Dear All,
For those of you intrigued by how the nose of dolphins produce sound this paper may be interest to you:
Nasal sound production in echolocating delphinids (Tursiops
truncatus and Pseudorca crassidens) is dynamic, but unilateral: clicking on the right side and whistling on the left side
1.
Peter
T. Madsen1,*,
2.
Marc
Lammers2,
3.
Danuta
Wisniewska1
and
+ Author Affiliations
1.
↵*Author
for correspondence (peter.madsen@biology.au.dk)
SUMMARY
Toothed whales produce sound in their nasal complex by pneumatic actuation of phonic lip pairs within the blowhole. It has been hypothesized that dual actuation
of the phonic lip pairs can generate two pulses that merge to form a single echolocation click with a higher source level, broader bandwidth and larger potential for beam steering than if produced by a single pair of phonic lips. Here, we test that hypothesis
by measuring the sound production of five echolocating delphinids using hydrophones around the animals and imbedded in on-animal suction cups. We show that the studied animals click with their right pair of phonic lips and whistle with their left pair. We
demonstrate that, with just a single pair of phonic lips, they can change the click energy levels over five orders of magnitude, change the click centroid frequencies over more than two octaves, and modulate the sound radiation from the melon for beam steering.
We conclude that all of the click dynamics ascribed to dual actuation of two phonic lip pairs can be achieved with actuation of just the right pair of phonic lips, and we propose that the large dynamic range of source outputs is achieved by highly controlled
modulation of the pneumatic driving pressure, the tension of the phonic lip labia and the conformation of the fatty melon and associated air sacs.
doi:
10.1242/jeb.091306 November 1, 2013
J Exp Biol216,
4091-4102.
The paper can be found here:
http://jeb.biologists.org/content/216/21/4091.abstract
Or requests for reprints can be made to:
peter.madsen@biology.au.dk
Best
Peter
Peter T. Madsen
Zoophysiology, Department of Bioscience
Aarhus University, Build. 1131, CF Mollers Alle
8000 Aarhus C, Denmark
Phone: 0045 8715 6501
email:
peter.madsen@biology.au.dk
Web:
www.marinebioacoustics.com
