Data from: Rival assessment among northern elephant seals: evidence of associative learning during male-male contests

Specialized signals emitted by competing males often convey honest
information about fighting ability. It is generally believed that
receivers use these signals to directly assess their opponents. Here, we
demonstrate an alternative communication strategy used by males in a
breeding system where the costs of conflict are extreme. We evaluated the
acoustic displays of breeding male northern elephant seals (Mirounga
angustirostris), and found that social knowledge gained through prior
experience with signallers was sufficient to maintain structured dominance
relationships. Using sound analysis and playback experiments with both
natural and modified signals, we determined that males do not rely on
encoded information about size or dominance status, but rather learn to
recognize individual acoustic signatures produced by their rivals.
Further, we show that behavioural responses to competitors' calls are
modulated by relative position in the hierarchy: the highest ranking
(alpha) males defend their harems from all opponents, whereas mid-ranking
(beta) males respond differentially to familiar challengers based on the
outcome of previous competitive interactions. Our findings demonstrate
that social knowledge of rivals alone can regulate dominance relationships
among competing males within large, spatially dynamic social groups, and
illustrate the importance of combining descriptive and experimental
methods when deciphering the biological relevance of animal signals.