Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology 293 (2010): 1240-1247, doi:10.1002/ar.21165
Description:
Rorqual whales (Balaenopteridae) lunge at high speed with mouth open to nearly 90 degrees in
order to engulf large volumes of prey-laden water. This feeding process is enabled by extremely
large skulls and mandibles that increase mouth area, thereby facilitating the flux of water into the
mouth. When these mandibles are lowered during lunge-feeding, they are exposed to high drag
and therefore may be subject to significant bending forces. We hypothesized that these
mandibles exhibited a mechanical design (shape and density distribution) that enables these
bones to accommodate high loads during lunge-feeding without exceeding their breaking
strength. We used quantitative computed tomography (QCT) to determine the three-dimensional
geometry and density distribution of a pair of sub-adult humpback whale (Megaptera
novaeangliae) mandibles (length = 2.10 m). QCT data indicated highest bone density and crosssectional
area, and therefore high resistance to bending and deflection, from the coronoid process
to the middle of the dentary, which then decreased towards the anterior end of the mandible.
These results differ from the caudorostral trends of increasing mandibular bone density in
mammals such as humans and the right whale, Eubalaena glacialis, indicating that adaptive bone
remodeling is a significant contributing factor in establishing mandibular bone density
distributions in rorquals.
Description:
This work was funded by an NSERC undergraduate summer research
award to Daniel J. Field, and by an NSERC discovery grant to Robert E. Shadwick.
Keywords:
Rorqual
;
Mandible
;
Lunge-feeding
;
Quantitative computed tomography
;
Flexural rigidity
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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