Abstract: Despite the important role that vocal communication plays in the social lives of nearly all mammals, few studies have documented the emergence and development of acoustic behavior within individuals throughout their lifetimes. It is even less common to examine learned vs innate aspects of vocal development in long-lived mammals. In this study, we routinely monitored spontaneous vocalizations produced by a male Pacific harbor seal (Phoca vitulina) and a female northern elephant seal (Mirounga angustirostris) raised in human care without conspecific individuals for more than 18 years. We used these unique longitudinal datasets to assess whether the call characteristics of captive individuals resembled those of wild conspecific seals. Additionally, we marked the developmental onset and seasonal timing of vocal activity to determine whether initial vocal expression coincided with reproductive maturity and to evaluate whether temporal patterns in vocal activity were similar across years. We found that resemblance of vocal behavior to that of wild individuals varied between subjects. Both seals showed appropriate maturational timing of vocal behavior associated with reproductive status. The male harbor seal showed a species-typical template for vocal production, whereas the female northern elephant seal produced calls with structure that differed considerably from those of wild individuals. These two case studies provide information relevant to ongoing studies on the ontogeny of sound production and the role that learning plays in vocal behavior.
Key Words: acoustic ontogeny, breeding behavior, vocal learning, vocal development, pinniped
Page Numbers: 499-514