Published online by Cambridge University Press: 27 March 2009
Seven-week-old White Rock males were exposed to step-wise increases in ambient temperatures from 7·7 to 37·7 °C in light and dark environments. Heart rate decreased with increasing ambient temperature with a quadratic slope (P ≤ 0·0001). Heart rate was lower during the dark period than during the light period (P ≤ 0·06). There was a positive linear correlation between heart rate and oxygen consumption (γ = 0·997) for ambient temperatures from 7·7 to 37·7 °C.
Body temperatures began to increase significantly when ambient temperature reached beyond 27·5 °C. The increases followed a quadratic slope (P ≤ 0·0001). Body temperatures during the light period were significantly higher than during the dark period (P ≤ 0·05).