Stability and change of killer whale (Orcinus orca) dialects ...

• Main Author: Deeke, Volker Bernt
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Killer Whale; Orca; Orcinus orca; Killer whale
• Online Access: https://dx.doi.org/10.14288/1.0074826; https://doi.library.ubc.ca/10.14288/1.0074826

Vocal dialects have been described in many species, but most studies so far have focused on territorial species such as songbirds and humans. This study investigates patterns of structural variation in the stereotyped calls of 9 matrilineal units of killer whales (Orcinusorca) with congruent home ranges. In Chapter I, I describe an index of acoustic similarity based on neural network analysis of frequency contours. I test this index on simulated signals, and compare it to similarity ratings from three human subjects. The index could discriminate along global differences in contour frequency, as well as localized differences in frequency and shape. It rated similarity comparably to humans, since differences between ratings among subjects exceeded differences between subject ratings and the neural network index. In the second Chapter, I analyse 2 call types used by 2 groups over a 12 year period to identify mechanisms of vocal differentiation. A test for structural modification detected significant changes in ...