The Weddell seal (Leptonychotes weddelli) is one of the most vocal pinnipeds. The repertoires of subice vocalizations of Weddell seals recorded at Palmer Peninsula and at McMurdo Sound, Antarctica, are different. Although seals at both sites give some of the same vocalizations, there are subtle spectral and temporal differences. In addition each population has unique vocalizations which are not heard at the other site. At Palmer Peninsula, there are several usage characteristics not exhibited at McMurdo Sound, such as mirror-image vocalization pairs and vocalization trios. Weddell seals in McMurdo Sound make extensive use of nine auxiliary sounds, while the Peninsula repertoire has none. Factors which appear to have been important in the development of these geographic differences appear to include strong fidelity to breeding sites, a polygynous mating system, and learning. Geographically different vocal repertoires have potential for identifying discrete breeding stocks of Antarctic seals.
