Cognitive biologists have found that ravens understand and keep track of the rank relations between other ravens, an ability that was considered unique to primates.
Like many social mammals, ravens form different types of social relationships - they may be friends, kin, or partners and they also form strict dominance relations.
From a cognitive perspective, understanding one's own relationships to others is a key ability in daily social life ("knowing who is nice or not"), researchers said.
Yet, also understanding the relationships group members have with each other sets the stage for "political" manoeuvres ("knowing who might support whom"), they said.
Researchers led by Thomas Bugnyar of the Department of Cognitive Biology at the University of Vienna in Austria, set out to test third-party knowledge in captive groups of ravens.
Using a playback design, they let individuals hear a dominance interaction between two other ravens.
These interactions were either in accordance with the existing dominance hierarchy in that group or they reflected a possible rank reversal, whereby a low-ranking individual was showing off to a higher-ranking bird.
In the latter case, the ravens reacted strongly with information seeking and stress-related behaviours, such as head turns and body shakes, suggesting that their expectations about how the dominance relations among others should look like were violated.
Similar to primates, ravens thus keep track of the rank relations of their group members.
Importantly, the researchers found that the ravens not only responded to simulated rank reversals in their own group but also to those in the neighbouring group.
These findings suggest that ravens can deduce others' rank relations just by watching them.
Moreover, it is the first time that animals are shown to be capable of tracking rank relations among individuals that do not belong to their own social group, researchers said.
The study is published in the scientific journal Nature Communications.
