Publications

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2008
Cranford, TW, McKenna MF, Soldevilla MS, Wiggins SM, Goldbogen JA, Shadwick RE, Krysl P, St Leger JA, Hildebrand JA.  2008.  Anatomic geometry of sound transmission and reception in Cuvier's beaked whale (Ziphius cavirostris). Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology. 291:353-378.   10.1002/ar.20652   AbstractWebsite

This study uses remote imaging technology to quantify, compare, and contrast the cephalic anatomy between a neonate female and a young adult male Cuvier's beaked whale. Primary results reveal details of anatomic geometry with implications for acoustic function and diving. Specifically, we describe the juxtaposition of the large pterygoid sinuses, a fibrous venous plexus, and a lipid-rich pathway that connects the acoustic environment to the bony ear complex. We surmise that the large pterygoid air sinuses are essential adaptations for maintaining acoustic isolation and auditory acuity of the ears at depth. In the adult male, an acoustic waveguide lined with pachyosteosclerotic bones is apparently part of a novel transmission pathway for outgoing biosonar signals. Substitution of dense tissue boundaries where we normally find air sacs in delphinoids appears to be a recurring theme in deep-diving beaked whales and sperm whales. The anatomic configuration of the adult male Ziphius forehead resembles an upside-down sperm whale nose and may be its functional equivalent, but the homologous relationships between forehead structures are equivocal. Anat Rec, 291:353-378, 2008. © 2008 Wiley-Liss, Inc.

2006
Krysl, P, Cranford TW, Wiggins SM, Hildebrand JA.  2006.  Simulating the effect of high-intensity sound on cetaceans: Modeling, approach and a case study for Cuvier's beaked whale (Ziphius cavirostris). Journal of the Acoustical Society of America. 120:2328-2339.   10.1121/1.2257988   AbstractWebsite

A finite element model is formulated to study the steady-state vibration response of the anatomy of a whale (Cetacea) submerged in seawater. The anatomy was reconstructed from a combination of two-dimensional (2D) computed tomography (CT) scan images, identification of Hounsfield units with tissue types, and mapping of mechanical properties. A partial differential equation model describes the motion of the tissues within a Lagrangean framework. The computational model was applied to the study of the response of the tissues within the head of a neonate Cuvier's beaked whale Ziphius cavirostris. The characteristics of the sound stimulus was a continuous wave excitation at 3500 Hz and 180 dB re: 1 mu Pa received level, incident as a plane wave. We model the beaked whale tissues embedded within a volume of seawater. To account for the finite dimensions of the computational volume, we increased the damping for viscous shear stresses within the water volume, in an attempt to reduce the contribution of waves reflected from the boundaries of the computational box. The mechanical response of the tissues was simulated including: strain amplitude; dissipated power; and pressure. The tissues are not likely to suffer direct mechanical or thermal damage, within the range of parameters tested. (c) 2006 Acoustical Society of America.

2005
Soldevilla, MS, McKenna ME, Wiggins SM, Shadwick RE, Cranford TW, Hildebrand JA.  2005.  Cuvier's beaked whale (Ziphius cavirostris) head tissues: physical properties and CT imaging. Journal of Experimental Biology. 208:2319-2332.   10.1242/jeb.01624   AbstractWebsite

Tissue physical properties from a Clavier's beaked whale (Ziphius cavirostris) neonate head are reported and compared with computed tomography (CT) X-ray imaging. Physical properties measured include longitudinal sound velocity, density, elastic modulus and hysteresis. Tissues were classified by type as follows: mandibular acoustic fat, mandibular blubber, forehead acoustic fat (melon), forehead blubber, muscle and connective tissue. Results show that each class of tissues has unique, co-varying physical properties. The mandibular acoustic fats had minimal values for sound speed (1350 +/- 10.6 m s(-1)) and mass density (890 +/- 23 kg m(-3)). These values increased through mandibular blubber (1376 +/- 13 m s(-1), 919 +/- 13 kg m(-3)), melon (1382 +/- 23m s(-1), 937 +/- 17 kg m(-3)), forehead blubber (1401 +/- 7.8 m s(-1), 935 +/- 25 kg m(-3)) and muscle (1517 +/- 46.8 m s(-1), 993 +/- 58 kg m(-3)). Connective tissue had the greatest I mean sound speed and density (1628 +/- 48.7 m s(-1)