Throughout time and across diverse works of literature, the Corvus corax or the common raven has been recognized as a symbol for clever trickery, death and wisdom.
Apollo -- the Greek god of music and twin brother of Artemis -- used ravens as his spies. It didn't fare well for his lover Coronis.
When Odin -- the Norse god of war, death, poetry and wisdom -- lost his eye to pay the price for never-ending wisdom, ravens had become his eyes and ears.
See the pattern? It's also fascinating to note that the collective term for a group of ravens is a "conspiracy." It evokes something sinister, something ominous, a chill to the bones, but the term is now obsolete.
It begs the question: do ravens in real life actually have spying skills?
Apparently, they do.
A new study featured in the journal Nature Communications revealed that ravens snoop on each other and can even infer when other birds are spying on them. This suggests how human-like and sophisticated these birds' cognitive abilities are.
Ravens Know When They're Being Watched
Philosopher Cameron Buckner of the University of Houston, the co-author of the study, said something helped humans learn languages, build institutions, and develop culture, and dive into the arts.
Many philosophers and biologists attribute it to our ability to see through another person's eyes and think about what they might be thinking. These closely-but-not-quite-telepathic skills are referred to as "Theory of Mind."
Buckner and his colleagues suggest that ravens also have the same skills, but without speech, how can they tell or know what another bird is thinking?
The study points to one answer: it's that ravens can sense it when they're being watched and they can project other ravens' motives.
For instance, a raven's food preferences aren't picky, and its favorite meal is meat. When a group of ravens see carrion, or dead animal flesh, and consume it as much as they can, the birds will keep remaining scraps of the carrion on their pouches. After that, they will scoot off to bury the bits in hidden places where they can come back to it later.
This is where the spying comes in: like a game of hide-and-seek, subordinate ravens often spy to see where a dominant raven stashed a meal. As soon as the latter takes off, the subordinate then tries to fly in for a taste of the hidden meal.
More often, the dominant raven knows that it is being watched. It's got plenty of tricks up its sleeve: burying its cache as quickly as possible, as well as digging behind a barrier. Afterwards, they might avoid the spot in order to not draw attention to their loot. Some are even clever enough to pretend to dig a hole while secretly keeping the scrap of carrion on their pouch until they find a safer spot.
But Are These Mere Animal Instincts?
However, there is a caveat. Are ravens aware of what they are doing or are these a result of their animal instincts?
"This was a really difficult problem to overcome," said Buckner.
Ravens hiding their loot might merely be "one-to-one stimulus responses", individual trial-and-error among ravens when they see another bird looking their way, researchers said.
So in order to prove that ravens do have Theory of Mind, Buckner and his colleagues got the second raven out of the picture. They created two separate experiment areas, divided by a wall with a window and a tiny peephole. When the window was shut, the peephole was visible.
Researchers offered food to ravens in both sides of the wall. First, the windows were open, and then they were closed. How could ravens disguise their food when their competitors can be observed without obstruction and when they were hidden from their view?
Ten ravens were also trained individually to peep through the hole to spy on a researcher who was burying some cheese. After that, the window was fully opened, and the ravens could get their reward.
Most of the ravens mastered the peephole training, but one raven named Rufus never did. He had to sit out the rest of the experiment.
And then there were nine. These remaining ravens entered the experiment area while the window was closed and the peephole was open. A loudspeaker on the other side played back sounds of the raven's noises during the first stage of the experiment.
Their competition wasn't visible, but the ravens, aware of the peephole, appeared to infer that someone could be watching them. The ravens hid their food more quickly and delayed visit to it. The behavior is very similar to what they do when they can see their competition.
Researchers said all Theory of Mind factors were controlled in the experiments, one of which is that no actual competitor whose gaze could be seen is present. This is a novel situation for the ravens.
In the end, Buckner and his team's findings suggest that the cognition of ravens cannot be reduced to behavior-reading.
Photo: Ingrid Taylar | Flickr