Characteristics of vocalizations in Steller sea lions

Characteristics of vocalizations in Steller sea lions

T.-G. Park, K. Iida, and T. Mukai

Characteristics of vocalizations in Steller sea lionsThis is part of Sea Lions of the World
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Description

We investigated the acoustics of Steller sea lion (Eumetopias jubatus) calls in wild individuals hauled out on shore reefs off the west coast of Hokkaido, northern Japan, and in captive sea lions at an aquarium using video camera observations. Steller sea lion calls were classified as "communication," "threat," "wheedling," and "acknowledge" according to associated behaviors. Classified calls were analyzed by means of sonograms for formant frequency (F1), sound duration (T), and pitch pattern. All sounds emitted by males were lower in formant frequency than those of females, while sounds made by wild animals were lower than those of captive animals. Sounds by males were also longer in duration than those by females, while those made by wild animals were shorter than those by captive ones. Pitch of "communication" calls was a long flat pattern type, "threat" was a short descending type, and "wheedling" was a short ascending type for wild animals and a short wave-like type for the captives. The characteristics of pitch patterns of wild and captive animals suggest that the calls of Steller sea lions are for communication.

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