"You can see where with a robotic device like this, observations could be made with less disturbance — or certainly getting farther into the colony than you otherwise would be able to without disturbing birds," said Ponganis, who studies penguins' diving behavior.
So the French researchers set to prove the rover's worth.
In Antarctica, the scientists tested the reactions of king penguins on Possession Island.
A penguin who feels threatened can shuffle away even while keeping its egg or baby chick balanced on its feet. When approached by a rover consisting of a platform and four wheels, penguins moved an average of about 3 inches. But when humans approached, the birds moved a whopping 17 inches.
On top of that, the penguins' movements pushed them into the space of other nearby penguins. Since king penguins can be territorial, the disturbance would ripple through the colony, resulting in fights and chaos for many rows beyond the target bird's area.
The researchers also found that a human who invaded a penguin's personal space caused the bird's heart rate to jack up much higher than the rover did. The effect from the human encounter lasted much longer, too.
"Human approaches led to an excess in [heart rate] approximately four times larger than that due to rover approaches," the French scientists reported.
So the rover, while not perfect, was a marked improvement on many levels — a finding echoed by additional rover tests among a population of emperor penguins within Antarctica's Adelie Land.
Emperor penguins are less territorial than the king penguins, and of the 158 birds tested, 28% "reacted with alertness," 47% didn't seem to react at all, and 25% appeared to be curious enough to come closer and check the rover out.
There, the scientists also tested a more penguin-friendly version of their rover — one that looked like a fuzzy chick on wheels. This adorable robotic spy was even more successful than its bare-bones predecessor.
"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," the study authors wrote. "Chicks and adults were even heard vocalizing at the camouflaged rover, and it was able to infiltrate a creche without disturbance."
Finally, the researchers tried their rover out on elephant seals, who didn't budge when a rover came close to their heads or tails (which is where they're usually tagged). That was a good sign; as a rule, an elephant seal does not react kindly to someone approaching its backside.
Such robots could be used to investigate the lives of all kinds of animals without disturbing them the way a human scientist's presence would, the study authors wrote.
They could also help scientists conduct research beyond simply identifying radio-tagged individuals, Ponganis added.
"For observational studies, you could have all types of cameras mounted to take photos for various purposes," he said.
Future rovers could even go beyond wheels. The French researchers imagined robots capable of tracking swimming and flying critters, too.