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Image Rendering Techniques in Postmortem Computed Tomography: Evaluation of Biological Health and Profile in Stranded Cetaceans
Published on: September 27, 2020
Lung size and thoracic morphology in shallow- and deep-diving cetaceans
Marina A Piscitelli1, William A McLellan, Sentiel A Rommel
1Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina 28403, USA. piscitellim@uncw.edu
Journal of Morphology
|January 16, 2010
Summary
Deep-diving whales have smaller lungs than shallow-diving dolphins, suggesting small lung size is an ancestral trait in toothed whales. Larger lungs in dolphins may aid gas exchange during short, shallow dives.
Area of Science:
- Marine biology
- Comparative anatomy
- Physiological ecology
Background:
- Bottlenose dolphins (Tursiops truncatus) are shallow divers, while pygmy and dwarf sperm whales (Kogia spp.) are deep divers.
- Ambient pressure at depth affects lung air volume and thoracic collapse.
- Diving adaptations in cetaceans involve trade-offs between lung size and thoracic mechanics.
Purpose of the Study:
- To test if deeper divers have reduced lung size and/or enhanced thoracic mobility.
- To compare lung mass and volume relative to body mass in dolphins and kogiids.
- To investigate thoracic cavity shape and volume changes in relation to diving behavior.
Main Methods:
- Comparative analysis of lung mass and volume in Tursiops truncatus and Kogia spp.
- Cross-sectioning of T. truncatus and K. sima to determine organ volumes.
- Mechanical manipulation of excised thoraxes from both species to assess thoracic compliance.
Main Results:
- Kogiid lungs were half the mass and one-fifth the volume of similarly sized dolphin lungs.
- Lungs occupied 15% of thoracic volume in K. sima versus 37% in T. truncatus.
- Thoracic changes were similar, but kogiid thoracic inlets were more constrained.
Conclusions:
- Small lung size in deep-diving odontocetes (toothed whales) may be an ancestral trait.
- Relatively large lungs in dolphins (delphinids and phocoenids) appear derived, possibly aiding gas exchange in shallow dives.
- Divergent lung sizes reflect adaptations to different diving depths and durations.
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