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Cook Islands Humpback Whale Survey 1998-2008
Research Methods: Photo Identification | Humpback song |Genetics & Toxicology
Humpback Song
Male humpback whales sing long and complex songs in the waters of the Cook Islands and other winter breeding grounds in the tropical oceans. Since male humpbacks usually only sing during the breeding season, it is likely that the song serves a reproductive function. The song may serve to attract females, to sort dominance among other males, or to maintain a distance between courting males. Songs are recorded using hydrophones (underwater microphones) and DAT recorders. Photo-IDs, video, and skin samples are collected from singers whenever practical. Song structure and form will be compared among the Cook Islands' humpbacks and songs recorded at other breeding grounds across the South Pacific and around the world. Because humpback song varies geographically, comparative analysis of song will be used in addition to comparative genetic techniques to determine the stock identity of Cook Islands humpbacks. Moreover, analysis of song and singers' behavior should yield insights into the functional significance of the humpback song. In the 2001 field season we recorded a humpback whale off Rarotonga with a new and different song. Shortly after that, the humpbacks in the Cook Islands waters included a phrase of that song into their familiar repertoire. We are working with acoustician, Michael Noad in Australia.
Singing Humpback Whales
Humpback whales sing hanging vertically, head down, motionless, with their heads 30m below the surface. Only male humpbacks are known to sing. Singing occurs on their winter breeding grounds.
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