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Field recordings of underwater sounds of the toothed whale Monodon monoceros exhibit consistent characteristics not noted in other odontocetes. The sounds were mostly narrow-band regularly spaced, and often high-frequency (to 24 kHz). The fundamentals of individual sound pulses ranged from 1.5 to 24 kHz. Both clicks (short pulses produced at repetition rates up to 300/sec) and tones (to 0.1-sec duration) were noted.

Descriptions and analyses are presented of underwater sounds made by six species of seals in captivity, Zalophus californianus, Phoca vitulina, P. (Pusa) hispida, P. (Pagophilus) groenlandica, Halichoerus grypus, and Cystophora cristata. The suitability of these very faint sounds for echolocation is discussed.

No abstract