Cooperative hunting behavior, prey selectivity and prey handling by pack ice killer whales ( Orcinus orca ), type B, in Antarctic Peninsula waters

• Main Authors: Pitman, Robert L., Durban, John W.
• Format: Text
• Language: unknown
• Published: DigitalCommons@University of Nebraska - Lincoln 2011
• Subjects: Antarctica; hunting behavior; killer whale; Leptonychotes weddellii; Orcinus orca; prey handling; prey specialization; Weddell seal; Environmental Sciences; Antarc*; Antarctic; Antarctic Minke whale; Antarctic Peninsula; Balaenoptera bonaerensis; Crabeater Seals; Hydrurga leptonyx; Killer Whale; Leopard Seals; minke whale; Orca; Weddell Seal; Weddell Seals; Killer whale
• Online Access: https://digitalcommons.unl.edu/usdeptcommercepub/306; https://digitalcommons.unl.edu/context/usdeptcommercepub/article/1305/viewcontent/Pitman_MMS_2011_Cooperative_hunting.pdf

Currently, there are three recognized ecotypes (or species) of killer whales (Orcinus orca) in Antarctic waters, including type B, a putative prey specialist on seals, which we refer to as “pack ice killer whale†(PI killer whale). During January 2009, we spent a total of 75.4 h observing three different groups of PI killer whales hunting off the western Antarctic Peninsula. Observed prey taken included 16 seals and 1 Antarctic minke whale (Balaenoptera bonaerensis). Weddell seals (Leptonychotes weddellii) were taken almost exclusively (14/15 identified seal kills), despite the fact that they represented only 15% of 365 seals identified on ice floes; the whales entirely avoided taking crabeater seals (Lobodon carcinophaga; 82% relative abundance) and leopard seals (Hydrurga leptonyx; 3%). Of the seals killed, the whales took 12/14 (86%) off ice floes using a cooperative wave-washing behavior; they produced 120 waves during 22 separate attacks and successfully took 12/16 (75%) of the Weddell seals attacked. The mean number of waves produced per successful attack was 4.1 (range 1–10) and the mean attack duration was 30.4 min (range 15–62). Seal remains that we examined from one of the kills provided evidence of meticulous postmortem prey processing perhaps best termed “butchering.â€