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Intense ultrasonic clicks from echolocating toothed whales do not
elicit anti-predator responses or debilitate the squid Loligo pealeii
Maria Wilson (1), Roger T. Hanlon (2), Peter L. Tyack (3), Peter T.
Madsen (1,3)
(1) Department of Zoophysiology, University of Aarhus, Building 1131,
8000 Aarhus C, Denmark
(2) Marine Biological Laboratory, Woods Hole, MA 02543, USA
(3) Biology Department WHOI, Woods Hole, MA 02543, USA
Abstract:
Toothed whales use intense ultrasonic clicks to echolocate prey and it
has been hypothesized that they also acoustically debilitate their
prey with these intense sound pulses to facilitate
capture. Cephalopods are an important food source for toothed whales,
and there has probably been an evolutionary selection pressure on
cephalopods to develop a mechanism for detecting and evading
sound-emitting toothed whale predators. Ultrasonic detection has
evolved in some insects to avoid echolocating bats, and it can be
hypothesized that cephalopods might have evolved similar ultrasound
detection as an anti-predation measure. We test this hypothesis in the
squid Loligo pealeii in a playback experiment using intense
echolocation clicks from two squid-eating toothed whale
species. Twelve squid were exposed to clicks at two repetition rates
(16 and 125 clicks per second) with received sound pressure levels of
199-226 dB re 1 uPa (pp) mimicking the sound exposure from an
echolocating toothed whale as it approaches and captures prey. We
demonstrate that intense ultrasonic clicks do not elicit any
detectable anti-predator behaviour in L. pealeii and that clicks with
received levels up to 226 dB re 1 uPa (pp) do not acoustically
debilitate this cephalopod species.
Keywords:
squid, toothed whales, echolocation, predation, defence
Best regards
Maria Wilson
PhD student
Department of Zoophysiology
Institute of Biology, Aarhus University
Build. 131, C.F. Moellers Alle
8000 Aarhus C, Denmark
Phone: 0045 8942 2693
Email:
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