Document Detail

Ascent exhalations of Antarctic fur seals: a behavioural adaptation for breath-hold diving?
MedLine Citation:
PMID:  15734689     Owner:  NLM     Status:  MEDLINE    
Novel observations collected from video, acoustic and conductivity sensors showed that Antarctic fur seals consistently exhale during the last 50-85% of ascent from all dives (10-160 m, n > 8000 dives from 50 seals). The depth of initial bubble emission was best predicted by maximum dive depth, suggesting an underlying physical mechanism. Bubble sound intensity recorded from one seal followed predictions of a simple model based on venting expanding lung air with decreasing pressure. Comparison of air release between dives, together with lack of variation in intensity of thrusting movement during initial descent regardless of ultimate dive depth, suggested that inhaled diving lung volume was constant for all dives. The thrusting intensity in the final phase of ascent was greater for dives in which ascent exhalation began at a greater depth, suggesting an energetic cost to this behaviour, probably as a result of loss of buoyancy from reduced lung volume. These results suggest that fur seals descend with full lung air stores, and thus face the physiological consequences of pressure at depth. We suggest that these regular and predictable ascent exhalations could function to reduce the potential for a precipitous drop in blood oxygen that would result in shallow-water blackout.
Sascha K Hooker; Patrick J O Miller; Mark P Johnson; Oliver P Cox; Ian L Boyd
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Proceedings. Biological sciences / The Royal Society     Volume:  272     ISSN:  0962-8452     ISO Abbreviation:  Proc. Biol. Sci.     Publication Date:  2005 Feb 
Date Detail:
Created Date:  2005-02-28     Completed Date:  2005-04-20     Revised Date:  2013-06-09    
Medline Journal Info:
Nlm Unique ID:  101245157     Medline TA:  Proc Biol Sci     Country:  England    
Other Details:
Languages:  eng     Pagination:  355-63     Citation Subset:  IM    
Sea Mammal Research Unit, University of St Andrews, Fife KY16 8LB, UK.
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MeSH Terms
Adaptation, Physiological*
Antarctic Regions
Diving / physiology*
Electric Conductivity
Exhalation / physiology*
Fur Seals / physiology*
Locomotion / physiology
Seawater / analysis
Sodium Chloride / analysis
Video Recording
Reg. No./Substance:
7647-14-5/Sodium Chloride

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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