A new study has found that 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.
A team of researchers led by Thomas Bugnyar of the Department of Cognitive Biology at the University of Vienna, 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 behaviors, 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 neighboring 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.
The results of this study have been published in the scientific journal Nature Communications.
