Charles Darwin University

CDU eSpace
Institutional Repository

 
CDU Staff and Student only
 

Oxygen transport in varanid lizards during exercise

Schultz, Timothy John (2002). Oxygen transport in varanid lizards during exercise. PhD Thesis, Northern Territory University.

Document type: Thesis
Citation counts: Google Scholar Search Google Scholar
Attached Files (Some files may be inaccessible until you login with your CDU eSpace credentials)
Name Description MIMEType Size Downloads
Download this reading Thesis_CDU_8294_Schultz_T.pdf PDF scanned and generated by CDU application/pdf 9.89MB 90
Reading the attached file works best in Firefox, Chrome and IE 9 or later.

Author Schultz, Timothy John
Title Oxygen transport in varanid lizards during exercise
Institution Northern Territory University
Publication Date 2002
Thesis Type PhD
Subjects 0608 - Zoology
Abstract I measured maximal oxygen consumption (Vo 2max) and standard metabolic rate in ten species of goannas to test whether, as a group, goannas have higher metabolic rates than other lizards. I found significant variation within this group of goannas, and no difference between goannas and other lizards in either measures of metabolic rate. Metabolism within the goannas was also examined with respect to foraging mode and habitat preference. Interspecific comparison of goanna metabolism adds support to the aerobic capacity hypothesis for the evolution of endothermy, and factorial scopes in lizards (≥10) are at least the equivalent of mammalian values.

Ventilation rate was measured concurrently with oxygen consumption in the experiments outlined above. During exercise, the increase in oxygen consumption rate was matched by a similar increase in ventilation rate, such that the ratio between ventilation and metabolism remained constant. This is significant given previous reports of hypoventilation (due to a mechanical constraint) and hyperventilation (in response to either an impairment to gas exchange or increased shunting). There is some evidence supporting the use of gular pumping in these goannas, and strong evidence for mouth breathing during exercise, which prohibits the sampling of nasal expiration only.

The present study is the first to measure pulmonary diffusing capacity (DLco ) during exercise in a reptile. I found that DLco doubled on average due to exercise, however, from five species (four varanids, one agamid) four different responses to exercise were apparent. These differences are most likely related to different behavioural responses to "resting" states, as well as differences in lung anatomy.

I examined the haematological and rheological response to exercise in a range of lizard species. Differences in aerobic ability of these species were not related to either haematology or rheology, with the exception of mean erythrocyte volume. The applications and methods of optimal haematocrit theory are considered.


© copyright

Every reasonable effort has been made to ensure that permission has been obtained for items included in CDU eSpace. If you believe that your rights have been infringed by this repository, please contact digitisation@cdu.edu.au.

 
Versions
Version Filter Type
Access Statistics: 73 Abstract Views, 90 File Downloads  -  Detailed Statistics
Created: Thu, 04 Feb 2010, 20:03:09 CST by Iwona Rohoza