Geographic vocal variation and perceptual discrimination abilities in male Australian sea lions

Heidi Ahonen*, Robert G. Harcourt, Adam J. Stow, Isabelle Charrier

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Vocal characteristics can vary among and within populations. In species with geographic variation in the structure of vocalizations, individuals may have the ability to discriminate between calls from local and non-local individuals. The ability to distinguish differences in acoustic signals is likely to have a significant influence on the outcome of social interactions between individuals, including potentially mate selection and breeding success. Pinnipeds (seals, fur seals, sea lions and walruses) are highly vocal yet the Australian sea lion (Neophoca cinerea) is the only eared seal known to show geographic vocal variation in male barks. Barks are produced in many social interactions and encode sufficient information for both individual and colony identity to be discriminable. Yet until now, whether males could themselves discriminate these bark differences was unclear. We performed playback experiments in four breeding colonies to investigate whether males can discriminate local from non-local barks. Overall, males responded more strongly to barks from their own colony compared to barks from other colonies regardless of whether those other colonies were close or distant. Competition for females is high in Australian sea lions, but mating periods are asynchronous across colonies. The ability to correctly assess whether a male is from the same colony, thus representing a potential competitor for mates, or merely a visitor from elsewhere, may influence how males interact with others. Given the high cost of fighting, the ability to discern competitors may influence the nature of male–male interactions and ultimately influence how they allocate reproductive effort.

Original languageEnglish
Pages (from-to)235–243
Number of pages9
JournalAnimal Cognition
Volume21
Issue number2
DOIs
Publication statusPublished - Mar 2018

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Keywords

  • acoustic behavior
  • Neophoca cinerea
  • otariid
  • perceptual discrimination
  • pinniped
  • vocal recognition

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