Factors influencing the prediction of metabolic rate in a reptile

TD Clark, Patrick Butler, PB Frappell

Research output: Contribution to journalArticle

20 Citations (Scopus)


1. Measurements of the rate of oxygen consumption (Vo(2)) in the field are usually impractical, so several studies of endotherms have utilized heart rate (f(H)) as a correlate of Vo(2) because of the tight relationship that often exists between the two variables. There have been several reports, however, where the relationship between f(H) and Vo(2) changes or disassociates under different physiological or psychological circumstances. This may be further confounded in ectothermic vertebrates, which experience relatively large fluctuations in body temperature (T-b). 2. The aim of the present study was to characterize in Rosenberg's Goanna (Varanus rosenbergi) the relationship that exists between T-b, f(H) and Vo(2) at rest and at different levels of exercise, during periods of heating and cooling, and following ingestion of a meal. 3. The combinations of T-b and f(H) were accurate at predicting Vo(2) of animals at different levels of exercise and recovery, and during the postprandial period. 4. Predictions of Vo(2) became less reliable during periods of relatively rapid heating when f(H) and blood flow increase for thermoregulatory purposes with no associated increase in Vo(2). To counter this, f(H) was excluded from the prediction equation when the rate of heating exceeded 20% of the predicted mass-dependent maximum attainable rate, and Vo(2) was predicted using T-b alone. 5. The resultant Vo(2) prediction equation was used to estimate Vo(2) of seven animals that were allowed to thermoregulate behaviourally, and the mean predicted Vo(2) (Vo(2pred)) was not significantly different from the mean measured Vo(2) (Vo(2meas)) for fasting or postprandial lizards.
Original languageEnglish
Pages (from-to)105-113
Number of pages9
JournalFunctional Ecology
Issue number1
Publication statusPublished - 1 Feb 2006


  • lizard
  • ectotherm
  • heart rate
  • body temperature
  • rate of oxygen consumption
  • energy expenditure


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