Document Detail

Diving behaviour of a reptile (Crocodylus johnstoni) in the wild: interactions with heart rate and body temperature.
MedLine Citation:
PMID:  15702457     Owner:  NLM     Status:  MEDLINE    
The differences in physical properties of air and water pose unique behavioural and physiological demands on semiaquatic animals. The aim of this study was to describe the diving behaviour of the freshwater crocodile Crocodylus johnstoni in the wild and to assess the relationships between diving, body temperature, and heart rate. Time-depth recorders, temperature-sensitive radio transmitters, and heart rate transmitters were deployed on each of six C. johnstoni (4.0-26.5 kg), and data were obtained from five animals. Crocodiles showed the greatest diving activity in the morning (0600-1200 hours) and were least active at night, remaining at the water surface. Surprisingly, activity pattern was asynchronous with thermoregulation, and activity was correlated to light rather than to body temperature. Nonetheless, crocodiles thermoregulated and showed a typical heart rate hysteresis pattern (heart rate during heating greater than heart rate during cooling) in response to heating and cooling. Additionally, dive length decreased with increasing body temperature. Maximum diving length was 119.6 min, but the greatest proportion of diving time was spent on relatively short (<45 min) and shallow (<0.4 m) dives. A bradycardia was observed during diving, although heart rate during submergence was only 12% lower than when animals were at the surface.
Frank Seebacher; Craig E Franklin; Mark Read
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Physiological and biochemical zoology : PBZ     Volume:  78     ISSN:  1522-2152     ISO Abbreviation:  Physiol. Biochem. Zool.     Publication Date:    2005 Jan-Feb
Date Detail:
Created Date:  2005-02-09     Completed Date:  2005-04-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100883369     Medline TA:  Physiol Biochem Zool     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1-8     Citation Subset:  IM    
School of Biological Sciences A08, University of Sydney, Sydney, New South Wales 2006, Australia.
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MeSH Terms
Activity Cycles / physiology
Alligators and Crocodiles / physiology*
Analysis of Variance
Body Temperature
Body Temperature Regulation / physiology*
Diving / physiology*
Fresh Water
Heart Rate / physiology*
Time Factors

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

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