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NOTES ON MALE SPERM WHALE REACTIONS TO KILLER WHALE ATTACK IN A HIGH LATITUDE FEEDING GROUND. Marta Acosta, Heike Vester , Ricardo Antunes , I va Kovacic & Luca Tassara. INTRODUCTION. Killer whales have a broad diet
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NOTES ON MALE SPERM WHALE REACTIONS TO KILLER WHALE ATTACK IN A HIGH LATITUDE FEEDING GROUND Marta Acosta, HeikeVester, Ricardo Antunes, IvaKovacic & Luca Tassara
INTRODUCTION • Killerwhaleshave a broaddiet • Aggressiveinteractionsmayunderlineecologicalinteractions (e.g.preycompetition) • To date, agressiveinteractionsbetweenkiller and spermwhales, refertofemalegroupswith calves • First compilation of (3 events) harassment/attack of killer whales towards adult male sperm whales and their response
EVENT 1 Late 90´s: A small group of killer whales was observed approaching and harassing a male sperm whale, that responded by defecating until the attackers left
EVENT 2 30/07/2009: A male sperm whale that surfaced in the middle of a group of killer whales feeding on herring triggered an aggressive response. The whale repelled the attack by shaking its peduncle 90º sideways
EVENT 3 • 23/07/2011: • 4 sperm whales vs 5 killer whales (1 calf) • Sperm whale diving interruption and clustering • Acoustic response: 5R, 5+1 • Silent killer whales? • Slight wounds
CONCLUSIONS • First compilation of killer whale harassment/attack on male sperm whales • Not homogeneous sperm whale response • First evidence of social response among males • Killer whale behaviour consistent with previous reports • Predator-prey? Competition?
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