Ravens Keep Track of Others' Ranks

755 Ravens Keep Track of Others' Ranks
Two ravens nurturing their good relationship by preening each other / Jorg Massen
Ravens are political animals. They can distinguish different sorts of interactions between other ravens, then alter their behavior accordingly. Like humans and other mammals, ravens not only understand, but also keep track of third party relationships. They’re the first bird known to do so. 
In certain social organizations and dominance hierarchies, the key to survival is social intelligence and an understanding of community dynamics. Not only do you need to know who’s nice and who’s not to get by on a daily basis, but for every political maneuver, it’s important to know who will support whom. 
To investigate this in these big brained birds, a team led by Jorg Massen from the University of Vienna, Austria, recorded audio files that contain vocal interactions between ravens and played them for a group of 16 captive ravens (Corvus corax). Pictured below, a raven playing close attention to a played-back stimulus.
They found that ravens paid especial attention and seemed stressed -- displaying behaviors like head turns and body shakes -- when they hear playbacks that simulate a rank reversal in their group. They just didn’t expect a low-ranking bird to show off to a higher-ranking one -- this violates their rank relations. They were fine when the dominance structure in the playback reflects their hierarchy accurately.
The ravens also responded to simulated rank reversals in neighboring groups, suggesting that they’ve figured out who’s boss among unknown birds just by watching and listening to them (since there was no physical contact between groups). It’s the first evidence of animals tracking rank relations of individuals that don’t belong to their own group -- a useful skill for a bird switching foraging units. 
Last week, we learned about cuckoos using mafia tactics, and here’s another metaphor for you. "When Tony Blundetto made fun about Tony Soprano, as spectators of the show, we immediately recognized that this was inappropriate with regard to the dominance order within the Soprano family,” Massen says in a news release. “We make this inference not by comparing our own rank relation with the two Tony's with each other, but instead we have a mental representation of the rank relation of the two that gets violated in the turn of these events."
The findings suggest that complex cognitive abilities evolved multiple times in species as distantly related as ravens and human, solving similar social issues.
The work was published in Nature Communications this week. 
Images: Jorg Massen


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