Generally speaking, wild animals don’t like humans all that much. Even animals that aren’t directly threatened by humans (and won’t immediately attempt to flee) get all kinds of stressed out to have tall squishy bipeds getting all up in their business. For scientists studying the behavior of wild animals, this presents a serious conflict, because trying to help those animals by collecting data on them also messes with them such that, in more extreme cases, the animals won’t be able to breed as effectively.
In the past, we’ve seen some remarkable pictures and video footage from small, remote-controlled rovers designed to carry cameras up to wild (and dangerous) animals without freaking them out too much. Now, in a paper just published in Nature Methods, researchers discuss using robots to get up close to penguins to collect data while disturbing the animals as little as possible.
To humans, penguins all look more or less the same, which has to make studying a large population of them a little bit frustrating. The solution is to tag the birds, and for a long time, putting colored or numbered bands around their legs or on their flippers was the way to go. However, in order to identify a penguin, you’d then have to physically examine the tag, which isn’t particularly pleasant for the penguin (or the human), and the tag itself can have detrimental effects on the birds as well.
More recently, researchers have been using subcutaneous passive integrated transponders (PIT tags), which are far less invasive since a bird’s unique identifier can be read passively from a distance. It’s not a long distance, though: 60 centimeters is about the maximum, which means that humans still have to walk around, waving a handheld RFID reader all over the place to identify birds.
The penguins are not fans of this. Nesting colonies of king penguins maintain territories around their nests that are defined by the maximum reach of each penguin. When a human shows up, the penguins (understandably) try to get out of the way, which moves them into the territories of other penguins nearby, causing disorganization and fighting that propagates through several rows of nests. This is bad.
Instead of doing data collection themselves, a group of researchers (led by Yvon Le Maho from the Institut Pluridisciplinaire Hubert Curien, part of France’s National Centre for Scientific Research) has spent the last five years experimenting with a little wheeled robot instead. The robot is equipped with a bunch of RFID readers, and is controlled remotely by a nearby human with a laptop. As the robot drives past penguins, it identifies them based on their PIT tags, and transmits those IDs (along with a GPS location) back to the laptop.
To determine how much better the robot made things for the penguins, the researchers needed to measure how stressed the penguins were getting when they interacted with both humans and the robot. The researchers went about this by sneaking up on a nesting penguin from behind, covering its eyes, and sticking a cardio-frequency monitor on its back and putting the receiver (a watch-like device) around its flipper.
Results showed that the penguins were much more freaked out by an approaching human, with an increase in heart rate of about four times larger than with an approaching robot. Furthermore, as soon as the robot stopped moving or departed, the penguins would almost immediately chill out, whereas with a human, it would take between 7 and 8 minutes for the bird’s heart rate to return to normal. Most importantly, an approaching human caused the penguins to move an average of 43 cm from their nest, whereas the robot displaced them an average of just 8 cm, which kept them within their territories and didn’t cause fights.
The researchers also tested their rover with emperor penguins, which are much more shy than the king penguins are. So, to make the rover less threatening, they camouflaged it with a little emperor penguin chick outfit:
Here’s what the researchers say about their penguin-bot:
To more broadly assess the utility of such rovers in colonial breeding birds, we tested the effect of rover approaches on emperor penguins (Aptenodytes forsteri), which are nonterritorial inside their colonies. Of the 158 birds tested, 44 individuals (28%) reacted with alertness, and the tests were immediately halted; 75 (47%) displayed no reaction at all; and 39 (25%) demonstrated curiosity toward the rover by approaching and investigating it. But 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. Chicks and adults were even heard vocalizing at the camouflaged rover, and it was able to infiltrate a crèche without disturbance.
The takeaway here is that by using a robot, and especially by using a camouflaged robot, the researchers have shown that it’s possible to monitor penguins in a way that’s non-invasive enough that the birds can be considered to be undisturbed while you’re doing it. This isn’t limited to RFID monitoring, since you could stuff all kinds of other sensors into the robot, and it’s certainly not limited to penguins, either: the robot was also tested successfully with elephant seals, and anecdotal evidence suggests that camouflaged robots could work quite well in other environments with other animals, too.
It’s also interesting to think about what other advantages robots could offer for studies like this. If you work some autonomy into the mix, along with solar charging, you could have a robot monitoring a colony of animals continuously, perhaps sending back data via satellite. There’s a lot of potential here, but the important thing is that this study has shown that it’s not just about making it more effective for the humans collecting the data: it’s making life better for the animals being studied, too.
[ Nature Methods ]