Distinctions in sound patterns of calls by killer whales (Orcinus Orca) from analysis of computer sound features

Watkins, William A.; Daher, Mary Ann; DiMarzio, Nancy A.; Reppucci, Gina

Distinctions in sound patterns of calls by killer whales (Orcinus Orca) from analysis of computer sound features

1998

Watkins, William A. | Daher, Mary Ann | DiMarzio, Nancy A. | Reppucci, Gina

Calls of killer whales, Orcinus orca, were analyzed using computed sound features to classify sound patterns andidentify call similarties. Calls were classified and separated according to the podfamily group within clans identifiedpreviously by John Ford (U. BC) in the Vancouver whale populations. Acoustic characteristics of the same call type fromdifferent individuals were extremely similar, so that discriminating these different sounds was the goal. The WHOIAcouStat program and associated database systems were used to define numerical statistics for each call, and then, thesewere compared to sort and classify the sounds. The results were in agreement with Ford's descriptions of the calls derivedfrom visual inspection of sound spectrograms of calls. The classification analyses demonstrated that although specificshared calls from different killer whales were much alike, they could be sorted by the pod/subpod of the whales producingthe calls. A typical analysis, for example, of the N4 call from Clan A (Vancouver, BC), classified 97% of the callscorrectly according to the pod/family of the whales producing the calls. Remaining calls were variant, and likely a result ofindividual differences in call sounds. Similar classification analysis were tested on unsorted, unalyzed recordings fromdifferent populations of whales, and these too could be distinguished, with 98.5% correct separation of the calls.

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