has been challenged (Tyack 2001) because the groups that showed vocal dialects are often only temporary aggregations of two or more social units, raising the question of how temporary social entities can maintain stable cultural characteristics (Mesnick 2001; Tyack 2001). Here, we answer this questi...
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.332.4558 http://whitelab.biology.dal.ca/lr/vocal clans in sperm whales.pdf |
| Summary: | has been challenged (Tyack 2001) because the groups that showed vocal dialects are often only temporary aggregations of two or more social units, raising the question of how temporary social entities can maintain stable cultural characteristics (Mesnick 2001; Tyack 2001). Here, we answer this question by using codas recorded over 15 years of research on sperm whales in the South Pacific and Caribbean to investigate variation in coda usage among groups. We find strong evidence for a higher level of social structure based on variation in vocal output, somewhat similar to the acoustic clans of killer whales. Sperm whale populations may thus be structured more along cultural lines than on a geographical basis, which has major implications for our understanding of the species’ behavioural and population biology. 2. MATERIAL AND METHODS (a) Coda recording Recordings were made using one of several sets of equipment, either an Offshore Acoustics hydrophone (frequency response 6Hz–10 kHz, ±3 dB) connected directly to a Sony TC-D5M cassette recorder, or either a Benthos AQ17 or a modified AQ21B hydrophone (frequency response 1–10 kHz, ±3 dB) connected via either Barcus-Berry ‘Standard ’ or Ithaca 453 preamplifiers |
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