Pilot whale vocalizations and acoustic behavior
While lowering a hydrophone into the aquatic habitat of short-finned pilot whales, the listener will sometimes detect a huge variety of sounds. Depending on the whales' behavioral context, the listener will hear vocalizations such as clicks (...here...), whistles (...here...) or calls (...here...). Very rare sounds still remain uncategorized (...here...). Next to these sounds produced by the whales' nasal passages, short-finned pilot whales also produce slapping sounds (...here...) with distinctive body parts. Though short-finned pilot whales are acoustically active animals, they also have prolonged periods of silence.
Click ...here... to see and mainly hear a group of short-finned pilot whales communicating (.mov file with 5.9 MB). The whales emit a variety of sounds such as clicks, whistles, grunts and calls.
Based on the time-frequency contour (= sonogram) of discrete calls, these vocalizations can be grouped into call types. Southwest off Tenerife each group presumably uses a unique call type repertoire which differs from other groups. Group-specifity and stability of discrete calls suggest that these signals serve for group identification (...here...).
Short-finned pilot whales are supposed to live in stable social groups (...here...) and even may form matrilinear family units. Recent spectrographic call analysis found call type matchings between recordings obtained southwest off Tenerife and those recorded southwest off La Gomera (...here...) which might indicate that groups travel between both islands.