Agonistic Behavior in the Male Northern Elephant Seal

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Abstract
At least 10 behavioral elements were involved in aggressive behavior. The frequency of nine of these among five males was determined. High ranking males were involved in more aggressive interactions than those of low rank, but overt fights were very rare. At least six elements of submissive behavior were observed among males and the frequency of these were determined. Submissive display among males (involving female mimicking behavior) effectively inhibited most overt aggression. Erection and maximal size of the proboscis always coincided with dominance and aggression while a small retracted proboscis coincided with the display of subdominance defence and submission. By the shape of the proboscis and no other criteria alone can the mood of the male be read at any moment. It is suggested that the proboscis has evolved mainly as an agonistic display organ. Adult males recognize each other vocally. It is suggested that the criterium for individual recognition is the structure of the pulse and not the number of pulses they emit in the most characteristic of the four distinct vocalizations that were recorded among males (VO 2). The high ranking males were active 11,5% of the day while the low ranking were significantly less active (6,4%).