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Dear All, This recent paper sheds new light on
how toothed whales use their nose to produce high powered echolocation clicks. Requests for reprints can be
directed to [email protected] Single source sound production and
dynamic beam formation in echolocating harbour porpoises (Phocoena
phocoena) P. T. Madsen*, D. Wisniewska and K.
Beedholm Zoophysiology, Department of Biological
Sciences, Aarhus University, Build 1131, 8000 Aarhus C, Denmark *Author for correspondence
([email protected]) Accepted 14 June 2010 The Journal of Experimental Biology 213,
3105-3110 © 2010. Published by The Company of
Biologists Ltd doi:10.1242/jeb.044420 SUMMARY Echolocating
toothed whales produce high-powered clicks by pneumatic actuation of phonic
lips in their nasal complexes. All non-physeteroid
toothed whales have two pairs of phonic lips allowing many of these species to
produce both whistles and clicks at
the same time. That has led to the hypothesis that toothed whales can increase
the power outputs and bandwidths of clicks, and
enable fast clicking and beam steering by acutely timed actuation of both
phonic lip pairs simultaneously. Here we test that hypothesis
by applying suction cup hydrophones on the sound-producing nasal complexes of
three echolocating porpoises (Phocoena
phocoena) with symmetrical pairs of phonic lips. Using time of arrival
differences on three hydrophones, we show that all
recorded clicks from these three porpoises are produced by the right pair of
phonic lips with no evidence of simultaneous or independent
actuation of the left pair. It is demonstrated that porpoises, despite
actuation of only one sound source, can change their
output and sound beam probably through conformation changes in the
sound-producing soft tissues and nasal sacs, and that
the coupling of the phonic lips and the melon acts as a waveguide for sound
energy between 100 and 160 kHz to generate a forward-directed
sound beam for echolocation. Peter T. Madsen Professor of Sensory Physiology Zoophysiology, Department of
Biological Sciences Aarhus University, Build. 1131,
CF Mollers Alle 8000 Aarhus C, Denmark Phone: 0045 89422602 email:
[email protected] Web: www.marinebioacoustics.com
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