Elephant seals of the Falklands

Acoustic communication Acoustic communication is a fundamental aspect of elephant seals social behaviour. Most of the studies concentrated on the northern species, while scarce information is available for the southern species. The most striking aspect of acoustic communication in southern elephant seals is male use of vocalizations to establish and maintain dominance. Agonistic contests have a stereotyped structure and almost invariably involve the emission of sounds by the contestants. The study of male vocalizations on Sea Lion Island revealed an high repeatability in the structure of sounds emitted by each individual, along with a very large variation of sound structure between individuals. This pattern of intraindividual constancy is evident both from in the macrostructure of the sound (i.e. its composition in syllables and part of syllable) and in the acoustic parameters (e.g. fundamental frequency). Notwithstanding this general constancy, there is also a substantial variation in acoustic parameters of the sounds emitted by a male in different moment of the breeding season. Evolutionary theory predicts that only signals that are good and honest indicators of phenotype quality may be maintained in steady state in natural populations. Hence, we expect elephant seals aggressive vocalizations to be correlated to male structural phenotype and his physiological state. All these traits are prone to substantial variation during the breeding season: vocal performance should be affected by the variation in hormonal levels and breeding status, or by variation in weight due to fasting.

Preliminary head up vocalization during a fight

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