Kinematics and acoustics of foraging behaviour by a specialist predator, the northern resident killer whale (Orcinus orca) ...

• Main Author: Wright, Brianna Margaret
• Format: Text
• Language: English
• Published: University of British Columbia 2014
• Subjects: Killer Whale; Orca; Orcinus orca; Killer whale
• Online Access: https://dx.doi.org/10.14288/1.0167497; https://doi.library.ubc.ca/10.14288/1.0167497

Foragers with narrow dietary niches often exhibit specialized hunting behaviours that improve their efficiency for capturing preferred prey, but can leave them vulnerable if the abundance of this prey declines. I examined the specificity of foraging behaviour by a highly selective predator, the northern resident killer whale (Orcinus orca), which specializes on Chinook salmon (Oncorhynchus tshawytscha). Northern residents are undoubtedly well adapted to capture Chinook, however, their hunting tactics have never been described due to the challenges of quantifying underwater behaviour. To address this research gap, I deployed archival tags (DTAGs) on 32 killer whales to measure their acoustic and kinematic behaviour during foraging dives. Reconstructed 3-dimensional tag tracks indicated that foraging and non-foraging dives were kinematically distinct. While engaged in hunting behaviour, whales dove deeper, remained submerged longer, swam faster, increased their dive path tortuosity, and rolled their bodies ...