Ravens understand when and why to keep a snack a secret
Ravens are apparently not very trustworthy, at least according to other ravens. If given more food than they’re ready to eat at the moment, they will do their best to hide the food, and then make a point of not revisiting their hiding place too often in the presence of other ravens. A recent study has found that this wariness of their fellow birds isn’t just a nervous, compulsive tick— the ravens seem to understand that for their food to be at risk, other birds need to first know that it’s there.
I know what you might know
Understanding the existence of food isn’t that big a deal. Understanding that other animals have different sets of knowledge than you do is a bit more sophisticated, and is called a “theory of mind.” What researchers were looking for was if ravens would be able to understand when their food-hiding was possibly exposed to another bird, and when it wasn’t. It would then require them to have a working understanding of what a raven other than themselves could do and see, which in this case was a snack room.
Learning to spy on snackers
Two rooms were set up to test the ravens in. In Room A, individual ravens were given access to snacks, plus some places where they could hide them if so inclined. A second bird was on the other side of a window in Room B, clearly watching. When the first raven saw his observer, he was likely to hide his snack quickly and avoid coming back to it, since that would give away its location. When the window between rooms was closed, the first bird was much more casual.
To make sure this shift in behavior wasn’t just reacting to the visual of a rival being there, they then brought the raven into Room B, and showed it that in addition to the window, there was also a peephole into room Room A. The bird was taught to watch its trainers set up food in Room A through the peephole, hopefully teaching it that it could be watched even when the window was closed.
The message seemed to get through, and when the first raven was returned to Room A with access to snacks, it started adjusting its actions depending on if the peephole from Room B was covered or not. Researchers did prompt the bird a bit by playing an audio recording of a raven in Room B, setting up a scenario for possible food-theft that the test subjects didn’t want to risk. Similar to when the window exposed a live bird, an open peephole was apparently reason enough to hide snacks within 8 seconds, instead of 14, and avoid revisiting them too often.
This doesn’t prove that ravens can imagine the state of mind of their fellow birds as much as humans can, but it does show that they can at least put themselves in another bird’s shoes for an activity they’ve done themselves. Being able to guard and predict their fellow ravens’ activities fits well with their other visual memories and social structures.
Source: Ravens’ fear of unseen snoopers hints they have theory of mind by Sam Wong, New Scientist
